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Sample records for students current hubble

  1. The Prevalence of Tobacco, Hubble-Bubble, Alcoholic Drinks, Drugs, and Stimulants among High-School Students

    Directory of Open Access Journals (Sweden)

    Roghayeh Alaee

    2011-08-01

    Full Text Available Introduction: The purpose of the present study was to investigate the prevalence of tobacco, hubble-bubble, alcoholic drinks, and other drugs among Karaj high-school students in 2011. Methods: The research method was a descriptive-sectional study. Participants of this study were 447 girl and boy high-school students of Karaj that were selected by clustering random sampling. For data gathering, drug abuse questionnaire, and risk and protective factors inventory were administered among selected sample. Results: According to the results, 57% of students in this study said that they have had experiences with a kind of drug including tobacco, hubble-bubble, alcoholic drinks, and other drugs at least once in their lives. The study showed the prevalence for soft drugs: hubble-bubble, tobacco, and alcoholic drinks, and for hard drugs ecstasy, opium, hashish, meth, crack, and heroin respectively. Conclusion: Soft drugs including hubble-bubble, tobacco, and alcoholic drinks, are the most common among Karaj high-school students. The prevalence of hard drugs among them is rather low.

  2. Delivering Hubble Discoveries to the Classroom

    Science.gov (United States)

    Eisenhamer, B.; Villard, R.; Weaver, D.; Cordes, K.; Knisely, L.

    2013-04-01

    Today's classrooms are significantly influenced by current news events, delivered instantly into the classroom via the Internet. Educators are challenged daily to transform these events into student learning opportunities. In the case of space science, current news events may be the only chance for educators and students to explore the marvels of the Universe. Inspired by these circumstances, the education and news teams developed the Star Witness News science content reading series. These online news stories (also available in downloadable PDF format) mirror the content of Hubble press releases and are designed for upper elementary and middle school level readers to enjoy. Educators can use Star Witness News stories to reinforce students' reading skills while exposing students to the latest Hubble discoveries.

  3. Accounting for Dark Current Accumulated during Readout of Hubble's ACS/WFC Detectors

    Science.gov (United States)

    Ryon, Jenna E.; Grogin, Norman A.; Coe, Dan A.; ACS Team

    2018-06-01

    We investigate the properties of excess dark current accumulated during the 100-second full-frame readout of the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) detectors. This excess dark current, called "readout dark", gives rise to ambient background gradients and hot columns in each ACS/WFC image. While readout dark signal is removed from science images during the bias correction step in CALACS, the additional noise from the readout dark is currently not taken into account. We develop a method to estimate the readout dark noise properties in ACS/WFC observations. We update the error (ERR) extensions of superbias images to include the appropriate noise from the ambient readout dark gradient and stable hot columns. In recent data, this amounts to about 5 e-/pixel added variance in the rows farthest from the WFC serial registers, and about 7 to 30 e-/pixel added variance along the stable hot columns. We also flag unstable hot columns in the superbias data quality (DQ) extensions. The new reference file pipeline for ACS/WFC implements these updates to our superbias creation process.

  4. Dismantling Hubble's Legacy?

    OpenAIRE

    Way, Michael J.

    2013-01-01

    Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and the general public. The origins of these discoveries are examined and it is demonstrated that, in each case, a great deal of supporting evidence was already in place. In some cases the discoveries had either already been made, or competing versions were not adopted for complex scientific and sociological reasons.

  5. HUBBLE VISION: A Planetarium Show About Hubble Space Telescope

    Science.gov (United States)

    Petersen, Carolyn Collins

    1995-05-01

    In 1991, a planetarium show called "Hubble: Report From Orbit" outlining the current achievements of the Hubble Space Telescope was produced by the independent planetarium production company Loch Ness Productions, for distribution to facilities around the world. The program was subsequently converted to video. In 1994, that program was updated and re-produced under the name "Hubble Vision" and offered to the planetarium community. It is periodically updated and remains a sought-after and valuable resource within the community. This paper describes the production of the program, and the role of the astronomical community in the show's production (and subsequent updates). The paper is accompanied by a video presentation of Hubble Vision.

  6. The Hubble Constant

    Directory of Open Access Journals (Sweden)

    Neal Jackson

    2015-09-01

    Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.

  7. Cosmological Hubble constant and nuclear Hubble constant

    International Nuclear Information System (INIS)

    Horbuniev, Amelia; Besliu, Calin; Jipa, Alexandru

    2005-01-01

    The evolution of the Universe after the Big Bang and the evolution of the dense and highly excited nuclear matter formed by relativistic nuclear collisions are investigated and compared. Values of the Hubble constants for cosmological and nuclear processes are obtained. For nucleus-nucleus collisions at high energies the nuclear Hubble constant is obtained in the frame of different models involving the hydrodynamic flow of the nuclear matter. Significant difference in the values of the two Hubble constant - cosmological and nuclear - is observed

  8. The Carnegie Hubble Program

    Science.gov (United States)

    Freedman, Wendy L.; Madore, Barry F.; Scowcroft, Vicky; Mnso, Andy; Persson, S. E.; Rigby, Jane; Sturch, Laura; Stetson, Peter

    2011-01-01

    We present an overview of and preliminary results from an ongoing comprehensive program that has a goal of determining the Hubble constant to a systematic accuracy of 2%. As part of this program, we are currently obtaining 3.6 micron data using the Infrared Array Camera (IRAC) on Spitzer, and the program is designed to include JWST in the future. We demonstrate that the mid-infrared period-luminosity relation for Cepheids at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid extragalactic distance scale. We discuss the advantages of 3.6 micron observations in minimizing systematic effects in the Cepheid calibration of the Hubble constant including the absolute zero point, extinction corrections, and the effects of metallicity on the colors and magnitudes of Cepheids. We are undertaking three independent tests of the sensitivity of the mid-IR Cepheid Leavitt Law to metallicity, which when combined will allow a robust constraint on the effect. Finally, we are providing a new mid-IR Tully-Fisher relation for spiral galaxies.

  9. Hubble Space Telescope via the Web

    Science.gov (United States)

    O'Dea, Christopher P.

    The Space Telescope Science Institute (STScI) makes available a wide variety of information concerning the Hubble Space Telescope (HST) via the Space Telescope Electronic Information Service (STEIS). STEIS is accessible via anonymous ftp, gopher, WAIS, and WWW. The information on STEIS includes how to propose for time on the HST, the current status of HST, reports on the scientific instruments, the observing schedule, data reduction software, calibration files, and a set of publicly available images in JPEG, GIF and TIFF format. STEIS serves both the astronomical community as well as the larger Internet community. WWW is currently the most widely used interface to STEIS. Future developments on STEIS are expected to include larger amounts of hypertext, especially HST images and educational material of interest to students, educators, and the general public, and the ability to query proposal status.

  10. Beyond the Hubble Constant

    Science.gov (United States)

    1995-08-01

    about the distances to galaxies and thereby about the expansion rate of the Universe. A simple way to determine the distance to a remote galaxy is by measuring its redshift, calculate its velocity from the redshift and divide this by the Hubble constant, H0. For instance, the measured redshift of the parent galaxy of SN 1995K (0.478) yields a velocity of 116,000 km/sec, somewhat more than one-third of the speed of light (300,000 km/sec). From the universal expansion rate, described by the Hubble constant (H0 = 20 km/sec per million lightyears as found by some studies), this velocity would indicate a distance to the supernova and its parent galaxy of about 5,800 million lightyears. The explosion of the supernova would thus have taken place 5,800 million years ago, i.e. about 1,000 million years before the solar system was formed. However, such a simple calculation works only for relatively ``nearby'' objects, perhaps out to some hundred million lightyears. When we look much further into space, we also look far back in time and it is not excluded that the universal expansion rate, i.e. the Hubble constant, may have been different at earlier epochs. This means that unless we know the change of the Hubble constant with time, we cannot determine reliable distances of distant galaxies from their measured redshifts and velocities. At the same time, knowledge about such change or lack of the same will provide unique information about the time elapsed since the Universe began to expand (the ``Big Bang''), that is, the age of the Universe and also its ultimate fate. The Deceleration Parameter q0 Cosmologists are therefore eager to determine not only the current expansion rate (i.e., the Hubble constant, H0) but also its possible change with time (known as the deceleration parameter, q0). Although a highly accurate value of H0 has still not become available, increasing attention is now given to the observational determination of the second parameter, cf. also the Appendix at the

  11. Hubble Legacy Archive And The Public

    Science.gov (United States)

    Harris, Jessica; Whitmore, B.; Eisenhamer, B.; Bishop, M.; Knisely, L.

    2012-01-01

    The Hubble Legacy Archive (HLA) at the Space Telescope Science Institute (STScI) hosts the Image of the Month (IOTM) Series. The HLA is a joint project of STScI, the Space Telescope European Coordinating Facility (ST-ECF), and the Canadian Astronomy Data Centre (CADC). The HLA is designed optimize science from the Hubble Space Telescope by providing online enhanced Hubble products and advanced browsing capabilities. The IOTM's are created for astronomers and the public to highlight various features within HLA, such as the "Interactive Display", "Footprint” and "Inventory” features to name a few. We have been working with the Office of Public Outreach (OPO) to create a standards based educational module for middle school to high school students of the IOTM: Rings and the Moons of Uranus. The set of Uranus activities are highlighted by a movie that displays the orbit of five of Uranus’ largest satellites. We made the movie based on eight visits of Uranus from 2000-06-16 to 2000-06-18, using the PC chip on the Wide Field Planetary Camera 2 (WFPC2) and filter F850LP (proposal ID: 8680). Students will be engaged in activities that will allow them to "discover” the rings and satellites around Uranus, calculate the orbit of the satellites, and introduces students to analyze real data from Hubble.

  12. Hubble 15 years of discovery

    CERN Document Server

    Lindberg Christensen, Lars; Kornmesser, M

    2006-01-01

    Hubble: 15 Years of Discovery was a key element of the European Space Agency's 15th anniversary celebration activities for the 1990 launch of the NASA/ESA Hubble Space Telescope. As an observatory in space, Hubble is one of the most successful scientific projects of all time, both in terms of scientific output and its immediate public appeal.

  13. Current Students | College of Engineering & Applied Science

    Science.gov (United States)

    Electrical Engineering Instructional Laboratories Student Resources Industrial & Manufacturing Engineering Industrial & Manufacturing Engineering Academic Programs Industrial & Manufacturing Engineering Major Industrial & Manufacturing Engineering Minor Industrial & Manufacturing Engineering

  14. Depression in medical students: current insights

    Directory of Open Access Journals (Sweden)

    Moir F

    2018-05-01

    Full Text Available Fiona Moir,1 Jill Yielder,2 Jasmine Sanson,3 Yan Chen4 1Department of General Practice and Primary Health Care, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; 2Medical Programme Directorate, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; 3Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; 4Centre for Medical and Health Sciences Education, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand Abstract: Medical students are exposed to multiple factors during their academic and clinical study that have been shown to contribute to high levels of depression, anxiety, and stress. The purpose of this article was to explore the issue of depression in the medical student population, including prevalence, causes, and key issues, along with suggestions for early identification and support from one medical school in New Zealand. After establishing that the prevalence of depression is higher for medical students than the general population, the key issues explored include assessment used in the program, characteristics of the student population (such as Type A personality and perfectionism, resilience, selection procedures, students’ motivation, and the nature of the clinical environment. This review includes several recommendations to improve students’ psychological health such as positioning well-being within an overarching comprehensive workplace wellness model and integrating peer and faculty-led support into the day-to-day running of the institution. It also highlights the advantages of the addition of a well-being curriculum, as skills to prevent and manage distress and depression are relevant in supporting the competencies required by medical practitioners. It concludes that medical schools need wide-ranging strategies to address the complexities associated with the particular student

  15. Undergraduate medical students' empathy: current perspectives

    Directory of Open Access Journals (Sweden)

    Quince T

    2016-08-01

    Full Text Available Thelma Quince, Pia Thiemann, John Benson, Sarah Hyde Primary Care Unit, Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, Cambridge, UK Abstract: Empathy is important to patient care. It enhances patients’ satisfaction, comfort, self-efficacy, and trust which in turn may facilitate better diagnosis, shared decision making, and therapy adherence. Empathetic doctors experience greater job satisfaction and psychological well-being. Understanding the development of empathy of tomorrow's health care professionals is important. However, clinical empathy is poorly defined and difficult to measure, while ways to enhance it remain unclear. This review examines empathy among undergraduate medical students, focusing upon three main questions: How is empathy measured? This section discusses the problems of assessing empathy and outlines the utility of the Jefferson Scale of Empathy – Student Version and Davis's Interpersonal Reactivity Index. Both have been used widely to assess medical students' empathy. Does empathy change during undergraduate medical education? The trajectory of empathy during undergraduate medical education has been and continues to be debated. Potential reasons for contrasting results of studies are outlined. What factors may influence the development of empathy? Although the influence of sex is widely recognized, the impact of culture, psychological well-being, and aspects of undergraduate curricula are less well understood. This review identifies three interrelated issues for future research into undergraduate medical students' empathy. First, the need for greater clarity of definition, recognizing that empathy is multidimensional. Second, the need to develop meaningful ways of measuring empathy which include its component dimensions and which are relevant to patients' experiences. Medical education research has generally relied upon single, self-report instruments, which have

  16. HST's 10th anniversary, ESA and Hubble : changing our vision

    Science.gov (United States)

    2000-04-01

    scientists still plan to use Hubble as one of their prime research tools, but they also expect to benefit from synergy between Hubble and the ground-based 8-metre class telescopes that are becoming available to scientists in Europe. Notes for editors The Hubble Space Telescope is an international cooperation project between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The partnership agreement between ESA and NASA was signed on 7 October 1977. ESA has provided, among other items, two pairs of solar panels and one of Hubble's scientific instruments (the Faint Object Camera). 15 European scientists are contributing to the science operation of the Hubble Observatory and are currently working at the Space Telescope Science Institute in Baltimore (STScI). In return for this contribution, European astronomers have guaranteed access to 15% of Hubble's observing time. Scientific operation of the Hubble Observatory is the responsibility of the Space Telescope Science Institute, which is run for NASA by the Association of Universities for Research in Astronomy (AURA). The Space Telescope European Coordinating Facility (ST-ECF), hosted by the European Southern Observatory (ESO) in Garching near Munich, Germany, provides support to European Hubble users. ESA and ESO jointly operate ST-ECF. From 27 April 2000 the "European Space Agency Hubble Information Centre" will be available with its services on the World Wide Web at http://hubble.esa.int as part of the recently upgraded ESA Science website http://sci.esa.int For more information, please contact : ESA - Communication Department Media Relations Office Tel: +33(0)1.53.69.7155 Fax: +33(0)1.53.69.7690 Press conference Thursday 27 April at 10:30h Location Space Telescope-European Coordinating Facility (ST-ECF) (c/o European Southern Observatory (ESO), K. Schwarzschild-Str. 2, Garching bei München, Germany), Auditorium.

  17. Hubble Source Catalog

    Science.gov (United States)

    Lubow, S.; Budavári, T.

    2013-10-01

    We have created an initial catalog of objects observed by the WFPC2 and ACS instruments on the Hubble Space Telescope (HST). The catalog is based on observations taken on more than 6000 visits (telescope pointings) of ACS/WFC and more than 25000 visits of WFPC2. The catalog is obtained by cross matching by position in the sky all Hubble Legacy Archive (HLA) Source Extractor source lists for these instruments. The source lists describe properties of source detections within a visit. The calculations are performed on a SQL Server database system. First we collect overlapping images into groups, e.g., Eta Car, and determine nearby (approximately matching) pairs of sources from different images within each group. We then apply a novel algorithm for improving the cross matching of pairs of sources by adjusting the astrometry of the images. Next, we combine pairwise matches into maximal sets of possible multi-source matches. We apply a greedy Bayesian method to split the maximal matches into more reliable matches. We test the accuracy of the matches by comparing the fluxes of the matched sources. The result is a set of information that ties together multiple observations of the same object. A byproduct of the catalog is greatly improved relative astrometry for many of the HST images. We also provide information on nondetections that can be used to determine dropouts. With the catalog, for the first time, one can carry out time domain, multi-wavelength studies across a large set of HST data. The catalog is publicly available. Much more can be done to expand the catalog capabilities.

  18. A Survey of Current Computer Information Science (CIS) Students.

    Science.gov (United States)

    Los Rios Community Coll. District, Sacramento, CA. Office of Institutional Research.

    This document is a survey designed to be completed by current students of Computer Information Science (CIS) in the Los Rios Community College District (LRCCD), which consists of three community colleges: American River College, Cosumnes River College, and Sacramento City College. The students are asked about their educational goals and how…

  19. Hubble Images Reveal Jupiter's Auroras

    Science.gov (United States)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.This image and other images and data

  20. The new European Hubble archive

    Science.gov (United States)

    De Marchi, Guido; Arevalo, Maria; Merin, Bruno

    2016-01-01

    The European Hubble Archive (hereafter eHST), hosted at ESA's European Space Astronomy Centre, has been released for public use in October 2015. The eHST is now fully integrated with the other ESA science archives to ensure long-term preservation of the Hubble data, consisting of more than 1 million observations from 10 different scientific instruments. The public HST data, the Hubble Legacy Archive, and the high-level science data products are now all available to scientists through a single, carefully designed and user friendly web interface. In this talk, I will show how the the eHST can help boost archival research, including how to search on sources in the field of view thanks to precise footprints projected onto the sky, how to obtain enhanced previews of imaging data and interactive spectral plots, and how to directly link observations with already published papers. To maximise the scientific exploitation of Hubble's data, the eHST offers connectivity to virtual observatory tools, easily integrates with the recently released Hubble Source Catalog, and is fully accessible through ESA's archives multi-mission interface.

  1. A Guided Inquiry on Hubble Plots and the Big Bang

    Science.gov (United States)

    Forringer, Ted

    2014-01-01

    In our science for non-science majors course "21st Century Physics," we investigate modern "Hubble plots" (plots of velocity versus distance for deep space objects) in order to discuss the Big Bang, dark matter, and dark energy. There are two potential challenges that our students face when encountering these topics for the…

  2. Making Data Mobile: The Hubble Deep Field Academy iPad app

    Science.gov (United States)

    Eisenhamer, Bonnie; Cordes, K.; Davis, S.; Eisenhamer, J.

    2013-01-01

    Many school districts are purchasing iPads for educators and students to use as learning tools in the classroom. Educators often prefer these devices to desktop and laptop computers because they offer portability and an intuitive design, while having a larger screen size when compared to smart phones. As a result, we began investigating the potential of adapting online activities for use on Apple’s iPad to enhance the dissemination and usage of these activities in instructional settings while continuing to meet educators’ needs. As a pilot effort, we are developing an iPad app for the “Hubble Deep Field Academy” - an activity that is currently available online and commonly used by middle school educators. The Hubble Deep Field Academy app features the HDF-North image while centering on the theme of how scientists use light to explore and study the universe. It also includes features such as embedded links to vocabulary, images and videos, teacher background materials, and readings about Hubble’s other deep field surveys. It is our goal is to impact students’ engagement in STEM-related activities, while enhancing educators’ usage of NASA data via new and innovative mediums. We also hope to develop and share lessons learned with the E/PO community that can be used to support similar projects. We plan to test the Hubble Deep Field Academy app during the school year to determine if this new activity format is beneficial to the education community.

  3. Mental health among currently enrolled medical students in Germany.

    Science.gov (United States)

    Wege, N; Muth, T; Li, J; Angerer, P

    2016-03-01

    The study identifies the prevalence of common mental disorders according to the patient health questionnaire (PHQ) and the use of psychotropic substances in a sample of currently enrolled medical students. A cross-sectional survey with a self-administrated questionnaire. All newly enrolled medical students at the University of Dusseldorf, with study beginning either in 2012 or 2013, respectively, were invited to participate. The evaluation was based on 590 completed questionnaires. Mental health outcomes were measured by the PHQ, including major depression, other depressive symptoms (subthreshold depression), anxiety, panic disorders and psychosomatic complaints. Moreover, information about psychotropic substances use (including medication) was obtained. Multiple logistic regression analysis was used to estimate associations between sociodemographic and socio-economic factors and mental health outcomes. The prevalence rates, measured by the PHQ, were 4.7% for major depression, 5.8% for other depressive symptoms, 4.4% for anxiety, 1.9% for panic disorders, and 15.7% for psychosomatic complaints. These prevalence rates were higher than those reported in the general population, but lower than in medical students in the course of medical training. In all, 10.7% of the students reported regular psychotropic substance use: 5.1% of students used medication 'to calm down,' 4.6% 'to improve their sleep,' 4.4% 'to elevate mood,' and 3.1% 'to improve cognitive performance.' In the fully adjusted model, expected financial difficulties were significantly associated with poor mental health (odds ratio [OR]: 2.14; 95% confidence interval [CI]: 1.31-3.48), psychosomatic symptoms (OR:1.85; 95% CI: 1.11-3.09) and psychotropic substances use (OR: 2.68; 95% CI: 1.51-4.75). The high rates of mental disorders among currently enrolled medical students call for the promotion of mental health, with a special emphasis on vulnerable groups. Copyright © 2016 The Royal Society for Public

  4. Building the Hubble Space Telescope

    International Nuclear Information System (INIS)

    O'dell, C.R.

    1989-01-01

    The development of the design for the Hubble Space Telescope (HST) is discussed. The HST optical system is described and illustrated. The financial and policy issues related to the development of the HST are considered. The actual construction of the HST optical telescope is examined. Also, consideration is given to the plans for the HST launch

  5. A Hubble Diagram for Quasars

    Directory of Open Access Journals (Sweden)

    Susanna Bisogni

    2018-01-01

    Full Text Available The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4 and that of the Cosmic Microwave Background (z ~ 1,100. Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as “standard candles” by employing the non-linear relation between their intrinsic UV and X-ray emission as an absolute distance indicator. We built a sample of ~1,900 quasars with available UV and X-ray observations, and produced a Hubble Diagram up to z ~ 5. The analysis of the quasar Hubble Diagram, when used in combination with supernovae, provides robust constraints on the matter and energy content in the cosmos. The application of this method to forthcoming, larger quasar samples, will also provide tight constraints on the dark energy equation of state and its possible evolution with time.

  6. HUBBLE CAPTURES MERGER BETWEEN QUASAR AND GALAXY

    Science.gov (United States)

    2002-01-01

    This NASA Hubble Space Telescope image shows evidence fo r a merger between a quasar and a companion galaxy. This surprising result might require theorists to rethink their explanations for the nature of quasars, the most energetic objects in the universe. The bright central object is the quasar itself, located several billion light-years away. The two wisps on the (left) of the bright central object are remnants of a bright galaxy that have been disrupted by the mutual gravitational attraction between the quasar and the companion galaxy. This provides clear evidence for a merger between the two objects. Since their discovery in 1963, quasars (quasi-stellar objects) have been enigmatic because they emit prodigious amounts of energy from a very compact source. The most widely accepted model is that a quasar is powered by a supermassive black hole in the core of a galaxy. These new observations proved a challenge for theorists as no current models predict the complex quasar interactions unveiled by Hubble. The image was taken with the Wide Field Planetary Camera-2. Credit: John Bahcall, Institute for Advanced Study, NASA.

  7. Chandra Independently Determines Hubble Constant

    Science.gov (United States)

    2006-08-01

    A critically important number that specifies the expansion rate of the Universe, the so-called Hubble constant, has been independently determined using NASA's Chandra X-ray Observatory. This new value matches recent measurements using other methods and extends their validity to greater distances, thus allowing astronomers to probe earlier epochs in the evolution of the Universe. "The reason this result is so significant is that we need the Hubble constant to tell us the size of the Universe, its age, and how much matter it contains," said Max Bonamente from the University of Alabama in Huntsville and NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala., lead author on the paper describing the results. "Astronomers absolutely need to trust this number because we use it for countless calculations." Illustration of Sunyaev-Zeldovich Effect Illustration of Sunyaev-Zeldovich Effect The Hubble constant is calculated by measuring the speed at which objects are moving away from us and dividing by their distance. Most of the previous attempts to determine the Hubble constant have involved using a multi-step, or distance ladder, approach in which the distance to nearby galaxies is used as the basis for determining greater distances. The most common approach has been to use a well-studied type of pulsating star known as a Cepheid variable, in conjunction with more distant supernovae to trace distances across the Universe. Scientists using this method and observations from the Hubble Space Telescope were able to measure the Hubble constant to within 10%. However, only independent checks would give them the confidence they desired, considering that much of our understanding of the Universe hangs in the balance. Chandra X-ray Image of MACS J1149.5+223 Chandra X-ray Image of MACS J1149.5+223 By combining X-ray data from Chandra with radio observations of galaxy clusters, the team determined the distances to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion

  8. The current status of the Korean student health examination

    Directory of Open Access Journals (Sweden)

    Hye-Jung Shin

    2013-08-01

    Full Text Available Recent trends place an emphasis on school health care, the ultimate goal of which is to protect,maintain, and promote students’ health. School health care is a program that integrates health careservices, health education, health counseling, and local social health services. The student healthexamination (SHE system is a part of school health care and schools and communities must beavailable to provide professional health services. Pediatricians also have important roles as experts inboth school health care and the SHE system. In this article, the history of school health care, its legalbasis, and the current status of the SHE system in Korea are reviewed. Furthermore, sample surveysfrom the past few years are reviewed. Through this holistic approach, future directions are proposed forthe improvement of SHE and school health care.

  9. Hubble Space Telescope electrical power system

    Science.gov (United States)

    Whitt, Thomas H.; Bush, John R., Jr.

    1990-01-01

    The Hubble Space Telescope (HST) electrical power system (EPS) is supplying between 2000 and 2400 W of continuous power to the electrical loads. The major components of the EPS are the 5000-W back surface field reflector solar array, the six nickel-hydrogen (NiH2) 22-cell 88-Ah batteries, and the charge current controllers, which, in conjunction with the flight computer, control battery charging. The operation of the HST EPS and the results of the HST NiH2 six-battery test are discussed, and preliminary flight data are reviewed. The HST NiH2 six-battery test is a breadboard of the HST EPS on test at Marshall Space Flight Center.

  10. Hubble expansion in static spacetime

    International Nuclear Information System (INIS)

    Rossler, Otto E.; Froehlich, Dieter; Movassagh, Ramis; Moore, Anthony

    2007-01-01

    A recently proposed mechanism for light-path expansion in a static spacetime is based on the moving-lenses paradigm. Since the latter is valid independently of whether space expands or not, a static universe can be used to better see the implications. The moving-lenses paradigm is related to the paradigm of dynamical friction. If this is correct, a Hubble-like law is implicit. It is described quantitatively. A bent in the Hubble-like line is predictably implied. The main underlying assumption is Price's Principle (PI 3 ). If the theory is sound, the greatest remaining problem in cosmology becomes the origin of hydrogen. Since Blandford's jet production mechanism for quasars is too weak, a generalized Hawking radiation hidden in the walls of cosmic voids is invoked. A second prediction is empirical: slow pattern changes in the cosmic microwave background. A third is ultra-high redshifts for Giacconi quasars. Bruno's eternal universe in the spirit of Augustine becomes a bit less outlandish

  11. The Hubble Tarantula Treasury Project

    Science.gov (United States)

    Sabbi, Elena; Lennon, D. J.; Anderson, J.; Van Der Marel, R. P.; Aloisi, A.; Boyer, M. L.; Cignoni, M.; De Marchi, G.; de Mink, S. E.; Evans, C. J.; Gallagher, J. S.; Gordon, K. D.; Gouliermis, D.; Grebel, E.; Koekemoer, A. M.; Larsen, S. S.; Panagia, N.; Ryon, J. E.; Smith, L. J.; Tosi, M.; Zaritsky, D. F.

    2014-01-01

    The Tarantula Nebula (a.k.a. 30 Doradus) in the Large Magellanic Cloud is one of the most famous objects in astronomy, with first astronomical references being more than 150 years old. Today the Tarantula Nebula and its ionizing cluster R136 are considered one of the few known starburst regions in the Local Group and an ideal test bed to investigate the temporal and spatial evolution of a prototypical starburst on a sub-cluster scale. The Hubble Tarantula Treasury Project (HTTP) is a panchromatic imaging survey of the stellar populations and ionized gas in the Tarantula Nebula that reaches into the sub-solar mass regime (eBook that explains how stars form and evolve using images from HTTP. The eBook utilizes emerging technology that works in conjunction with the built-in accessibility features in the Apple iPad to allow totally blind users to interactively explore complex astronomical images.

  12. College Students' News Gratifications, Media Use, and Current Events Knowledge.

    Science.gov (United States)

    Vincent, Richard C.; Basil, Michael D.

    1997-01-01

    Results of testing uses and gratifications theory with college students show students' media use and surveillance needs increase college year. Demographic differences and gratifications sought drive news media use. Surveillance needs result in increased use of all news media, whereas entertainment needs result in television news and CNN viewing.…

  13. Medical Students' Perspective on Current and Future Training in Anatomy

    NARCIS (Netherlands)

    Triepels, C.P.R.; Koppes, D.M.; Kuijk, S.M.J. Van; Popeijus, H.E.; Lamers, W.H.; Gorp, T. Van; Futterer, J.J.; Kruitwagen, R.; Notten, K.J.B.

    2018-01-01

    Gaining sufficient knowledge of anatomy is an important part of medical education. Factors that influence how well students learn anatomical structures include available sources, learning time and study assistance. This study explores the attitude of medical students with regard to studying anatomy

  14. Online Student Services: Current Practices and Recommendations for Implementation

    Science.gov (United States)

    Bailey, Tabitha L.; Brown, Abbie

    2016-01-01

    Recommendations for planning and development of online student services based on a review of the literature on research conducted in a variety of college settings. Focus topics include the institutional website, help desks and information centers, student orientation, academic support, and library services.

  15. Supporting Students with Asperger Syndrome on College Campuses: Current Practices

    Science.gov (United States)

    Barnhill, Gena P.

    2016-01-01

    With the increasing number of students with Asperger syndrome (AS) and high functioning autism (HFA) enrolling in college, it has become apparent that support services are greatly needed to assist these students in navigating college life, both academically and socially. Yet, there is a dearth of research describing the specific supports needed…

  16. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY

    International Nuclear Information System (INIS)

    Dalcanton, Julianne J.; Williams, Benjamin F.; Rosenfield, Philip; Weisz, Daniel R.; Gilbert, Karoline M.; Gogarten, Stephanie M.; Lang, Dustin; Lauer, Tod R.; Dong Hui; Kalirai, Jason S.; Boyer, Martha L.; Gordon, Karl D.; Seth, Anil C.; Dolphin, Andrew; Bell, Eric F.; Bianchi, Luciana C.; Caldwell, Nelson; Dorman, Claire E.; Guhathakurta, Puragra; Girardi, Léo

    2012-01-01

    The Panchromatic Hubble Andromeda Treasury is an ongoing Hubble Space Telescope Multi-Cycle Treasury program to image ∼1/3 of M31's star-forming disk in six filters, spanning from the ultraviolet (UV) to the near-infrared (NIR). We use the Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) to resolve the galaxy into millions of individual stars with projected radii from 0 to 20 kpc. The full survey will cover a contiguous 0.5 deg 2 area in 828 orbits. Imaging is being obtained in the F275W and F336W filters on the WFC3/UVIS camera, F475W and F814W on ACS/WFC, and F110W and F160W on WFC3/IR. The resulting wavelength coverage gives excellent constraints on stellar temperature, bolometric luminosity, and extinction for most spectral types. The data produce photometry with a signal-to-noise ratio of 4 at m F275W = 25.1, m F336W = 24.9, m F475W = 27.9, m F814W = 27.1, m F110W = 25.5, and m F160W = 24.6 for single pointings in the uncrowded outer disk; in the inner disk, however, the optical and NIR data are crowding limited, and the deepest reliable magnitudes are up to 5 mag brighter. Observations are carried out in two orbits per pointing, split between WFC3/UVIS and WFC3/IR cameras in primary mode, with ACS/WFC run in parallel. All pointings are dithered to produce Nyquist-sampled images in F475W, F814W, and F160W. We describe the observing strategy, photometry, astrometry, and data products available for the survey, along with extensive testing of photometric stability, crowding errors, spatially dependent photometric biases, and telescope pointing control. We also report on initial fits to the structure of M31's disk, derived from the density of red giant branch stars, in a way that is independent of assumed mass-to-light ratios and is robust to variations in dust extinction. These fits also show that the 10 kpc ring is not just a region of enhanced recent star formation, but is instead a dynamical structure containing a significant overdensity of

  17. An updated Type II supernova Hubble diagram

    Science.gov (United States)

    Gall, E. E. E.; Kotak, R.; Leibundgut, B.; Taubenberger, S.; Hillebrandt, W.; Kromer, M.; Burgett, W. S.; Chambers, K.; Flewelling, H.; Huber, M. E.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Smith, K.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

    2018-03-01

    We present photometry and spectroscopy of nine Type II-P/L supernovae (SNe) with redshifts in the 0.045 ≲ z ≲ 0.335 range, with a view to re-examining their utility as distance indicators. Specifically, we apply the expanding photosphere method (EPM) and the standardized candle method (SCM) to each target, and find that both methods yield distances that are in reasonable agreement with each other. The current record-holder for the highest-redshift spectroscopically confirmed supernova (SN) II-P is PS1-13bni (z = 0.335-0.012+0.009), and illustrates the promise of Type II SNe as cosmological tools. We updated existing EPM and SCM Hubble diagrams by adding our sample to those previously published. Within the context of Type II SN distance measuring techniques, we investigated two related questions. First, we explored the possibility of utilising spectral lines other than the traditionally used Fe IIλ5169 to infer the photospheric velocity of SN ejecta. Using local well-observed objects, we derive an epoch-dependent relation between the strong Balmer line and Fe IIλ5169 velocities that is applicable 30 to 40 days post-explosion. Motivated in part by the continuum of key observables such as rise time and decline rates exhibited from II-P to II-L SNe, we assessed the possibility of using Hubble-flow Type II-L SNe as distance indicators. These yield similar distances as the Type II-P SNe. Although these initial results are encouraging, a significantly larger sample of SNe II-L would be required to draw definitive conclusions. Tables A.1, A.3, A.5, A.7, A.9, A.11, A.13, A.15 and A.17 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A25

  18. Hubble Observes Surface of Titan

    Science.gov (United States)

    1994-01-01

    Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia.Titan, larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface, albeit oceans and rain of ethane-methane rather than water. Scientists suspect that Titan's present environment -- although colder than minus 289 degrees Fahrenheit, so cold that water ice would be as hard as granite -- might be similar to that on Earth billions of years ago, before life began pumping oxygen into the atmosphere.Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory and his team took the images with the Hubble Space Telescope during 14 observing runs between Oct. 4 - 18. Smith announced the team's first results last week at the 26th annual meeting of the American Astronomical Society Division for Planetary Sciences in Bethesda, Md. Co-investigators on the team are Mark Lemmon, a doctoral candidate with the UA Lunar and Planetary Laboratory; John Caldwell of York University, Canada; Larry Sromovsky of the University of Wisconsin; and Michael Allison of the Goddard Institute for Space Studies, New York City.Titan's atmosphere, about four times as dense as Earth's atmosphere, is primarily nitrogen laced with such poisonous substances as methane and ethane. This thick, orange, hydrocarbon haze was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The haze is formed as methane in the atmosphere is destroyed by sunlight. The hydrocarbons produced by this methane destruction form a smog similar to that found over large cities, but is much thicker

  19. High-Performance Reaction Wheel Optimization for Fine-Pointing Space Platforms: Minimizing Induced Vibration Effects on Jitter Performance plus Lessons Learned from Hubble Space Telescope for Current and Future Spacecraft Applications

    Science.gov (United States)

    Hasha, Martin D.

    2016-01-01

    The Hubble Space Telescope (HST) applies large-diameter optics (2.5-m primary mirror) for diffraction-limited resolution spanning an extended wavelength range (approx. 100-2500 nm). Its Pointing Control System (PCS) Reaction Wheel Assemblies (RWAs), in the Support Systems Module (SSM), acquired an unprecedented set of high-sensitivity Induced Vibration (IV) data for 5 flight-certified RWAs: dwelling at set rotation rates. Focused on 4 key ratios, force and moment harmonic values (in 3 local principal directions) are extracted in the RWA operating range (0-3000 RPM). The IV test data, obtained under ambient lab conditions, are investigated in detail, evaluated, compiled, and curve-fitted; variational trends, core causes, and unforeseen anomalies are addressed. In aggregate, these values constitute a statistically-valid basis to quantify ground test-to-test variations and facilitate extrapolations to on-orbit conditions. Accumulated knowledge of bearing-rotor vibrational sources, corresponding harmonic contributions, and salient elements of IV key variability factors are discussed. An evolved methodology is presented for absolute assessments and relative comparisons of macro-level IV signal magnitude due to micro-level construction-assembly geometric details/imperfections stemming from both electrical drive and primary bearing design parameters. Based upon studies of same-size/similar-design momentum wheels' IV changes, upper estimates due to transitions from ground tests to orbital conditions are derived. Recommended HST RWA choices are discussed relative to system optimization/tradeoffs of Line-Of-Sight (LOS) vector-pointing focal-plane error driven by higher IV transmissibilities through low-damped structural dynamics that stimulate optical elements. Unique analytical disturbance results for orbital HST accelerations are described applicable to microgravity efforts. Conclusions, lessons learned, historical context/insights, and perspectives on future applications

  20. Hubble's View of Little Blue Dots

    Science.gov (United States)

    Kohler, Susanna

    2018-02-01

    The recent discovery of a new type of tiny, star-forming galaxy is the latest in a zoo of detections shedding light on our early universe. What can we learn from the unique little blue dots found in archival Hubble data?Peas, Berries, and DotsGreen pea galaxies identified by citizen scientists with Galaxy Zoo. [Richard Nowell Carolin Cardamone]As telescope capabilities improve and we develop increasingly deeper large-scale surveys of our universe, we continue to learn more about small, faraway galaxies. In recent years, increasing sensitivity first enabled the detection of green peas luminous, compact, low-mass (10 billion solar masses; compare this to the Milky Ways 1 trillion solar masses!) galaxies with high rates of star formation.Not long thereafter, we discovered galaxies that form stars similarly rapidly, but are even smaller only 330 million solar masses, spanning less than 3,000 light-years in size. These tiny powerhouses were termed blueberries for their distinctive color.Now, scientists Debra and Bruce Elmegreen (of Vassar College and IBM Research Division, respectively) report the discovery of galaxies that have even higher star formation rates and even lower masses: little blue dots.Exploring Tiny Star FactoriesThe Elmegreens discovered these unique galaxies by exploring archival Hubble data. The Hubble Frontier Fields data consist of deep images of six distant galaxy clusters and the parallel fields next to them. It was in the archival data for two Frontier Field Parallels, those for clusters Abell 2744 and MAS J0416.1-2403, that the authors noticed several galaxies that stand out as tiny, bright, blue objects that are nearly point sources.Top: a few examples of the little blue dots recently identified in two Hubble Frontier Field Parallels. Bottom: stacked images for three different groups of little blue dots. [Elmegreen Elmegreen 2017]The authors performed a search through the two Frontier Field Parallels, discovering a total of 55 little blue dots

  1. The Far-Field Hubble Constant

    Science.gov (United States)

    Lauer, Tod

    1995-07-01

    We request deep, near-IR (F814W) WFPC2 images of five nearby Brightest Cluster Galaxies (BCG) to calibrate the BCG Hubble diagram by the Surface Brightness Fluctuation (SBF) method. Lauer & Postman (1992) show that the BCG Hubble diagram measured out to 15,000 km s^-1 is highly linear. Calibration of the Hubble diagram zeropoint by SBF will thus yield an accurate far-field measure of H_0 based on the entire volume within 15,000 km s^-1, thus circumventing any strong biases caused by local peculiar velocity fields. This method of reaching the far field is contrasted with those using distance ratios between Virgo and Coma, or any other limited sample of clusters. HST is required as the ground-based SBF method is limited to team developed the SBF method, the first BCG Hubble diagram based on a full-sky, volume-limited BCG sample, played major roles in the calibration of WFPC and WFPC2, and are conducting observations of local galaxies that will validate the SBF zeropoint (through GTO programs). This work uses the SBF method to tie both the Cepheid and Local Group giant-branch distances generated by HST to the large scale Hubble flow, which is most accurately traced by BCGs.

  2. NASA and ESA astronauts visit ESO. Hubble repair team meets European astronomers in Garching.

    Science.gov (United States)

    1994-02-01

    On Wednesday, February 16, 1994, seven NASA and ESA astronauts and their spouses will spend a day at the Headquarters of the European Southern Observatory. They are the members of the STS-61 crew that successfully repaired the Hubble Space Telescope during a Space Shuttle mission in December 1993. This will be the only stop in Germany during their current tour of various European countries. ESO houses the Space Telescope European Coordinating Facility (ST/ECF), a joint venture by the European Space Agency and ESO. This group of astronomers and computer specialists provide all services needed by European astronomers for observations with the Space Telescope. Currently, the European share is about 20 of the total time available at this telescope. During this visit, a Press Conference will be held on Wednesday, February 16, 11:45 - 12:30 at the ESO Headquarters Karl-Schwarzschild-Strasse 2 D-85748 Garching bei Munchen. Please note that participation in this Press Conference is by invitation only. Media representatives may obtain invitations from Mrs. E. Volk, ESO Information Service at this address (Tel.: +49-89-32006276; Fax.: +49-89-3202362), until Friday, February 11, 1994. After the Press Conference, between 12:30 - 14:00, a light refreshment will be served at the ESO Headquarters to all participants. >From 14:00 - 15:30, the astronauts will meet with students and teachers from the many scientific institutes in Garching in the course of an open presentation at the large lecture hall of the Physics Department of the Technical University. It is a 10 minute walk from ESO to the hall. Later the same day, the astronauts will be back at ESO for a private discussion of various space astronomy issues with their astronomer colleagues, many of whom are users of the Hubble Space Telescope, as well as ground-based telescopes at the ESO La Silla Observatory and elsewhere. The astronauts continue to Switzerland in the evening.

  3. Hubble and the Language of Images

    Science.gov (United States)

    Levay, Z. G.

    2005-12-01

    Images released from the Hubble Space Telescope have been very highly regarded by the astronomy-attentive public for at least a decade. Due in large part to these images, Hubble has become an iconic figure, even among the general public. This iconic status is both a boon and a burden for those who produce the stream of images fl owing from this telescope. While the benefits of attention are fairly obvious, the negative aspects are less visible. One of the most persistent challenges is the need to continue to deliver images that "top" those released before. In part this can be accomplished because of Hubble's upgraded instrumentation. But it can also be a source of pressure that could, if left unchecked, erode ethical boundaries in our communication with the public. These pressures are magnified in an atmosphere of uncertainty with regard to the future of the mission.

  4. Testing the isotropy of the Hubble expansion

    OpenAIRE

    Migkas, K.; Plionis, M.

    2016-01-01

    Abstract: We have used the Union2.1 SNIa compilation to search for possible Hubble expansion anisotropies, dividing the sky in 9 solid angles containing roughly the same number of SNIa, as well as in two Galactic hemispheres. We identified only one sky region, containing 82 SNIa (~15% of total sample with z > 0.02), that indeed appears to share a Hubble expansion significantly different from the rest of the sample. However, this behaviour can be attributed to the joint "erratic" behaviour of ...

  5. Past Expectations, Current Experiences, and Imagined Futures: Narrative Accounts of Chinese International Students in Canada

    OpenAIRE

    Zhang, Zhihua

    2017-01-01

    The internationalization of higher education has led to the influx of Chinese international students in Canada. The literature on these students usually addresses the factors that drive them to Canada, their learning experiences, and the impact of the stereotypical constructions of “Chinese learners” on their language learning. But the literature does not connect the current learning experiences of these students to their past back in China and the futures in their imagination. This narrative...

  6. Students and Instant Messaging: Survey on Current Use and Demands for Higher Education

    NARCIS (Netherlands)

    De Bakker, Gijs; Sloep, Peter; Jochems, Wim

    2008-01-01

    De Bakker, G., Sloep, P. B., & Jochems, W. M. G. (2007). Students and instant messaging: survey on current use and demands for higher education. Research in Learning Technology (ALT-J), 15(2), 143-153.

  7. Current Trends in Developing Medical Students' Critical Thinking Abilities

    Directory of Open Access Journals (Sweden)

    Peter H. Harasym

    2008-07-01

    Full Text Available Health care is fallible and prone to diagnostic and management errors. The major categories of diagnostic errors include: (1 no-fault errors—the disease is present but not detected; (2 system errors—a diagnosis is delayed or missed because of the imperfection in the health care system; and (3 cognitive errors—a misdiagnosis from faulty data collection or interpretation, flawed reasoning, or incomplete knowledge. Approximately one third of patient problems are mismanaged because of diagnostic errors. Part of the solution lies in improving the diagnostic skills and critical thinking abilities of physicians as they progress through medical school and residency training. However, this task is challenging since both medical problem-solving and the learning environments are complex and not easily understood. There are many interacting variables including the motivation of the medical student (e.g. deep versus surface learning, the acquisition and evolution of declarative and conditional knowledge (e.g. reduced, dispersed, elaborated, scheme, and scripted, problem-solving strategies (e.g. procedural knowledge—guessing, hypothetical deductive, scheme inductive, and pattern recognition, curricular models (e.g. apprenticeship, discipline-based, body system-based, case-based, clinical presentation-based, teaching strategies (e.g. teaching general to specific or specific to general, the presented learning opportunities (PBL versus scheme inductive PBL, and the nature of the learning environment (e.g. modeling critical thinking and expert problem-solving. This paper elaborates on how novices differ from experts and how novices can be educated in a manner that enhances their level of expertise and diagnostic abilities as they progress through several years of medical training.

  8. On the determination of the Hubble constant

    International Nuclear Information System (INIS)

    Gurzadyan, V.G.; Harutyunyan, V.V.; Kocharyan, A.A.

    1990-10-01

    The possibility of an alternative determination of the distance scale of the Universe and the Hubble constant based on the numerical analysis of the hierarchical nature of the large scale Universe (galaxies, clusters and superclusters) is proposed. The results of computer experiments performed by means of special numerical algorithms are represented. (author). 9 refs, 7 figs

  9. Dark Energy and the Hubble Law

    Science.gov (United States)

    Chernin, A. D.; Dolgachev, V. P.; Domozhilova, L. M.

    The Big Bang predicted by Friedmann could not be empirically discovered in the 1920th, since global cosmological distances (more than 300-1000 Mpc) were not available for observations at that time. Lemaitre and Hubble studied receding motions of galaxies at local distances of less than 20-30 Mpc and found that the motions followed the (nearly) linear velocity-distance relation, known now as Hubble's law. For decades, the real nature of this phenomenon has remained a mystery, in Sandage's words. After the discovery of dark energy, it was suggested that the dynamics of local expansion flows is dominated by omnipresent dark energy, and it is the dark energy antigravity that is able to introduce the linear velocity-distance relation to the flows. It implies that Hubble's law observed at local distances was in fact the first observational manifestation of dark energy. If this is the case, the commonly accepted criteria of scientific discovery lead to the conclusion: In 1927, Lemaitre discovered dark energy and Hubble confirmed this in 1929.

  10. HUBBLE PINPOINTS WHITE DWARFS IN GLOBULAR CLUSTER

    Science.gov (United States)

    2002-01-01

    Peering deep inside a cluster of several hundred thousand stars, NASA's Hubble Space Telescope uncovered the oldest burned-out stars in our Milky Way Galaxy. Located in the globular cluster M4, these small, dying stars - called white dwarfs - are giving astronomers a fresh reading on one of the biggest questions in astronomy: How old is the universe? The ancient white dwarfs in M4 are about 12 to 13 billion years old. After accounting for the time it took the cluster to form after the big bang, astronomers found that the age of the white dwarfs agrees with previous estimates for the universe's age. In the top panel, a ground-based observatory snapped a panoramic view of the entire cluster, which contains several hundred thousand stars within a volume of 10 to 30 light-years across. The Kitt Peak National Observatory's 0.9-meter telescope took this picture in March 1995. The box at left indicates the region observed by the Hubble telescope. The Hubble telescope studied a small region of the cluster. A section of that region is seen in the picture at bottom left. A sampling of an even smaller region is shown at bottom right. This region is only about one light-year across. In this smaller region, Hubble pinpointed a number of faint white dwarfs. The blue circles pinpoint the dwarfs. It took nearly eight days of exposure time over a 67-day period to find these extremely faint stars. Globular clusters are among the oldest clusters of stars in the universe. The faintest and coolest white dwarfs within globular clusters can yield a globular cluster's age. Earlier Hubble observations showed that the first stars formed less than 1 billion years after the universe's birth in the big bang. So, finding the oldest stars puts astronomers within arm's reach of the universe's age. M4 is 7,000 light-years away in the constellation Scorpius. Hubble's Wide Field and Planetary Camera 2 made the observations from January through April 2001. These optical observations were combined to

  11. Version 1 of the Hubble Source Catalog

    Science.gov (United States)

    Whitmore, Bradley C.; Allam, Sahar S.; Budavári, Tamás; Casertano, Stefano; Downes, Ronald A.; Donaldson, Thomas; Fall, S. Michael; Lubow, Stephen H.; Quick, Lee; Strolger, Louis-Gregory; Wallace, Geoff; White, Richard L.

    2016-06-01

    The Hubble Source Catalog is designed to help optimize science from the Hubble Space Telescope (HST) by combining the tens of thousands of visit-based source lists in the Hubble Legacy Archive (HLA) into a single master catalog. Version 1 of the Hubble Source Catalog includes WFPC2, ACS/WFC, WFC3/UVIS, and WFC3/IR photometric data generated using SExtractor software to produce the individual source lists. The catalog includes roughly 80 million detections of 30 million objects involving 112 different detector/filter combinations, and about 160,000 HST exposures. Source lists from Data Release 8 of the HLA are matched using an algorithm developed by Budavári & Lubow. The mean photometric accuracy for the catalog as a whole is better than 0.10 mag, with relative accuracy as good as 0.02 mag in certain circumstances (e.g., bright isolated stars). The relative astrometric residuals are typically within 10 mas, with a value for the mode (I.e., most common value) of 2.3 mas. The absolute astrometric accuracy is better than 0''\\hspace{-0.5em}. 1 for most sources, but can be much larger for a fraction of fields that could not be matched to the PanSTARRS, SDSS, or 2MASS reference systems. In this paper we describe the database design with emphasis on those aspects that enable the users to fully exploit the catalog while avoiding common misunderstandings and potential pitfalls. We provide usage examples to illustrate some of the science capabilities and data quality characteristics, and briefly discuss plans for future improvements to the Hubble Source Catalog.

  12. Hubble expansion in a Euclidean framework

    International Nuclear Information System (INIS)

    Alfven, H.

    1979-01-01

    There now seems to be strong evidence for a non-cosmological interpretation of the QSO redshift - in any case, so strong that it is of interest to investigate the consequences. The purpose of this paper is to construct a model of the Hubble expansion which is as far as possible from the conventional Big Bang model without coming in conflict with any well-established observational results (while introducing no new laws of physics). This leads to an essentially Euclidean metagalactic model (see Table I) with very little mass outside one-third or half of the Hubble radius. The total kinetic energy of the Hubble expansion need only to be about 5% of the rest mass energy. Present observations support backwards in time extrapolation of the Hubble expansion to a 'minimum size galaxy' Rsub(m), which may have any value in 0 26 cm. Other arguments speak in favor of a size close to the upper value, say Rsub(m) = 10 26 cm (Table II). As this size is probably about 100 times the Schwarzschild limit, an essentially Euclidean description is allowed. The kinetic energy of the Hubble expansion may derive from an intense QSO-like activity in the minimum size metagalaxy, with an energy release corresponding to the annihilation of a few solar masses per galaxy per year. Some of the conclusions based on the Big Bang hypothesis are criticized and in several cases alternative interpretations are suggested. A comparison between the Euclidean and the conventional models is given in Table III. (orig.)

  13. The Hubble series: convergence properties and redshift variables

    International Nuclear Information System (INIS)

    Cattoen, Celine; Visser, Matt

    2007-01-01

    In cosmography, cosmokinetics and cosmology, it is quite common to encounter physical quantities expanded as a Taylor series in the cosmological redshift z. Perhaps the most well-known exemplar of this phenomenon is the Hubble relation between distance and redshift. However, we now have considerable high-z data available; for instance, we have supernova data at least back to redshift z ∼ 1.75. This opens up the theoretical question as to whether or not the Hubble series (or more generally any series expansion based on the z-redshift) actually converges for large redshift. Based on a combination of mathematical and physical reasonings, we argue that the radius of convergence of any series expansion in z is less than or equal to 1, and that z-based expansions must break down for z > 1, corresponding to a universe less than half of its current size. Furthermore, we shall argue on theoretical grounds for the utility of an improved parametrization y = z/(1 + z). In terms of the y-redshift, we again argue that the radius of convergence of any series expansion in y is less than or equal to 1, so that y-based expansions are likely to be good all the way back to the big bang (y = 1), but that y-based expansions must break down for y < -1, now corresponding to a universe more than twice its current size

  14. Family meal traditions. Comparing reported childhood food habits to current food habits among university students.

    Science.gov (United States)

    De Backer, Charlotte J S

    2013-10-01

    The aim of this study is to investigate if reported childhood food habits predict the food habits of students at present. Questions addressed are: does the memory of childhood family meals promote commensality among students? Does the memory of (grand)parents' cooking influence students' cooking? And, is there still a gender difference in passing on everyday cooking skills? Using a cross-sectional survey, 104 students were asked about their current eating and cooking habits, and their eating habits and the cooking behavior of their (grand)parents during their childhood. Results show that frequencies in reported childhood family meals predict frequencies of students' commensality at present. The effects appear for breakfast and dinner, and stay within the same meal: recalled childhood family breakfasts predict current breakfast commensality, recalled childhood family dinners predict current dinner commensality. In terms of recalled cookery of (grand)parents and the use of family recipes a matrilineal dominance can be observed. Mothers are most influential, and maternal grandmothers outscore paternal grandmothers. Yet, fathers' childhood cooking did not pass unnoticed either. They seem to influence male students' cookery. Overall, in a life-stage of transgression students appear to maintain recalled childhood food rituals. Suggestions are discussed to further validate these results. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. HUBBLE SPIES MOST DISTANT SUPERNOVA EVER SEEN

    Science.gov (United States)

    2002-01-01

    Using NASA's Hubble Space Telescope, astronomers pinpointed a blaze of light from the farthest supernova ever seen, a dying star that exploded 10 billion years ago. The detection and analysis of this supernova, called 1997ff, is greatly bolstering the case for the existence of a mysterious form of dark energy pervading the cosmos, making galaxies hurl ever faster away from each other. The supernova also offers the first glimpse of the universe slowing down soon after the Big Bang, before it began speeding up. This panel of images, taken with the Wide Field and Planetary Camera 2, shows the supernova's cosmic neighborhood; its home galaxy; and the dying star itself. Astronomers found this supernova in 1997 during a second look at the northern Hubble Deep Field [top panel], a tiny region of sky first explored by the Hubble telescope in 1995. The image shows the myriad of galaxies Hubble spied when it peered across more than 10 billion years of time and space. The white box marks the area where the supernova dwells. The photo at bottom left is a close-up view of that region. The white arrow points to the exploding star's home galaxy, a faint elliptical. Its redness is due to the billions of old stars residing there. The picture at bottom right shows the supernova itself, distinguished by the white dot in the center. Although this stellar explosion is among the brightest beacons in the universe, it could not be seen directly in the Hubble images. The stellar blast is so distant from Earth that its light is buried in the glow of its host galaxy. To find the supernova, astronomers compared two pictures of the 'deep field' taken two years apart. One image was of the original Hubble Deep Field; the other, the follow-up deep-field picture taken in 1997. Using special computer software, astronomers then measured the light from the galaxies in both images. Noting any changes in light output between the two pictures, the computer identified a blob of light in the 1997 picture

  16. BEAUTY IN THE EYE OF HUBBLE

    Science.gov (United States)

    2002-01-01

    A dying star, IC 4406, dubbed the 'Retina Nebula' is revealed in this month's Hubble Heritage image. Like many other so-called planetary nebulae, IC 4406 exhibits a high degree of symmetry; the left and right halves of the Hubble image are nearly mirror images of the other. If we could fly around IC4406 in a starship, we would see that the gas and dust form a vast donut of material streaming outward from the dying star. From Earth, we are viewing the donut from the side. This side view allows us to see the intricate tendrils of dust that have been compared to the eye's retina. In other planetary nebulae, like the Ring Nebula (NGC 6720), we view the donut from the top. The donut of material confines the intense radiation coming from the remnant of the dying star. Gas on the inside of the donut is ionized by light from the central star and glows. Light from oxygen atoms is rendered blue in this image; hydrogen is shown as green, and nitrogen as red. The range of color in the final image shows the differences in concentration of these three gases in the nebula. Unseen in the Hubble image is a larger zone of neutral gas that is not emitting visible light, but which can be seen by radio telescopes. One of the most interesting features of IC 4406 is the irregular lattice of dark lanes that criss-cross the center of the nebula. These lanes are about 160 astronomical units wide (1 astronomical unit is the distance between the Earth and Sun). They are located right at the boundary between the hot glowing gas that produces the visual light imaged here and the neutral gas seen with radio telescopes. We see the lanes in silhouette because they have a density of dust and gas that is a thousand times higher than the rest of the nebula. The dust lanes are like a rather open mesh veil that has been wrapped around the bright donut. The fate of these dense knots of material is unknown. Will they survive the nebula's expansion and become dark denizens of the space between the stars

  17. Hubble Space Telescope - Scientific, Technological and Social Contributions to the Public Discourse on Science

    Science.gov (United States)

    Wiseman, Jennifer

    2012-01-01

    The Hubble Space Telescope has unified the world with a sense of awe and wonder for 2 I years and is currently more scientifically powerful than ever. I will present highlights of discoveries made with the Hubble Space Telescope, including details of planetary weather, star formation, extra-solar planets, colliding galaxies, and a universe expanding with the acceleration of dark energy. I will also present the unique technical challenges and triumphs of this phenomenal observatory, and discuss how our discoveries in the cosmos affect our sense of human unity, significance, and wonder.

  18. Multilevel analysis of school anti-smoking education and current cigarette use among South African students.

    Science.gov (United States)

    Talley, Brandon; Masyn, Katherine; Chandora, Rachna; Vivolo-Kantor, Alana

    2017-01-01

    South Africa (SA) implemented the Global Youth Tobacco Survey (GYTS) four times between 1999 and 2011. Data from the four surveys indicated that downward trends in cigarette use among students may have stalled. Understanding the effect of school anti-smoking education on current smoking among students within schools and variability across schools may provide important insights into policies aimed at preventing or reducing tobacco use among students. The objective was to assess the student- and school-level effects of students' exposure to school anti-smoking education on current cigarette use among the study population using the most recent wave of GYTS data in SA (2011). An analytic sample of students 13-15 years of age was selected (n=3,068) from the SA GYTS 2011. A taxonomy of two-level logistic regression models was fit to assess the relationship of various tobacco use, control, and exposure predictor variables on current cigarette smoking among the study population. At the student-level in the full model, secondhand smoke (SHS) exposure, peer smoking, and ownership of a promotional item were significantly associated with higher risk of current smoking. At the school-level in the full model, average exposure to peer smoking was associated with significant increases in the prevalence of current cigarette use, while average family anti-smoking education was significantly associated with decreases in the outcome variable. School anti-smoking education was not a statistically significant predictor at the student- or school-levels. in this study, exposure to school anti-smoking education had no association with current cigarette smoking among the study population. Consistent with previous studies, having peers that smoked was highly associated with a student being a current smoker. Interestingly, at the school-level in the multilevel analysis, schools with higher rates of average family anti-smoking education had lower prevalence of current smoking. This finding has

  19. New Hubble Servicing Mission to upgrade instruments

    Science.gov (United States)

    2006-10-01

    The history of the NASA/ESA Hubble Space Telescope is dominated by the familiar sharp images and amazing discoveries that have had an unprecedented scientific impact on our view of the world and our understanding of the universe. Nevertheless, such important contributions to science and humankind have only been possible as result of regular upgrades and enhancements to Hubble’s instrumentation. Using the Space Shuttle for this fifth Servicing Mission underlines the important role that astronauts have played and continue to play in increasing the Space Telescope’s lifespan and scientific power. Since the loss of Columbia in 2003, the Shuttle has been successfully launched on three missions, confirming that improvements made to it have established the required high level of safety for the spacecraft and its crew. “There is never going to be an end to the science that we can do with a machine like Hubble”, says David Southwood, ESA’s Director of Science. “Hubble is our way of exploring our origins. Everyone should be proud that there is a European element to it and that we all are part of its success at some level.” This Servicing Mission will not just ensure that Hubble can function for perhaps as much as another ten years; it will also increase its capabilities significantly in key areas. This highly visible mission is expected to take place in 2008 and will feature several space walks. As part of the upgrade, two new scientific instruments will be installed: the Cosmic Origins Spectrograph and Wide Field Camera 3. Each has advanced technology sensors that will dramatically improve Hubble’s potential for discovery and enable it to observe faint light from the youngest stars and galaxies in the universe. With such an astounding increase in its science capabilities, this orbital observatory will continue to penetrate the most distant regions of outer space and reveal breathtaking phenomena. “Today, Hubble is producing more science than ever before in

  20. Investigating students' view on STEM in learning about electrical current through STS approach

    Science.gov (United States)

    Tupsai, Jiraporn; Yuenyong, Chokchai

    2018-01-01

    This study aims to investigate Grade 11 students' views on Science Technology Engineering Mathematics (STEM) with the integration of learning about electrical current based on Science Technology Society (STS) approach [8]. The participants were 60 Grade 11 students in Demonstration Secondary School, Khon Kaen University, Khon Kaen Province, Thailand. The methodology is in the respect of interpretive paradigm. The teaching and learning about Electrical Current through STS approach carried out over 6 weeks. The Electrical Current unit through STS approach was developed based on framework[8] that consists of five stages including (1) identification of social issues, (2) identification of potential solutions, (3) need for knowledge, (4) decision making, and (5) socialization stage. To start with, the question "what if this world is lack of electricity" was challenged in the class in order to move students to find the problem of how to design Electricity Generation from Clean Energy. Students were expected to apply scientific and other knowledge to design of Electricity Generation. Students' views on STEM were collected during their learning by participant' observation and students' tasks. Their views on STEM were categorized when they applied their knowledge for designing the Electricity Generation. The findings indicated that students cooperatively work to solve the problem when applying knowledge about the content of Science and Mathematics and processing skill of Technology and Engineering. It showed that students held the integration of science, technology, engineering and mathematics to design their possible solutions in learning about Electrical Current. The paper also discusses implications for science teaching and learning through STS in Thailand.

  1. Education technology with continuous real time monitoring of the current functional and emotional students' states

    Science.gov (United States)

    Alyushin, M. V.; Kolobashkina, L. V.

    2017-01-01

    The education technology with continuous monitoring of the current functional and emotional students' states is suggested. The application of this technology allows one to increase the effectiveness of practice through informed planning of the training load. For monitoring the current functional and emotional students' states non-contact remote technologies of person bioparameters registration are encouraged to use. These technologies are based on recording and processing in real time the main person bioparameters in a purely passive mode. Experimental testing of this technology has confirmed its effectiveness.

  2. PACMan to Help Sort Hubble Proposals

    Science.gov (United States)

    Kohler, Susanna

    2017-04-01

    Every year, astronomers submit over a thousand proposals requesting time on the Hubble Space Telescope (HST). Currently, humans must sort through each of these proposals by hand before sending them off for review. Could this burden be shifted to computers?A Problem of VolumeAstronomer Molly Peeples gathered stats on the HST submissions sent in last week for the upcoming HST Cycle 25 (the deadline was Friday night), relative to previous years. This years proposal round broke the record, with over 1200 proposals submitted in total for Cycle 25. [Molly Peeples]Each proposal cycle for HST time attracts on the order of 1100 proposals accounting for far more HST time than is available. The proposals are therefore carefully reviewed by around 150 international members of the astronomy community during a six-month process to select those with the highest scientific merit.Ideally, each proposal will be read by reviewers that have scientific expertise relevant to the proposal topic: if a proposal requests HST time to study star formation, for instance, then the reviewers assigned to it should have research expertise in star formation.How does this matching of proposals to reviewers occur? The current method relies on self-reported categorization of the submitted proposals. This is unreliable, however; proposals are often mis-categorized by submitters due to misunderstanding or ambiguous cases.As a result, the Science Policies Group at the Space Telescope Science Institute (STScI) which oversees the review of HST proposals must go through each of the proposals by hand and re-categorize them. The proposals are then matched to reviewers with self-declared expertise in the same category.With the number of HST proposals on the rise and the expectation that the upcoming James Webb Space Telescope (JWST) will elicit even more proposals for time than Hubble scientists at STScI and NASA are now asking: could the human hours necessary for this task be spared? Could a computer program

  3. Students' perceptions of motivation in high school biology class: Informing current theories

    Science.gov (United States)

    McManic, Janet A.

    The purpose of this study was to investigate students' perceptions of motivation to achieve while participating in general level high school biology classes. In a national poll of teacher's attitudes, student's motivation was a top concern of teachers (Elam, 1989). The student's perceptions of motivation are important to understand if improvements and advancements in motivation are to be implemented in the science classroom. This qualitative study was conducted in an urban high school that is located in a major metropolitan area in the southeast of the United States. The student body of 1100 is composed of Caucasian, African-American, Hispanic, and Asian students. The focus question of the study was: What are students' perceptions of their motivation in biology class? From general level biology classes, purposeful sampling narrowed the participants to fifteen students. Semi-structured interviews were conducted with the participants having varying measurements of motivation on the Scale of Intrinsic versus Extrinsic Orientation in the Classroom (Harter, 1980). The interviews were recorded and transcribed. After transcription, the interviews were coded by the constant comparative method (Glaser & Strauss, 1967). The coded data of students' responses were analyzed and compared to current theories of motivation. The current theories are the social-cognitive model (Bandura, 1977), attribution theory (Weiner, 1979), basic needs theory (Maslow, 1954) and choice theory (Glasser, 1986). The results of this study support the social cognitive model of motivation (Bandura, 1977) through the description of family structure and its relationship to motivation (Gonzalez, 2002). The study upheld previous research in that extrinsic orientation was shown to be prevalent in older students (Harter, 1981; Anderman & Maehr, 1994). In addition, the students' responses disclosed the difficulties encountered in studying biology. Students expressed the opinion that biology terms are

  4. Students and recorded lectures: survey on current use and demands for higher education

    NARCIS (Netherlands)

    Gorissen, Pierre; Van Bruggen, Jan; Jochems, Wim

    2012-01-01

    Gorissen, P., Van Bruggen, J., & Jochems, W. M. G. (2012). Students and recorded lectures: survey on current use and demands for higher education. Research In Learning Technology, 20(3). doi:10.3402/rlt.v20i0.17299

  5. Covariates of Current Cigarette Smoking among Secondary School Students in Budapest, Hungary, 1999

    Science.gov (United States)

    Easton, Alyssa; Kiss, Eva

    2005-01-01

    To date, few studies have examined the relationship between health behavior risk factors and cigarette smoking in Hungary. From 1995 to 1999, the prevalence of current smoking increased from 35.9 to 46.0% among secondary students in Budapest, Hungary. The objective of the present study was to examine the association between smoking and other…

  6. Tuition Elasticity of the Demand for Higher Education among Current Students: A Pricing Model.

    Science.gov (United States)

    Bryan, Glenn A.; Whipple, Thomas W.

    1995-01-01

    A pricing model is offered, based on retention of current students, that colleges can use to determine appropriate tuition. A computer-based model that quantifies the relationship between tuition elasticity and projected net return to the college was developed and applied to determine an appropriate tuition rate for a small, private liberal arts…

  7. The Vilification of Smokers: Students' Perceptions of Current Smokers, Former Smokers, and Nonsmokers.

    Science.gov (United States)

    Baker, Kathleen; Katona, Chris; Brosh, Joanne; Shull, Mary; Chambliss, Catherine

    Smokers are increasingly stigmatized in our society. Pressures to limit public smoking have mounted, and there is evidence of discrimination against smokers in the workplace. This study examined how current smokers, former smokers, and nonsmokers were differentially characterized by students drawn from a suburban high school and college. Students…

  8. Relationship between Counseling Students' Childhood Memories and Current Negative Self-Evaluations When Receiving Corrective Feedback

    Science.gov (United States)

    Stroud, Daniel; Olguin, David; Marley, Scott

    2016-01-01

    This article entails a study focused on the relationship between counseling students' negative childhood memories of receiving corrective feedback and current negative self-evaluations when receiving similar feedback in counselor education programs. Participants (N = 186) completed the Corrective Feedback Instrument-Revised (CFI-R; Hulse-Killacky…

  9. Construcción de un diagrama de Hubble: Una herramienta para la Enseñanza de la Astronomía

    Directory of Open Access Journals (Sweden)

    Giovanni Cardona Rodriguez

    2016-06-01

    Full Text Available Se presenta una actividad que puede apoyar el trabajo de los docentes que dirigen  clubes de Astronomía y quieren abordar el tema de evolución del Universo, ya que   se  reconstruye  la ley de Hubble  a partir de la construcción de un Diagrama de Hubble con  datos  tomados del Sloan Digital Sky Survey   (SDSS ,  del  cual se obtiene el valor del parámetro de Hubble y se infiere la expansión del Universo. Esta actividad  didáctica permite a los profesores orientar a sus estudiantes por el camino que siguió Hubble  para determinar su ley, en este sentido se exponen algunas implicaciones de aplicación de la misma en el contexto de la formación de profesores de física y de los clubes de Astronomía.  Construction of a Hubble Diagram: A tool for teaching astronomy This article presents the construction and analysis of an activity that can support the work of teachers who run Astronomy clubs and want to address the issue of evolution of the Universe. Here Hubble's law is reconstructed by reproducing a Hubble diagram with Sloan Digital Sky Survey's (SDSS data, from which the Hubble parameter value is obtained and the expansion of the Universe is inferred. This educational activity allows teachers to guide their students along the path followed by Hubble to determine his law. In this sense some implications of applying the latter are discussed in the context of teacher's training in Physics and Astronomy clubs. Construção de um diagrama de Hubble: Uma ferramenta para ensino de astronomía Se apresenta uma actividade que pode apoiar o trabalho dos professores que dirigem clubes de Astronomia e querem abordar a questão da evolução do Universo, como a lei de Hubble é reconstruída a partir da reprodução de um diagrama de Hubble com os dados tomados do Sloan digital Sky Survey (SDSS, é achado o parâmetro de Hubble e inferida a expansão do universo. Esta actividade educativa permite aos professores orientar seus alunos ao

  10. NASA Astrophysics E/PO: A Quarter Century of Discovery and Inspiration with the Hubble Space Telescope

    Science.gov (United States)

    Jirdeh, Hussein; Straughn, Amber; Smith, Denise Anne; Eisenhamer, Bonnie

    2015-08-01

    April 24, 2015 marked the 25th anniversary of the launch of the Hubble Space Telescope. In its quarter-century in orbit, the Hubble Space Telescope has transformed the way we understand the Universe, helped us find our place among the stars, and paved the way to incredible advancements in science and technology.In this presentation, we explain how NASA and ESA, including the Space Telescope Science Institute (STScI) and partners, is using the 25th anniversary of Hubble’s launch as a unique opportunity to communicate to students, educators, and the public the significance of the past quarter-century of discovery with the Hubble Space Telescope. We describe the various programs, resources, and experiences we are utilizing to enhancethe public understanding of Hubble’s many contributions to the scientific world. These include educator professional development opportunities, exhibits, events, traditional and social media, and resources for educators (formal k-12, informal, and higher education). We also highlight how we are capitalizing on Hubble’s cultural popularity to make the scientific connection to NASA’s next Great Observatory, the James Webb Space Telescope.This presentation highlights many of the opportunities by which students, educators, and the public are joining in the anniversary activities, both in-person and online. Find out more at hubble25th.org and follow #Hubble25 on social media.

  11. "HUBBLE, the astronomer, the telescope, the results"

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    The fundamental discoveries made by Edwin Hubble in the first quarter of the last century will be presented. The space telescope bearing his name will be introduced, as well as the strategy put in place by NASA and the European Space Agency for its operation and its maintenance on-orbit. The personal experience of the speaker having participated in two of five servicing mission will be exposed and illustrated by pictures taken on-orbit. Finally, the main results obtained by the orbital observatory will be presented, in particular the ones related to the large scale structure of the Universe and its early history

  12. Hubble Captures Volcanic Eruption Plume From Io

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through the plume and is

  13. Initial Hubble Diagram Results from the Nearby Supernova Factory

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, S. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Aldering, G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Antilogus, P. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Aragon, C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baltay, C. [Yale Univ., New Haven, CT (United States); Bongard, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Buton, C [Inst. of Nuclear Physics of Lyon (France); Childress, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Copin, Y. [Inst. of Nuclear Physics of Lyon (France); Gangler, E. [Inst. of Nuclear Physics of Lyon (France); Loken, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Nugent, P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pain, R. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Pecontal, E. [Center of Research Astrophysics of Lyon (CRAL) (France); Pereira, R. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Perlmutter, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rabinowitz, D. [Yale Univ., New Haven, CT (United States); Rigaudier, G. [Center of Research Astrophysics of Lyon (CRAL) (France); Ripoche, P. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Runge, K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Scalzo, R. [Yale Univ., New Haven, CT (United States); Smadja, G. [Inst. of Nuclear Physics of Lyon (France); Tao, C. [Inst. of Nuclear Physics of Lyon (France); Thomas, R. C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, C. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France)

    2017-07-06

    The use of Type Ia supernovae as distance indicators led to the discovery of the accelerating expansion of the universe a decade ago. Now that large second generation surveys have significantly increased the size and quality of the high-redshift sample, the cosmological constraints are limited by the currently available sample of ~50 cosmologically useful nearby supernovae. The Nearby Supernova Factory addresses this problem by discovering nearby supernovae and observing their spectrophotometric time development. Our data sample includes over 2400 spectra from spectral timeseries of 185 supernovae. This talk presents results from a portion of this sample including a Hubble diagram (relative distance vs. redshift) and a description of some analyses using this rich dataset.

  14. Current Situation of Scientific Research at the University of Jordan from the Viewpoint of Graduate Students

    Directory of Open Access Journals (Sweden)

    Atif Omar Bin Tareef

    2017-05-01

    Full Text Available This study aimed to identify the current status of scientific research at the University of Jordan as perceived by graduate students and the differences between students of science and humanities faculties, and to identify their opinions regarding ways to improve scientific research at the University of Jordan. The study followed a descriptive methodology based on a survey that was developed specifically for the purpose of this study. The survey consisted of 40 items covering 5 themes, and was distributed to a sample of 104 male and female participants representing science and humanities faculties. The data were analyzed, using the two-way ANOVA, the standard deviation and means. In addition, students’ opinions and obstacles to effective participation of graduate students were categorized. The results showed significant differences between students’ assessment of the status of scientific research in science and humanities faculties, which was (3.2 for students in humanities faculties and (2.8 for students in science faculties. The difference also appeared in all the five domains of the scientific research, while there was no presence of gender effect, neither was there effect for the interaction between the variables (gender and the faculty. The study recommended to provide financial support to scientific research, and to establish a refereed scientific Journal for publishing students’ innovative ideas and research projects. Keywords: Scientific research, Graduate students.

  15. Dental Student Academic Integrity in U.S. Dental Schools: Current Status and Recommendations for Enhancement.

    Science.gov (United States)

    Graham, Bruce S; Knight, G William; Graham, Linda

    2016-01-01

    Cheating incidents in 2006-07 led U.S. dental schools to heighten their efforts to enhance the environment of academic integrity in their institutions. The aims of this study were to document the measures being used by U.S. dental schools to discourage student cheating, determine the current incidence of reported cheating, and make recommendations for enhancing a culture of integrity in dental education. In late 2014-early 2015, an online survey was distributed to academic deans of all 61 accredited U.S. dental schools that had four classes of dental students enrolled; 50 (82%) responded. Among measures used, 98% of respondents reported having policy statements regarding student academic integrity, 92% had an Honor Code, 96% provided student orientation to integrity policies, and most used proctoring of final exams (91%) and tests (93%). Regarding disciplinary processes, 27% reported their faculty members only rarely reported suspected cheating (though required in 76% of the schools), and 40% disseminated anonymous results of disciplinary hearings. A smaller number of schools (n=36) responded to the question about student cheating than to other questions; those results suggested that reported cheating had increased almost threefold since 1998. The authors recommend that schools add cheating case scenarios to professional ethics curricula; disseminate outcomes of cheating enforcement actions; have students sign a statement attesting to compliance with academic integrity policies at every testing activity; add curricular content on correct writing techniques to avoid plagiarism; require faculty to distribute retired test items; acquire examination-authoring software programs to enable faculty to generate new multiple-choice items and different versions of the same multiple-choice tests; avoid take-home exams when assessing independent student knowledge; and utilize student assessment methods directly relevant to clinical practice.

  16. Characteristics of gifted and talented student: the current situation in Portugal

    Directory of Open Access Journals (Sweden)

    Leandro Almeida

    2010-04-01

    Full Text Available This article presents the current situation in Portugal with regard to high capability and talented students, focusing on the authors’ experience in the National Association for Study and Intervention in Giftedness (ANEIS. In a sequential argument, we focus on the concept of giftedness, the most specific characteristics of high ability students, and the procedures used in their initial identification and assessment. Also, the most frequent educational responses to these students are described. Finally, we underline some studies conducted as a result of the collaboration between ANEIS and several Portuguese universities. These studies refer to the instruments and procedures used for the assessment of giftedness and talent, and the impact of the implemented educational measures.

  17. Using ASM Podcasts to Excite Undergraduate Students about Current Microbiological Research

    Directory of Open Access Journals (Sweden)

    Stacey E. Lettini

    2014-08-01

    Full Text Available Innovative technology is often used as a mechanism to engage students in and out of the classroom and can be used to increase critical thinking skills. Podcasts are an excellent way to introduce students to current topics and research in microbiology. The American Society for Microbiology (ASM produces three podcasts that are microbiologically focused: This Week in Microbiology (TWiM, This Week in Parasitology (TWiP, and This Week in Virology (TWiV. These podcasts are usually presented in a manner similar to a journal club, as the presenters regularly invite guests to discuss current research papers. Since students often find reading scientific literature difficult and get bogged down in the details rather than seeing the over-arching purpose of a paper, these podcasts have been used in a General Microbiology course to introduce recent research articles. The students were first assigned an original research article to read and review, and they were asked to generate questions pertaining to things they did not understand. Next, students listened to the corresponding podcast that discussed the article and used it to answer their questions. This was followed by a classroom discussion of the article and the podcast. The ASM podcast helped to demystify original research by providing details of the experimental design and presentation of the results in a language that is more casual and relatable. Students demonstrated greater critical thinking and comprehension of microbiology literature after listening to the podcast. This activity can be used in a variety of courses in the biology curriculum.

  18. Improving medical students' knowledge of genetic disease: a review of current and emerging pedagogical practices.

    Science.gov (United States)

    Wolyniak, Michael J; Bemis, Lynne T; Prunuske, Amy J

    2015-01-01

    Genetics is an essential subject to be mastered by health professional students of all types. However, technological advances in genomics and recent pedagogical research have changed the way in which many medical training programs teach genetics to their students. These advances favor a more experience-based education focused primarily on developing student's critical thinking skills. In this review, we examine the current state of genetics education at both the preclinical and clinical levels and the ways in which medical and pedagogical research have guided reforms to current and emerging teaching practices in genetics. We discover exciting trends taking place in which genetics is integrated with other scientific disciplines both horizontally and vertically across medical curricula to emphasize training in scientific critical thinking skills among students via the evaluation of clinical evidence and consultation of online databases. These trends will produce future health professionals with the skills and confidence necessary to embrace the new tools of medical practice that have emerged from scientific advances in genetics, genomics, and bioinformatics.

  19. Improving medical students' knowledge of genetic disease: a review of current and emerging pedagogical practices

    Directory of Open Access Journals (Sweden)

    Wolyniak MJ

    2015-10-01

    Full Text Available Michael J Wolyniak,1 Lynne T Bemis,2 Amy J Prunuske2 1Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA, 2Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, USA Abstract: Genetics is an essential subject to be mastered by health professional students of all types. However, technological advances in genomics and recent pedagogical research have changed the way in which many medical training programs teach genetics to their students. These advances favor a more experience-based education focused primarily on developing student's critical thinking skills. In this review, we examine the current state of genetics education at both the preclinical and clinical levels and the ways in which medical and pedagogical research have guided reforms to current and emerging teaching practices in genetics. We discover exciting trends taking place in which genetics is integrated with other scientific disciplines both horizontally and vertically across medical curricula to emphasize training in scientific critical thinking skills among students via the evaluation of clinical evidence and consultation of online databases. These trends will produce future health professionals with the skills and confidence necessary to embrace the new tools of medical practice that have emerged from scientific advances in genetics, genomics, and bioinformatics. Keywords: genetics education, medical genetics, pedagogical practice, active learning, problem-based learning

  20. Relationship between Childhood Meal Scenes at Home Remembered by University Students and their Current Personality

    OpenAIRE

    恩村, 咲希; Onmura, Saki

    2013-01-01

    This study examines the relationship between childhood meal scenes at home that are remembered by university students and their current personality. The meal scenes are analyzed in terms of companions, conversation content, conversation frequency, atmosphere, and consideration of meals. The scale of the conversation content in childhood meal scenes was prepared on the basis of the results of a preliminary survey. The result showed that a relationship was found between personality traits and c...

  1. The Prevalence of Substance Use among Bandar Abas Azad Islamic University Students

    Directory of Open Access Journals (Sweden)

    Hamid Mardani

    2012-11-01

    Full Text Available Aim: Substance abuse is one of the most important problem and disease in current century that produced wide worry in the entire world. The solving of addiction among young and educated population is more important issue. The current research was aimed the study of the prevalence rate of the substance use (included: opium, alcohol, cigarette, Hubble bubble among Bandar Abas azad Islamic university students. Method: In this cross sectional study 310 university students were selected by stratified random sampling. For gathering data the prevalence substance use questionnaire was used. Results: The findings showed the start age was 22-25 years old. Also, prevalence rate of cigarette, Hubble bubble, opium, and alcohol were higher in boy students in comparison of girl students. The rate of difference was significant by run of chi square analysis. Conclusion: Sex, the history of substance use in family member, and friends were risk factors of substance use.

  2. Topics in Current Science Research: Closing the Achievement Gap for Under Resourced Students of Color

    Science.gov (United States)

    Loya Villalpando, Alvaro; Daal, Miguel; Phipps, Arran; Speller, Danielle; Sadoulet, Bernard; Winheld, Rachel; Cryogenic Dark Matter Search Collaboration

    2015-04-01

    Topics in Current Science Research (TCSR) is a five-week summer course offered at the University of California, Berkeley through a collaboration between the Level Playing Field Institute's Summer Math and Science Honors Academy (SMASH) Program and the Cryogenic Dark Matter Search (CDMS) group at UC Berkeley. SMASH is an academic enrichment program geared towards under-resourced, high school students of color. The goals of the course are to expand the students' conception of STEM, to teach the students that science is a method of inquiry and not just a collection of facts that are taught in school, and to expose the scholars to critical thinking within a scientific setting. The course's curriculum engages the scholars in hands-on scientific research, project proposal writing, and presentation of their scientific work to their peers as well as to a panel of UC Berkeley scientists. In this talk, we describe the course and the impact it has had on previous scholars, we discuss how the course's pedagogy has evolved over the past 10 years to enhance students' perception and understanding of science, and we present previous participants' reflections and feedback about the course and its success in providing high school students a genuine research experience at the university level.

  3. Hubble peers inside a celestial geode

    Science.gov (United States)

    2004-08-01

    celestial geode hi-res Size hi-res: 148 Kb Credits: ESA/NASA, Yäel Nazé (University of Liège, Belgium) and You-Hua Chu (University of Illinois, Urbana, USA) Hubble peers inside a celestial geode In this unusual image, the NASA/ESA Hubble Space Telescope captures a rare view of the celestial equivalent of a geode - a gas cavity carved by the stellar wind and intense ultraviolet radiation from a young hot star. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. Low resolution version (JPG format) 148 Kb High resolution version (TIFF format) 1929 Kb Acknowledgment: This image was created with the help of the ESA/ESO/NASA Photoshop FITS Liberator. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. The object, called N44F, is being inflated by a torrent of fast-moving particles (what astronomers call a 'stellar wind') from an exceptionally hot star (the bright star just below the centre of the bubble) once buried inside a cold dense cloud. Compared with our Sun (which is losing mass through the so-called 'solar wind'), the central star in N44F is ejecting more than a 100 million times more mass per second and the hurricane of particles moves much faster at 7 million km per hour

  4. The Current Mental State of School Students in Online Learning Conditions

    Directory of Open Access Journals (Sweden)

    Kovalevskaya E.V.,

    2015-08-01

    Full Text Available This article discusses the results of a study of actual mental state of high school students who are active subjects of career self-determination in terms of interactive learning. There are four groups of methods of interactive training: psychological training, art therapy, cognitive, and game training. The main task, which is solved by a researcher in a formative experiment with the use of each of these methods, is to establish significant differences in health, activity and mood as the indicators of current mental state of students in the classroom. As a result, we found that the most significant improvements in the current mental state takes place when using art and game therapy, so these techniques should be used in groups of students with low motivation to work, as well as in the adverse psychological climate. Less significant was the improvement of the current mental state after psychological training due to the fact that this method allow to update and seek solutions to the most important intrapersonal issues and require the implementation of a deeper reflection

  5. Eyes on the Universe: The Legacy of the Hubble Space Telescope and Looking to the Future with the James Webb Space Telescope

    Science.gov (United States)

    Straughn, Amber

    2011-01-01

    Over the past 20 years the Hubble Space Telescope has revolutionized our understanding of the Universe. Most recently, the complete refurbishment of Hubble in 2009 has given new life to the telescope and the new science instruments have already produced groundbreaking science results, revealing some of the most distant galaxy candidates ever discovered. Despite the remarkable advances in astrophysics that Hubble has provided, the new questions that have arisen demand a new space telescope with new technologies and capabilities. I will present the exciting new technology development and science goals of NASA's James Webb Space Telescope, which is currently being built and tested and will be launched this decade.

  6. Hubble Space Telescope: The Telescope, the Observations & the Servicing Mission

    Science.gov (United States)

    1999-11-01

    NICMOS enabling it to resume operation, and install a new set of solar panels. Replacement of the thermal insulation will continue and the telescope will be reboosted to a higher orbit. The plans for the fourth Servicing Mission are preliminary at this time, but two new science instruments are being developed for that mission: Cosmic Origins Spectrograph (COS), which will replace COSTAR, and Wide Field Camera 3 (WFC3), which will replace WFPC2. It is planned to retrieve Hubble at the end of its life (around 2010) and bring it back to Earth. In the future ESA may have the opportunity to continue its collaboration with NASA on the Next Generation Space Telescope (NGST), which in many ways can be seen as Hubble's successor. The plan is to launch NGST in 2008, and ESA is currently considering a possible role in the project. Piero Benvenuti concludes: "The European Space Agency, in deciding to join NASA on the HST Project, made a very successful investment on behalf of European science. Today, NASA would not consider proceeding alone on the continued operation of HST or on the design of NGST. Not just because of the benefit of shared cost, but mainly because of the intellectual contribution by the European astronomers, who have made such effective scientific use of HST." Hubble Space Telescope - Fact sheet Description The Hubble Space Telescope (HST) is a co-operation between ESA and NASA. It is a long-term space-based observatory. Its observations are carried out in visible, infrared and ultraviolet light. HST has in many ways revolutionised modern astronomy, being a highly efficient tool for making new discoveries, but also by driving astronomical research in general. Objective HST was designed to take advantage of being above the Earth's disturbing atmosphere, and thereby providing astronomers with observations of very high resolution - opening new windows on planets, stars and galaxies. HST was designed as a flagship mission of the highest standard, and has served to pave

  7. The Hubble Constant from SN Refsdal

    Science.gov (United States)

    Vega-Ferrero, J.; Diego, J. M.; Miranda, V.; Bernstein, G. M.

    2018-02-01

    Hubble Space Telescope observations from 2015 December 11 detected the expected fifth counter-image of supernova (SN) Refsdal at z = 1.49. In this Letter, we compare the time-delay predictions from numerous models with the measured value derived by Kelly et al. from very early data in the light curve of the SN Refsdal and find a best value for {H}0={64}-11+9 {km} {{{s}}}-1 {{Mpc}}-1 (68% CL), in excellent agreement with predictions from cosmic microwave background and recent weak lensing data + baryon acoustic oscillations + Big Bang nucleosynthesis (from the DES Collaboration). This is the first constraint on H 0 derived from time delays between multiple-lensed SN images, and the first with a galaxy cluster lens, subject to systematic effects different from other time-delay H 0 estimates. Additional time-delay measurements from new multiply imaged SNe will allow derivation of competitive constraints on H 0.

  8. Automation of Hubble Space Telescope Mission Operations

    Science.gov (United States)

    Burley, Richard; Goulet, Gregory; Slater, Mark; Huey, William; Bassford, Lynn; Dunham, Larry

    2012-01-01

    On June 13, 2011, after more than 21 years, 115 thousand orbits, and nearly 1 million exposures taken, the operation of the Hubble Space Telescope successfully transitioned from 24x7x365 staffing to 815 staffing. This required the automation of routine mission operations including telemetry and forward link acquisition, data dumping and solid-state recorder management, stored command loading, and health and safety monitoring of both the observatory and the HST Ground System. These changes were driven by budget reductions, and required ground system and onboard spacecraft enhancements across the entire operations spectrum, from planning and scheduling systems to payload flight software. Changes in personnel and staffing were required in order to adapt to the new roles and responsibilities required in the new automated operations era. This paper will provide a high level overview of the obstacles to automating nominal HST mission operations, both technical and cultural, and how those obstacles were overcome.

  9. Current drinking and health-risk behaviors among male high school students in central Thailand

    Directory of Open Access Journals (Sweden)

    Pichainarong Natchaporn

    2011-04-01

    Full Text Available Abstract Background Alcohol drinking is frequently related to behavioral problems, which lead to a number of negative consequences. This study was to evaluate the characteristics of male high school students who drink, the drinking patterns among them, and the associations between current drinking and other health risk behaviors which focused on personal safety, violence-related behaviors, suicide and sexual behaviors. Method A cross-sectional study was conducted to explore current alcohol drinking and health-risk behaviors among male high school students in central Thailand. Five thousand one hundred and eighty four male students were classified into 2 groups according to drinking in the previous 30 days (yes = 631, no = 4,553. Data were collected by self-administered, anonymous questionnaire which consisted of 3 parts: socio-demographic factors, health-risk behaviors and alcohol drinking behavior during the past year from December 2007 to February 2008. Results The results showed that the percent of current drinking was 12.17. Most of them were 15-17 years (50.21%. Socio-demographic factors such as age, educational level, residence, cohabitants, grade point average (GPA, having a part time job and having family members with alcohol/drug problems were significantly associated with alcohol drinking (p Conclusions An increased risk of health-risk behaviors, including driving vehicles after drinking, violence-related behaviors, sad feelings and attempted suicide, and sexual behaviors was higher among drinking students that led to significant health problems. Effective intervention strategies (such as a campaign mentioning the adverse health effects and social consequences to the risk groups, and encouraging parental and community efforts to prevent drinking among adolescents should be implemented to prevent underage drinking and adverse consequences.

  10. Solar system anomalies: Revisiting Hubble's law

    Science.gov (United States)

    Plamondon, R.

    2017-12-01

    This paper investigates the impact of a new metric recently published [R. Plamondon and C. Ouellet-Plamondon, in On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, edited by K. Rosquist, R. T. Jantzen, and R. Ruffini (World Scientific, Singapore, 2015), p. 1301] for studying the space-time geometry of a static symmetric massive object. This metric depends on a complementary error function (erfc) potential that characterizes the emergent gravitation field predicted by the model. This results in two types of deviations as compared to computations made on the basis of a Newtonian potential: a constant and a radial outcome. One key feature of the metric is that it postulates the existence of an intrinsic physical constant σ , the massive object-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we use a heuristic to estimate its value and point out some latent relationships between the Hubble constant, the secular increase in the astronomical unit, and the Pioneers delay. Indeed, highlighting the systematic errors that emerge when the effect of σ is neglected, one can link the Hubble constant H 0 to σ Sun and the secular increase V AU to σ Earth . The accuracy of the resulting numerical predictions, H 0 = 74 . 42 ( 0 . 02 ) ( km / s ) / Mpc and V AU ≅ 7.8 cm yr-1 , calls for more investigations of this new metric by specific experts. Moreover, we investigate the expected impacts of the new metric on the flyby anomalies, and we revisit the Pioneers delay. It is shown that both phenomena could be partly taken into account within the context of this unifying paradigm, with quite accurate numerical predictions. A correction for the osculating asymptotic velocity at the perigee of the order of 10 mm/s and an inward radial acceleration of 8 . 34 × 10 - 10 m / s 2 affecting the Pioneer ! space crafts could be explained by this new model.

  11. Neural and psychological characteristics of college students with alcoholic parents differ depending on current alcohol use.

    Science.gov (United States)

    Brown-Rice, Kathleen A; Scholl, Jamie L; Fercho, Kelene A; Pearson, Kami; Kallsen, Noah A; Davies, Gareth E; Ehli, Erik A; Olson, Seth; Schweinle, Amy; Baugh, Lee A; Forster, Gina L

    2018-02-02

    A significant proportion of college students are adult children of an alcoholic parent (ACoA), which can confer greater risk of depression, poor self-esteem, alcohol and drug problems, and greater levels of college attrition. However, some ACoA are resilient to these negative outcomes. The goal of this study was to better understand the psychobiological factors that distinguish resilient and vulnerable college-aged ACoAs. To do so, scholastic performance and psychological health were measured in ACoA college students not engaged in hazardous alcohol use (resilient) and those currently engaged in hazardous alcohol use (vulnerable). Neural activity (as measured by functional magnetic resonance imaging) in response to performing working memory and emotion-based tasks were assessed. Furthermore, the frequency of polymorphisms in candidate genes associated with substance use, risk taking and stress reactivity were compared between the two ACoA groups. College ACoAs currently engaged in hazardous alcohol use reported more anxiety, depression and posttraumatic stress symptoms, and increased risky nicotine and marijuana use as compared to ACoAs resistant to problem alcohol use. ACoA college students with current problem alcohol showed greater activity of the middle frontal gyrus and reduced activation of the posterior cingulate in response to visual working memory and emotional processing tasks, which may relate to increased anxiety and problem alcohol and drug behaviors. Furthermore, polymorphisms of cholinergic receptor and the serotonin transporter genes also appear to contribute a role in problem alcohol use in ACoAs. Overall, findings point to several important psychobiological variables that distinguish ACoAs based on their current alcohol use that may be used in the future for early intervention. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Universities with multicultural disrupted past: what meanings current students attribute to them?

    Directory of Open Access Journals (Sweden)

    Olena Dobosh

    2016-09-01

    Full Text Available The changing of pre-war borders of Central and Eastern Europe after WW II caused not only belonging of certain territories to definite countries but also the massive forced relocation of population from those territories. The total change of the population in the multicultural cities affected also institutions, such as universities by changing their staff, language, and national profile. Nowadays, when modern universities are facing post-modernity challenges it is extremely difficult to talk about role, mission, and meaning of this institution, especially in the context of disrupted historical tradition. Look at the problem from the different perspective, from inside will show the tendencies of meanings current students of the universities with long but disrupted historical past attribute to their Alma maters. Are they aware of the presence of representatives of different national groups that created university community before WW II? This article will present results of three studies conducted at three universities that changed their national profile after WWII: Vilnius University in Lithuania (formerly a Polish university, Lviv University in Ukraine (formerly a Polish university and Wrocław University in Poland (formerly a German university. Both at Vilnius University and Lviv Universiy 150 university students participated in the study. At Wrocław University 152 university students participated in the study. The present analysis will try to explore the variety of meanings current students of those three universities attribute to their place of study. It will try to show if current students are aware of the university’s complex history and, if they include/exclude historical meanings connected with representatives of the different national group? Also, it will look at the possible differences between meaning attribution and perception of the university past among representatives of these three universities. Lviv, Wrocław, and Vilnius

  13. THE CHALLENGE OF KEEPING-UP: CURRENT METHODOLOGIES IN ANALYZING THE STUDENTS RECRUITING AREA BY UNIVERSITIES

    Directory of Open Access Journals (Sweden)

    MĂLĂESCU SIMONA

    2013-11-01

    Full Text Available The challenge of keeping-up: current methodologies in analyzing the students recruiting area by universities. Despite all progress made in the field and in some collateral areas extremely useful methodologically (e.g. the use of GIS, for some countries emerging from communist space methodologically upgrading to the latest advances in modelling and forecast of students recruitment by universities remains a difficult challenge. The analysis and modelling of the geographical area of recruiting students for a particular university represents even for the foreign literature a niche, not necessarily consciously neglected but only reached sidely due, most likely, to ignoring the benefits which the focus of concerns on this aspect would bring into focus and directing more efficiently university marketing efforts. This paper aims precisely to seek, through a meta-analysis of existing literature, disparate developments that led in some form or will allow improved modeling spatial areas of recruitment of students by universities and the challenges and limitations that apply methodological advances the area where universities belonging to the ex-communist involved. Beyond the theoretical benefit from a practical perspective, the meta-analysis aimed at synthesizing elements of good practice that can be applied to the local university system.

  14. Impact of current video game playing on robotic simulation skills among medical students.

    Science.gov (United States)

    Öge, Tufan; Borahay, Mostafa A; Achjian, Tamar; Kılıç, Sami Gökhan

    2015-01-01

    To evaluate the impact of current and prior video game playing on initial robotic simulation skill acquisition. This cross-sectional descriptive study (Canadian Task Force Classification II-1) was conducted at a medical university training center. The study subjects were medical students who currently played video games (Group I) and those who had not played video games in the last 2 years (Group II). The robotic skills of both groups were assessed using simulation. Twenty-two students enrolled in this study; however, only 21 completed it. The median age of the participants was 23 (22-24) years and 24 (23-26) years in Groups I and II, respectively. Among the participants, 15 (71.4%) were male and 6 (28.5%) were female, and 90.4% of the students started playing video games in primary school. When the 2 groups were compared according to the completion time of each exercise, Group I finished more quickly than Group II in the Peg Board-1 exercise (p>0.05), whereas Group II had better results in 3 exercises including Pick and Place, Ring and Rail, and Thread the Rings-1. However, none of the differences were found to be statistically significant (p>.05), and according to the overall scores based on the time to complete exercises, economy of motion, instrument collision, use of excessive instrument force, instruments out of view, and master workspace range, the scores were not statistically different between Groups I and II (p>.05). According to the basic robotic simulation exercise results, there was no difference between medical students who used to play video games and those who still played video games. Studies evaluating baseline visuospatial skills with larger sample sizes are needed.

  15. Current provision of rheumatology education for undergraduate nursing, occupational therapy and physiotherapy students in the UK.

    Science.gov (United States)

    Almeida, C; Clarke, B; O'Brien, A; Hammond, A; Ryan, S; Kay, L; Hewlett, S

    2006-07-01

    Rheumatological conditions are common and all health professionals (HPs) therefore need sufficient knowledge and skills to manage patients safely and effectively. The aim of this study was to examine current undergraduate education in rheumatology for HPs in the UK. A questionnaire was sent to curriculum organizers and clinical placement officers for all undergraduate courses in adult nursing, occupational therapy (OT) and physiotherapy (PT) in the UK to ascertain the nature and amount of rheumatology theory and clinical exposure provided. Of the 47 adult nursing, 26 OT and 30 PT undergraduate courses surveyed, 85-90% responded. Overall, rheumatology teaching is 5-10 h over 3 yr. Nursing students receive moderate/in-depth teaching on rheumatoid arthritis (RA) in only 52% of courses (OT 91%, PT 96%) and on osteoarthritis (OA) in 63% (OT 91%, PT 92%). Clinical experience of RA is probably/definitely available in only 56% of nursing courses (OT 72%, PT 88%), with similar results in OA. Overall, nursing students receive the least rheumatology exposure, particularly in psychosocial issues and symptom management, while PT students receive the most. OT students have limited opportunities for clinical exposure to psychosocial and joint protection issues. Use of local rheumatology clinical HP experts is variable (18-93%) and cross-disciplinary exposure is limited (0-36%). Many educators consider their rheumatology training to be insufficient (nursing 50%, PT 42%, OT 24%). Rheumatology training for undergraduate HPs is limited in key areas and often fails to take advantage of local clinical expertise, with nursing students particularly restricted. Clinical HP experts should consider novel methods of addressing these shortfalls within the limited curriculum time available.

  16. HUBBLE CAPTURES THE HEART OF STAR BIRTH

    Science.gov (United States)

    2002-01-01

    NASA Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has captured a flurry of star birth near the heart of the barred spiral galaxy NGC 1808. On the left are two images, one superimposed over the other. The black-and-white picture is a ground-based view of the entire galaxy. The color inset image, taken with the Hubble telescope's Wide Field and Planetary Camera 2 (WFPC2), provides a close-up view of the galaxy's center, the hotbed of vigorous star formation. The ground-based image shows that the galaxy has an unusual, warped shape. Most spiral galaxies are flat disks, but this one has curls of dust and gas at its outer spiral arms (upper right-hand corner and lower left-hand corner). This peculiar shape is evidence that NGC 1808 may have had a close interaction with another nearby galaxy, NGC 1792, which is not in the picture Such an interaction could have hurled gas towards the nucleus of NGC 1808, triggering the exceptionally high rate of star birth seen in the WFPC2 inset image. The WFPC2 inset picture is a composite of images using colored filters that isolate red and infrared light as well as light from glowing hydrogen. The red and infrared light (seen as yellow) highlight older stars, while hydrogen (seen as blue) reveals areas of star birth. Colors were assigned to this false-color image to emphasize the vigorous star formation taking place around the galaxy's center. NGC 1808 is called a barred spiral galaxy because of the straight lines of star formation on both sides of the bright nucleus. This star formation may have been triggered by the rotation of the bar, or by matter which is streaming along the bar towards the central region (and feeding the star burst). Filaments of dust are being ejected from the core into a faint halo of stars surrounding the galaxy's disk (towards the upper left corner) by massive stars that have exploded as supernovae in the star burst region. The portion of the galaxy seen in this 'wide-field' image is

  17. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    "We are beginning to understand that because of these observations we are going to have to change the way we look at the Universe," said ESA's Dr Duccio Macchetto, Associate Director for Science Programs at the Space Telescope Science Institute (STScI), Baltimore, Maryland, USA. The European Space Agency plays a major role in the Hubble Space Telescope programme. The Agency provided one of the telescope's four major instruments, called the Faint Object Camera, and two sets of electricity-generating solar arrays. In addition, 15 ESA scientific and technical staff work at the STScI. In return for this contribution, European astronomers are entitled to 15 percent of the telescope's observing time, although currently they account for 20 percent of all observations. "This is a testimony to the quality of the European science community", said Dr Roger Bonnet, Director of Science at ESA. "We are only guaranteed 15 percent of the telescope's use, but consistently receive much more than that." Astronomers from universities, observatories and research institutes across Europe lead more than 60 investigations planned for the telescope's fifth observing cycle, which begins this summer. Many more Europeans contribute to teams led by other astronomers. Looking back to the very start of time European astronomer Dr Peter Jakobsen used ESA's Faint Object Camera to confirm that helium was present in the early Universe. Astronomers had long predicted that 90 percent of the newly born Universe consisted of hydrogen, with helium making up the remainder. Before the refurbished Hubble came along, it was easy to detect the hydrogen, but the primordial helium remained elusive. The ultraviolet capabilities of the telescope, combined with the improvement in spatial resolution following the repair, made it possible for Dr Jakobsen to obtain an image of a quasar close to the edge of the known Universe. A spectral analysis of this picture revealed the quasar's light, which took 13 billion years

  18. A Unique test for Hubble's new Solar Arrays

    Science.gov (United States)

    2000-10-01

    In mid-October, a team from the European Space Agency (ESA) and NASA will perform a difficult, never-before-done test on one of the Hubble Space Telescope's new solar array panels. Two of these panels, or arrays, will be installed by astronauts in November 2001, when the Space Shuttle Columbia visits Hubble on a routine service mission. The test will ensure that the new arrays are solid and vibration free before they are installed on orbit. The test will be conducted at ESA's European Space Research and Technology Center (ESTEC) in Noordwijk, The Netherlands. Because of the array's size, the facility's special features, and ESA's longstanding experience with Hubble's solar arrays, ESTEC is the only place in the world the test can be performed. This test is the latest chapter in a longstanding partnership between ESA and NASA on the Hubble Space Telescope. The Large Space Simulator at ESTEC, ESA's world-class test facility, features a huge vacuum chamber containing a bank of extremely bright lights that simulate the Sun's intensity - including sunrise and sunset. By exposing the solar wing to the light and temperature extremes of Hubble's orbit, engineers can verify how the new set of arrays will act in space. Hubble orbits the Earth once every 90 minutes. During each orbit, the telescope experiences 45 minutes of searing sunlight and 45 minutes of frigid darkness. This test will detect any tiny vibrations, or jitters, caused by these dramatic, repeated changes. Even a small amount of jitter can affect Hubble's sensitive instruments and interfere with observations. Hubble's first set of solar arrays experienced mild jitter and was replaced in 1993 with a much more stable pair. Since that time, advances in solar cell technology have led to the development of even more efficient arrays. In 2001, NASA will take advantage of these improvements, by fitting Hubble with a third-generation set of arrays. Though smaller, this new set generates more power than the previous

  19. The Hubble Legacy Archive ACS grism data

    Science.gov (United States)

    Kümmel, M.; Rosati, P.; Fosbury, R.; Haase, J.; Hook, R. N.; Kuntschner, H.; Lombardi, M.; Micol, A.; Nilsson, K. K.; Stoehr, F.; Walsh, J. R.

    2011-06-01

    A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55-1.00 μm, with a dispersion of 40 Å/pixel and a resolution of ~80 Å for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73,581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47 919 datasets (65% of the total number of extracted spectra) for 32 149 unique objects, with a median iAB-band magnitude of 23.7, reaching 26.5 AB for the faintest objects. Each released dataset contains science-ready 1D and 2D spectra, as well as multi-band image cutouts of corresponding sources and a useful preview page summarising the direct and slitless data, astrometric and photometric parameters. This release is part of the continuing effort to enhance the content of the Hubble Legacy Archive (HLA) with highly processed data products which significantly facilitate the scientific exploitation of the Hubble data. In order to characterize the slitless spectra, emission-line flux and equivalent width sensitivity of the ACS data were compared with public ground-based spectra in the GOODS-South field. An example list of emission line galaxies with two or more identified lines is also included, covering the redshift range 0.2 - 4.6. Almost all redshift determinations outside of the GOODS fields are new. The scope of science projects

  20. The Hubble Space Telescope: UV, Visible, and Near-Infrared Pursuits

    Science.gov (United States)

    Wiseman, Jennifer

    2010-01-01

    The Hubble Space Telescope continues to push the limits on world-class astrophysics. Cameras including the Advanced Camera for Surveys and the new panchromatic Wide Field Camera 3 which was installed nu last year's successful servicing mission S2N4,o{fer imaging from near-infrared through ultraviolet wavelengths. Spectroscopic studies of sources from black holes to exoplanet atmospheres are making great advances through the versatile use of STIS, the Space Telescope Imaging Spectrograph. The new Cosmic Origins Spectrograph, also installed last year, is the most sensitive UV spectrograph to fly io space and is uniquely suited to address particular scientific questions on galaxy halos, the intergalactic medium, and the cosmic web. With these outstanding capabilities on HST come complex needs for laboratory astrophysics support including atomic and line identification data. I will provide an overview of Hubble's current capabilities and the scientific programs and goals that particularly benefit from the studies of laboratory astrophysics.

  1. Hubble induced mass after inflation in spectator field models

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Tomohiro [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA 94306 (United States); Harigaya, Keisuke, E-mail: tomofuji@stanford.edu, E-mail: keisukeh@icrr.u-tokyo.ac.jp [Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2016-12-01

    Spectator field models such as the curvaton scenario and the modulated reheating are attractive scenarios for the generation of the cosmic curvature perturbation, as the constraints on inflation models are relaxed. In this paper, we discuss the effect of Hubble induced masses on the dynamics of spectator fields after inflation. We pay particular attention to the Hubble induced mass by the kinetic energy of an oscillating inflaton, which is generically unsuppressed but often overlooked. In the curvaton scenario, the Hubble induced mass relaxes the constraint on the property of the inflaton and the curvaton, such as the reheating temperature and the inflation scale. We comment on the implication of our discussion for baryogenesis in the curvaton scenario. In the modulated reheating, the predictions of models e.g. the non-gaussianity can be considerably altered. Furthermore, we propose a new model of the modulated reheating utilizing the Hubble induced mass which realizes a wide range of the local non-gaussianity parameter.

  2. Hubble Space Telescope: Should NASA Proceed with a Servicing Mission?

    National Research Council Canada - National Science Library

    Morgan, Daniel

    2006-01-01

    The National Aeronautics and Space Administration (NASA) estimates that without a servicing mission to replace key components, the Hubble Space Telescope will cease scientific operations in 2008 instead of 2010...

  3. Hubble Space Telescope, Faint Object Camera

    Science.gov (United States)

    1981-01-01

    This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  4. UV/Visible Telescope with Hubble Disposal

    Science.gov (United States)

    Benford, Dominic J.

    2013-01-01

    Submission Overview: Our primary objective is to convey a sense of the significant advances possible in astrophysics investigations for major Cosmic Origins COR program goals with a 2.4m telescope asset outfitted with one or more advanced UV visible instruments. Several compelling science objectives were identified based on community meetings these science objectives drove the conceptual design of instruments studied by the COR Program Office during July September 2012. This RFI submission encapsulates the results of that study, and suggests that a more detailed look into the instrument suite should be conducted to prove viability and affordability to support the demonstrated scientific value. This study was conducted in the context of a larger effort to consider the options available for a mission to dispose safely of Hubble hence, the overall architecture considered for the mission we studied for the 2.4m telescope asset included resource sharing. This mitigates combined cost and risk and provides naturally for a continued US leadership role in astrophysics with an advanced, general-purpose UV visible space telescope.

  5. Price of shifting the Hubble constant

    Science.gov (United States)

    Evslin, Jarah; Sen, Anjan A.; Ruchika

    2018-05-01

    An anisotropic measurement of the baryon acoustic oscillation (BAO) feature fixes the product of the Hubble constant and the acoustic scale H0rd. Therefore, regardless of the dark energy dynamics, to accommodate a higher value of H0 one needs a lower rd and so necessarily a modification of early time cosmology. One must either reduce the age of the Universe at the drag epoch or else the speed of sound in the primordial plasma. The first can be achieved, for example, with dark radiation or very early dark energy, automatically preserving the angular size of the acoustic scale in the cosmic microwave background (CMB) with no modifications to post-recombination dark energy. However, it is known that the simplest such modifications fall afoul of CMB constraints at higher multipoles. As an example, we combine anisotropic BAO with geometric measurements from strong lensing time delays from H0LiCOW and megamasers from the Megamaser Cosmology Project to measure rd, with and without the local distance ladder measurement of H0. We find that the best fit value of rd is indeed quite insensitive to the dark energy model and is also hardly affected by the inclusion of the local distance ladder data.

  6. Planetary nebulae: 20 years of Hubble inquiry

    Science.gov (United States)

    Balick, Bruce

    2012-08-01

    The Hubble Space Telescope has served the critical roles of microscope and movie camera in the past 20 years of research on planetary nebulae (``PNe''). We have glimpsed the details of the evolving structures of neutral and ionized post-AGB objects, built ingenious heuristic models that mimic these structures, and constrained most of the relevant physical processes with careful observations and interpretation. We have searched for close physical binary stars with spatial resolution ~50 AU at 1 AU, located jets emerging from the nucleus at speeds up to 2000 km s-1 and matched newly discovered molecular and X-ray emission regions to physical substructures in order to better understand how stellar winds and ionizing radiation interact to form the lovely symmetries that are observed. Ultraviolet spectra of CNO in PNe help to uncover how stars process deep inside AGB stars with unstable nuclear burning zones. HST broadband imaging has been at the forefront of uncovering surprisingly complex wind morphologies produced at the tip of the AGB, and has led to an increasing realization of the potentially vital roles of close binary stars and emerging magnetic fields in shaping stellar winds.

  7. Development of alternating current circuit simulation as essential learning support for senior high school student

    Directory of Open Access Journals (Sweden)

    Mayang Dwinta Trisniarti

    2017-02-01

    Full Text Available In this study an interactive simulation of Alternating Current circuit was developed by using Articulate Storyline 2 and Adobe Flash CS 6 programs. The aim of this study was providing a computer interactive simulation as essential learning support for Senior High School student. One of the most important features of AC circuit simulation is the easily and continuous material to attain learning objectivity and interest toward students. This AC circuit simulation is built to create real-time sine wave graphs so that student could compare the result if the variable were changed gradually. The validation is held through several experts and reviewers due to get obtained through questionnaires. The results of this research could be concluded that AC circuit simulation for Senior High School Physics have good criteria based on user interface, i.e. 50% of respondents rated enough, 16.67% of respondents rated good, and 33.33% of respondents rated very good. Based on maintenance, i.e. 50% of respondents rated enough, 20% of respondents rated good, and 30% of respondents rated very good. Then based on usability, i.e. 6.67% of respondents rated good and 93.33% rated very good. Furthermore, based on understanding, i.e. 6.67% of respondents rated enough, 30% of respondents rated good, and 73.33% of respondents rated very good. The use of AC circuit simulation could improve the senior high school students’ cognitive ability on the Physics’s course, i.e. with the average score increased from 68.67 to 80.5 based on 30 students.

  8. Life satisfaction, health, self-evaluation and sexuality in current university students of sport sciences, education and natural sciences

    Directory of Open Access Journals (Sweden)

    Martin Sigmund

    2014-12-01

    Full Text Available Background: Lifestyle and health of an individual are influenced by many factors; a significant factor is life satisfaction. Life satisfaction is understood as a multidimensional construct closely related to the area of personal wellbeing and quality of life. Life satisfaction in university students represents one of the determinants of good health, high motivation for studying, work productivity, satisfactory interpersonal relationships and overall healthy lifestyle. Objective: The main objective of the present study is to identify and compare the level of overall life satisfaction and selected components of health, self-evaluation and sexuality in current university students with respect to their study specialization. Methods: The study included a total of 522 students from Palacký University. These were students from the Faculty of Physical Culture (n = 118, Faculty of Education (n = 218 and Faculty of Science (n = 186. In terms of age, the study focused on young adults aged 19 to 26. To assess the current level of life satisfaction, the research study used a standardized psychodiagnostic tool - Life Satisfaction Questionnaire (LSQ. The used diagnostic methods are fully standardized and contain domestic normative values. Statistical result processing was conducted using the Statistica programme v10.0. Results: The highest level of overall life satisfaction was revealed in university students of sport sciences. In comparison with the students of education and students of natural sciences the difference is significant. Satisfaction with health among the students of sport sciences is significantly higher than in the students of education (p ≤ .001; d = 0.53 and the students of natural sciences (p ≤ .05; d = 0.38. Similar results were found in the area of satisfaction with own person and self-evaluation, where the values of the students of sport sciences were significantly higher compared with the students of education (p

  9. Current and Future School Psychologists' Preparedness to Work with LGBT Students: Role of Education and Gay-Straight Alliances

    Science.gov (United States)

    Arora, Prerna G.; Kelly, Jennifer; Goldstein, Thalia R.

    2016-01-01

    This study sought to assess current and future school psychologists' attitudes toward and preparedness to address the needs of lesbian, gay, bisexual, and transgender (LGBT) students in schools. Two-hundred seventy-nine school psychologists (n = 162, 58%) and school psychology graduate students (n = 117, 42%) were included in the study.…

  10. Replacement vs. Renovation: The Reincarnation of Hubble Middle School

    Science.gov (United States)

    Ogurek, Douglas J.

    2010-01-01

    At the original Hubble Middle School, neither the views (a congested Roosevelt Road and glimpses of downtown Wheaton) nor the century-old facility that offered them was very inspiring. Built at the start of the 20th century, the 250,000-square-foot building was converted from Wheaton Central High School to Hubble Middle School in the early 1980s.…

  11. THE 2012 HUBBLE ULTRA DEEP FIELD (UDF12): OBSERVATIONAL OVERVIEW

    Energy Technology Data Exchange (ETDEWEB)

    Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ellis, Richard S.; Schenker, Matthew A. [Department of Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); McLure, Ross J.; Dunlop, James S.; Bowler, Rebecca A. A.; Rogers, Alexander B.; Curtis-Lake, Emma; Cirasuolo, Michele; Wild, V.; Targett, T. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Robertson, Brant E.; Schneider, Evan; Stark, Daniel P. [Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Ono, Yoshiaki; Ouchi, Masami [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa City, Chiba 277-8582 (Japan); Charlot, Stephane [UPMC-CNRS, UMR7095, Institut d' Astrophysique de Paris, F-75014, Paris (France); Furlanetto, Steven R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2013-11-01

    We present the 2012 Hubble Ultra Deep Field campaign (UDF12), a large 128 orbit Cycle 19 Hubble Space Telescope program aimed at extending previous Wide Field Camera 3 (WFC3)/IR observations of the UDF by quadrupling the exposure time in the F105W filter, imaging in an additional F140W filter, and extending the F160W exposure time by 50%, as well as adding an extremely deep parallel field with the Advanced Camera for Surveys (ACS) in the F814W filter with a total exposure time of 128 orbits. The principal scientific goal of this project is to determine whether galaxies reionized the universe; our observations are designed to provide a robust determination of the star formation density at z ∼> 8, improve measurements of the ultraviolet continuum slope at z ∼ 7-8, facilitate the construction of new samples of z ∼ 9-10 candidates, and enable the detection of sources up to z ∼ 12. For this project we committed to combining these and other WFC3/IR imaging observations of the UDF area into a single homogeneous dataset to provide the deepest near-infrared observations of the sky. In this paper we present the observational overview of the project and describe the procedures used in reducing the data as well as the final products that were produced. We present the details of several special procedures that we implemented to correct calibration issues in the data for both the WFC3/IR observations of the main UDF field and our deep 128 orbit ACS/WFC F814W parallel field image, including treatment for persistence, correction for time-variable sky backgrounds, and astrometric alignment to an accuracy of a few milliarcseconds. We release the full, combined mosaics comprising a single, unified set of mosaics of the UDF, providing the deepest near-infrared blank-field view of the universe currently achievable, reaching magnitudes as deep as AB ∼ 30 mag in the near-infrared, and yielding a legacy dataset on this field.

  12. THE 2012 HUBBLE ULTRA DEEP FIELD (UDF12): OBSERVATIONAL OVERVIEW

    International Nuclear Information System (INIS)

    Koekemoer, Anton M.; Ellis, Richard S.; Schenker, Matthew A.; McLure, Ross J.; Dunlop, James S.; Bowler, Rebecca A. A.; Rogers, Alexander B.; Curtis-Lake, Emma; Cirasuolo, Michele; Wild, V.; Targett, T.; Robertson, Brant E.; Schneider, Evan; Stark, Daniel P.; Ono, Yoshiaki; Ouchi, Masami; Charlot, Stephane; Furlanetto, Steven R.

    2013-01-01

    We present the 2012 Hubble Ultra Deep Field campaign (UDF12), a large 128 orbit Cycle 19 Hubble Space Telescope program aimed at extending previous Wide Field Camera 3 (WFC3)/IR observations of the UDF by quadrupling the exposure time in the F105W filter, imaging in an additional F140W filter, and extending the F160W exposure time by 50%, as well as adding an extremely deep parallel field with the Advanced Camera for Surveys (ACS) in the F814W filter with a total exposure time of 128 orbits. The principal scientific goal of this project is to determine whether galaxies reionized the universe; our observations are designed to provide a robust determination of the star formation density at z ∼> 8, improve measurements of the ultraviolet continuum slope at z ∼ 7-8, facilitate the construction of new samples of z ∼ 9-10 candidates, and enable the detection of sources up to z ∼ 12. For this project we committed to combining these and other WFC3/IR imaging observations of the UDF area into a single homogeneous dataset to provide the deepest near-infrared observations of the sky. In this paper we present the observational overview of the project and describe the procedures used in reducing the data as well as the final products that were produced. We present the details of several special procedures that we implemented to correct calibration issues in the data for both the WFC3/IR observations of the main UDF field and our deep 128 orbit ACS/WFC F814W parallel field image, including treatment for persistence, correction for time-variable sky backgrounds, and astrometric alignment to an accuracy of a few milliarcseconds. We release the full, combined mosaics comprising a single, unified set of mosaics of the UDF, providing the deepest near-infrared blank-field view of the universe currently achievable, reaching magnitudes as deep as AB ∼ 30 mag in the near-infrared, and yielding a legacy dataset on this field

  13. Hubble Space Telescope: a Vision to 2020 and Beyond: The Hubble Source Catalog

    Science.gov (United States)

    Strolger, Louis-Gregory

    2016-01-01

    The Hubble Source Catalog (HSC) is an initiative centered on what science would be enabled by a master catalog of all the sources HST has imaged over its lifetime. The first version of this catalog was released in early 2015, and included approximately 30 million sources from archived direct imaging with WFPC2, ACS (through 2011), and WFC3 (to 2014). Version 2, scheduled for release in early 2016, will feed off the Hubble Legacy Archive DR9 release, updating the ACS sources with more detections, and more direct imaging, through to mid-2015. This talk will overview the properties and goals of the HSC in terms of its source detection, object resolution, confusion limits, and overall astrometric and photometric precision. I will also discuss the connections to other MAST activities (e.g., the Discovery Portal interface), to STScI and user products (e.g., the Spectroscopic Catalog and High-Level Science Products), and to community resources (e.g., Pan-STARRS, SDSS, and eventually GAIA). The HSC successfully amalgamates the diverse observations with HST, and despite the limitations in uniformity on the sky, will be an important reference for JWST, LSST, and other future telescopes.

  14. Hubble Space Telescope Image of Omega Nebula

    Science.gov (United States)

    2002-01-01

    This sturning image, taken by the newly installed Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST), is an image of the center of the Omega Nebula. It is a hotbed of newly born stars wrapped in colorful blankets of glowing gas and cradled in an enormous cold, dark hydrogen cloud. The region of nebula shown in this photograph is about 3,500 times wider than our solar system. The nebula, also called M17 and the Swan Nebula, resides 5,500 light-years away in the constellation Sagittarius. The Swan Nebula is illuminated by ultraviolet radiation from young, massive stars, located just beyond the upper-right corner of the image. The powerful radiation from these stars evaporates and erodes the dense cloud of cold gas within which the stars formed. The blistered walls of the hollow cloud shine primarily in the blue, green, and red light emitted by excited atoms of hydrogen, nitrogen, oxygen, and sulfur. Particularly striking is the rose-like feature, seen to the right of center, which glows in the red light emitted by hydrogen and sulfur. As the infant stars evaporate the surrounding cloud, they expose dense pockets of gas that may contain developing stars. One isolated pocket is seen at the center of the brightest region of the nebula. Other dense pockets of gas have formed the remarkable feature jutting inward from the left edge of the image. The color image is constructed from four separate images taken in these filters: blue, near infrared, hydrogen alpha, and doubly ionized oxygen. Credit: NASA, H. Ford (JHU), G. Illingworth (USCS/LO), M. Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA.

  15. Promoting Undergraduate Surgical Education: Current Evidence and Students' Views on ESMSC International Wet Lab Course.

    Science.gov (United States)

    Sideris, Michail; Papalois, Apostolos; Theodoraki, Korina; Dimitropoulos, Ioannis; Johnson, Elizabeth O; Georgopoulou, Efstratia-Maria; Staikoglou, Nikolaos; Paparoidamis, Georgios; Pantelidis, Panteleimon; Tsagkaraki, Ismini; Karamaroudis, Stefanos; Potoupnis, Michael E; Tsiridis, Eleftherios; Dedeilias, Panagiotis; Papagrigoriadis, Savvas; Papalois, Vassilios; Zografos, Georgios; Triantafyllou, Aggeliki; Tsoulfas, Georgios

    2017-04-01

    Undergraduate Surgical Education is becoming an essential element in the training of the future generation of safe and efficient surgeons. Essential Skills in the Management of Surgical Cases (ESMSC), is an international, joint applied surgical science and simulation-based learning wet lab course. We performed a review of the existing literature on the topic of undergraduate surgical education. Following that, we analyzed the feedback questionnaire received 480 from 2 recent series of ESMSC courses (May 2015, n = 49 and November 2015, n = 40), in order to evaluate European Union students' (UK, Germany, Greece) views on the ESMSC course, as well as on the undergraduate surgical education. Results Using a 10 point graded scale, the overall ESMSC concept was positively evaluated, with a mean score of 9.41 ± 0.72 (range: 8-10) and 8.94 ± 1.1 (range: 7-10). The majority of delegates from both series [9.86 ± 0.43 (range: 8-10) and 9.58 ± 0.91 (range: 6-10), respectively] believed that ESMSC should be incorporated in the undergraduate surgical curriculum. Comparison of responses from the UK to the Greek Medical Student, as well as the findings from the third and fourth year versus the fifth and sixth year Medical Students, revealed no statistically significant differences pertaining to any of the questions (p > 0.05). Current evidence in the literature supports the enhancement of surgical education through the systematic use of various modalities that provide Simulation-Based Training (SBT) hands-on experience, starting from the early undergraduate level. The findings of the present study are in agreement with these previous reports.

  16. The effect of interacting dark energy on local measurements of the Hubble constant

    International Nuclear Information System (INIS)

    Odderskov, Io; Baldi, Marco; Amendola, Luca

    2016-01-01

    In the current state of cosmology, where cosmological parameters are being measured to percent accuracy, it is essential to understand all sources of error to high precision. In this paper we present the results of a study of the local variations in the Hubble constant measured at the distance scale of the Coma Cluster, and test the validity of correcting for the peculiar velocities predicted by gravitational instability theory. The study is based on N-body simulations, and includes models featuring a coupling between dark energy and dark matter, as well as two ΛCDM simulations with different values of σ 8 . It is found that the variance in the local flows is significantly larger in the coupled models, which increases the uncertainty in the local measurements of the Hubble constant in these scenarios. By comparing the results from the different simulations, it is found that most of the effect is caused by the higher value of σ 8 in the coupled cosmologies, though this cannot account for all of the additional variance. Given the discrepancy between different estimates of the Hubble constant in the universe today, cosmological models causing a greater cosmic variance is something that we should be aware of.

  17. The effect of interacting dark energy on local measurements of the Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Odderskov, Io [Department of Physics and Astronomy, University of Aarhus, Ny Munkegade 120, Aarhus C (Denmark); Baldi, Marco [Dipartimento di Fisica e Astronomia, Alma Mater Studiorum Università di Bologna, viale Berti Pichat 6/2, I-40127, Bologna (Italy); Amendola, Luca, E-mail: isho07@phys.au.dk, E-mail: marco.baldi5@unibo.it, E-mail: l.amendola@thphys.uni-heidelberg.de [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)

    2016-05-01

    In the current state of cosmology, where cosmological parameters are being measured to percent accuracy, it is essential to understand all sources of error to high precision. In this paper we present the results of a study of the local variations in the Hubble constant measured at the distance scale of the Coma Cluster, and test the validity of correcting for the peculiar velocities predicted by gravitational instability theory. The study is based on N-body simulations, and includes models featuring a coupling between dark energy and dark matter, as well as two ΛCDM simulations with different values of σ{sub 8}. It is found that the variance in the local flows is significantly larger in the coupled models, which increases the uncertainty in the local measurements of the Hubble constant in these scenarios. By comparing the results from the different simulations, it is found that most of the effect is caused by the higher value of σ{sub 8} in the coupled cosmologies, though this cannot account for all of the additional variance. Given the discrepancy between different estimates of the Hubble constant in the universe today, cosmological models causing a greater cosmic variance is something that we should be aware of.

  18. Constraining dark energy with Hubble parameter measurements: an analysis including future redshift-drift observations

    International Nuclear Information System (INIS)

    Guo, Rui-Yun; Zhang, Xin

    2016-01-01

    The nature of dark energy affects the Hubble expansion rate (namely, the expansion history) H(z) by an integral over w(z). However, the usual observables are the luminosity distances or the angular diameter distances, which measure the distance.redshift relation. Actually, the property of dark energy affects the distances (and the growth factor) by a further integration over functions of H(z). Thus, the direct measurements of the Hubble parameter H(z) at different redshifts are of great importance for constraining the properties of dark energy. In this paper, we show how the typical dark energy models, for example, the ΛCDM, wCDM, CPL, and holographic dark energy models, can be constrained by the current direct measurements of H(z) (31 data used in total in this paper, covering the redshift range of z @ element of [0.07, 2.34]). In fact, the future redshift-drift observations (also referred to as the Sandage-Loeb test) can also directly measure H(z) at higher redshifts, covering the range of z @ element of [2, 5]. We thus discuss what role the redshift-drift observations can play in constraining dark energy with the Hubble parameter measurements. We show that the constraints on dark energy can be improved greatly with the H(z) data from only a 10-year observation of redshift drift. (orig.)

  19. A comprehensive survey of current and former college students with autism spectrum disorders.

    Science.gov (United States)

    Gelbar, Nicholas W; Shefyck, Allison; Reichow, Brian

    2015-03-01

    There is a paucity of research concerning individuals with autism spectrum disorders (ASD) pursuing higher education. This study sought to augment this gap in the literature by surveying individuals with ASD who are currently college students or who have previously attended college. Thirty-five individuals completed an online survey. These individuals reported receiving extensive academic supports that enabled their academic success. Their reported difficulties in the social and emotional domains received less support. In addition, not all areas of campus life were supportive, as study abroad and career service offices were reported to not understand individuals with ASD. Overall, the results of this survey indicate the importance of self-advocacy and the need for institutions of higher education to provide comprehensive supports for individuals with ASD in the academic, social, and emotional domains in order to effectively integrate this group into the campus environment.

  20. Carnegie Hubble Program: A Mid-Infrared Calibration of the Hubble Constant

    Science.gov (United States)

    Freedman, Wendy L.; Madore, Barry F.; Scowcroft, Victoria; Burns, Chris; Monson, Andy; Persson, S. Eric; Seibert, Mark; Rigby, Jane

    2012-01-01

    Using a mid-infrared calibration of the Cepheid distance scale based on recent observations at 3.6 micrometers with the Spitzer Space Telescope, we have obtained a new, high-accuracy calibration of the Hubble constant. We have established the mid-IR zero point of the Leavitt law (the Cepheid period-luminosity relation) using time-averaged 3.6 micrometers data for 10 high-metallicity, MilkyWay Cepheids having independently measured trigonometric parallaxes. We have adopted the slope of the PL relation using time-averaged 3.6micrometers data for 80 long-period Large Magellanic Cloud (LMC) Cepheids falling in the period range 0.8 < log(P) < 1.8.We find a new reddening-corrected distance to the LMC of 18.477 +/- 0.033 (systematic) mag. We re-examine the systematic uncertainties in H(sub 0), also taking into account new data over the past decade. In combination with the new Spitzer calibration, the systematic uncertainty in H(sub 0) over that obtained by the Hubble Space Telescope Key Project has decreased by over a factor of three. Applying the Spitzer calibration to the Key Project sample, we find a value of H(sub 0) = 74.3 with a systematic uncertainty of +/-2.1 (systematic) kilometers per second Mpc(sup -1), corresponding to a 2.8% systematic uncertainty in the Hubble constant. This result, in combination with WMAP7measurements of the cosmic microwave background anisotropies and assuming a flat universe, yields a value of the equation of state for dark energy, w(sub 0) = -1.09 +/- 0.10. Alternatively, relaxing the constraints on flatness and the numbers of relativistic species, and combining our results with those of WMAP7, Type Ia supernovae and baryon acoustic oscillations yield w(sub 0) = -1.08 +/- 0.10 and a value of N(sub eff) = 4.13 +/- 0.67, mildly consistent with the existence of a fourth neutrino species.

  1. Protein Supplement Usage Among Male University Students: Comparisons Between Current and Previous Users.

    Science.gov (United States)

    Sung, Youngmo; Choi, Jinkyung

    2018-02-01

    Interest in specialized dietary supplements is leading market growth, and protein supplements are popular for increasing muscle mass among young males. Therefore, this study investigated the attitudes toward and satisfaction with protein supplements to identify detailed consumer behaviors related to the consumption of protein supplements. The study sample includes male university students in their 20s in South Korea. In total, 223 responses were entered for analysis. Questions related to attitudes, satisfaction, and future behavioral intentions were asked using 5-point Likert scales. The responses were divided into two groups, current and previous users, to identify significant differences in terms of attitudes, satisfaction, and future behavioral intentions. A descriptive analysis, analysis of variance (ANOVA), and multiple regression were run. The majority of respondents prefer the powdered form of supplements in bulk with a price range between 30,000 won and 60,000 won. Online shopping was preferred, while word of mouth and friends/family were considered credible information sources. The most common side effects experienced were problems with digestion and hives, although more than 78% did not experience side effects. In comparison between current and previous users in terms of attitudes and satisfaction, the following areas showed significances. Regarding attitudes, the importance of brand, preference for products from overseas, the search for nutritional facts, and reading carefully all product information were significant, while regarding satisfaction, price, effectiveness, and ease of consumption were significant. All significances showed that current users had more positive attitudes and greater satisfaction. Overall, consumers' satisfaction regarding ease of consumption influenced future behavioral intentions. The market for protein supplements has been growing, so measuring consumers' attitudes and satisfaction would help attract potential consumers. In

  2. The prevalence of and factors associated with current smoking among College of Health Sciences students, Mekelle University in northern Ethiopia.

    Science.gov (United States)

    Eticha, Tadele; Kidane, Feven

    2014-01-01

    Tobacco smoking is one of the greatest causes of preventable morbidity and mortality globally, and is responsible for many causes of untimely deaths. This survey was aimed to determine prevalence and factors associated with current smoking among the students of College of Health Sciences, Mekelle University, Ethiopia. A cross-sectional study was employed using a structured self-administered questionnaire among College of Health Sciences students in March 2013. A stratified random sampling method was employed to select study participants. Data were entered and analysed using of Statistical Package for Social Sciences (SPSS) version 20.0. Of the 193 students, 57 (29.5%) of the students were current smokers. Most of the current smokers (89.4%) smoked between 1-10 sticks of cigarette per day. The two main reasons cited for smoking cigarettes were peer pressure (43.9%) and to relieve stress (36.8%). Being female (adjusted OR [AOR] = 0.49; 95% CI: 0.25, 0.95) and Tigre by ethnicity (AOR = 0.32; 95% CI: 0.14, 0.74) were significantly less associated with current smoking. On the other hand, being second year students (AOR = 3.84; 95% CI: 1.41, 10.46), khat chewing (AOR = 8.36; 95% CI: 2.60, 26.85) and taking illicit drugs (AOR = 10.59; 95% CI: 2.77, 40.51) were positively associated with current smoking cigarettes. The current smoking prevalence among students in College of Health Sciences, Mekelle University is high and therefore, effective smoking prevention and cessation intervention programs are required to reduce smoking among university students.

  3. Survey on the Assessment of the Current Actual Expenses Incurred by Students on the Meals and Accommodation within and around the Campuses: The Case of Tanzania Higher Education Students' Loans Beneficiaries

    Science.gov (United States)

    Nyahende, Veronica R.; Bangu, Asangye N.; Chakaza, Benedicto C.

    2015-01-01

    This Survey analyses the current actual expenses incurred by students on the meals and accommodation within and around the campuses. The study was geared towards achieving the following objectives: (i) to examine the current cost incurred by a students for meals In Campus, (ii) to examine the current cost incurred by a students for accommodation…

  4. [Current status of malaria control knowledge awareness of primary and sec- ondary school students in Xuzhou City].

    Science.gov (United States)

    Sun, Xing-sheng; Li, Li; Zhang, Kan-kan

    2015-12-01

    To understand the current status of malaria control knowledge awareness of primary and secondary school students and its influencing factors in Yunlong District, Xuzhou City, so as to provide the evidence for improving the malaria prevention work. A total of 800 students from 4 urban and rural primary and secondary schools were randomly selected and investigated with questionnaires. The total awareness rate of malaria control knowledge was 61.27%, and the awareness rates of symptoms of malaria and malaria prevention were only 38.99% and 57.59% respectively. The main approach of obtaining the malaria control knowledge was media (51.52%). The univariate analysis showed that sex, area and different education levels affected the awareness rates of malaria control knowledge (P knowledge of country students was lower than that of urban students (P knowledge of the secondary school students was higher than that of the primary school students (P knowledge of primary and secondary school students in Yunlong District is lower than that required by the national standard. Therefore, the health education of malaria control should be strengthened, especially in countryside school students and primary school students.

  5. Hubble 2020: Outer Planet Atmospheres Legacy (OPAL) Program

    Science.gov (United States)

    Simon, Amy

    2017-08-01

    Long time base observations of the outer planets are critical in understanding the atmospheric dynamics and evolution of the gas giants. We propose yearly monitoring of each giant planet for the remainder of Hubble's lifetime to provide a lasting legacy of increasingly valuable data for time-domain studies. The Hubble Space Telescope is a unique asset to planetary science, allowing high spatial resolution data with absolute photometric knowledge. For the outer planets, gas/ice giant planets Jupiter, Saturn, Uranus and Neptune, many phenomena happen on timescales of years to decades, and the data we propose are beyond the scope of a typical GO program. Hubble is the only platform that can provide high spatial resolution global studies of cloud coloration, activity, and motion on a consistent time basis to help constrain the underlying mechanics.

  6. Cosmic Collisions The Hubble Atlas of Merging Galaxies

    CERN Document Server

    Christensen, Lars Lindberg; Martin, Davide

    2009-01-01

    Lars Lindberg Christensen, Raquel Yumi Shida & Davide De Martin Cosmic Collisions: The Hubble Atlas of Merging Galaxies Like majestic ships in the grandest night, galaxies can slip ever closer until their mutual gravitational interaction begins to mold them into intricate figures that are finally, and irreversibly, woven together. It is an immense cosmic dance, choreographed by gravity. Cosmic Collisions contains a hundred new, many thus far unpublished, images of colliding galaxies from the NASA/ESA Hubble Space Telescope. It is believed that many present-day galaxies, including the Milky Way, were assembled from such a coalescence of smaller galaxies, occurring over billions of years. Triggered by the colossal and violent interaction between the galaxies, stars form from large clouds of gas in firework bursts, creating brilliant blue star clusters. The importance of these cosmic encounters reaches far beyond the stunning Hubble images. They may, in fact, be among the most important processes that shape ...

  7. Hubble Space Telescope EVA Power Ratchet Tool redesign

    Science.gov (United States)

    Richards, Paul W.; Park, Chan; Brown, Lee

    The Power Ratchet Tool (PRT) is a self contained, power-driven, 3/8 inch drive ratchet wrench which will be used by astronauts during Extravehicular Activities (EVA). This battery-powered tool is controlled by a dedicated electonic controller. The PRT was flown during the Hubble Space Telescope (HST) Deployment Mission STS-31 to deploy the solar arrays if the automatic mechanisms failed. The PRT is currently intended for use during the first HST Servicing Mission STS-61 as a general purpose power tool. The PRT consists of three major components; the wrench, the controller, and the battery module. Fourteen discrete combinations of torque, turns, and speed may be programmed into the controller before the EVA. The crewmember selects the desired parameter profile by a switch mounted on the controller. The tool may also be used in the manual mode as a non-powered ratchet wrench. The power is provided by a silver-zinc battery module, which fits into the controller and is replaceable during an EVA. The original PRT did not meet the design specification of torque output and hours of operation. To increase efficiency and reliability the PRT underwent a redesign effort. The majority of this effort focused on the wrench. The original PRT drive train consisted of a low torque, high speed brushless DC motor, a face gear set, and a planocentric gear assembly. The total gear reduction was 300:1. The new PRT wrench consists of a low speed, high torque brushless DC motor, two planetary gear sets and a bevel gear set. The total gear reduction is now 75:1. A spline clutch has also been added to disengage the drive train in the manual mode. The design changes to the controller will consist of only those modifications necessary to accomodate the redesigned wrench.

  8. Designing a Summer Transition Program for Incoming and Current College Students on the Autism Spectrum: A Participatory Approach

    Directory of Open Access Journals (Sweden)

    Emily Hotez

    2018-02-01

    Full Text Available Students with Autism Spectrum Disorder (ASD face unique challenges transitioning from high school to college and receive insufficient support to help them navigate this transition. Through a participatory collaboration with incoming and current autistic college students, we developed, implemented, and evaluated two intensive week-long summer programs to help autistic students transition into and succeed in college. This process included: (1 developing an initial summer transition program curriculum guided by recommendations from autistic college students in our ongoing mentorship program, (2 conducting an initial feasibility assessment of the curriculum [Summer Transition Program 1 (STP1], (3 revising our initial curriculum, guided by feedback from autistic students, to develop a curriculum manual, and (4 pilot-testing the manualized curriculum through a quasi-experimental pre-test/post-test assessment of a second summer program [Summer Transition Program 2 (STP2]. In STP2, two autistic college students assumed a leadership role and acted as “mentors” and ten incoming and current autistic college students participated in the program as “mentees.” Results from the STP2 pilot-test suggested benefits of participatory transition programming for fostering self-advocacy and social skills among mentees. Autistic and non-autistic mentors (but not mentees described practicing advanced forms of self-advocacy, specifically leadership, through their mentorship roles. Autistic and non-autistic mentors also described shared (e.g., empathy and unique (an intuitive understanding of autism vs. an intuitive understanding of social interaction skills that they contributed to the program. This research provides preliminary support for the feasibility and utility of a participatory approach in which autistic college students are integral to the development and implementation of programming to help less experienced autistic students develop the self

  9. Constraining the evolution of the Hubble Parameter using cosmic chronometers

    Science.gov (United States)

    Dickinson, Hugh

    2017-08-01

    Substantial investment is being made in space- and ground-based missions with the goal of revealing the nature of the observed cosmic acceleration. This is one of the most important unsolved problems in cosmology today.We propose here to constrain the evolution of the Hubble parameter [H(z)] between 1.3 fundamental nature of dark energy.

  10. Hubble Space Telescope nickel hydrogen battery system briefing

    Science.gov (United States)

    Nawrocki, David; Saldana, David; Rao, Gopal

    1993-01-01

    The topics covered are presented in viewgraph form and include the following: the Hubble Space Telescope (HST) Mission; system constraints; battery specification; battery module; simplified block diagram; cell design summary; present status; voltage decay; system depth of discharge; pressure since launch; system capacity; eclipse time vs. trickle charge; capacity test objectives; and capacity during tests.

  11. Remarks on the low value obtained for the Hubble constant

    International Nuclear Information System (INIS)

    Jaakkola, Toivo

    1975-01-01

    Some remarks are made on the basis of the data given by Sandage and Tamman, suggesting that these authors have over-estimated the distances to the most luminous galaxies and obtained a value too low for the Hubble constant [fr

  12. Hubble's Law Implies Benford's Law for Distances to Galaxies ...

    Indian Academy of Sciences (India)

    in both time and space, predicts that conformity to Benford's law will improve as more data on distances to galaxies becomes available. Con- versely, with the logical derivation of this law presented here, the recent empirical observations may beviewed as independent evidence of the validity of Hubble's law. Key words.

  13. Type I supernovae and angular anisotropy of the Hubble constant

    International Nuclear Information System (INIS)

    Le Denmat, Gerard; Vigier, J.-P.

    1975-01-01

    The observation of type I supernovae in distant galaxies yields an homogeneous sample of sources to evaluate their true distance. An examination of their distribution in the sky provides a significant confirmation of the angular anisotropy of the Hubble constant already observed by Rubin, Rubin and Ford [fr

  14. The Rhodes Scholarship in the Current Era of Student Activism: What Do We Consider "Prestigious" and Who Benefits?

    Science.gov (United States)

    Adam, LeAnn

    2016-01-01

    Contemporary student activism has revealed deep feelings of alienation on college campuses, prompting strong reactions to current and historical racial injustice, including the history of Cecil Rhodes. Can advisors promote restorative justice by encouraging reflection upon privileges afforded to Rhodes scholars and their responsibility to address…

  15. A Study of Second-Year Engineering Students' Alternative Conceptions about Electric Potential, Current Intensity and Ohm's Law

    Science.gov (United States)

    Periago, M. Cristina; Bohigas, Xavier

    2005-01-01

    The aim of this research was to evaluate and analyse second-year industrial engineering and chemical engineering students prior knowledge of conceptual aspects of "circuit theory". Specifically, we focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between them as expressed by Ohm's law.…

  16. Evaluation of Student Models on Current Socio-Scientific Topics Based on System Dynamics

    Science.gov (United States)

    Nuhoglu, Hasret

    2014-01-01

    This study aims to 1) enable primary school students to develop models that will help them understand and analyze a system, through a learning process based on system dynamics approach, 2) examine and evaluate students' models related to socio-scientific issues using certain criteria. The research method used is a case study. The study sample…

  17. Showing You're Working: A Project Using Former Pupils' Experiences to Engage Current Mathematics Students

    Science.gov (United States)

    Musto, Garrod

    2008-01-01

    To help students view mathematics in a more favourable light, a number of former pupils were contacted and asked to give details of how they use mathematics in their daily lives. This information was gathered through an online questionnaire or visits to the school to talk to pupils--a booklet of responses was also given to students. Attitudinally…

  18. Self-Monitoring Interventions for Students with Behavior Problems: A Systematic Review of Current Research

    Science.gov (United States)

    Bruhn, Allison; McDaniel, Sara; Kreigh, Christi

    2015-01-01

    Explicitly teaching skills associated with self-determination has been promoted to support students' independence and control over their own lives. This is especially important for students with behavior problems. One self-determination skill or behavior that has been studied widely is self-monitoring. Although multiple reviews of various…

  19. Music Student Teaching Seminars: An Examination of Current Practices Across the United States

    Science.gov (United States)

    Baumgartner, Christopher M.; Councill, Kimberly H.

    2017-01-01

    The purpose of this study was to examine the structure and content of music student teaching seminars at 4-year, degree-granting institutions accredited by the National Association of Schools of Music across the United States. A secondary purpose was to determine how these seminars (a) addressed perceived needs of student teachers and beginning…

  20. College Students' Volunteering: Factors Related to Current Volunteering, Volunteer Settings, and Motives for Volunteering

    Science.gov (United States)

    Moore, Erin W.; Warta, Samantha; Erichsen, Kristen

    2014-01-01

    Research has not explored the types of settings that college students prefer to volunteer for and how these settings might be influenced by personal factors (e.g., demographic, academic major, volunteering motivation, religiosity). Students from a Midwestern university (N = 406, 71.9% female) completed a survey that inquired about their…

  1. Student Loan Debt and Economic Outcomes. Current Policy Perspective No. 14-7

    Science.gov (United States)

    Cooper, Daniel; Wang, J. Christina

    2014-01-01

    This policy brief advances the growing literature on how student loan debt affects individuals' other economic decisions. Specifically, it examines the impact of student loan liabilities on individuals' homeownership status and wealth accumulation. The analysis employs a rich set of financial and demographic control variables that are not…

  2. South African medical schools: Current state of selection criteria and medical students' demographic profile.

    Science.gov (United States)

    van der Merwe, L J; van Zyl, G J; St Clair Gibson, A; Viljoen, M; Iputo, J E; Mammen, M; Chitha, W; Perez, A M; Hartman, N; Fonn, S; Green-Thompson, L; Ayo-Ysuf, O A; Botha, G C; Manning, D; Botha, S J; Hift, R; Retief, P; van Heerden, B B; Volmink, J

    2015-12-16

    Selection of medical students at South African (SA) medical schools must promote equitable and fair access to students from all population groups, while ensuring optimal student throughput and success, and training future healthcare practitioners who will fulfil the needs of the local society. In keeping with international practices, a variety of academic and non-academic measures are used to select applicants for medical training programmes in SA medical schools. To provide an overview of the selection procedures used by all eight medical schools in SA, and the student demographics (race and gender) at these medical schools, and to determine to what extent collective practices are achieving the goals of student diversity and inclusivity. A retrospective, quantitative, descriptive study design was used. All eight medical schools in SA provided information regarding selection criteria, selection procedures, and student demographics (race and gender). Descriptive analysis of data was done by calculating frequencies and percentages of the variables measured. Medical schools in SA make use of academic and non-academic criteria in their selection processes. The latter include indices of socioeconomic disadvantage. Most undergraduate medical students in SA are black (38.7%), followed by white (33.0%), coloured (13.4%) and Indian/Asian (13.6%). The majority of students are female (62.2%). The number of black students is still proportionately lower than in the general population, while other groups are overrepresented. Selection policies for undergraduate medical programmes aimed at redress should be continued and further refined, along with the provision of support to ensure student success.

  3. Complementary and Alternative Medicine: Comparison of Current Knowledge, Attitudes and Interest among German Medical Students and Doctors

    Directory of Open Access Journals (Sweden)

    Karsten Münstedt

    2011-01-01

    Full Text Available Although it has been agreed that complementary and alternative medicine (CAM should be included in the German medical curriculum, there is no consensus on which methods and how it should be taught. This study aimed to assess needs for CAM education by evaluating current knowledge, attitudes and interests of medical students, general physicians and gynecologists. Two instruments based on established and validated questionnaires were developed. One was given to seventh semester medical students and the other to office-based doctors. Data were analyzed by bivariate correlation and cross-tabulation. Altogether 550 questionnaires were distributed—280 to doctors and 270 to medical students. Completed questionnaires were returned by 80.4% of students and 78.2% of doctors. Although 73.8% (160/219 of doctors and 40% (87/217 of students had already informed themselves about CAM, neither group felt that they knew much about CAM. Doctors believed that CAM was most useful in general medicine, supportive oncology, pediatrics, dermatology and gynecology, while students believed that dermatology, general medicine, psychiatry and rheumatology offered opportunities; both recommended that CAM should be taught in these areas. Both groups believed that CAM should be included in medical education; however, they believed that CAM needed more investigation and should be taught “critically". German doctors and students would like to be better informed about CAM. An approach which teaches fundamental competences to students, chooses specific content based on evidence, demographics and medical conditions and provides students with the skills they need for future learning should be adopted.

  4. Panchromatic Hubble Andromeda Treasury. IX. A photometric survey of planetary nebulae in M31

    Energy Technology Data Exchange (ETDEWEB)

    Veyette, Mark J.; Williams, Benjamin F.; Dalcanton, Julianne J.; Balick, Bruce; Fouesneau, Morgan [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Girardi, Léo [Osservatorio Astronomico di Padova—INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Gordon, Karl D.; Kalirai, Jason [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Rosenfield, Philip [Department of Physics and Astronomy G. Galilei, University of Padova, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Seth, Anil C., E-mail: mveyette@uw.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)

    2014-09-10

    We search the Hubble Space Telescope (HST) Advanced Camera for Surveys and Wide Field Camera 3 broadband imaging data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey to identify detections of cataloged planetary nebulae (PNs). Of the 711 PNs currently in the literature within the PHAT footprint, we find 467 detected in the broadband. For these 467, we are able to refine their astrometric accuracy from ∼0.''3 to 0.''05. Using the resolution of the HST, we are able to show that 152 objects currently in the catalogs are definitively not PNs, and we show that 32 objects thought to be extended in ground-based images are actually point-like and therefore good PN candidates. We also find one PN candidate that is marginally resolved. If this is a PN, it is up to 0.7 pc in diameter. With our new photometric data, we develop a method of measuring the level of excitation in individual PNs by comparing broadband and narrowband imaging and describe the effects of excitation on a PN's photometric signature. Using the photometric properties of the known PNs in the PHAT catalogs, we search for more PNs, but do not find any new candidates, suggesting that ground-based emission-line surveys are complete in the PHAT footprint to F475W ≅ 24.

  5. Hubble again views Saturn's Rings Edge-on

    Science.gov (United States)

    1995-01-01

    Saturn's magnificent ring system is seen tilted edge-on -- for the second time this year -- in this NASA Hubble Space Telescope picture taken on August 10, 1995, when the planet was 895 million miles (1,440 million kilometers) away. Hubble snapped the image as Earth sped back across Saturn's ring plane to the sunlit side of the rings. Last May 22, Earth dipped below the ring plane, giving observers a brief look at the backlit side of the rings. Ring-plane crossing events occur approximately every 15 years. Earthbound observers won't have as good a view until the year 2038. Several of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are from left to right, Enceladus, Tethys, Dione and Mimas. 'The Hubble data shows numerous faint satellites close to the bright rings, but it will take a couple of months to precisely identify them,' according to Steve Larson (University of Arizona). During the May ring plane crossing, Hubble detected two, and possibly four, new moons orbiting Saturn. These new observations also provide a better view of the faint E ring, 'to help determine the size of particles and whether they will pose a collision hazard to the Cassini spacecraft,' said Larson. The picture was taken with Hubble's Wide Field Planetary Camera 2 in wide field mode. This image is a composite view, where a long exposure of the faint rings has been combined with a shorter exposure of Saturn's disk to bring out more detail. When viewed edge-on, the rings are so dim they almost disappear because they are very thin -- probably less than a mile thick.The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  6. Current knowledge of scoliosis in physiotherapy students trained in the United Kingdom.

    Science.gov (United States)

    Black, D A Jason; Pilcher, Christine; Drake, Shawn; Maude, Erika; Glynn, David

    2017-01-01

    It has been highlighted in both Poland and the United States of America (USA) that knowledge of idiopathic scoliosis (IS) among physiotherapy students is limited with respect to the 2011 International Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) guidelines. Early detection of scoliosis and correct initial management is essential in effective care, and thus physiotherapists should be aware of the basic criteria for diagnosis and indications for treatment. The aim of this study was to evaluate the basic knowledge of IS in physiotherapy students trained in the United Kingdom (UK). A previously designed and tested 10-question survey, including knowledge of the 2011 SOSORT guidelines, was transcribed onto an online-survey platform. Questions were designed to analyse knowledge of definition, cause, development, prevalence, diagnosis, treatment and bracing of scoliosis. All UK universities offering physiotherapy degrees were invited to participate, with the programme lead of each institution asked to distribute the questionnaire to all penultimate and final year physiotherapy students (bachelor's and master's degrees). The final number of students who received the study invitation is unknown. The survey link closed after 8 weeks of data collection. Two hundred and six students, split over 12 institutions, successfully completed the questionnaire. Analysis showed that 79% of students recognised when IS is likely to develop, yet only 52% recognised that IS's aetiology is unknown. Eighty-eight percent of students incorrectly defined IS as a 2-dimensional deformity, with only 24% successfully recognising the prevalence of IS within the scoliosis population. Just 12% knew the criteria for diagnosis; however, 93% were unable to recognise the appropriate treatment approach through therapeutic exercise. Finally, 54% of students managed to identify correctly when bracing is recommended for IS. In comparison to previous studies within the USA, students in

  7. A nuclear data approach for the Hubble constant measurements

    Directory of Open Access Journals (Sweden)

    Pritychenko Boris

    2017-01-01

    Full Text Available An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.2(69 (km/sec/Mpc. This recommended value is based on the last 20 years of experimental research and includes contributions from different types of measurements. The present result implies (14.55 ± 1.51 × 109 years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.

  8. European astronaut selected for the third Hubble Space Telescope

    Science.gov (United States)

    1998-08-01

    The STS-104 crew will rendezvous with the orbiting Hubble Space Telescope, which is the size of a city bus, capture it using the Shuttle's Canadian robot arm and secure it in Columbia's payload bay. Then, working in teams of two, the four astronauts will leave the Shuttle's pressurised cabin and venture into the payload bay, performing a variety of tasks that will improve the productivity and reliability of the telescope. The four astronauts will perform a series of six "extravehicular" activities in the open space environment. Such activities are commonly called spacewalks, but this term does little justice to the considerable physical and mental efforts that astronauts need to make in doing the very demanding work involved. The Shuttle commander and pilot for this flight have not yet been appointed, but the four designated mission specialists begin training for the STS-104 mission immediately. "The ambitious nature of this mission, with its six spacewalks, made it important for the payload crew to begin training as early as possible," said David C. Leestma, NASA Director of Flight Crew Operations at the Johnson Space Center in Houston, to which Claude Nicollier is on resident assignment from ESA's European Astronaut Centre in Cologne, Germany, the home base of the European astronaut corps. The Hubble Space Telescope was launched into orbit in April 1990. It is one of the most capable optical telescopes available to astronomers today, producing images and spectral observations at the forefront of astronomy. The European Space Agency contributed a 15 share to the development of Hubble. One of the five scientific instruments on board, the Faint Object Camera, was built by a European industrial consortium made up of British Aerospace, Dornier and Matra under a contract with the European Space Agency. The solar arrays which provide Hubble with electrical power were manufactured by British Aerospace and Dornier. In its eight years of operation, the telescope has not

  9. Nickel-hydrogen battery testing for Hubble Space Telescope

    Science.gov (United States)

    Baggett, Randy M.; Whitt, Thomas H.

    1989-01-01

    The authors identify objectives and provide data from several nickel-hydrogen battery tests designed to evaluate the possibility of launching Ni-H2 batteries on the Hubble Space Telescope (HST). Test results from a 14-cell battery, a 12-cell battery, and a 4-cell pack are presented. Results of a thermal vacuum test to verify the battery-module/bay heat rejection capacity are reported. A 6-battery system simulation breadboard is described, and test results are presented.

  10. The Hubble Space Telescope nickel-hydrogen battery design

    Science.gov (United States)

    Nawrocki, D. E.; Armantrout, J. D.; Standlee, D. J.; Baker, R. C.; Lanier, J. R.

    1990-01-01

    Details are presented of the HST (Hubble Space Telescope) battery cell, battery package, and module mechanical and electrical designs. Also included are a summary of acceptance, qualification, and vibration tests and thermal vacuum testing. Unique details of battery cell charge retention performance characteristics associated with prelaunch hold conditions are discussed. Special charge control methods to minimize thermal dissipation during pad charging operations are summarized. This module design meets all NASA fracture control requirements for manned missions.

  11. Type Ia supernova Hubble residuals and host-galaxy properties

    International Nuclear Information System (INIS)

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Fleury, M.; Guy, J.; Baltay, C.; Buton, C.; Feindt, U.; Greskovic, P.; Kowalski, M.; Childress, M.; Chotard, N.; Copin, Y.; Gangler, E.

    2014-01-01

    Kim et al. introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ± 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at <<1σ, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement of the Hubble residual step with the host mass is 0.045 ± 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch parameters: steps at >2σ significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light-curve width and color around peak (similar to the Δm 15 and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20-30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  12. On the Luminosity Distance and the Hubble Constant

    OpenAIRE

    Yuri Heymann

    2013-01-01

    By differentiating luminosity distance with respect to time using its standard formula we find that the peculiar velocity is a time varying velocity of light. Therefore, a new definition of the luminosity distance is provided such that the peculiar velocity is equal to c. Using this definition a Hubble constant H0 = 67.3 km s−1 Mpc−1 is obtained from supernovae data.

  13. Current State of Climate Education in the United States: Are Graduate Students being Adequately Prepared to Address Climate Issues?

    Science.gov (United States)

    Kuster, E.; Fox, G.

    2016-12-01

    Climate change is happening; scientists have already observed changes in sea level, increases in atmospheric carbon dioxide, and declining polar ice. The students of today are the leaders of tomorrow, and it is our duty to make sure they are well equipped and they understand the implications of climate change as part of their research and professional careers. Graduate students, in particular, are gaining valuable and necessary research, leadership, and critical thinking skills, but we need to ensure that they are receiving the appropriate climate education in their graduate training. Previous studies have primarily focused on capturing the K-12, college level, and general publics' knowledge of the climate system, concluding with recommendations on how to improve climate literacy in the classroom. While this is extremely important to study, very few studies have captured the current perception that graduate students hold regarding the amount of climate education being offered to them. This information is important to capture, as it can inform future curriculum development. We developed and distributed a nationwide survey (495 respondents) for graduate students to capture their perception on the level of climate system education being offered and their view on the importance of having climate education. We also investigated differences in the responses based on either geographic area or discipline. We compared how important graduate students felt it was to include climate education in their own discipline versus outside disciplines. The authors will discuss key findings from this ongoing research.

  14. Promoting practical clinical management learning: the current situation about Information and Communications Technology capability development in student nurses.

    Science.gov (United States)

    Willmer, Marian

    2005-11-01

    This paper is about work-based learning in information management for student nurses. It seeks, through a literature review, to make a case for and promote Information and Communications Technology capability development in student nurses within their clinical environment. The profession of nursing, like many other jobs, is facing the increasing usage of information technology in day-to-day operations. Admission and discharges of patients have been held on computer databases since at least the 1980s. With the new Labour Government in 1997, increasing focus was placed on the effectiveness of the National Health Service and using computers as one way to assist in achieving greater effectiveness. Nurse education therefore needed to reflect this need and support trainee nurses to acquire skills in Information and Communications Technology. This paper is part of an ongoing professional doctorate inquiry into Information and Communications Technology capability development in student nurses. A literature search was conducted on teaching information and technology skills via Cumulative Index to Nursing and Allied Health Literature. Most of the available studies were neither based on the UK nor were they about student nurses. As there is a dearth of published work in this specific area, relevant, related and tangential literature was reviewed. It is argued that current practice and published work on Information and Communications Technology capability development by student nurses hardly exists. The literature confirmed that success in this area requires sound change management, an understanding of National Health Service culture, and effective people leadership skills. Nurse educators and managers need to pay more attention to understand how organizations work, particularly organizations where student nurses carry out their work. As the search revealed a significant gap in the literature in this area, a practical conceptual framework to fully analyse, develop and

  15. First results from the Hubble OPAL Program: Jupiter in 2015

    Science.gov (United States)

    Simon, Amy A.; Wong, Michael H.; Orton, Glenn S.

    2015-11-01

    The Hubble 2020: Outer Planet Atmospheres Legacy (OPAL) program is a Director's Discretionary program designed to generate two yearly global maps for each of the outer planets to enable long term studies of atmospheric color, structure and two-dimensional wind fields. This presentation focuses on Jupiter results from the first year of the campaign. Data were acqured January 19, 2015 with the WFC3/UVIS camera and the F275W, F343N, F395N, F467M, F502N, F547M, F631N, F658N, and F889N filters. Global maps were generated and are publicly available through the High Level Science Products archive: https://archive.stsci.edu/prepds/opal/Using cross-correlation on the global maps, the zonal wind profile was measured between +/- 50 degrees latitude and is in family with Voyager and Cassini era profiles. There are some variations in mid to high latitude wind jet magnitudes, particularly at +40°and -35° planetographic latitude. The Great Red Spot continues to maintain an intense orange coloration, as it did in 2014. However, the interior shows changed structure, including a reduced core and new filamentary features. Finally, a wave not previously seen in Hubble images was also observed and is interpreted as a baroclinic instability with associated cyclone formation near 16° N latitude. A similar feature was observed faintly in Voyager 2 images, and is consistent with the Hubble feature in location and scale.

  16. Cataclysmic variables, Hubble-Sandage variables and eta Carinae

    International Nuclear Information System (INIS)

    Bath, G.T.

    1980-01-01

    The Hubble-Sandage variables are the most luminous stars in external galaxies. They were first investigated by Hubble and Sandage (1953) for use as distance indicators. Their main characteristics are high luminosity, blue colour indices, and irregular variability. Spectroscopically they show hydrogen and helium in emission with occasionally weaker FeII and [FeII], and no Balmer jump (Humphreys 1975, 1978). In this respect they closely resemble cataclysmic variables, particularly dwarf novae. In the quiescent state dwarf novae show broad H and HeI, together with a strong UV continuum. In contrast to the spectroscopic similarities, the luminosities could hardly differ more. Rather than being the brightest stars known, quiescent dwarf novae are as faint or fainter than the sun. It is suggested that the close correspondence between the spectral appearance of the two classes combined with the difference in luminosity is well accounted for by a model of Hubble-Sandage variables in which the same physical processes are occurring, but on a larger scale. (Auth.)

  17. A Toy Cosmology Using a Hubble-Scale Casimir Effect

    Directory of Open Access Journals (Sweden)

    Michael E. McCulloch

    2014-02-01

    Full Text Available The visible mass of the observable universe agrees with that needed for a flat cosmos, and the reason for this is not known. It is shown that this can be explained by modelling the Hubble volume as a black hole that emits Hawking radiation inwards, disallowing wavelengths that do not fit exactly into the Hubble diameter, since partial waves would allow an inference of what lies outside the horizon. This model of “horizon wave censorship” is equivalent to a Hubble-scale Casimir effect. This incomplete toy model is presented to stimulate discussion. It predicts a minimum mass and acceleration for the observable universe which are in agreement with the observed mass and acceleration, and predicts that the observable universe gains mass as it expands and was hotter in the past. It also predicts a suppression of variation on the largest cosmic scales that agrees with the low-l cosmic microwave background anomaly seen by the Planck satellite.

  18. College Students' Attitudes & Responses toward the Current Economy and Its Implications for Marketing Managers

    Science.gov (United States)

    Gray, Lauren; Lamanette, Michelle; Silva, Alberto; Budden, Michael C.

    2009-01-01

    Since the early months of 2009, the undeniable woes of the economy are being felt by many. With a record number of corporate closings, rising unemployment and the crises in the financial markets, this may prove to be a difficult year for many. This paper uses empirical evidence collected from Southeastern Louisiana University students to learn how…

  19. Current Trends, Challenges and Prospects of Student Mobility in the African Higher Education Landscape

    Science.gov (United States)

    Woldegiorgis, Emnet Tadesse; Doevenspeck, Martin

    2015-01-01

    Since the 1990s, the development in the international dimension of higher education including student/scholar mobility, regional and international research networks and initiatives have brought new opportunities for African higher education to be incorporated in the global knowledge production and circulation processes. One of the instruments of…

  20. Current Practices in Global/International Advanced Pharmacy Practice Experiences: Preceptor and Student Considerations.

    Science.gov (United States)

    Dornblaser, Emily K; Ratka, Anna; Gleason, Shaun E; Ombengi, David N; Tofade, Toyin; Wigle, Patricia R; Zapantis, Antonia; Ryan, Melody; Connor, Sharon; Jonkman, Lauren J; Ochs, Leslie; Jungnickel, Paul W; Abrons, Jeanine P; Alsharif, Naser Z

    2016-04-25

    The objective of this article is to describe the key areas of consideration for global/international advanced pharmacy practice experience (G/I APPE) preceptors, students and learning objectives. At the 2013 Annual Meeting of the American Association of Colleges of Pharmacy (AACP), the GPE SIG prepared and presented an initial report on the G/IAPPE initiatives. Round table discussions were conducted at the 2014 AACP Annual Meeting to document GPE SIG member input on key areas in the report. Literature search of PubMed, Google Scholar and EMBASE with keywords was conducted to expand this report. In this paper, considerations related to preceptors and students and learning outcomes are described. Preceptors for G/I APPEs may vary based on the learning outcomes of the experience. Student learning outcomes for G/I APPEs may vary based on the type of experiential site. Recommendations and future directions for development of G/IAPPEs are presented. Development of a successful G/I APPE requires significant planning and consideration of appropriate qualifications for preceptors and students.

  1. Achieving Inclusion of Students with Disabilities in Turkey: Current Challenges and Future Prospects

    Science.gov (United States)

    Sakiz, Halis; Woods, Charlotte

    2015-01-01

    Developing inclusion in schools has been an objective for many countries in recent decades, giving rise to a variety of definitions, policy-making activities and school practices. This paper focuses on the attempts made towards inclusion of students with disabilities in Turkey. We start by introducing inclusive education and its parameters, and…

  2. Ways of Thinking Globalisation--Insights into a Currently Running Investigation of Students' Ideas of Globalisation

    Science.gov (United States)

    Fischer, Sebastian; Fischer, Florian; Kleinschmidt, Malte; Lange, Dirk

    2014-01-01

    The investigation is about which ideas ninth form students at grammar schools and secondary modern schools have about globalisation. It shall be investigated if the perception of and judgement on globalisation-connected contexts happens along social structure-specific patterns. At first, by way of a questionnaire, the field of ideas is supposed to…

  3. Student Failure in the First Year of University in France: Current Situation and Future Prospects

    Science.gov (United States)

    Leroux, Jean-Yves

    2011-01-01

    Faced with persisting massive failure rates in the first year of university, the French authorities have decided to implement measures to improve study conditions. Although these measures translate into additional resources for universities, the latter are placed under an obligation to achieve results, because student success rates at the end of…

  4. Current Piano Education of Turkish Music Teacher Candidates: Comparisons of Instructors and Students Perceptions

    Science.gov (United States)

    Jelen, Birsen

    2015-01-01

    In recent years almost every newly opened government funded university in Turkey has established a music department where future music teachers are educated and piano is compulsory for every single music teacher candidate in Turkey. The aim of this research is to compare piano teaching instructors' and their students' perceptions about the current…

  5. College Student Academic Online Reading: A Review of the Current Literature

    Science.gov (United States)

    Sandberg, Kate

    2011-01-01

    Teaching college students how to read online effectively is an important area of concern. Libraries have become digitized with online articles and e-books; e-textbooks are available and used; and instructors routinely assign online articles of some length. It is critical that instructors who teach reading at the college level understand the theory…

  6. Constraints on inflation revisited. An analysis including the latest local measurement of the Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Rui-Yun [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Zhang, Xin [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Peking University, Center for High Energy Physics, Beijing (China)

    2017-12-15

    We revisit the constraints on inflation models by using the current cosmological observations involving the latest local measurement of the Hubble constant (H{sub 0} = 73.00 ± 1.75 km s{sup -1} Mpc{sup -1}). We constrain the primordial power spectra of both scalar and tensor perturbations with the observational data including the Planck 2015 CMB full data, the BICEP2 and Keck Array CMB B-mode data, the BAO data, and the direct measurement of H{sub 0}. In order to relieve the tension between the local determination of the Hubble constant and the other astrophysical observations, we consider the additional parameter N{sub eff} in the cosmological model. We find that, for the ΛCDM+r+N{sub eff} model, the scale invariance is only excluded at the 3.3σ level, and ΔN{sub eff} > 0 is favored at the 1.6σ level. Comparing the obtained 1σ and 2σ contours of (n{sub s},r) with the theoretical predictions of selected inflation models, we find that both the convex and the concave potentials are favored at 2σ level, the natural inflation model is excluded at more than 2σ level, the Starobinsky R{sup 2} inflation model is only favored at around 2σ level, and the spontaneously broken SUSY inflation model is now the most favored model. (orig.)

  7. Reexploration of interacting holographic dark energy model. Cases of interaction term excluding the Hubble parameter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hai-Li; Zhang, Jing-Fei; Feng, Lu [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Zhang, Xin [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Peking University, Center for High Energy Physics, Beijing (China)

    2017-12-15

    In this paper, we make a deep analysis for the five typical interacting holographic dark energy models with the interaction terms Q = 3βH{sub 0}ρ{sub de}, Q = 3βH{sub 0}ρ{sub c}, Q = 3βH{sub 0}(ρ{sub de} + ρ{sub c}), Q = 3βH{sub 0}√(ρ{sub de}ρ{sub c}), and Q = 3βH{sub 0}(ρ{sub de}ρ{sub c})/(ρ{sub de}+ρ{sub c}), respectively. We obtain observational constraints on these models by using the type Ia supernova data (the Joint Light-Curve Analysis sample), the cosmic microwave background data (Planck 2015 distance priors), the baryon acoustic oscillations data, and the direct measurement of the Hubble constant. We find that the values of χ{sub min}{sup 2} for all the five models are almost equal (around 699), indicating that the current observational data equally favor these IHDE models. In addition, a comparison with the cases of an interaction term involving the Hubble parameter H is also made. (orig.)

  8. Does current provision of undergraduate education prepare UK medical students in ENT? A systematic literature review.

    Science.gov (United States)

    Ferguson, Gary R; Bacila, Irina A; Swamy, Meenakshi

    2016-04-15

    To systematically identify and analyse all published literature relating to the provision of undergraduate education for preparedness in ear, nose and throat (ENT) surgery, as perceived by medical students and clinicians in the UK. Systematic literature review. 5 major databases were searched: MEDLINE, EMBASE, ERIC, Cochrane and Web of Science. The literature search was conducted from February to April 2015. Primary research or studies that report on the provision of undergraduate education for preparedness in ENT, from the perspective of medical students and clinicians in the UK. The timescale of searches was limited from 1999 onwards (ie, the past 15 years). The literature search was conducted by 2 independent reviewers. Search terms used involved the combination and variation of 5 key concepts, namely: medical student, clinician, ENT, undergraduate medical education and UK. A data extraction form was designed for and used in this study, based on guidelines provided by the UK National Health Service (NHS) Centre for Reviews and Dissemination. Textual narrative synthesis was used for data analysis. A total of 7 studies were included in the final review. 4 main themes were identified: confidence in managing patients, teaching delivery, student assessment and duration of rotations. A consistent finding in this review was that the majority of final year medical students and junior doctors did not feel adequately prepared to practise ENT. Important factors influencing preparedness in ENT included the duration of clinical rotations, the opportunity for hands-on learning and formal assessment. The findings of this review suggest the need for further development of the ENT undergraduate curricula across the UK. However, there is insufficient evidence from which to draw strong conclusions; this in itself is beneficial as it highlights a gap in the existing literature and supports the need for primary research. Published by the BMJ Publishing Group Limited. For

  9. HUBBLE provides multiple views of how to feed a black hole

    Science.gov (United States)

    1998-05-01

    fuel from a devoured galaxy, it may be oblivious to the rest of the galaxy and the collision," said Ethan Schreier of the Space Telescope Science Institute, Baltimore, MD. Schreier and an international team of co-investigators used Hubble's Near Infrared Camera and Multi-Object Spectrometer to probe deeper into the galaxy's mysterious heart than anyone has before. The hot gas disk viewed by Hubble investigators is perpendicular to the galaxy's outer dust belt, while the black hole's own internal accretion disk of superhot gas falling into it is tilted approximately diagonally to these axes. "We have found a complicated situation of a disk within a disk within a disk, all pointing in different directions," Schreier said. It is not clear if the black hole was always present in the host galaxy or belonged to the spiral galaxy that fell into the core, or if it is the product of the merger of a pair of smaller black holes that lived in the two once-separate galaxies. Having an active galaxy just 10 million light-years away from Earth rather than hundreds of millions or billions of light-years distant offers astronomers a unique laboratory for understanding the elusive details of the behavior of supermassive black holes as fueled by galaxy collisions. "Though Hubble has seen hot gas disks around black holes in other galaxies, the infrared camera has for the first time allowed us to peer at this relatively nearby, very active, but obscured black hole region," Schreier added. The team of astronomers is awaiting further Hubble data to continue its study of the disk, as well as ground-based spectroscopic observations to measure the velocity of entrapped material around the black hole. This will allow the astronomers to better calculate the black hole's mass. The current results are scheduled to appear in the June 1, 1998 issue of Astrophysical Journal Letters. Images and further information related to these results are available on the Internet at the following URLs: http

  10. Observations of the Hubble Deep Field with the Infrared Space Observatory .4. Association of sources with Hubble Deep Field galaxies

    DEFF Research Database (Denmark)

    Mann, R.G.; Oliver, S.J.; Serjeant, S.B.G.

    1997-01-01

    We discuss the identification of sources detected by the Infrared Space Observatory (ISO) at 6.7 and 15 mu m in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources with objects in existing optical and near-infrared HDF catalogues using the likelihood ratio method, confirming...... these results (and, in one case, clarifying them) with independent visual searches, We find 15 ISO sources to be reliably associated with bright [I-814(AB) HDF, and one with an I-814(AB)=19.9 star, while a further 11 are associated with objects in the Hubble Flanking Fields (10 galaxies...... and one star), Amongst optically bright HDF galaxies, ISO tends to detect luminous, star-forming galaxies at fairly high redshift and with disturbed morphologies, in preference to nearby ellipticals....

  11. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope.

    Science.gov (United States)

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-05-28

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current.

  12. [Current situation of sleeping duration in Chinese Han students in 2010].

    Science.gov (United States)

    Song, Yi; Zhang, Bing; Hu, Peijin; Ma, Jun

    2014-07-01

    To analyze the characteristics of sleep duration in Chinese primary and middle school students. The data was collected from 30 provinces (Autonomous regions, Municipalities) in 165 363 Han Primary school students above 4 grade, the junior and senior high school students who participated in 2010 National Physical Fitness and Health Surveillance by using stratified random cluster sampling method, and the questionnaire of sleep duration, insufficient sleep and commuting way from school was conducted at the same time.χ² test and χ² linear-by-linear test were used to analyze the difference between the different groups, and logistic regression was used to analyze the factors of insufficient sleep. Nationwide in 2010, 39.09% (64 646/165 363) of students reported they had more than 8 hours sleep duration per day, the prevalence was lower among urban (37.06% (30 767/83 027)) than rural (41.15% (33 879/82 336)) students (χ² = 290.53, P sleep duration per day in 9-12 years group, 13-15 years group and 16-18 years group was 70.24% (43 934/62 549), 31.31% (16 166/51 652) and 8.89% (546/51 162), respectively, and decreased with the age increasing (χ² linear-by-linear = 50 617.75, P sleep was 93.64% (154 838/165 363) in total students, the prevalence was higher among urban (94.94% (78 829/83 027)) than rural students (92.32% (76 009/82 336)) (χ² = 479.14, P sleep in 9-12 years group, 13-15 years group and 16-18 years group was 96.42% (60 310/62 549), 92.76% (47 912/51 562) and 91.11% (46 616/51 162), respectively. A multivariate logistic regression analysis (OR (95% CI)) revealed that the insufficient sleep was significantly associated with being urban (1.58 (1.51-1.65)), being girls (1.39 (1.34-1.45)), being 9-12 years group (2.77 (2.62-2.93)), living in the middle (1.19 (1.13-1.25)) or western (1.08 (1.03-1.13)) of China, and commuting from school by bicycle (1.21 (1.14-1.28)), bus/car (1.09 (1.03-1.15)), or in a boarding school (1.17 (1.10-1.24)). The sleep duration

  13. The Taxonomy for Learning, Teaching and Assessing: Current Practices at Polytechnics in Bangladesh and its Effects in Developing Students' Competences

    Directory of Open Access Journals (Sweden)

    Faruque A. Haolader

    2015-09-01

    Full Text Available Polytechnics in Bangladesh endeavour to produce quality graduates for national and international job markets. The quality of graduates depends on several factors. This study examines the implementation process of the polytechnic curriculum with the objectives of determining the current level of practices in learn-ing/teaching material design, in delivering curriculum content, in assessing students and its effect on students' competence development. Data was collected through observation, opinion survey and competence test. Qualitative and quantitative methodologies were used for data interpretation and analysis in this descriptive type of research study. Findings revealed that the learning materials are mainly theory oriented and mostly cover those contents usually common in exams. About half of teachers are aware of the taxonomy for learning, teaching and assessing, but they rarely put importance on it. In the classroom, teachers spend only a little time for delivering content at the level of apply/analyse. However, a significant number of tasks performed in labs are practical and occupation relevant and can be classified at higher levels of the taxonomy. In student assessment, the test-items assess mainly theoretical knowledge at the level of remember. The effect of these practices is reflected in demonstrating student performance in a competence test. The study concludes with some recommendations.

  14. Young adult sexual health: current and prior sexual behaviors among non-Hispanic white U.S. college students

    Science.gov (United States)

    Higgins, Jenny A.; Trussell, James; Moore, Nelwyn B.; Davidson, J. Kenneth

    2013-01-01

    Objective Less is known about the sexual health of young adults compared to adolescents, despite 20-24 year olds' greater risk of unintended pregnancy and sexually transmitted infections. This paper provides information on college students' prior and current sexual practices, including oral sex, vaginal intercourse, anal intercourse, and masturbation. Methods We analyzed data from a cross-sectional sexuality survey of students from two university campuses in the USA, one Midwestern and one Southwestern (N=1504). The sample consisted of non-Hispanic white, never-married students who identified as heterosexual. Results Of 16 possible combinations of four sexual activities (solitary masturbation, oral sex, vaginal intercourse, and anal intercourse), only four contained more than 5% of respondents: masturbation, oral sex, and vaginal intercourse (37%); oral sex and vaginal intercourse only (20%); all four (14%); and none (8%). Twenty percent had ever engaged in anal intercourse. Women were significantly less likely than men to have ever masturbated (48% versus 92%). Analyses exhibited several sexual health challenges, including lack of verbal sexual consent, alcohol use proximal to sex, and lack of contraceptive use. Conclusions Although few young adults are substituting it for vaginal intercourse, anal intercourse is increasingly common, and safer sex efforts should encourage condom use during both sexual activities. Masturbation should be encouraged as an alternative to higher risk sexual practices and an essential aspect of sexual well-being. Finally, practitioners should continue to address specific threats to college students' sexual health, including alcohol use and nonverbal consent. PMID:20152094

  15. Young adult sexual health: current and prior sexual behaviours among non-Hispanic white US college students.

    Science.gov (United States)

    Higgins, Jenny A; Trussell, James; Moore, Nelwyn B; Davidson, J Kenneth

    2010-03-01

    Less is known about the sexual health of young adults than about adolescents, despite 20 to 24-year-olds' greater risk of unintended pregnancy and sexually transmissible infections. This paper provides information on college students' prior and current sexual practices including oral sex, vaginal intercourse, anal intercourse and masturbation. We analysed data from a cross-sectional sexuality survey of students from two university campuses in the USA, one Mid-western and one South-western (n = 1504). The sample consisted of non-Hispanic white, never-married students who identified as heterosexual. Of 16 possible combinations of four sexual activities (solitary masturbation, oral sex, vaginal intercourse and anal intercourse), only four contained more than 5% of respondents: masturbation, oral sex and vaginal intercourse (37%); oral sex and vaginal intercourse only (20%); all four (14%); and none (8%). Twenty percent had ever engaged in anal intercourse. Women were significantly less likely than men to have ever masturbated (48 v. 92%). Analyses exhibited several sexual health challenges, including lack of verbal sexual consent, alcohol use proximal to sex and lack of contraceptive use. Although few young adults are substituting it for vaginal intercourse, anal intercourse is increasingly common and safer sex efforts should encourage condom use during both sexual activities. Masturbation should be encouraged as an alternative to higher risk sexual practices and an essential aspect of sexual well being. Finally, practitioners should continue to address specific threats to college students' sexual health, including alcohol use and non-verbal consent.

  16. The Carnegie–Chicago Hubble Program. III. The Distance to NGC 1365 via the Tip of the Red Giant Branch

    Science.gov (United States)

    Jang, In Sung; Hatt, Dylan; Beaton, Rachael L.; Lee, Myung Gyoon; Freedman, Wendy L.; Madore, Barry F.; Hoyt, Taylor J.; Monson, Andrew J.; Rich, Jeffrey A.; Scowcroft, Victoria; Seibert, Mark

    2018-01-01

    The Carnegie–Chicago Hubble Program (CCHP) seeks to anchor the distance scale of Type Ia supernovae via the Tip of the Red Giant Branch (TRGB) method. Based on deep Hubble Space Telescope ACS/WFC imaging, we present an analysis of the TRGB for the metal-poor halo of NGC 1365, a giant spiral galaxy in the Fornax cluster that was host to the Type Ia supernova SN 2012fr. We have measured the extinction-corrected TRGB magnitude of NGC 1365 to be F814W = 27.34 ± 0.03stat ± 0.04sys mag. In advance of future direct calibration by Gaia, we adopt a provisional I-band TRGB luminosity set at the Large Magellanic Cloud and find a true distance modulus μ 0 = 31.29 ± 0.04stat ± 0.06sys mag or D = 18.1 ± 0.3stat ± 0.5sys Mpc. This measurement is in excellent agreement with recent Cepheid-based distances to NGC 1365 and reveals no significant difference in the distances derived from stars of Populations I and II for this galaxy. We revisit the error budget for the CCHP path to the Hubble constant based on the analysis presented here, i.e., that for one of the most distant Type Ia supernova hosts within our Program, and find that a 2.5% measurement is feasible with the current sample of galaxies and TRGB absolute calibration. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13691.

  17. Current Alcohol Use is Associated with Sleep Patterns in First-Year College Students.

    Science.gov (United States)

    Van Reen, Eliza; Roane, Brandy M; Barker, David H; McGeary, John E; Borsari, Brian; Carskadon, Mary A

    2016-06-01

    To examine whether differences exist in self-reported sleep patterns and self-reported alcohol use for first-semester college students who do or do not report drinking during the last 6 months (mo) of high school. Participants were 878 first-year college students. Students completed a survey in late May/early June about alcohol use and consequences, during the last 6 mo of high school; they later completed a daily record of sleep behavior and alcohol use across the first 9 weeks of the first semester of college. High school drinking status (past 6 mo) was classified as positive (HS-6 mo+) or negative (HS-6mo-) based on any indication of drinking on the May/June survey. Collegiate drinking was determined from first-semester daily diary alcohol reports as non-drinkers (0 reported drinks), drinkers (one or fewer heavy episodic drinking episodes (HED)), and drinkers reporting more than one HED episode. Sleep patterns were compared for non-drinkers, drinkers, and HED with no high school drinking history (HS-6mo-/HED). In addition, a separate analysis compared sleep patterns for college HED with (HS-6mo+/HED) and without (HS-6mo-/HED) high school self-reported alcohol use. Increased alcohol consumption in the first semester of college was associated with later bedtimes and rise times. We found no association of high school alcohol use and sleep in those with collegiate HED. Later sleep timing in those with greater alcohol use, supports a connection between sleep patterns and alcohol use. Such an early appearance of this connection may herald the development of alcohol use disorder in some individuals. © 2016 Associated Professional Sleep Societies, LLC.

  18. Childhood and current ADHD symptom dimensions are associated with more severe cannabis outcomes in college students.

    Science.gov (United States)

    Bidwell, L C; Henry, E A; Willcutt, E G; Kinnear, M K; Ito, T A

    2014-02-01

    Numerous studies have shown that attention deficit/hyperactivity disorder (ADHD) is associated higher risk of cannabis use disorders (CUD). However, these studies are limited in that most did not: (a) differentiate the role of hyperactivity-impulsivity (HI) and inattention (IN); (b) control for associated psychopathology; and (c) consider more fine-grained CUD-related measures. Our aim was to clarify the unique and interactive contributions of inattention and hyperactivity symptoms to age of cannabis initiation and DSM-IV cannabis dependence, craving, and severity of problems related to cannabis use while statistically controlling for symptoms of comorbid psychopathology in a non-clinical sample of young adults. Cannabis variables, current use of cigarettes and alcohol, current and childhood ADHD, and comorbid internalizing and externalizing psychopathology were assessed in 376 male and female undergraduates. Results indicate that current and childhood IN were independently associated with more severe cannabis use, craving, and problem use-related outcomes in young adulthood (p'scannabis (pcannabis use. Associations with ADHD symptom dimensions and current use of alcohol and cigarettes were also present. Thus, current and childhood inattention symptoms as well as childhood hyperactive-impulsive symptoms emerged as significant factors in cannabis-related outcomes in young adults, even after statistically controlling for important confounding variables. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  19. Moncton’s Student Protest Wave of 1968: Local Issues, Global Currents and the Birth of Acadian Neo-Nationalism

    Directory of Open Access Journals (Sweden)

    Joel Belliveau

    2013-01-01

    Full Text Available When Acadian students put forward a new, left-leaning brand of nationalism at the end of the 1960s, most observers concluded that it was simply a “spill-over” effect of Quebec’s “Quiet Revolution”. This paper will put forward the case that Acadian néo-nationalisme had a lot more to do with global currents of ideas than with Québécois nationalism. It is through a New Left inspired analysis of regional inequalities that Acadian student militants became aware of disparities between the province’s linguistic groups, and through the loose adoption of an anticolonial viewpoint that they reconciled themselves to the idea of nationalism. Moreover, at all times, these actors felt and imagined their struggle to be part of a broader progressive movement.

  20. Comparison of midwifery students' satisfaction with direct observation of procedural skills and current methods in evaluation of procedural skills in Mashhad Nursing and Midwifery School.

    Science.gov (United States)

    Hoseini, Bibi Leila; Mazloum, Seyed Reza; Jafarnejad, Farzaneh; Foroughipour, Mohsen

    2013-03-01

    The clinical evaluation, as one of the most important elements in medical education, must measure students' competencies and abilities. The implementation of any assessment tool is basically dependent on the acceptance of students. This study tried to assess midwifery students' satisfaction with Direct Observation of Procedural Skills (DOPS) and current clinical evaluation methods. This quasi-experimental study was conducted in the university hospitals affiliated to Mashhad University of Medical Sciences. The subjects comprised 67 undergraduate midwifery students selected by convenience sampling and allocated to control and intervention groups according to the training transposition. Current method was performed in the control group, and DOPS was conducted in the intervention group. The applied tools included DOPS rating scales, logbook, and satisfaction questionnaires with clinical evaluation methods. Validity and reliability of these tools were approved. At the end of training, students' satisfaction with the evaluation methods was assessed by the mentioned tools. The data were analyzed by descriptive and analytical statistics. Satisfaction mean scores of midwifery students with DOPS and current methods were 76.7 ± 12.9 and 62.6 ± 14.7 (out of 100), respectively. DOPS students' satisfaction mean score was significantly higher than the score obtained in current method (P satisfactory domains in the current method were "consistence with learning objectives" (71.2 ± 14.9) and "objectiveness" in DOPS (87.9 ± 15.0). In contrast, the least satisfactory domains in the current method were "interested in applying the method" (57.8 ± 26.5) and "number of assessments for each skill" (58.8 ± 25.9) in DOPS method. This study showed that DOPS method is associated with greater students' satisfaction. Since the students' satisfaction with the current method was also acceptable, we recommend combining this new clinical evaluation method with the current method, which covers

  1. The Current Experiences of Physical Education Teachers at Schools for Blind Students in the United States

    Science.gov (United States)

    Haegele, Justin A.; Lieberman, Lauren J.

    2016-01-01

    Introduction: It has been well established that children with visual impairments tend to be less physically active and more delayed in motor skills than their sighted peers. As a result, there has been some research focusing on inclusive physical education for these children. However, there is a clear lack of research on the current status of…

  2. Assessment of BSBA Students' Conversancy in Current Business Issues: A Case Study

    Science.gov (United States)

    Hogan, Eileen A.; Maskulka, Therese A.; Kaminski, Kathleen A.

    2014-01-01

    In 2008, the faculty of the College of Business at Kutztown University developed a set of five learning goals for its BSBA program. In fall, 2011, the college's Assurance of Learning Committee began to pursue the assessment of the last of these goals: "BSBA graduates will be conversant in current business issues, including ethics, social…

  3. The Persistence of Prior Concepts about Electric Potential, Current Intensity and Ohm’s Law in Students of Engineering

    Directory of Open Access Journals (Sweden)

    María Cristina Periago

    2005-11-01

    Full Text Available The aim of this research was to evaluate and analyze second-year industrial-engineering and chemical-engineering students’ prior knowledge of conceptual aspects of circuit theory. Specifically, we have focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between these as expressed by Ohm’s Law. In order to find out what the students’ prior concepts were, we applied a survey containing nine questions dealing with the most basic concepts of circuit theory. Let us emphasize that there was little information available about the prior concepts of the population type (university students investigated in this research.

  4. Electrostatic Studies for the 2008 Hubble Service Repair Mission

    Science.gov (United States)

    Buhler, C. R.; Clements, J. S.; Calle, C. I.

    2012-01-01

    High vacuum triboelectric testing of space materials was required to identify possible Electrostatic Discharge (ESD) concerns for the astronauts in space during electronics board replacement on the Hubble Space Telescope. Testing under high vacuum conditions with common materials resulted in some interesting results. Many materials were able to charge to high levels which did not dissipate quickly even when grounded. Certain materials were able to charge up in contact with grounded metals while others were not. An interesting result was that like materials did not exchange electrostatic charge under high vacuum conditions. The most surprising experimental result is the lack of brush discharges from charged insulators under high vacuum conditions.

  5. Dark energy and the quietness of the local Hubble flow

    International Nuclear Information System (INIS)

    Axenides, M.; Perivolaropoulos, L.

    2002-01-01

    The linearity and quietness of the local ( X (t 0 ) of dark energy obeying the time independent equation of state p X =wρ X . We find that dark energy can indeed cool the LHF. However the dark energy parameter values required to make the predicted velocity dispersion consistent with the observed value v rms ≅40 km/s have been ruled out by other observational tests constraining the dark energy parameters w and Ω X . Therefore despite the claims of recent qualitative studies, dark energy with time independent equation of state cannot by itself explain the quietness and linearity of the local Hubble flow

  6. Super-Hubble de Sitter fluctuations and the dynamical RG

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, C.P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario (Canada); Leblond, L.; Shandera, S. [Perimeter Institute for Theoretical Physics, Waterloo, Ontario (Canada); Holman, R., E-mail: cburgess@perimeterinstitute.ca, E-mail: lleblond@perimeterinstitute.ca, E-mail: rha@andrew.cmu.edu, E-mail: sshandera@perimeterinstitute.ca [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2010-03-01

    Perturbative corrections to correlation functions for interacting theories in de Sitter spacetime often grow secularly with time, due to the properties of fluctuations on super-Hubble scales. This growth can lead to a breakdown of perturbation theory at late times. We argue that Dynamical Renormalization Group (DRG) techniques provide a convenient framework for interpreting and resumming these secularly growing terms. In the case of a massless scalar field in de Sitter with quartic self-interaction, the resummed result is also less singular in the infrared, in precisely the manner expected if a dynamical mass is generated. We compare this improved infrared behavior with large-N expansions when applicable.

  7. Observational constraints on Hubble parameter in viscous generalized Chaplygin gas

    Science.gov (United States)

    Thakur, P.

    2018-04-01

    Cosmological model with viscous generalized Chaplygin gas (in short, VGCG) is considered here to determine observational constraints on its equation of state parameters (in short, EoS) from background data. These data consists of H(z)-z (OHD) data, Baryonic Acoustic Oscillations peak parameter, CMB shift parameter and SN Ia data (Union 2.1). Best-fit values of the EoS parameters including present Hubble parameter (H0) and their acceptable range at different confidence limits are determined. In this model the permitted range for the present Hubble parameter and the transition redshift (zt) at 1σ confidence limits are H0= 70.24^{+0.34}_{-0.36} and zt=0.76^{+0.07}_{-0.07} respectively. These EoS parameters are then compared with those of other models. Present age of the Universe (t0) have also been determined here. Akaike information criterion and Bayesian information criterion for the model selection have been adopted for comparison with other models. It is noted that VGCG model satisfactorily accommodates the present accelerating phase of the Universe.

  8. HUBBLE'S PANORAMIC PORTRAIT OF A VAST STAR-FORMING REGION

    Science.gov (United States)

    2002-01-01

    NASA's Hubble Space Telescope has snapped a panoramic portrait of a vast, sculpted landscape of gas and dust where thousands of stars are being born. This fertile star-forming region, called the 30 Doradus Nebula, has a sparkling stellar centerpiece: the most spectacular cluster of massive stars in our cosmic neighborhood of about 25 galaxies. The mosaic picture shows that ultraviolet radiation and high-speed material unleashed by the stars in the cluster, called R136 [the large blue blob left of center], are weaving a tapestry of creation and destruction, triggering the collapse of looming gas and dust clouds and forming pillar-like structures that are incubators for nascent stars. The photo offers an unprecedented, detailed view of the entire inner region of 30 Doradus, measuring 200 light-years wide by 150 light-years high. The nebula resides in the Large Magellanic Cloud (a satellite galaxy of the Milky Way), 170,000 light-years from Earth. Nebulas like 30 Doradus are the 'signposts' of recent star birth. High-energy ultraviolet radiation from the young, hot, massive stars in R136 causes the surrounding gaseous material to glow. Previous Hubble telescope observations showed that R136 contains several dozen of the most massive stars known, each about 100 times the mass of the Sun and about 10 times as hot. These stellar behemoths all formed at the same time about 2 million years ago. The stars in R136 are producing intense 'stellar winds' (streams of material traveling at several million miles an hour), which are wreaking havoc on the gas and dust in the surrounding neighborhood. The winds are pushing the gas away from the cluster and compressing the inner regions of the surrounding gas and dust clouds [the pinkish material]. The intense pressure is triggering the collapse of parts of the clouds, producing a new generation of star formation around the central cluster. The new stellar nursery is about 30 to 50 light-years from R136. Most of the stars in the

  9. MOVING OBJECTS IN THE HUBBLE ULTRA DEEP FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Mukremin; Gianninas, Alexandros [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Von Hippel, Ted, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu, E-mail: ted.vonhippel@erau.edu [Embry-Riddle Aeronautical University, 600 S. Clyde Morris Blvd., Daytona Beach, FL 32114 (United States)

    2013-09-01

    We identify proper motion objects in the Hubble Ultra Deep Field (UDF) using the optical data from the original UDF program in 2004 and the near-infrared data from the 128 orbit UDF 2012 campaign. There are 12 sources brighter than I = 27 mag that display >3{sigma} significant proper motions. We do not find any proper motion objects fainter than this magnitude limit. Combining optical and near-infrared photometry, we model the spectral energy distribution of each point-source using stellar templates and state-of-the-art white dwarf models. For I {<=} 27 mag, we identify 23 stars with K0-M6 spectral types and two faint blue objects that are clearly old, thick disk white dwarfs. We measure a thick disk white dwarf space density of 0.1-1.7 Multiplication-Sign 10{sup -3} pc{sup -3} from these two objects. There are no halo white dwarfs in the UDF down to I = 27 mag. Combining the Hubble Deep Field North, South, and the UDF data, we do not see any evidence for dark matter in the form of faint halo white dwarfs, and the observed population of white dwarfs can be explained with the standard Galactic models.

  10. Metrical connection in space-time, Newton's and Hubble's laws

    International Nuclear Information System (INIS)

    Maeder, A.

    1978-01-01

    The theory of gravitation in general relativity is not scale invariant. Here, we follow Dirac's proposition of a scale invariant theory of gravitation (i.e. a theory in which the equations keep their form when a transformation of scale is made). We examine some concepts of Weyl's geometry, like the metrical connection, the scale transformations and invariance, and we discuss their consequences for the equation of the geodetic motion and for its Newtonian limit. Under general conditions, we show that the only non-vanishing component of the coefficient of metrical connection may be identified with Hubble's constant. In this framework, the equivalent to the Newtonian approximation for the equation of motion contains an additional acceleration term Hdr vector /dt, which produces an expansion of gravitational systems. The velocity of this expansion is shown to increase linearly with the distance between interacting objects. The relative importance of this new expansion term to the Newtonian one varies like (2rhosub(c)/rho)sup(1/2), where rhosub(c) is the critical density of the Einsteinde Sitter model and rho is the mean density of the considered gravitational configuration. Thus, this 'generalized expansion' is important essentially for systems of mean density not too much above the critical density. Finally, our main conclusion is that in the integrable Weyl geometry, Hubble's law - like Newton's law - would appear as an intrinsic property of gravitation, being only the most visible manifestation of a general effect characterizing the gravitational interaction. (orig.) [de

  11. Astronaut Anna Fisher in NBS Training For Hubble Space Telescope

    Science.gov (United States)

    1980-01-01

    The Hubble Space Telescope (HST) is a cooperative program of the European Space Agency (ESA) and the National Aeronautical and Space Administration (NASA) to operate a long-lived space-based observatory. It was the flagship mission of NASA's Great Observatories program. The HST program began as an astronomical dream in the 1940s. During the 1970s and 1980s, the HST was finally designed and built becoming operational in the 1990s. The HST was deployed into a low-Earth orbit on April 25, 1990 from the cargo bay of the Space Shuttle Discovery (STS-31). The design of the HST took into consideration its length of service and the necessity of repairs and equipment replacement by making the body modular. In doing so, subsequent shuttle missions could recover the HST, replace faulty or obsolete parts and be re-released. Marshall Space Flight Center's (MSFC's) Neutral Buoyancy Simulator (NBS) served as the test center for shuttle astronauts training for Hubble related missions. Shown is astronaut Anna Fisher training on a mock-up of a modular section of the HST for an axial scientific instrument change out.

  12. An independent determination of the local Hubble constant

    Science.gov (United States)

    Fernández Arenas, David; Terlevich, Elena; Terlevich, Roberto; Melnick, Jorge; Chávez, Ricardo; Bresolin, Fabio; Telles, Eduardo; Plionis, Manolis; Basilakos, Spyros

    2018-02-01

    The relationship between the integrated H β line luminosity and the velocity dispersion of the ionized gas of H II galaxies and giant H II regions represents an exciting standard candle that presently can be used up to redshifts z ˜ 4. Locally it is used to obtain precise measurements of the Hubble constant by combining the slope of the relation obtained from nearby (z ≤ 0.2) H II galaxies with the zero-point determined from giant H II regions belonging to an `anchor sample' of galaxies for which accurate redshift-independent distance moduli are available. We present new data for 36 giant H II regions in 13 galaxies of the anchor sample that includes the megamaser galaxy NGC 4258. Our data are the result of the first 4 yr of observation of our primary sample of 130 giant H II regions in 73 galaxies with Cepheid determined distances. Our best estimate of the Hubble parameter is 71.0 ± 2.8(random) ± 2.1(systematic) km s- 1Mpc- 1. This result is the product of an independent approach and, although at present less precise than the latest SNIa results, it is amenable to substantial improvement.

  13. A Scientific Revolution: The Hubble and James Webb Space Telescopes

    Science.gov (United States)

    Gardner, Jonathan P.

    2010-01-01

    Astronomy is going through a scientific revolution, responding to a flood of data from the Hubble Space Telescope, other space missions, and large telescopes on the ground. In this talk, I will discuss some of the important discoveries of the last decade, from dwarf planets in the outer Solar System to the mysterious dark energy that overcomes gravity to accelerate the expansion of the Universe. The next decade will be equally bright with the newly refurbished Hubble and the promise of its successor, the James Webb Space Telescope. An infrared-optimized 6.5m space telescope, Webb is designed to find the first galaxies that formed in the early universe and to peer into the dusty gas clouds where stars and planets are born. With MEMS technology, a deployed primary mirror and a tennis-court sized sunshield, the mission presents many technical challenges. I will describe Webb's scientific goals, its design and recent progress in constructing the observatory. Webb is scheduled for launch in 2014.

  14. Dynamical interpretation of the Hubble sequence of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Dallaporta, N; Secco, L [Padua Univ. (Italy). Istituto di Astronomia

    1977-08-01

    Brosche (1970) has proposed a theory in which the energy loss due to collisions among gas clouds contained in a galaxy constitutes the driving mechanism for its evolution, through virial equilibrium states, which, from an initial spherical shape, makes it to contract towards an elongated form; moreover, the value of the total angular momentum, assumed as given by uniform rotation, is assumed to determine the galaxy type on the Hubble sequence and to influence strongly the contraction time from the initial spherical to the final flat configuration. The authors modify Brosche's scheme by assuming as models the rotating polytropes of Chandrasekhar and Lebovitz with variable density from centre to border. As a consequence of this change, centrifugal shedding of matter is attained at the equator of the contracting ellipsoid for a configuration with an axial ratio different from zero, so that, hereafter, a flat disk is formed surrounding the internal bulge, with a decreasing overall eccentricity; the rotation curve assumes then an aspect qualitatively similar to the one observed for spiral galaxies. The feedback of star formation which, by exhausting the material of the gas clouds, is able to stop the driving mechanism of evolution before the final flat stage is attained has also been considered at several positions according to the value of the angular momentum. Numerical calculations seem to indicate that one can obtain in this way, by varying the angular momentum and the initial number of clouds, different galaxy types (elliptical, lenticular, spiral) resembling those of the Hubble sequence.

  15. Dynamical friction: The Hubble diagram as a cosmological test

    International Nuclear Information System (INIS)

    Gunn, J.E.; Tinsley, B.M.

    1976-01-01

    Effects on the Hubble diagram of the frictional accretion of small cluster galaxies by large ones, to which Ostriker and Tremaine have recently drawn attention, must be accurately determined if the magnitude-redshift relation is to become a viable cosmological test. We find that the process might be detectable through the concomitant change in galaxy colors, but that its effect on the dispersion of magnitudes of first-ranked cluster galaxies would be negligible even if the change in average magnitude is very important. The sign of the effect of accretion on the luminosity observed within a given aperture depends on the structures of the galaxies involved. The size of the effect not only depends sensitively on the galaxy structures, but is also amplified when the relatively recent collapse times of the clusters are taken into account. It is vital to answer the complicated observational and theoretical questions raised by these preliminary calculations, because the Hubble diagram remains the most promising approach to the deceleration parameter q 0 . Local tests of the density of the universe do not give equivalent information

  16. Comparison between current and ideal condition of educational justice from the students' viewpoints at Jahrom Nursing and Paramedical School.

    Science.gov (United States)

    Montaseri, Mohammad Ali; Hojat, Mohsen; Karimyar Jahromi, Mahdi

    2014-01-01

    Educational justice is a process by which all those involved in education are pondering and seeking to establish it in their regulatory environments. This study aimed to investigate effective factors in an ideal educational justice and the current condition of educational justice from the students' viewpoint and ultimately increase the awareness and understanding of authorities and educational planners of the existing shortcomings.  This is a descriptive-analytical study. Samples include all nursing, operating room, and anesthesia students of nursing and paramedical college who had passed at least 5 semesters. Data collection was carried out through a scholar questionnaire. Validity was assessed through content validity and reliability of the questionnaire was evaluated using a pilot study.  In order to determine the status of the scores, 5 points (very high), 4 (often), 3 (moderate), 2 (low) and 1 (very low) were assigned, respectively. To determine the justice level, a 35 score interval was considered as very low, low, medium, high and very high. SPSS software, descriptive statistics, independent t-test and ANOVA were used to analyze the data.  There was a significant difference between the ideal and the current conditions in all items (p≤0.001) and also in the total mean score of ideal condition  and mean score of current condition (p=0.010). In an educational system, educational methods and aims should be regulated in a way that principles and components of justice are attainable and distribution and allocation of educational facilities of justice are considered thoroughly.

  17. European astronomers' successes with the Hubble Space Telescope*

    Science.gov (United States)

    1997-02-01

    [Figure: Laguna Nebula] Their work spans all aspects of astronomy, from the planets to the most distant galaxies and quasars, and the following examples are just a few European highlights from Hubble's second phase, 1994-96. A scarcity of midget stars Stars less massive and fainter than the Sun are much numerous in the Milky Way Galaxy than the big bright stars that catch the eye. Guido De Marchi and Francesco Paresce of the European Southern Observatory as Garching, Germany, have counted them. With the wide-field WFPC2 camera, they have taken sample censuses within six globular clusters, which are large gatherings of stars orbiting independently in the Galaxy. In every case they find that the commonest stars have an output of light that is only one-hundredth of the Sun's. They are ten times more numerous than stars like the Sun. More significant for theories of the Universe is a scarcity of very faint stars. Some astronomers have suggested that vast numbers of such stars could account for the mysterious dark matter, which makes stars and galaxies move about more rapidly than expected from the mass of visible matter. But that would require an ever-growing count of objects at low brightnesses, and De Marchi and Paresce find the opposite to be the case -- the numbers diminish. There may be a minimum size below which Nature finds starmaking difficult. The few examples of very small stars seen so far by astronomers may be, not the heralds of a multitude of dark-matter stars, but rareties. Unchanging habits in starmaking Confirmation that very small stars are scarce comes from Gerry Gilmore of the Institute of Astronomy in Cambridge (UK). He leads a European team that analyses long-exposure images in the WFPC2 camera, obtained as a by-product when another instrument is examining a selected object. The result is an almost random sample of well-observed stars and galaxies. The most remarkable general conclusion is that the make-up of stellar populations never seems to

  18. Hubble diagram as a probe of minicharged particles

    International Nuclear Information System (INIS)

    Ahlers, Markus

    2009-01-01

    The luminosity-redshift relation of cosmological standard candles provides information about the relative energy composition of our Universe. In particular, the observation of type Ia supernovae up to a redshift of z∼2 indicates a universe which is dominated today by dark matter and dark energy. The propagation distance of light from these sources is of the order of the Hubble radius and serves as a very sensitive probe of feeble inelastic photon interactions with background matter, radiation, or magnetic fields. In this paper we discuss the limits on minicharged particle models arising from a dimming effect in supernova surveys. We briefly speculate about a strong dimming effect as an alternative to dark energy.

  19. Second generation spectrograph for the Hubble Space Telescope

    Science.gov (United States)

    Woodgate, B. E.; Boggess, A.; Gull, T. R.; Heap, S. R.; Krueger, V. L.; Maran, S. P.; Melcher, R. W.; Rebar, F. J.; Vitagliano, H. D.; Green, R. F.; Wolff, S. C.; Hutchings, J. B.; Jenkins, E. B.; Linsky, J. L.; Moos, H. W.; Roesler, F.; Shine, R. A.; Timothy, J. G.; Weistrop, D. E.; Bottema, M.; Meyer, W.

    1986-01-01

    The preliminary design for the Space Telescope Imaging Spectrograph (STIS), which has been selected by NASA for definition study for future flight as a second-generation instrument on the Hubble Space Telescope (HST), is presented. STIS is a two-dimensional spectrograph that will operate from 1050 A to 11,000 A at the limiting HST resolution of 0.05 arcsec FWHM, with spectral resolutions of 100, 1200, 20,000, and 100,000 and a maximum field-of-view of 50 x 50 arcsec. Its basic operating modes include echelle model, long slit mode, slitless spectrograph mode, coronographic spectroscopy, photon time-tagging, and direct imaging. Research objectives are active galactic nuclei, the intergalactic medium, global properties of galaxies, the origin of stellar systems, stelalr spectral variability, and spectrographic mapping of solar system processes.

  20. Selections from 2017: Hubble Survey Explores Distant Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2017-12-01

    Editors note:In these last two weeks of 2017, well be looking at a few selections that we havent yet discussed on AAS Nova from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume in January.CANDELS Multi-Wavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOSSurvey FieldPublished January2017Main takeaway:A publication led byHooshang Nayyeri(UC Irvine and UC Riverside) early this year details acatalog of sources built using the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey(CANDELS), a survey carried out by cameras on board the Hubble Space Telescope. The catalogliststhe properties of 38,000 distant galaxies visiblewithin the COSMOS field, a two-square-degree equatorial field explored in depthto answer cosmological questions.Why its interesting:Illustration showing the three-dimensional map of the dark matter distribution in theCOSMOS field. [Adapted from NASA/ESA/R. Massey(California Institute of Technology)]The depth and resolution of the CANDELS observations areuseful for addressingseveral major science goals, including the following:Studying the most distant objects in the universe at the epoch of reionization in the cosmic dawn.Understanding galaxy formation and evolution during the peak epoch of star formation in the cosmic high noon.Studying star formation from deep ultravioletobservations and studying cosmology from supernova observations.Why CANDELS is a major endeavor:CANDELS isthe largest multi-cycle treasury program ever approved on the Hubble Space Telescope using over 900 orbits between 2010 and 2013 withtwo cameras on board the spacecraftto study galaxy formation and evolution throughout cosmic time. The CANDELS images are all publicly available, and the new catalogrepresents an enormous source of information about distant objectsin our universe.CitationH. Nayyeri et al 2017 ApJS 228 7. doi:10.3847/1538-4365/228/1/7

  1. The Hubble Constant to 1%: Physics beyond LambdaCDM

    Science.gov (United States)

    Riess, Adam

    2017-08-01

    By steadily advancing the precision and accuracy of the Hubble constant, we now see 3.4-sigma evidence for a deviation from the standard LambdaCDM model and thus the exciting chance of discovering new fundamental physics such as exotic dark energy, a new relativistic particle, dark matter interactions, or a small curvature, to name a few possibilities. We propose a coordinated program to accomplish three goals with one set of observations: (1) improve the precision of the best route to H_0 with HST observations of Cepheids in the hosts of 11 SNe Ia, lowering the uncertainty to 1.3% to reach the discovery threshold of 5-sigma and begin resolving the underlying source of the deviation; (2) continue testing the quality of Cepheid distances, so far the most accurate and reliable indicators in the near Universe, using the tip of the red giant branch (TRGB); and (3) use oxygen-rich Miras to confirm the present tension with the CMB and establish a future route available to JWST. We can achieve all three goals with one dataset and take the penultimate step to reach 1% precision in H_0 after Gaia. With its long-pass filter and NIR capability, we can collect these data with WFC3 many times faster than previously possible while overcoming the extinction and metallicity effects that challenged the first generation of H_0 measurements. Our results will complement the leverage available at high redshift from other cosmological tools such as BAO, the CMB, and SNe Ia, and will provide a 40% improvement on the WFIRST measurements of dark energy. Reaching this precision will be a fitting legacy for the telescope charged to resolve decades of uncertainty regarding the Hubble constant.

  2. Preparing nursing students for enhanced roles in primary care: The current state of prelicensure and RN-to-BSN education.

    Science.gov (United States)

    Wojnar, Danuta M; Whelan, Ellen Marie

    With the current emphasis on including registered nurses (RNs) on the primary care teams, it is essential that nursing programs prepare students for employment in these settings. This study explored the current state of prelicensure and RN-to-Bachelor of Science in Nursing (BSN) online education regarding the implementation of primary care content in the curricula. A sample of 1,409 schools and/or colleges from across the United States was invited to participate in an online survey. About 529 surveys were returned for an overall response rate of 37.5%. Summative content analysis was used to analyze survey data. Although most respondents have implemented some primary care content, some found it challenging and others have demurred from incorporating primary care content altogether. Nursing leaders and faculty in academia must collaborate with clinical partners to design and expand didactic and clinical learning experiences that emphasize primary care content in the prelicensure and RN-to-BSN education. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. The role of academic motivation in high school students' current and lifetime alcohol consumption: adopting a self-determination theory perspective.

    Science.gov (United States)

    Wormington, Stephanie V; Anderson, Kristen G; Corpus, Jennifer Henderlong

    2011-11-01

    The current study investigated the relationship between different types of academic motives-specifically, intrinsic motivation, introjected regulation, and external regulation-and high school students' current and lifetime alcohol consumption. One thousand sixty-seven high school students completed measures of academic motivation, other school-related factors, and lifetime and current alcohol consumption. Using structural equation modeling, different types of motivation and school-related factors were differentially related to student drinking. Specifically, intrinsic motivation was negatively related to lifetime and current alcohol consumption. External regulation, on the other hand, was positively associated with current drinking. Grade point average was the only school-related factor related to student alcohol use. These findings suggest that motivation is an important construct to consider in predicting students' alcohol use, even when other more commonly studied educational variables are considered. In addition, it supports the adoption of a motivation framework that considers different types of motivation in understanding the relationship between academic motivation and alcohol use. Suggestions for incorporating the self-determination model of motivation into studies of alcohol and substance use, as well as potential impacts on intervention efforts, are discussed. In particular, it may be important to foster only certain types of motivation, rather than all types of academically-focused motives, in efforts to deter alcohol use.

  4. Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel Observations

    Science.gov (United States)

    Yan, Haojing; Yan, Lin; Zamojski, Michel A.; Windhorst, Rogier A.; McCarthy, Patrick J.; Fan, Xiaohui; Röttgering, Huub J. A.; Koekemoer, Anton M.; Robertson, Brant E.; Davé, Romeel; Cai, Zheng

    2011-02-01

    We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis includes 26 widely separated fields observed by the Wide Field Camera 3, which amounts to 122.8 arcmin2 in total area. We have found three bright Y 098-dropouts, which are candidate galaxies at z >~ 7.4. One of these objects shows an indication of peculiar variability and its nature is uncertain. The other two objects are among the brightest candidate galaxies at these redshifts known to date (L>2L*). Such very luminous objects could be the progenitors of the high-mass Lyman break galaxies observed at lower redshifts (up to z ~ 5). While our sample is still limited in size, it is much less subject to the uncertainty caused by "cosmic variance" than other samples because it is derived using fields along many random sightlines. We find that the existence of the brightest candidate at z ≈ 7.4 is not well explained by the current luminosity function (LF) estimates at z ≈ 8. However, its inferred surface density could be explained by the prediction from the LFs at z ≈ 7 if it belongs to the high-redshift tail of the galaxy population at z ≈ 7. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11700 and 11702.

  5. Mach's Principle to Hubble's Law and Light Relativity

    Science.gov (United States)

    Zhang, Tianxi

    2018-01-01

    Discovery of the redshift-distance relation to be linear (i.e. Hubble's law) for galaxies in the end of 1920s instigated us to widely accept expansion of the universe, originated from a big bang around 14 billion years ago. Finding of the redshift-distance relation to be weaker than linear for distant type Ia supernovae nearly two decades ago further precipitated us to largely agree with recent acceleration of the universe, driven by the mysterious dark energy. The time dilation measured for supernovae has been claimed as a direct evidence for the expansion of the universe, but scientists could not explain why quasars and gamma-ray bursts had not similar time dilations. Recently, an anomaly was found in the standard template for the width of supernova light curves to be proportional to the wavelength, which exactly removed the time dilation of supernovae and hence was strongly inconsistent with the conventional redshift mechanism. In this study, we have derived a new redshift-distance relation from Mach's principle with light relativity that describes the effect of light on spacetime as well as the influence of disturbed spacetime on the light inertia or frequency. A moving object or photon, because of its continuously keeping on displacement, disturbs the rest of the entire universe or distorts/curves the spacetime. The distorted or curved spacetime then generates an effective gravitational force to act back on the moving object or photon, so that reduces the object inertia or photon frequency. Considering the disturbance of spacetime by a photon is extremely weak, we have modelled the effective gravitational force to be Newtonian and derived the new redshift-distance relation that can not only perfectly explain the redshift-distance measurement of distant type Ia supernovae but also inherently obtain Hubble's law as an approximate at small redshift. Therefore, the result obtained from this study does neither support the acceleration of the universe nor the

  6. Finding our Origins with the Hubble and James Webb Space Telescopes

    Science.gov (United States)

    Gardner, Jonathan P.

    2009-01-01

    NASA is planning a successor to the Hubble Space Telescope designed to study the origins of galaxies, stars, planets and life in the universe. In this talk, Dr. Gardner will discuss the origin and evolution of galaxies, beginning with the Big Bang and tracing what we have learned with Hubble through to the present day. He will show that results from studies with Hubble have led to plans for its successor, the James Webb Space Telescope. Webb is scheduled to launch in 2014, and is designed to find the first galaxies that formed in the distant past and to penetrate the dusty clouds of gas where stars are still forming today. He will compare Webb to Hubble, and discuss recent progress in the construction of the observatory.

  7. Hubble Servicing Challenges Drive Innovation of Shuttle Rendezvous Techniques

    Science.gov (United States)

    Goodman, John L.; Walker, Stephen R.

    2009-01-01

    Hubble Space Telescope (HST) servicing, performed by Space Shuttle crews, has contributed to what is arguably one of the most successful astronomy missions ever flown. Both nominal and contingency proximity operations techniques were developed to enable successful servicing, while lowering the risk of damage to HST systems, and improve crew safety. Influencing the development of these techniques were the challenges presented by plume impingement and HST performance anomalies. The design of both the HST and the Space Shuttle was completed before the potential of HST contamination and structural damage by shuttle RCS jet plume impingement was fully understood. Relative navigation during proximity operations has been challenging, as HST was not equipped with relative navigation aids. Since HST reached orbit in 1990, proximity operations design for servicing missions has evolved as insight into plume contamination and dynamic pressure has improved and new relative navigation tools have become available. Servicing missions have provided NASA with opportunities to gain insight into servicing mission design and development of nominal and contingency procedures. The HST servicing experiences and lessons learned are applicable to other programs that perform on-orbit servicing and rendezvous, both human and robotic.

  8. The Hubble IR cutoff in holographic ellipsoidal cosmologies

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Universidad del Bio-Bio, Departamento de Fisica, Facultad de Ciencias, Concepcion (Chile); Cruz, Norman [Grupo de Cosmologia y Gravitacion-UBB, Concepcion (Chile)

    2018-01-15

    It is well known that for spatially flat FRW cosmologies, the holographic dark energy disfavors the Hubble parameter as a candidate for the IR cutoff. For overcoming this problem, we explore the use of this cutoff in holographic ellipsoidal cosmological models, and derive the general ellipsoidal metric induced by a such holographic energy density. Despite the drawbacks that this cutoff presents in homogeneous and isotropic universes, based on this general metric, we developed a suitable ellipsoidal holographic cosmological model, filled with a dark matter and a dark energy components. At late time stages, the cosmic evolution is dominated by a holographic anisotropic dark energy with barotropic equations of state. The cosmologies expand in all directions in accelerated manner. Since the ellipsoidal cosmologies given here are not asymptotically FRW, the deviation from homogeneity and isotropy of the universe on large cosmological scales remains constant during all cosmic evolution. This feature allows the studied holographic ellipsoidal cosmologies to be ruled by an equation of state ω = p/ρ, whose range belongs to quintessence or even phantom matter. (orig.)

  9. The Hubble Space Telescope from concept to success

    CERN Document Server

    Shayler, David J

    2016-01-01

    The highly successful Hubble Space Telescope was meant to change our view and understanding of the universe. Within weeks of its launch in 1990, however, the space community was shocked to find out that the primary mirror of the telescope was flawed. It was only the skills of scientists and engineers on the ground and the daring talents of astronauts sent to service the telescope in December 1993 that saved the mission. For over two decades NASA had developed the capabilities to service a payload in orbit. This involved numerous studies and the creation of a ground-based infrastructure to support the challenging missions. Unique tools and EVA hardware supported the skills developed in crew training that then enabled astronauts to complete a demanding series of spacewalks. Drawing upon first hand interviews with those closely involved in the project over thirty years ago this story explains the development of the servicing mission concept and the hurdles that had to be overcome to not only launch the telescope...

  10. Spike: Artificial intelligence scheduling for Hubble space telescope

    Science.gov (United States)

    Johnston, Mark; Miller, Glenn; Sponsler, Jeff; Vick, Shon; Jackson, Robert

    1990-01-01

    Efficient utilization of spacecraft resources is essential, but the accompanying scheduling problems are often computationally intractable and are difficult to approximate because of the presence of numerous interacting constraints. Artificial intelligence techniques were applied to the scheduling of the NASA/ESA Hubble Space Telescope (HST). This presents a particularly challenging problem since a yearlong observing program can contain some tens of thousands of exposures which are subject to a large number of scientific, operational, spacecraft, and environmental constraints. New techniques were developed for machine reasoning about scheduling constraints and goals, especially in cases where uncertainty is an important scheduling consideration and where resolving conflicts among conflicting preferences is essential. These technique were utilized in a set of workstation based scheduling tools (Spike) for HST. Graphical displays of activities, constraints, and schedules are an important feature of the system. High level scheduling strategies using both rule based and neural network approaches were developed. While the specific constraints implemented are those most relevant to HST, the framework developed is far more general and could easily handle other kinds of scheduling problems. The concept and implementation of the Spike system are described along with some experiments in adapting Spike to other spacecraft scheduling domains.

  11. Hubble evolution of fireball in relativistic nuclear collisions

    International Nuclear Information System (INIS)

    Zgura, Sorin; Besliu, Calin; Jipa, Alexandru

    2004-01-01

    The final state of Au + Au collisions at √s = 130 A GeV and 200 A GeV at RHIC has been reconstructed within the framework of the Buda-Lund hydro model, by performing a simultaneous fit to preliminary BRAHMS, PHENIX, PHOBOS and STAR data on two-particle Bose-Einstein correlations and identified single particle spectra. The Hubble constant is determined for cosmology. From this reconstructed final state and the knowledge of the equation of state of hot and dense hadronic matter (e.g. from lattice QCD calculations) one can, in principle, reconstruct the initial state of the reaction by running the (relativistic) hydrodynamical equations backwards in time and determine if this initial state had been in the QGP phase or not. Here we report on such a reconstruction within the framework of the Buda-Lund hydro model. This model fits are compared to RHIC's experiment data on identified particle spectra, two-particle Bose-Einstein or HBT correlations. (authors)

  12. Constraining the evolution of the Hubble Parameter using cosmic chronometer

    Science.gov (United States)

    Scarlata, Claudia; Dickinson, Hugh

    2018-01-01

    The Lambda-CDM model of Big Bang cosmology relies heavily on the assumption that two components - dark energy and dark matter - encompass 95% of the energy density of the Universe. Despite the dominant influence of these components, their nature is still entirely unknown.We present the initial results from a project that aims to provide new insights regarding the Dark Energy component. We do this by deriving independent constraints on the time-evolution of the Hubble parameter (H_0) using the “cosmic chronometer” method.By analyzing the HST NIR spectra from a large archival sample of passively evolving galaxies in distinct redshift bins between 1.3 and 2 we measure the typical stellar population ages (A) for the galaxies in each bin. The differential evolution of stellar population age with redshift (dA/dz) can be used to infer the corresponding evolution of H_0 which will provide important constraints on the nature of Dark Energy and its equation of state.

  13. HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81

    International Nuclear Information System (INIS)

    Nantais, Julie B.; Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay

    2011-01-01

    We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m V ≤ 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3σ color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V ∼ (20.26 ± 0.13) mag, corresponding to a distance of ∼3.7 ± 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

  14. Measurement of Hubble constant: non-Gaussian errors in HST Key Project data

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Meghendra [Dr. A.P.J. Abdul Kalam Technical University, Uttar Pradesh, Lucknow, 226021 India (India); Gupta, Shashikant; Pandey, Ashwini [Amity University Haryana, Gurgaon, Haryana, 122413 India (India); Sharma, Satendra, E-mail: meghendrasingh_db@yahoo.co.in, E-mail: shashikantgupta.astro@gmail.com, E-mail: satyamkashwini@gmail.com, E-mail: ssharma_phy@yahoo.co.uk [Yobe State University, Damaturu, Yobe State (Nigeria)

    2016-08-01

    Assuming the Central Limit Theorem, experimental uncertainties in any data set are expected to follow the Gaussian distribution with zero mean. We propose an elegant method based on Kolmogorov-Smirnov statistic to test the above; and apply it on the measurement of Hubble constant which determines the expansion rate of the Universe. The measurements were made using Hubble Space Telescope. Our analysis shows that the uncertainties in the above measurement are non-Gaussian.

  15. PROBING VERY BRIGHT END OF GALAXY LUMINOSITY FUNCTION AT z ∼> 7 USING HUBBLE SPACE TELESCOPE PURE PARALLEL OBSERVATIONS

    International Nuclear Information System (INIS)

    Yan Haojing; Yan Lin; Zamojski, Michel A.; Windhorst, Rogier A.; McCarthy, Patrick J.; Fan Xiaohui; Dave, Romeel; Roettgering, Huub J. A.; Koekemoer, Anton M.; Robertson, Brant E.; Cai Zheng

    2011-01-01

    We report the first results from the Hubble Infrared Pure Parallel Imaging Extragalactic Survey, which utilizes the pure parallel orbits of the Hubble Space Telescope to do deep imaging along a large number of random sightlines. To date, our analysis includes 26 widely separated fields observed by the Wide Field Camera 3, which amounts to 122.8 arcmin 2 in total area. We have found three bright Y 098 -dropouts, which are candidate galaxies at z ∼> 7.4. One of these objects shows an indication of peculiar variability and its nature is uncertain. The other two objects are among the brightest candidate galaxies at these redshifts known to date (L>2L*). Such very luminous objects could be the progenitors of the high-mass Lyman break galaxies observed at lower redshifts (up to z ∼ 5). While our sample is still limited in size, it is much less subject to the uncertainty caused by 'cosmic variance' than other samples because it is derived using fields along many random sightlines. We find that the existence of the brightest candidate at z ∼ 7.4 is not well explained by the current luminosity function (LF) estimates at z ∼ 8. However, its inferred surface density could be explained by the prediction from the LFs at z ∼ 7 if it belongs to the high-redshift tail of the galaxy population at z ∼ 7.

  16. The Legal Implications of Student Use of Social Networking Sites in the UK and US: Current Concerns and Lessons for the Future

    Science.gov (United States)

    Davies, Mark R.; Lee, Barbara A.

    2008-01-01

    This paper provides a comparative snapshot of the current state of the law in the US and UK with respect to potential liability of university and college students for use (and misuse) of social networking sites. It reviews the limited case law on this topic, highlights the differences in the two nations' laws of defamation and the various possible…

  17. Smoking frequency among current college student smokers: distinguishing characteristics and factors related to readiness to quit smoking

    Science.gov (United States)

    Berg, Carla J.; Ling, Pamela M.; Hayes, Rashelle B.; Berg, Erin; Nollen, Nikki; Nehl, Eric; Choi, Won S.; Ahluwalia, Jasjit S.

    2012-01-01

    Given the increased prevalence of non-daily smoking and changes in smoking patterns, particularly among young adults, we examined correlates of smoking level, specifically motives for smoking, and readiness to quit smoking among 2682 college undergraduates who completed an online survey. Overall, 64.7% (n = 1736) were non-smokers, 11.6% (n = 312) smoked 1–5 days, 10.5% (n = 281) smoked 6–29 days and 13.2% (n = 353) were daily smokers. Ordinal regression analyses modeling smoking level indicated that correlates of higher smoking level included having more friends who smoke (β = 0.63, 95% CI 0.57–0.69) and more frequent other tobacco use (β = 0.04, 95% CI 0.02–0.05), drinking (β = 0.04, 95% CI 0.02–0.07) and binge drinking (β = 0.09, 95% CI 0.06–0.13). Bivariate analyses indicated that daily smokers (versus the subgroups of non-daily smokers) were less likely to smoke for social reasons but more likely to smoke for self-confidence, boredom, and affect regulation. Controlling for sociodemographics, correlates of readiness to quit among current smokers included fewer friends who smoke (P = 0.002), less frequent binge drinking (P = 0.03), being a social smoker (P confidence (P = 0.04), smoking more for boredom (P = 0.03) and less frequent smoking (P = 0.001). Specific motives for smoking and potential barriers to cessation particularly may be relevant to different groups of college student smokers. PMID:22156071

  18. Smoking frequency among current college student smokers: distinguishing characteristics and factors related to readiness to quit smoking.

    Science.gov (United States)

    Berg, Carla J; Ling, Pamela M; Hayes, Rashelle B; Berg, Erin; Nollen, Nikki; Nehl, Eric; Choi, Won S; Ahluwalia, Jasjit S

    2012-02-01

    Given the increased prevalence of non-daily smoking and changes in smoking patterns, particularly among young adults, we examined correlates of smoking level, specifically motives for smoking, and readiness to quit smoking among 2682 college undergraduates who completed an online survey. Overall, 64.7% (n = 1736) were non-smokers, 11.6% (n = 312) smoked 1-5 days, 10.5% (n = 281) smoked 6-29 days and 13.2% (n = 353) were daily smokers. Ordinal regression analyses modeling smoking level indicated that correlates of higher smoking level included having more friends who smoke (β = 0.63, 95% CI 0.57-0.69) and more frequent other tobacco use (β = 0.04, 95% CI 0.02-0.05), drinking (β = 0.04, 95% CI 0.02-0.07) and binge drinking (β = 0.09, 95% CI 0.06-0.13). Bivariate analyses indicated that daily smokers (versus the subgroups of non-daily smokers) were less likely to smoke for social reasons but more likely to smoke for self-confidence, boredom, and affect regulation. Controlling for sociodemographics, correlates of readiness to quit among current smokers included fewer friends who smoke (P = 0.002), less frequent binge drinking (P = 0.03), being a social smoker (P smoking less for self-confidence (P = 0.04), smoking more for boredom (P = 0.03) and less frequent smoking (P = 0.001). Specific motives for smoking and potential barriers to cessation particularly may be relevant to different groups of college student smokers.

  19. Ultracompact Blue Dwarf Galaxies: Hubble Space Telescope Imaging and Stellar Population Analysis

    Science.gov (United States)

    Corbin, Michael R.; Vacca, William D.; Cid Fernandes, Roberto; Hibbard, John E.; Somerville, Rachel S.; Windhorst, Rogier A.

    2006-11-01

    We present deep Hubble Space Telescope (HST) Advanced Camera for Surveys/High Resolution Channel U-, narrow-V-, and I-band images of nine ``ultracompact'' blue dwarf galaxies (UCBDs) selected from the Sloan Digital Sky Survey (SDSS). We define UCBDs as local (zPOX 186, but the structure of several of them suggests that their current star formation has been triggered by the collisions/mergers of smaller clumps of stars. In one case, HS 0822+3542, the images resolve what may be two small (~100 pc) components that have recently collided, supporting this interpretation. In six of the objects much of the star formation is concentrated in young massive clusters, contributing to their compactness in ground-based images. The evidence that the galaxies consist mainly of ~10 Gyr old stars establishes that they are not protogalaxies, forming their first generation of stars. Their low metallicities are more likely to be the result of the escape of supernova ejecta, rather than youth.

  20. The Hubble constant estimation using 18 gravitational lensing time delays

    Science.gov (United States)

    Jaelani, Anton T.; Premadi, Premana W.

    2014-03-01

    Gravitational lens time delay method has been used to estimate the rate of cosmological expansion, called the Hubble constant, H0, independently of the standard candle method. This gravitational lensing method requires a good knowledge of the lens mass distribution, reconstructed using the lens image properties. The observed positions of the images, and the redshifts of the lens and the images serve as strong constraints to the lens equations, which are then solved as a set of simultaneous linear equations. Here we made use of a non-parametric technique to reconstruct the lens mass distribution, which is manifested in a linear equations solver named PixeLens. Input for the calculation is chosen based on prior known parameters obtained from analyzed result of the lens case observations, including time-delay, position angles of the images and the lens, and their redshifts. In this project, 18 fairly well studied lens cases are further grouped according to a number of common properties to examine how each property affects the character of the data, and therefore affects the calculation of H0. The considered lens case properties are lens morphology, number of image, completeness of time delays, and symmetry of lens mass distribution. Analysis of simulation shows that paucity of constraints on mass distribution of a lens yields wide range value of H0, which reflects the uniqueness of each lens system. Nonetheless, gravitational lens method still yields H0 within an acceptable range of value when compared to those determined by many other methods. Grouping the cases in the above manner allowed us to assess the robustness of PixeLens and thereby use it selectively. In addition, we use glafic, a parametric mass reconstruction solver, to refine the mass distribution of one lens case, as a comparison.

  1. Thick Disks in the Hubble Space Telescope Frontier Fields

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Elmegreen, Debra Meloy; Tompkins, Brittany; Jenks, Leah G., E-mail: bge@us.ibm.com, E-mail: elmegreen@vassar.edu [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States)

    2017-09-20

    Thick disk evolution is studied using edge-on galaxies in two Hubble Space Telescope Frontier Field Parallels. The galaxies were separated into 72 clumpy types and 35 spiral types with bulges. Perpendicular light profiles in F435W, F606W, and F814W ( B , V , and I ) passbands were measured at 1 pixel intervals along the major axes and fitted to sech{sup 2} functions convolved with the instrument line spread function (LSF). The LSF was determined from the average point spread function of ∼20 stars in each passband and field, convolved with a line of uniform brightness to simulate disk blurring. A spread function for a clumpy disk was also used for comparison. The resulting scale heights were found to be proportional to galactic mass, with the average height for a 10{sup 10±0.5} M {sub ⊙} galaxy at z = 2 ± 0.5 equal to 0.63 ± 0.24 kpc. This value is probably the result of a blend between thin and thick disk components that cannot be resolved. Evidence for such two-component structure is present in an inverse correlation between height and midplane surface brightness. Models suggest that the thick disk is observed best between the clumps, and there the average scale height is 1.06 ± 0.43 kpc for the same mass and redshift. A 0.63 ± 0.68 mag V − I color differential with height is also evidence for a mixture of thin and thick components.

  2. HUBBLE SPACE TELESCOPE ASTROMETRY OF THE PROCYON SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Gilliland, Ronald L.; Kozhurina-Platais, Vera; Nelan, Edmund P. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Schaefer, Gail H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Demarque, Pierre; Girard, Terrence M. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520 (United States); Holberg, Jay B. [Lunar and Planetary Laboratory, University of Arizona, 1541 E. University Blvd., Tucson, AZ 85721 (United States); Gudehus, Donald [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Mason, Brian D. [U.S. Naval Observatory, 3450 Massachusetts Ave., Washington, DC 20392 (United States); Burleigh, Matthew R.; Barstow, Martin A., E-mail: heb11@psu.edu [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom)

    2015-11-10

    The nearby star Procyon is a visual binary containing the F5 IV-V subgiant Procyon A, orbited in a 40.84-year period by the faint DQZ white dwarf (WD) Procyon B. Using images obtained over two decades with the Hubble Space Telescope, and historical measurements back to the 19th century, we have determined precise orbital elements. Combined with measurements of the parallax and the motion of the A component, these elements yield dynamical masses of 1.478 ± 0.012 M{sub ⊙} and 0.592 ± 0.006 M{sub ⊙} for A and B, respectively. The mass of Procyon A agrees well with theoretical predictions based on asteroseismology and its temperature and luminosity. Use of a standard core-overshoot model agrees best for a surprisingly high amount of core overshoot. Under these modeling assumptions, Procyon A’s age is ∼2.7 Gyr. Procyon B’s location in the H-R diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass. Its position in the mass–radius plane is also consistent with theory, assuming a carbon–oxygen core and a helium-dominated atmosphere. Its progenitor’s mass was 1.9–2.2 M{sub ⊙}, depending on its amount of core overshoot. Several astrophysical puzzles remain. In the progenitor system, the stars at periastron were separated by only ∼5 AU, which might have led to tidal interactions and even mass transfer; yet there is no direct evidence that these have occurred. Moreover the orbital eccentricity has remained high (∼0.40). The mass of Procyon B is somewhat lower than anticipated from the initial-to-final-mass relation seen in open clusters. The presence of heavy elements in its atmosphere requires ongoing accretion, but the place of origin is uncertain.

  3. Hubble Space Telescope Astrometry of the Procyon System

    Science.gov (United States)

    Bond, Howard E.; Gilliland, Ronald L.; Schaefer, Gail H.; Demarque, Pierre; Girard, Terrence M.; Holberg, Jay B.; Gudehus, Donald; Mason, Brian D.; Kozhurina-Platais, Vera; Burleigh, Matthew R.

    2015-01-01

    The nearby star Procyon is a visual binary containing the F5 IV-V subgiant Procyon A, orbited in a 40.84-year period by the faint DQZ white dwarf (WD) Procyon B. Using images obtained over two decades with the Hubble Space Telescope, and historical measurements back to the 19th century, we have determined precise orbital elements. Combined with measurements of the parallax and the motion of the A component, these elements yield dynamical masses of 1.478 plus or minus 0.012M and 0.592 plus or minus 0.006M for A and B, respectively. The mass of Procyon A agrees well with theoretical predictions based on asteroseismology and its temperature and luminosity. Use of a standard core-overshoot model agrees best for a surprisingly high amount of core overshoot. Under these modeling assumptions, Procyon A's age is approximately 2.7 Gyr. Procyon B's location in the H-R diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass. Its position in the mass-radius plane is also consistent with theory, assuming a carbon-oxygen core and a helium-dominated atmosphere. Its progenitor's mass was 1.9-2.2M, depending on its amount of core overshoot. Several astrophysical puzzles remain. In the progenitor system, the stars at periastron were separated by only approximately AU, which might have led to tidal interactions and even mass transfer; yet there is no direct evidence that these have occurred. Moreover the orbital eccentricity has remained high (approximately 0.40). The mass of Procyon B is somewhat lower than anticipated from the initial-to-final-mass relation seen in open clusters. The presence of heavy elements in its atmosphere requires ongoing accretion, but the place of origin is uncertain.

  4. Distance determinations to shield galaxies from Hubble space telescope imaging

    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Kristen B. W.; Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, 116 Church Street, S.E., Minneapolis, MN 55455 (United States); Cannon, John M.; Cave, Ian [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Salzer, John J. [Department of Astronomy, Indiana University, 727 East 3rd Street, Bloomington, IN 47405 (United States); Haynes, Martha P.; Adams, Elizabeth; Giovanelli, Riccardo [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Elson, Ed C. [Astrophysics, Cosmology and Gravity Centre (ACGC), Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Ott, Juërgen [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States); Saintonge, Amélie, E-mail: kmcquinn@astro.umn.edu [Max-Planck-Institute for Astrophysics, D-85741 Garching (Germany)

    2014-04-10

    The Survey of H I in Extremely Low-mass Dwarf (SHIELD) galaxies is an ongoing multi-wavelength program to characterize the gas, star formation, and evolution in gas-rich, very low-mass galaxies. The galaxies were selected from the first ∼10% of the H I Arecibo Legacy Fast ALFA (ALFALFA) survey based on their inferred low H I mass and low baryonic mass, and all systems have recent star formation. Thus, the SHIELD sample probes the faint end of the galaxy luminosity function for star-forming galaxies. Here, we measure the distances to the 12 SHIELD galaxies to be between 5 and 12 Mpc by applying the tip of the red giant method to the resolved stellar populations imaged by the Hubble Space Telescope. Based on these distances, the H I masses in the sample range from 4 × 10{sup 6} to 6 × 10{sup 7} M {sub ☉}, with a median H I mass of 1 × 10{sup 7} M {sub ☉}. The tip of the red giant branch distances are up to 73% farther than flow-model estimates in the ALFALFA catalog. Because of the relatively large uncertainties of flow-model distances, we are biased toward selecting galaxies from the ALFALFA catalog where the flow model underestimates the true distances. The measured distances allow for an assessment of the native environments around the sample members. Five of the galaxies are part of the NGC 672 and NGC 784 groups, which together constitute a single structure. One galaxy is part of a larger linear ensemble of nine systems that stretches 1.6 Mpc from end to end. Three galaxies reside in regions with 1-9 neighbors, and four galaxies are truly isolated with no known system identified within a radius of 1 Mpc.

  5. Hubble Space Telescope Image, Supernova Remnant Cassiopeia A

    Science.gov (United States)

    2000-01-01

    The colorful streamers that float across the sky in this photo taken by NASA's Hubble Space Telescope (HST) were created by the universe's biggest firecracker, the titanic supernova explosion of a massive star. The light from the exploding star reached Earth 320 years ago, nearly a century before the United States celebrated its birth with a bang. The dead star's shredded remains are called Cassiopeia A, or 'Cas A' for short. Cas A is the youngest known supernova remnant in our Milky Way Galaxy and resides 10,000 light-years away in the constellation Cassiopeia, so the star actually blew up 10,000 years before the light reached Earth in the late 1600s. This HST image of Cas A shows for the first time that the debris is arranged into thousands of small, cooling knots of gas. This material eventually will be recycled into building new generations of stars and planets. Our own Sun and planets are constructed from the debris of supernovae that exploded billions of years ago. This photo shows the upper rim of the super nova remnant's expanding shell. Near the top of the image are dozens of tiny clumps of matter. Each small clump, originally just a small fragment of the star, is tens of times larger than the diameter of our solar system. The colors highlight parts of the debris where chemical elements are glowing. The dark blue fragments, for example, are richest in oxygen; the red material is rich in sulfur. The images were taken with the Wide Field and Planetary Camera 2 in January 2000 and January 2002. Image Credit: NASA and HST team (Stoics/AURA). Acknowledgment: R. Fesen (Darmouth) and J. Morse ( Univ. of Colorado).

  6. Determination and characterization of the Hubble Space Telescope pointing stability

    Science.gov (United States)

    Bradley, A. J.; Connor, C. T.; del Toro, Y.; Andersen, G. C.; Bely, Pierre Y.; Decker, J.; Franz, O. G.; Wasserman, L. H.; van Altena, William F.

    The Hubble Space Telescope (HST) was designed to maintian a pointing stability (jitter) of 0.007 arc seconds rms throughout every observing period, which can last from a few seconds to several orbits. On-orbit measurements indicate that the hardware excitation induced by the reaction wheels. gyros, high gain antennae, science instrument mechanisms and tape recorders are well within specifications. Unexpectedly, the solar arrays because the dominant source of jitter. Every passage through an orbital terminator produces vibrations which emanate from the solar arrays due to thermal effects, which affect the relative positional stability. Broadband frequencies centered about 0.11 and 0.65 Hz were detected in the frequency content of the vehicle jitter. On-board modifications to the control law have attenuated the disturbance torques and reduced the vehicle jitter close to specification. Replacement of the solar arrays in December, 1993, should eliminate the torque distubances. Astrometric science observations are extremely susceptible to corruption from vehicle jitter. The removal of vehicle jitter from astrometric Transfer function scans of binary stars is explained in detail. A binary star separation of 16 milli-seconds of arc has been achieved, a separation resolution of 10 to 12 milli-seconds of arc appears feasible, with a binary star magnitude of 9 m(sub V). The achievement of this resolution is in part due to vehicle jitter removal. Comparison of vehicle jitter measurements from the position path of the vehicle control law, or from the guiding Fine Guidance Sensors (FGS), are shown to be equivalent to approximately 0.001 arc second.

  7. HUBBLE CLICKS IMAGES OF IO SWEEPING ACROSS JUPITER

    Science.gov (United States)

    2002-01-01

    While hunting for volcanic plumes on Io, NASA's Hubble Space Telescope captured these images of the volatile moon sweeping across the giant face of Jupiter. Only a few weeks before these dramatic images were taken, the orbiting telescope snapped a portrait of one of Io's volcanoes spewing sulfur dioxide 'snow.' These stunning images of the planetary duo are being released to commemorate the ninth anniversary of the Hubble telescope's launch on April 24, 1990. All of these images were taken with the Wide Field and Planetary Camera 2. The three overlapping snapshots show in crisp detail Io passing above Jupiter's turbulent clouds. The close-up picture of Io (bottom right) reveal a 120-mile-high (200-kilometer) plume of sulfur dioxide 'snow' emanating from Pillan, one of the moon's active volcanoes. 'Other observations have inferred sulfur dioxide 'snow' in Io's plumes, but this image offers direct observational evidence for sulfur dioxide 'snow' in an Io plume,' explains John R. Spencer of Lowell Observatory in Flagstaff, Ariz. A Trip Around Jupiter The three snapshots of the volcanic moon rounding Jupiter were taken over a 1.8-hour time span. Io is roughly the size of Earth's moon but 2,000 times farther away. In two of the images, Io appears to be skimming Jupiter's cloud tops, but it's actually 310,000 miles (500,000 kilometers) away. Io zips around Jupiter in 1.8 days, whereas the moon circles Earth every 28 days. The conspicuous black spot on Jupiter is Io's shadow and is about the size of the moon itself (2,262 miles or 3,640 kilometers across). This shadow sails across the face of Jupiter at 38,000 mph (17 kilometers per second). The smallest details visible on Io and Jupiter measure 93 miles (150 kilometers) across, or about the size of Connecticut. These images were further sharpened through image reconstruction techniques. The view is so crisp that one would have to stand on Io to see this much detail on Jupiter with the naked eye. The bright patches on Io

  8. Current state of knowledge, beliefs, and attitudes toward organ transplantation among academic students in Poland and the potential means for altering them.

    Science.gov (United States)

    Nowak, E; Pfitzner, R; Koźlik, P; Kozynacka, A; Durajski, L; Przybyłowski, P

    2014-10-01

    Students manifest a high level of social commitment. Improving their knowledge and developing more positive attitudes toward organ transplantation may increase the number of organ donations. This study was an assessment of the knowledge and attitudes toward organ transplantation among young people in Poland, with an overview of current beliefs and potential methods for improving transplantology awareness. The study included 400 medical students and 400 nonmedical students from public universities in Kraków, Poland. Data were collected by using an anonymous questionnaire examining demographic factors and transplantology issues. Despite the overall positive attitude toward transplantology among academic students in Poland, the state of knowledge of the nonmedical population remains relatively low. The most important issues for social education to focus on are the role of presumed consent and brain death diagnosis, actual hazards of living donations, recipient qualification criteria, and the attitudes of religious authorities. The overall level of knowledge and the number of positive attitudes were significantly higher among medical students than among nonmedical students, proving that formal educational programs are more efficient than the more accessible but less reliable sources of knowledge. Introduction of transplantology issues in schools and churches, promoting the positive outcomes of organ transplantation rather than negating false beliefs, and eliminating misleading information from the media may significantly increase young people's knowledge and result in more positive attitudes toward transplantology in a society-wide fashion. This outcome could create a favorable background for introducing an opt-in system of consent for organ donation.

  9. A comparison of professional-level faculty and student perceptions of active learning: its current use, effectiveness, and barriers

    Science.gov (United States)

    Metz, Michael J.

    2014-01-01

    Active learning is an instructional method in which students become engaged participants in the classroom through the use of in-class written exercises, games, problem sets, audience-response systems, debates, class discussions, etc. Despite evidence supporting the effectiveness of active learning strategies, minimal adoption of the technique has occurred in many professional programs. The goal of this study was to compare the perceptions of active learning between students who were exposed to active learning in the classroom (n = 116) and professional-level physiology faculty members (n = 9). Faculty members reported a heavy reliance on lectures and minimal use of educational games and activities, whereas students indicated that they learned best via the activities. A majority of faculty members (89%) had observed active learning in the classroom and predicted favorable effects of the method on student performance and motivation. The main reported barriers by faculty members to the adoption of active learning were a lack of necessary class time, a high comfort level with traditional lectures, and insufficient time to develop materials. Students hypothesized similar obstacles for faculty members but also associated many negative qualities with the traditional lecturers. Despite these barriers, a majority of faculty members (78%) were interested in learning more about the alternative teaching strategy. Both faculty members and students indicated that active learning should occupy portions (29% vs. 40%) of face-to-face class time. PMID:25179615

  10. A comparison of professional-level faculty and student perceptions of active learning: its current use, effectiveness, and barriers.

    Science.gov (United States)

    Miller, Cynthia J; Metz, Michael J

    2014-09-01

    Active learning is an instructional method in which students become engaged participants in the classroom through the use of in-class written exercises, games, problem sets, audience-response systems, debates, class discussions, etc. Despite evidence supporting the effectiveness of active learning strategies, minimal adoption of the technique has occurred in many professional programs. The goal of this study was to compare the perceptions of active learning between students who were exposed to active learning in the classroom (n = 116) and professional-level physiology faculty members (n = 9). Faculty members reported a heavy reliance on lectures and minimal use of educational games and activities, whereas students indicated that they learned best via the activities. A majority of faculty members (89%) had observed active learning in the classroom and predicted favorable effects of the method on student performance and motivation. The main reported barriers by faculty members to the adoption of active learning were a lack of necessary class time, a high comfort level with traditional lectures, and insufficient time to develop materials. Students hypothesized similar obstacles for faculty members but also associated many negative qualities with the traditional lecturers. Despite these barriers, a majority of faculty members (78%) were interested in learning more about the alternative teaching strategy. Both faculty members and students indicated that active learning should occupy portions (29% vs. 40%) of face-to-face class time. Copyright © 2014 The American Physiological Society.

  11. Crew of Hubble Space Telescope servicing mission visits Europe

    Science.gov (United States)

    1994-01-01

    The Hubble Space telescope servicing mission in December (STS-61) was a great success and the fully refurbished orbiting telescope produced absolutely remarkable first results just two weeks ago. The 7-member crew who carried out the mission will soon be in Europe to share their experience with the Press, ESA space specialists and the European space community. Public conferences will also be held in Switzerland, the home country of ESA astronaut Claude Nicollier. The visit of the STS-61 crew is scheduled as follows: Friday 11 February, 1994 - ESA Paris, France Presentation and Press Conference Location: ESA, 8/10 Rue Mario Nikis, 75015 Paris time: 16:00 hrs - 17:30 hrs contact: ESA, Public Relations Office Tel. (+33) 1 42 73 71 55 Fax. (+33) 1 42 73 76 90 Monday 14 February, 1994 - British Aerospace, Bristol, United Kingdom Presentation and Press Conference Location: British Aerospace, FPC 333, Filton, Bristol BS12 7QW time: 10:00 hrs - 12:00 hrs contact: BAe, Public Relations Tel. (+44) 272 36 33 69 Tel. (+44) 272 36 33 68 Tuesday 15 February, 1994 - ESA/ESTEC, Noordwijk, the Netherlands Presentation and Press Conference Location: Noordwijk Space Expo, Keplerlaan 3, 2201 AZ Noordwijk, the Netherlands time: 09:30 hrs - 12:00 hrs contact: ESTEC Public Relations Office Tel. (+31) 1719 8 3006 Fax. (+31) 1719 17 400 Wednesday 16 February, 1944 - ESO, Garching - Munich, Germany Presentation and Press Conference Location: European Southern Observatory, Karl- Schwarzschild-Str. 2, 85748 Garching -Munich, Germany time: to be decided contact: ESO Information Service Tel. (+49) 89 32 006 276 Fax. (+49) 89 320 23 62 Thursday 17 February, 1994 - Bern, Switzerland a. Presentation and Press Conference Location: Hotel Bern, Zeughausgasse 9, 3001 Bern, Switzerland time: 09:30 hrs contact: Press & Information Service of the Federal Dept. for Education & Sciences Tel. (+41) 31 322 80 34 Fax. (+41) 31 312 30 15 b. Public conference Location: University of Bern, Institute of Physics

  12. Launch-Off-Need Shuttle Hubble Rescue Mission: Medical Issues

    Science.gov (United States)

    Hamilton, Douglas; Gillis, David; Ilcus, Linda; Perchonok, Michele; Polk, James; Brandt, Keith; Powers, Edward; Stepaniak, Phillip

    2008-01-01

    The Space Shuttle Hubble repair mission (STS-125) is unique in that a rescue mission (STS-400) has to be ready to launch before STS-125 life support runs out should the vehicle become stranded. The shuttle uses electrical power derived from fuel cells that use cryogenic oxygen and hydrogen (CRYO) to run all subsystems including the Environmental Control System. If the STS-125 crew cannot return to Earth due to failure of a critical subsystem, they must power down all nonessential systems and wait to be rescued by STS-400. This power down will cause the cabin temperature to be 60 F or less and freeze the rest of the vehicle, preventing it from attempting a reentry. After an emergency has been declared, STS-125 must wait at least 7 days to power down since that is the earliest that STS-400 can be launched. Problem The delayed power down of STS-125 causes CYRO to be consumed at high rates and limits the survival time after STS-400 launches to 10 days or less. CRYO will run out sooner every day that the STS-400 launch is delayed (weather at launch, technical issues etc.). To preserve CRYO and lithium hydroxide (LiOH - carbon dioxide removal) the crew will perform no exercise to reduce their metabolic rates, yet each deconditioned STS-125 crewmember must perform an EVA to rescue himself. The cabin may be cold for 10 days, which may cause shivering, increasing the metabolic rate of the STS-125 crew. Solution To preserve LiOH, the STS-125 manifest includes nutrition bars with low carbohydrate content to maintain crew respiratory quotient (RQ) below 0.85 as opposed to the usual shuttle galley food which is rich in carbohydrates and keeps the RQ at approximately 0.95. To keep the crew more comfortable in the cold vehicle warm clothing also has been included. However, with no exercise and limited diet, the deconditioned STS-125 crew returning on STS-400 may not be able to egress the vehicle autonomously requiring a supplemented crash-and-rescue capability.

  13. Testing backreaction effects with observational Hubble parameter data

    Science.gov (United States)

    Cao, Shu-Lei; Teng, Huan-Yu; Wan, Hao-Yi; Yu, Hao-Ran; Zhang, Tong-Jie

    2018-02-01

    The spatially averaged inhomogeneous Universe includes a kinematical backreaction term Q_{D} that is relate to the averaged spatial Ricci scalar _{D} in the framework of general relativity. Under the assumption that Q_{D} and _{D} obey the scaling laws of the volume scale factor a_{D}, a direct coupling between them with a scaling index n is remarkable. In order to explore the generic properties of a backreaction model for explaining the accelerated expansion of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter κ _{D}(t) is employed. However, we doubt the validity of the prescription for κ _{D}, which motivates us apply observational Hubble parameter data (OHD) to constrain parameters in dust cosmology. First, for FLRW metric, by getting best-fit constraints of Ω^{D_0}_m = 0.25^{+0.03}_{-0.03}, n = 0.02^{+0.69}_{-0.66}, and H_{D_0} = 70.54^{+4.24}_{-3.97} km s^{-1 Mpc^{-1}}, the evolutions of parameters are explored. Second, in template metric context, by marginalizing over H_{D_0} as a prior of uniform distribution, we obtain the best-fit values of n=-1.22^{+0.68}_{-0.41} and Ωm^{D0}=0.12^{+0.04}_{-0.02}. Moreover, we utilize three different Gaussian priors of H_{D_0}, which result in different best-fits of n, but almost the same best-fit value of Ωm^{D0}˜ 0.12. Also, the absolute constraints without marginalization of parameter are obtained: n=-1.1^{+0.58}_{-0.50} and Ωm^{D0}=0.13± 0.03. With these constraints, the evolutions of the effective deceleration parameter q^{D} indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra dark energy component in the scaling solution context. Nevertheless, the results also verify that the prescription of κ _{D} is insufficient and should be improved.

  14. Testing backreaction effects with observational Hubble parameter data

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shu-Lei; Teng, Huan-Yu [Beijing Normal University, Department of Astronomy, Beijing (China); Wan, Hao-Yi [Beijing Normal University, Department of Astronomy, Beijing (China); National Astronomical Observatories, Chinese Academy of Sciences, Beijing (China); Yu, Hao-Ran [Shanghai Jiao Tong University, Tsung-Dao Lee Institute, Shanghai (China); Zhang, Tong-Jie [Dezhou University, Dezhou (China); Beijing Normal University, Department of Astronomy, Beijing (China)

    2018-02-15

    The spatially averaged inhomogeneous Universe includes a kinematical backreaction term Q{sub D} that is relate to the averaged spatial Ricci scalar left angle R right angle {sub D} in the framework of general relativity. Under the assumption that Q{sub D} and left angle R right angle {sub D} obey the scaling laws of the volume scale factor a{sub D}, a direct coupling between them with a scaling index n is remarkable. In order to explore the generic properties of a backreaction model for explaining the accelerated expansion of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter κ{sub D}(t) is employed. However, we doubt the validity of the prescription for κ{sub D}, which motivates us apply observational Hubble parameter data (OHD) to constrain parameters in dust cosmology. First, for FLRW metric, by getting best-fit constraints of Ω{sup D{sub 0m}} = 0.25{sup +0.03}{sub -0.03}, n = 0.02{sup +0.69}{sub -0.66}, and H{sub D{sub 0}} = 70.544{sup +4.24}{sub -3.97} km s{sup -1} Mpc{sup -1}, the evolutions of parameters are explored. Second, in template metric context, by marginalizing over H{sub D{sub 0}} as a prior of uniform distribution, we obtain the best-fit values of n = -1.22{sup +0.68}{sub -0.41} and Ω{sub m}{sup D{sub 0}} = 0.12{sup +0.04}{sub -0.02}. Moreover, we utilize three different Gaussian priors of H{sub D{sub 0}}, which result in different best-fits of n, but almost the same best-fit value of Ω{sub m}{sup D{sub 0}} ∝ 0.12. Also, the absolute constraints without marginalization of parameter are obtained: n = -1.1{sup +0.58}{sub -0.50} and Ω{sub m}{sup D{sub 0}} = 0.13 ± 0.03. With these constraints, the evolutions of the effective deceleration parameter q{sup D} indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra

  15. Observational constraint on spherical inhomogeneity with CMB and local Hubble parameter

    Science.gov (United States)

    Tokutake, Masato; Ichiki, Kiyotomo; Yoo, Chul-Moon

    2018-03-01

    We derive an observational constraint on a spherical inhomogeneity of the void centered at our position from the angular power spectrum of the cosmic microwave background (CMB) and local measurements of the Hubble parameter. The late time behaviour of the void is assumed to be well described by the so-called Λ-Lemaȋtre-Tolman-Bondi (ΛLTB) solution. Then, we restrict the models to the asymptotically homogeneous models each of which is approximated by a flat Friedmann-Lemaȋtre-Robertson-Walker model. The late time ΛLTB models are parametrized by four parameters including the value of the cosmological constant and the local Hubble parameter. The other two parameters are used to parametrize the observed distance-redshift relation. Then, the ΛLTB models are constructed so that they are compatible with the given distance-redshift relation. Including conventional parameters for the CMB analysis, we characterize our models by seven parameters in total. The local Hubble measurements are reflected in the prior distribution of the local Hubble parameter. As a result of a Markov-Chains-Monte-Carlo analysis for the CMB temperature and polarization anisotropies, we found that the inhomogeneous universe models with vanishing cosmological constant are ruled out as is expected. However, a significant under-density around us is still compatible with the angular power spectrum of CMB and the local Hubble parameter.

  16. The H II galaxy Hubble diagram strongly favours Rh = ct over ΛCDM

    Science.gov (United States)

    Wei, Jun-Jie; Wu, Xue-Feng; Melia, Fulvio

    2016-12-01

    We continue to build support for the proposal to use H II galaxies (HIIGx) and giant extragalactic H II regions (GEHR) as standard candles to construct the Hubble diagram at redshifts beyond the current reach of Type Ia supernovae. Using a sample of 25 high-redshift HIIGx, 107 local HIIGx, and 24 GEHR, we confirm that the correlation between the emission-line luminosity and ionized-gas velocity dispersion is a viable luminosity indicator, and use it to test and compare the standard model ΛCDM and the Rh = ct universe by optimizing the parameters in each cosmology using a maximization of the likelihood function. For the flat ΛCDM model, the best fit is obtained with Ω _m= 0.40_{-0.09}^{+0.09}. However, statistical tools, such as the Akaike (AIC), Kullback (KIC) and Bayes (BIC) Information Criteria favour Rh = ct over the standard model with a likelihood of ≈94.8-98.8 per cent versus only ≈1.2-5.2 per cent. For wCDM (the version of ΛCDM with a dark-energy equation of state wde ≡ pde/ρde rather than wde = wΛ = -1), a statistically acceptable fit is realized with Ω _m=0.22_{-0.14}^{+0.16} and w_de= -0.51_{-0.25}^{+0.15} which, however, are not fully consistent with their concordance values. In this case, wCDM has two more free parameters than Rh = ct, and is penalized more heavily by these criteria. We find that Rh = ct is strongly favoured over wCDM with a likelihood of ≈92.9-99.6 per cent versus only 0.4-7.1 per cent. The current HIIGx sample is already large enough for the BIC to rule out ΛCDM/wCDM in favour of Rh = ct at a confidence level approaching 3σ.

  17. Prevalence and Determinants of Current Smoking and Intention to Smoke among Secondary School Students: A Cross-Sectional Survey among Han and Tujia Nationalities in China.

    Science.gov (United States)

    Xu, Xianglong; Liu, Dengyuan; Sharma, Manoj; Zhao, Yong

    2017-10-30

    Objectives: This study examined the patterns and determinants of current smoking and intention to smoke among secondary school students of Han and Tujia nationalities in China. Methods: A cross-sectional survey was conducted in three regions, namely, Chongqing, Liaocheng, and Tianjin, of China in 2015. A structured self-administered questionnaire was used for data collection. Results: Of the total subjects ( n = 1805), 78.9% were ethnic Han and 21.1% were ethnic Tujia. Overall 9.4% (Han: 7.7%; Tujia: 15.5%) secondary school students were smokers and 37.28% smoked more than once per day. Of the non-smoker students ( n = 1636), 17.4% have an intention to smoke. A total of 81.1% of students reportedly had never been taught throughout school about smoking or tobacco prevention. When compared to the students who were taught in the school about smoking or tobacco prevention (18.90%) students who were never taught were more likely to smoke (OR = 2.39; 95% CI = 1.14-5.01). As compared to Han nationality students who were from Tujia nationality were more likely to smoke (OR = 2.76; 95% CI = 1.88-4.04) and were more likely to have a higher frequency of smoking (95% CI (0.88, 0.88), p = 0.010). Non-smokers who were high school students (OR = 4.29; 95% CI = 2.12-8.66), whose academic performance were situated in the last 25% (OR = 2.23; 95% CI = 1.48-3.34) and lower than 50% (OR = 1.50; 95% CI = 1.02-2.20) were more likely to have an intention of smoking. Conclusions: About one in ten secondary school students was a smoker, one in three smokers smoked more than one time per day, and a quarter of non-smokers had an intention of smoking in China. Smoking rate was higher among students from Tujia than the Han nationality. This study provided some important information for future tobacco control programs among secondary school students in the ethnic minority autonomous region and minority settlements in a multi-ethnic country.

  18. Developing and Implementing Lab Skills Seminars, a Student-Led Learning Approach in the Organic Chemistry Laboratory: Mentoring Current Students While Benefiting Facilitators

    Science.gov (United States)

    Sabanayagam, Kalyani; Dani, Vivek D.; John, Matthew; Restivo, Wanda; Mikhaylichenko, Svetlana; Dalili, Shadi

    2017-01-01

    This paper describes the successful adaptation of certain components of peer-led team learning (PLTL) as well as service learning principles into our initiative: lab skills seminars (LSS). These seminars were organized for large, second year organic chemistry laboratory courses. Prior to LSS, the only help available for students was traditional…

  19. A Self-Instructional Course in Student Financial Aid Administration. Module 2--Federal Student Financial Aid: History & Current Sources. Second Edition.

    Science.gov (United States)

    Washington Consulting Group, Inc., Washington, DC.

    The second of 17 modules in a self-instructional course on student financial aid administration, this module offers novice financial aid administrators and other institutional personnel a systematic introduction to the management of federal financial aid programs authorized by the Higher Education Act Title IV. It traces the history of federal…

  20. The Hubble Legacy Archive: Data Processing in the Era of AstroDrizzle

    Science.gov (United States)

    Strolger, Louis-Gregory; Hubble Legacy Archive Team, The Hubble Source Catalog Team

    2015-01-01

    The Hubble Legacy Archive (HLA) expands the utility of Hubble Space Telescope wide-field imaging data by providing high-level composite images and source lists, perusable and immediately available online. The latest HLA data release (DR8.0) marks a fundamental change in how these image combinations are produced, using DrizzlePac tools and Astrodrizzle to reduce geometric distortion and provide improved source catalogs for all publicly available data. We detail the HLA data processing and source list schemas, what products are newly updated and available for WFC3 and ACS, and how these data products are further utilized in the production of the Hubble Source Catalog. We also discuss plans for future development, including updates to WFPC2 products and field mosaics.

  1. The current status of education and career paths of students after completion of medical physicist programs in Japan: a survey by the Japanese Board for Medical Physicist Qualification.

    Science.gov (United States)

    Kadoya, Noriyuki; Karasawa, Kumiko; Sumida, Iori; Arimura, Hidetaka; Yamada, Syogo

    2015-07-01

    To standardize educational programs and clinical training for medical physics students, the Japanese Board for Medical Physicist Qualification (JBMP) began to accredit master's, doctorate, and residency programs for medical physicists in 2012. At present, 16 universities accredited by the JBMP offer 22 courses. In this study, we aimed to survey the current status of educational programs and career paths of students after completion of the medical physicist program in Japan. A questionnaire was sent in August 2014 to 32 universities offering medical physicist programs. The questionnaire was created and organized by the educational course certification committee of the JBMP and comprised two sections: the first collected information about the university attended, and the second collected information about characteristics and career paths of students after completion of medical physicist programs from 2008 to 2014. Thirty universities (16 accredited and 14 non-accredited) completed the survey (response rate 94 %). A total of 209, 40, and 3 students graduated from the master's, doctorate, and residency programs, respectively. Undergraduates entered the medical physicist program constantly, indicating an interest in medical physics among undergraduates. A large percentage of the students held a bachelor's degree in radiological technology (master's program 94 %; doctorate program 70 %); graduates obtained a national radiological technologist license. Regarding career paths, although the number of the graduates who work as medical physicist remains low, 7 % with a master's degree and 50 % with a doctorate degree worked as medical physicists. Our results could be helpful for improving the medical physicist program in Japan.

  2. Information and Communication Technology to Facilitate Learning for Students in the Health Professions: Current Uses, Gaps, and Future Directions

    Science.gov (United States)

    Costello, Ellen; Corcoran, Mary; Barnett, Jacqueline S.; Birkmeier, Marisa; Cohn, Rhea; Ekmekci, Ozgur; Falk, Nancy L.; Harrod, Thomas; Herrmann, Debra; Robinson, Sean; Walker, Bryan

    2014-01-01

    Changes in the U.S. Healthcare System along with the need for institutions of higher education to prepare a work force ready to address the challenges of today and tomorrow have highlighted the need to incorporate technology in its broadest sense as part of the student learning experience. In health professional education, this becomes challenging…

  3. An Exploration of Policies Governing Faculty-to-Student Consensual Sexual Relationships on University Campuses: Current Strategies and Future Directions

    Science.gov (United States)

    Richards, Tara N.; Crittenden, Courtney; Garland, Tammy S.; McGuffee, Karen

    2014-01-01

    Consensual sexual relationships between students and faculty have traditionally been viewed as private matters and have been ignored by university administrators except in cases that resulted in sexual harassment claims. Due to increasing sexual harassment litigation and the liabilities associated with such relationships, universities have…

  4. A Comparison of Professional-Level Faculty and Student Perceptions of Active Learning: Its Current Use, Effectiveness, and Barriers

    Science.gov (United States)

    Miller, Cynthia J.; Metz, Michael J.

    2014-01-01

    Active learning is an instructional method in which students become engaged participants in the classroom through the use of in-class written exercises, games, problem sets, audience-response systems, debates, class discussions, etc. Despite evidence supporting the effectiveness of active learning strategies, minimal adoption of the technique has…

  5. Research of Competitive Orientation Among Secondary School Seniour Students: Current Trends and Prospects for Nurturing (Case Study of Tyumen Region

    Directory of Open Access Journals (Sweden)

    Gennady F. Shafranov-Kutsev

    2017-12-01

    Full Text Available Introduction: the priorities of socio-economic development facing our country set new requirements to secondary education; a graduate should not only have a certain amount of knowledge, but also be able to build an effective communication strategy, to be prepared for constant professional self-development, to take the initiative, to interact under conditions of rivalry, in other words, to be competitive. Addressing these issues will contribute to the creation of conditions in which objective requirements of the social system would have found understanding among secondary school students, therefore it is necessary to form competitive thinking. The aim of the study was to consider the factors enabling secondary school students to accept knowledge, values and skills of a competitive person needed for further su stainable development. Materials and Methods: a questionnaire survey of high school students was selected for its reliability and validity in studying competitive skills. The design of the questionnaire was developed by the team of the Sociological Laboratory of the Chair of General and Economic Sociology at Tyumen State University. IBM SPSS Statistics 23 software product was used to process and ana lyse the obtained data. Results: the research provides important insights into the dynamics of the social well-being of secondary school students, defines the main determinants of the formation of skills in competitive environment. The results of this study highlight obstacles to this process as well. Discussion and Conclusions: this paper argues that self-dependent decision-making, critical perception of information, willingness to compete enable to form a competitive personality. The findings from this study have significant potential implications for future educational practice. These research materials are relevant for improving the methods and skills of teaching activities and for development of youth policy. Possible areas for further

  6. Hubble space telescope near-ir transmission spectroscopy of the super-Earth HD 97658B

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Dragomir, Diana [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Kreidberg, Laura; Bean, Jacob L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); McCullough, P. R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gillon, Michael [Institut d' Astrophysique et de Géophysique, Universiteé de Liége, Liége 1 (Belgium); Homeier, Derek [Centre de Recherche Astrophysique de Lyon, F-69364 Lyon (France); Howard, Andrew W., E-mail: hknutson@caltech.edu [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2014-10-20

    Recent results from the Kepler mission indicate that super-Earths (planets with masses between 1-10 times that of the Earth) are the most common kind of planet around nearby Sun-like stars. These planets have no direct solar system analogue, and are currently one of the least well-understood classes of extrasolar planets. Many super-Earths have average densities that are consistent with a broad range of bulk compositions, including both water-dominated worlds and rocky planets covered by a thick hydrogen and helium atmosphere. Measurements of the transmission spectra of these planets offer the opportunity to resolve this degeneracy by directly constraining the scale heights and corresponding mean molecular weights of their atmospheres. We present Hubble Space Telescope near-infrared spectroscopy of two transits of the newly discovered transiting super-Earth HD 97658b. We use the Wide Field Camera 3's (WFC3) scanning mode to measure the wavelength-dependent transit depth in 30 individual bandpasses. Our averaged differential transmission spectrum has a median 1σ uncertainty of 23 ppm in individual bins, making this the most precise observation of an exoplanetary transmission spectrum obtained with WFC3 to date. Our data are inconsistent with a cloud-free solar metallicity atmosphere at the 10σ level. They are consistent at the 0.4σ level with a flat line model, as well as effectively flat models corresponding to a metal-rich atmosphere or a solar metallicity atmosphere with a cloud or haze layer located at pressures of 10 mbar or higher.

  7. System Design and Performance of the Two-Gyro Science Mode For the Hubble Space Telescope

    Science.gov (United States)

    Prior, Michael; Dunham, Larry

    2005-01-01

    For fifteen years, the science mission of the Hubble Space Telescope (HST) required using at least three of the six on-board rate gyros for attitude control. Failed gyros were eventually replaced through Space Shuttle Servicing Missions. The tragic loss of the Space Shuttle Columbia has resulted in the cancellation of all planned Shuttle based missions to HST. While a robotic servicing mission is currently being planned instead, controlling with alternate sensors to replace failed gyros can extend the HST science gathering until a servicing mission can be performed, and also extend science at HST s end of life. Additionally, sufficient performance may allow a permanent transition to operations with less than 3 gyros (by intentionally turning off working gyros saving them for later use) allowing for an even greater science mission extension. To meet this need, a Two Gyro Science (TGS) mode has been designed and implemented using magnetometers (Magnetic Sensing System - MSS), Fixed Head Star Trackers (FHSTs), and Fine Guidance Sensors (FGSs) to control vehicle rate about the missing gyro input axis. The development of the TGS capability is the largest re-design of HST operations undertaken, since it affects several major spacecraft subsystems, the most heavily being the Pointing Control System (PCS) and Flight Software (FSW). Additionally, and equally important, are the extensive modifications and enhancements of the Planning and Scheduling system which must now be capable of scheduling science observations while taking into account several new constraints imposed by the TGS operational modes (such as FHST availability and magnetic field geometry) that will impact science gathering efficiency and target availability. This paper discusses the systems engineering design, development, and performance of the TGS mode, now in its final stages of completion.

  8. Little Blue Dots in the Hubble Space Telescope Frontier Fields: Precursors to Globular Clusters?

    Science.gov (United States)

    Elmegreen, Debra Meloy; Elmegreen, Bruce G.

    2017-12-01

    Galaxies with stellar masses {10}-7.4 yr‑1 were examined on images of the Hubble Space Telescope Frontier Field Parallels for Abell 2744 and MACS J0416.1-02403. They appear as unresolved “Little Blue Dots” (LBDs). They are less massive and have higher specific star formation rates (sSFRs) than “blueberries” studied by Yang et al. and higher sSFRs than “Blue Nuggets” studied by Tacchella et al. We divided the LBDs into three redshift bins and, for each, stacked the B435, V606, and I814 images convolved to the same stellar point-spread function (PSF). Their radii were determined from PSF deconvolution to be ∼80 to ∼180 pc. The high sSFRs suggest that their entire stellar mass has formed in only 1% of the local age of the universe. The sSFRs at similar epochs in local dwarf galaxies are lower by a factor of ∼100. Assuming that the star formation rate is {ε }{ff}{M}{gas}/{t}{ff} for efficiency {ε }{ff}, gas mass M gas, and free-fall time, t ff, the gas mass and gas-to-star mass ratio are determined. This ratio exceeds 1 for reasonable efficiencies, and is likely to be ∼5 even with a high {ε }{ff} of 0.1. We consider whether these regions are forming today’s globular clusters. With their observed stellar masses, the maximum likely cluster mass is ∼ {10}5 {M}ȯ , but if star formation continues at the current rate for ∼ 10{t}{ff}∼ 50 {Myr} before feedback and gas exhaustion stop it, then the maximum cluster mass could become ∼ {10}6 {M}ȯ .

  9. Current Tobacco Smoking and Desire to Quit Smoking Among Students Aged 13-15 Years - Global Youth Tobacco Survey, 61 Countries, 2012-2015.

    Science.gov (United States)

    Arrazola, René A; Ahluwalia, Indu B; Pun, Eugene; Garcia de Quevedo, Isabel; Babb, Stephen; Armour, Brian S

    2017-05-26

    Tobacco use is the world's leading cause of preventable morbidity and mortality, resulting in nearly 6 million deaths each year (1). Smoked tobacco products, such as cigarettes and cigars, are the most common form of tobacco consumed worldwide (2), and most tobacco smokers begin smoking during adolescence (3). The health benefits of quitting are greater for persons who stop smoking at earlier ages; however, quitting smoking at any age has health benefits (4). CDC used the Global Youth Tobacco Survey (GYTS) data from 61 countries across the six World Health Organization (WHO) regions from 2012 to 2015 to examine the prevalence of current tobacco smoking and desire to quit smoking among students aged 13-15 years. Across all 61 countries, the median current tobacco smoking prevalence among students aged 13-15 years was 10.7% (range = 1.7%, Sri Lanka to 35.0%, Timor-Leste). By sex, the median current tobacco smoking prevalence was 14.6% among males (range = 2.9%, Tajikistan to 61.4%, Timor-Leste) and 7.5% among females (range = 1.6%, Tajikistan to 29.0%, Bulgaria). In the majority of countries assessed, the proportion of current tobacco smokers who desired to quit smoking exceeded 50%. These findings could be used by country level tobacco control programs to inform strategies to prevent and reduce youth tobacco use (1,4).

  10. [Study on the current situation and influential factors of anxiety sensitivity among middle school students in Chongqing].

    Science.gov (United States)

    Li, Qian-Qian; Zhang, Da-Jun; Guo, Lan-Ting; Feng, Zheng-Zhi; Wu, Ming-Xia

    2007-09-01

    To explore the status and influencing factors on anxiety sensitivity among middle school students in Chongqing. 58 classes from 12 schools were randomly selected in four administrative districts of Chongqing city. A total number of 2700 students was included for final analysis including 48.5% from junior high school and 51.5% from senior high school students with 49.2% boys and 50.8% girls. The Chinese version of the Anxiety Sensitivity Index-Revision, Adolescent Self-Rating Life Events Check List (ASLEC) and State-Trait Anxiety Inventory (STAI) were used. (1) There was no significant difference between grade groups (P = 0.49). (2) The level of girl's anxiety sensitivity was always higher than boy's (P < 0.001). (3) Data from multiple linear regression showed that the influential factors to the degree of anxiety sensitivity were: state of anxiety, trait anxiety, life events, sex, stress from learning, etc (standard coefficients of regression were 0.258, 0.163, 0.112, 0.093, 0.124, -0.096, 0.096). The major influential factors of anxiety sensitivity would include: sex, stress from learning, life events, interpersonal relationship, state of anxiety and trait anxiety.

  11. Current Use of E-Cigarettes and Conventional Cigarettes Among US High School Students in Urban and Rural Locations: 2014 National Youth Tobacco Survey.

    Science.gov (United States)

    Noland, Melody; Rayens, Mary Kay; Wiggins, Amanda T; Huntington-Moskos, Luz; Rayens, Emily A; Howard, Tiffany; Hahn, Ellen J

    2017-01-01

    Adolescent tobacco use is higher in rural than in urban areas. While e-cigarette use is increasing rapidly among this age group, differences in prevalence between rural versus urban populations for this relatively novel product have not been explored. The purpose is to investigate whether location of school (rural-urban) is associated with e-cigarette use and dual use (defined as the use of both e-cigarettes and conventional cigarettes) among high school students. Cross-sectional survey obtained using a stratified, 3-stage cluster sample design. United States. A nationally representative sample of US high school students (N = 11 053) who completed the 2014 National Youth Tobacco Survey (NYTS); slightly more than half were urban (54%). The NYTS measures tobacco-related knowledge, attitudes, and use behavior and demographics of students in the United States. Weighted logistic regression assessed the relationships of urban-rural location with current e-cigarette use and dual use, adjusting for demographic factors, perceived risk, and social norms. There were clear differences in patterns of adolescent e-cigarette and cigarette use in rural versus urban areas. Social norms and perceptions may play a role in understanding these differences. Urban youth current cigarette smokers were nearly twice as likely as rural cigarette smokers to also use e-cigarettes. Reasons for urban-rural differences need to be taken into account when designing prevention programs and policy changes.

  12. Observations of the Hubble Deep Field with the Infrared Space Observatory .2. Source detection and photometry

    DEFF Research Database (Denmark)

    Goldschmidt, P.; Oliver, S.J.; Serjeant, S.B.G.

    1997-01-01

    We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 mu m. We have constructed algorithmically selected 'complete' flux-limited samples of 19 sources in the 15-mu m image, and seven sources in the 6.7-mu m...

  13. Discovery of Hubble's Law as a Series of Type III Errors

    Science.gov (United States)

    Belenkiy, Ari

    2015-01-01

    Recently much attention has been paid to the history of the discovery of Hubble's law--the linear relation between the rate of recession of the remote galaxies and distance to them from Earth. Though historians of cosmology now mention several names associated with this law instead of just one, the motivation of each actor of that remarkable…

  14. A guide to hubble space telescope objects their selection, location, and significance

    CERN Document Server

    Chen, James L

    2015-01-01

    From the authors of "How to Find the Apollo Landing Sites," this is a guide to connecting the view above with the history of recent scientific discoveries from the Hubble Space Telescope. Each selected HST photo is shown with a sky map and a photograph or drawing to illustrate where to find it and how it should appear from a backyard telescope. Here is the casual observer's chance to locate the deep space objects visually, and appreciate the historic Hubble photos in comparison to what is visible from a backyard telescope. HST objects of all types are addressed, from Messier objects, Caldwell objects, and NGC objects, and are arranged in terms of what can be seen during the seasons. Additionally, the reader is given an historical perspective on the work of Edwin Hubble, while locating and viewing the deep space objects that changed astronomy forever.  Countless people have seen the amazing photographs taken by the Hubble Space Telescope. But how many people can actually point out where in the sky ...

  15. The Great Attractor: At the Limits of Hubble's Law of the Expanding Universe.

    Science.gov (United States)

    Murdin, Paul

    1991-01-01

    Presents the origin and mathematics of Hubble's Law of the expanding universe. Discusses limitations to this law and the related concepts of standard candles, elliptical galaxies, and streaming motions, which are conspicuous deviations from the law. The third of three models proposed as explanations for streaming motions is designated: The Great…

  16. HFF-DeepSpace Photometric Catalogs of the 12 Hubble Frontier Fields, Clusters, and Parallels: Photometry, Photometric Redshifts, and Stellar Masses

    Science.gov (United States)

    Shipley, Heath V.; Lange-Vagle, Daniel; Marchesini, Danilo; Brammer, Gabriel B.; Ferrarese, Laura; Stefanon, Mauro; Kado-Fong, Erin; Whitaker, Katherine E.; Oesch, Pascal A.; Feinstein, Adina D.; Labbé, Ivo; Lundgren, Britt; Martis, Nicholas; Muzzin, Adam; Nedkova, Kalina; Skelton, Rosalind; van der Wel, Arjen

    2018-03-01

    We present Hubble multi-wavelength photometric catalogs, including (up to) 17 filters with the Advanced Camera for Surveys and Wide Field Camera 3 from the ultra-violet to near-infrared for the Hubble Frontier Fields and associated parallels. We have constructed homogeneous photometric catalogs for all six clusters and their parallels. To further expand these data catalogs, we have added ultra-deep K S -band imaging at 2.2 μm from the Very Large Telescope HAWK-I and Keck-I MOSFIRE instruments. We also add post-cryogenic Spitzer imaging at 3.6 and 4.5 μm with the Infrared Array Camera (IRAC), as well as archival IRAC 5.8 and 8.0 μm imaging when available. We introduce the public release of the multi-wavelength (0.2–8 μm) photometric catalogs, and we describe the unique steps applied for the construction of these catalogs. Particular emphasis is given to the source detection band, the contamination of light from the bright cluster galaxies (bCGs), and intra-cluster light (ICL). In addition to the photometric catalogs, we provide catalogs of photometric redshifts and stellar population properties. Furthermore, this includes all the images used in the construction of the catalogs, including the combined models of bCGs and ICL, the residual images, segmentation maps, and more. These catalogs are a robust data set of the Hubble Frontier Fields and will be an important aid in designing future surveys, as well as planning follow-up programs with current and future observatories to answer key questions remaining about first light, reionization, the assembly of galaxies, and many more topics, most notably by identifying high-redshift sources to target.

  17. Quantum fields from the Hubble to the Planck scale

    CERN Document Server

    Kachelriess, Michael

    2017-01-01

    This book introduces quantum field theory, together with its most important applications to cosmology and astroparticle physics, in a coherent framework. The path integral approach is employed right from the start, and the use of Green functions and generating functionals is illustrated first in quantum mechanics and then in scalar field theory. Massless spin one and two fields are discussed on an equal footing, and gravity is presented as a gauge theory in close analogy with the Yang-Mills case. Concepts relevant to modern research such as helicity methods, effective theories, decoupling, or the stability of the electroweak vacuum are introduced. Various applications such as topological defects, dark matter, baryogenesis, processes in external gravitational fields, inflation and black holes help students to bridge the gap between undergraduate courses and the research literature.

  18. Galaxy formation in the reionization epoch as hinted by Wide Field Camera 3 observations of the Hubble Ultra Deep Field

    International Nuclear Information System (INIS)

    Yan Haojing; Windhorst, Rogier A.; Cohen, Seth H.; Hathi, Nimish P.; Ryan, Russell E.; O'Connell, Robert W.; McCarthy, Patrick J.

    2010-01-01

    We present a large sample of candidate galaxies at z ∼ 7-10, selected in the Hubble Ultra Deep Field using the new observations of the Wide Field Camera 3 that was recently installed on the Hubble Space Telescope. Our sample is composed of 20 z 850 -dropouts (four new discoveries), 15 Y 105 -dropouts (nine new discoveries) and 20 J 125 -dropouts (all new discoveries). The surface densities of the z 850 -dropouts are close to what was predicted by earlier studies, however, those of the Y 105 - and J 125 -dropouts are quite unexpected. While no Y 105 - or J 125 -dropouts have been found at AB ≤ 28.0 mag, their surface densities seem to increase sharply at fainter levels. While some of these candidates seem to be close to foreground galaxies and thus could possibly be gravitationally lensed, the overall surface densities after excluding such cases are still much higher than what would be expected if the luminosity function does not evolve from z ∼ 7 to 10. Motivated by such steep increases, we tentatively propose a set of Schechter function parameters to describe the luminosity functions at z ∼ 8 and 10. As compared to their counterpart at z ∼ 7, here L * decreases by a factor of ∼ 6.5 and φ * increases by a factor of 17-90. Although such parameters are not yet demanded by the existing observations, they are allowed and seem to agree with the data better than other alternatives. If these luminosity functions are still valid beyond our current detection limit, this would imply a sudden emergence of a large number of low-luminosity galaxies when looking back in time to z ∼ 10, which, while seemingly exotic, would naturally fit in the picture of the cosmic hydrogen reionization. These early galaxies could easily account for the ionizing photon budget required by the reionization, and they would imply that the global star formation rate density might start from a very high value at z ∼ 10, rapidly reach the minimum at z ∼ 7, and start to rise again

  19. The ESA Hubble 15th Anniversary Campaign: A Trans-European collaboration project

    Science.gov (United States)

    Zoulias, Manolis; Christensen, Lars Lindberg; Kornmesser, Martin

    2006-08-01

    On April 24th 2005, NASA/ESA Hubble Space Telescope had been in orbit for 15 years. The anniversary was celebrated by ESA with the production of an 83 min. scientific movie and a 120 pages book, both titled ``Hubble, 15 years of discovery''. In order to cross language and distribution barriers a network of 16 translators and 22 partners from more than 10 countries was established. The DVD was distributed in approximately 700,000 copies throughout Europe. The project was amongst the largest of its kind with respect to collaboration, distribution and audience impact. It clearly demonstrated how international collaboration can produce effective cross-cultural educational and outreach products for astronomy.

  20. Testing the Interacting Dark Energy Model with Cosmic Microwave Background Anisotropy and Observational Hubble Data

    Directory of Open Access Journals (Sweden)

    Weiqiang Yang

    2017-07-01

    Full Text Available The coupling between dark energy and dark matter provides a possible approach to mitigate the coincidence problem of the cosmological standard model. In this paper, we assumed the interacting term was related to the Hubble parameter, energy density of dark energy, and equation of state of dark energy. The interaction rate between dark energy and dark matter was a constant parameter, which was, Q = 3 H ξ ( 1 + w x ρ x . Based on the Markov chain Monte Carlo method, we made a global fitting on the interacting dark energy model from Planck 2015 cosmic microwave background anisotropy and observational Hubble data. We found that the observational data sets slightly favored a small interaction rate between dark energy and dark matter; however, there was not obvious evidence of interaction at the 1 σ level.

  1. Asteroseismology of the Transiting Exoplanet Host HD 17156 with Hubble Space Telescope Fine Guidance Sensor

    DEFF Research Database (Denmark)

    Gilliland, Ronald L.; McCullough, Peter R.; Nelan, Edmund P.

    2011-01-01

    light curve. Using the density constraint from asteroseismology, and stellar evolution modeling results in M * = 1.285 ± 0.026 M sun, R * = 1.507 ± 0.012 R sun, and a stellar age of 3.2 ± 0.3 Gyr. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science......Observations conducted with the Fine Guidance Sensor on the Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in 2008 December on the host star of the transiting exoplanet HD 17156b. During this time, 1.0 × 1012 photons...... Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555....

  2. The variance of the locally measured Hubble parameter explained with different estimators

    DEFF Research Database (Denmark)

    Odderskov, Io Sandberg Hess; Hannestad, Steen; Brandbyge, Jacob

    2017-01-01

    We study the expected variance of measurements of the Hubble constant, H0, as calculated in either linear perturbation theory or using non-linear velocity power spectra derived from N-body simulations. We compare the variance with that obtained by carrying out mock observations in the N......-body simulations, and show that the estimator typically used for the local Hubble constant in studies based on perturbation theory is different from the one used in studies based on N-body simulations. The latter gives larger weight to distant sources, which explains why studies based on N-body simulations tend...... to obtain a smaller variance than that found from studies based on the power spectrum. Although both approaches result in a variance too small to explain the discrepancy between the value of H0 from CMB measurements and the value measured in the local universe, these considerations are important in light...

  3. Light dark photon and fermionic dark radiation for the Hubble constant and the structure formation

    OpenAIRE

    Ko, P.; Tang, Yong

    2018-01-01

    Motivated by the tensions in the Hubble constant $H_0$ and the structure growth $\\sigma_8$ between $Planck$ results and other low redshift measurements, we discuss some cosmological effects of a dark sector model in which dark matter (DM) interacts with fermionic dark radiation (DR) through a light gauge boson (dark photon). Such kind of models are very generic in particle physics with a dark sector with dark gauge symmetries. The effective number of neutrinos is increased by $\\delta N_{eff} ...

  4. Charge retention test experiences on Hubble Space Telescope nickel-hydrogen battery cells

    Science.gov (United States)

    Nawrocki, Dave E.; Driscoll, J. R.; Armantrout, J. D.; Baker, R. C.; Wajsgras, H.

    1993-01-01

    The Hubble Space Telescope (HST) nickel-hydrogen battery module was designed by Lockheed Missile & Space Co (LMSC) and manufactured by Eagle-Picher Ind. (EPI) for the Marshall Space Flight Center (MSFC) as an Orbital Replacement Unit (ORU) for the nickel-cadmium batteries originally selected for this low earth orbit mission. The design features of the HST nickel hydrogen battery are described and the results of an extended charge retention test are summarized.

  5. A knowledge-based system for monitoring the electrical power system of the Hubble Space Telescope

    Science.gov (United States)

    Eddy, Pat

    1987-01-01

    The design and the prototype for the expert system for the Hubble Space Telescope's electrical power system are discussed. This prototype demonstrated the capability to use real time data from a 32k telemetry stream and to perform operational health and safety status monitoring, detect trends such as battery degradation, and detect anomalies such as solar array failures. This prototype, along with the pointing control system and data management system expert systems, forms the initial Telemetry Analysis for Lockheed Operated Spacecraft (TALOS) capability.

  6. Distance to M33 determined from magnitude corrections to Hubble's original cepheid photometry

    International Nuclear Information System (INIS)

    Sandage, A.

    1983-01-01

    New photoelectric photometry in Selected Area 45, and transfers from a faint photoelectric sequence adjacent to the south-preceding arm in M33 have been made to the comparison stars for Hubble's Cepheids in M33. Progressive magnitude corrections are required to Hubble's M33 scales, reaching 2.8 mag at the limit of the Mount Wilson 2.5-m Hooker reflector. Hubble's Cepheid light curves have been corrected to the B photoelectric system, and new photometric parameters are given for 35 of his variables. The P-L relation agrees in zero point to within 0.2 mag of the P-L relation from independent data by Sandage and Carlson for 12 new Cepheids in an outlying region of M33. Application of an adopted absolute P-L relation, calibrated by Martin, Warren, and Feast, to these data gives an apparent blue modulus of (m-M)/sup AB//sub M33/ = 25.35, which is 0.67 mag fainter than a previously adopted value, and represents a factor of 4.2 increase of Hubble's earliest distance. Three consequences of this larger apparent distance modulus are (1) the mean absolute magnitude of the first three brightest red supergiants is M/sup max//sub left-angle-bracketV/(3)> = -8.7 rather than approx.-8.0 in M33, complicating but not destroying use of red supergiants as distance indicators, (2) the mean absolute magnitude of the two brightest blue irregular supergiant variables is M/sub left-angle-bracketB/(2)> = -9.95, which is close to the value for the brightest known supergiants in the galaxy, and (3) the absolute magnitude of M33 itself is brighter than heretofore assumed

  7. Predicting Medical Students' Current Attitudes Toward Psychiatry, Interest in Psychiatry, and Estimated Likelihood of Working in Psychiatry: A Cross-Sectional Study in Four European Countries.

    Science.gov (United States)

    Warnke, Ingeborg; Gamma, Alex; Buadze, Maria; Schleifer, Roman; Canela, Carlos; Strebel, Bernd; Tényi, Tamás; Rössler, Wulf; Rüsch, Nicolas; Liebrenz, Michael

    2018-01-01

    Psychiatry as a medical discipline is becoming increasingly important due to the high and increasing worldwide burden associated with mental disorders. Surprisingly, however, there is a lack of young academics choosing psychiatry as a career. Previous evidence on medical students' perspectives is abundant but has methodological shortcomings. Therefore, by attempting to avoid previous shortcomings, we aimed to contribute to a better understanding of the predictors of the following three outcome variables: current medical students' attitudes toward psychiatry, interest in psychiatry, and estimated likelihood of working in psychiatry. The sample consisted of N  = 1,356 medical students at 45 medical schools in Germany and Austria as well as regions of Switzerland and Hungary with a German language curriculum. We used snowball sampling via Facebook with a link to an online questionnaire as recruitment procedure. Snowball sampling is based on referrals made among people. This questionnaire included a German version of the Attitudes Toward Psychiatry Scale (ATP-30-G) and further variables related to outcomes and potential predictors in terms of sociodemography (e.g., gender) or medical training (e.g., curriculum-related experience with psychiatry). Data were analyzed by linear mixed models and further regression models. On average, students had a positive attitude to and high general interest in, but low professional preference for, psychiatry. A neutral attitude to psychiatry was partly related to the discipline itself, psychiatrists, or psychiatric patients. Female gender and previous experience with psychiatry, particularly curriculum-related and personal experience, were important predictors of all outcomes. Students in the first years of medical training were more interested in pursuing psychiatry as a career. Furthermore, the country of the medical school was related to the outcomes. However, statistical models explained only a small proportion of variance. The

  8. Enhancing Hubble's vision service missions that expanded our view of the universe

    CERN Document Server

    Shayler, David J

    2016-01-01

    After a 20-year struggle to place a large, sophisticated optical telescope in orbit the Hubble Space Telescope was finally launched in 1990, though its primary mirror was soon found to be flawed. A dramatic mission in 1993 installed corrective optics so that the intended science program could finally begin. Those events are related in a companion to this book, The Hubble Space Telescope: From Concept to Success.   Enhancing Hubble’s Vision: Service Missions That Expanded Our View of the Universe tells the story of the four missions between 1997 and 2009 that repaired, serviced and upgraded the instruments on the telescope to maintain its state-of-the-art capabilities. It draws on first hand interviews with those closely involved in the project. The spacewalking skills and experiences gained from maintaining and upgrading Hubble had direct application to the construction of the International Space Station and help with its maintenance. These skills can be applied to future human and robotic satellite servic...

  9. UVUDF: Ultraviolet Imaging of the Hubble Ultra Deep Field with Wide-Field Camera 3

    Science.gov (United States)

    Teplitz, Harry I.; Rafelski, Marc; Kurczynski, Peter; Bond, Nicholas A.; Grogin, Norman; Koekemoer, Anton M.; Atek, Hakim; Brown, Thomas M.; Coe, Dan; Colbert, James W.; Ferguson, Henry C.; Finkelstein, Steven L.; Gardner, Jonathan P.; Gawiser, Eric; Giavalisco, Mauro; Gronwall, Caryl; Hanish, Daniel J.; Lee, Kyoung-Soo; de Mello, Duilia F.; Ravindranath, Swara; Ryan, Russell E.; Siana, Brian D.; Scarlata, Claudia; Soto, Emmaris; Voyer, Elysse N.; Wolfe, Arthur M.

    2013-12-01

    We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: (1) investigate the episode of peak star formation activity in galaxies at 1 dropouts at redshifts 1.7, 2.1, and 2.7 is largely consistent with the number predicted by published luminosity functions. We also confirm that the image mosaics have sufficient sensitivity and resolution to support the analysis of the evolution of star-forming clumps, reaching 28-29th magnitude depth at 5σ in a 0.''2 radius aperture depending on filter and observing epoch. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are #12534.

  10. Studying Galaxy Formation with the Hubble, Spitzer and James Webb Space Telescopes

    Science.gov (United States)

    Gardner, Jonathan P.

    2009-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts z greater than 6, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z greater than 10, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (less than 50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth-Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. In addition to JWST's ability to study the formation and evolution of galaxies, I will also briefly review its expected contributions to studies of the formation of stars and planetary systems, and discuss recent progress in constructing the observatory.

  11. Leadership training for radiologists: a survey of opportunities and participants in MBA and MPH programs by medical students, residents, and current chairpersons.

    Science.gov (United States)

    Baker, Stephen; Daginawala, Naznin

    2011-08-01

    The aim of this study was to determine opportunities for students and trainees to obtain an MPH or MBA degree during either medical school or radiology residency and to determine the prevalence of such degree possession by chairpersons in radiology. All allopathic medical schools in the United States were surveyed to chart the number of MD/MPH and MD/MBA degree programs available to students. Program directors were contacted to assess the number of MPH or MBA courses of study administratively related to their residencies. Also, an e-mail survey was sent to all members of the Society of Chairs of Academic Radiology Departments inquiring whether each chairperson had earned an additional degree. Currently, 81 allopathic medical schools in the United States offer MD/MPH degrees, and 52 offer MD/MBA degrees. Six residencies provide access to MPH programs, and 3 residencies provide the opportunity to pursue an MBA in conjunction with residency. Of these, only 1 MPH program and no MBA programs had trainees enrolled at present. Twenty-six percent of the chairpersons surveyed possessed advanced degrees other than MDs. There has been rapid growth in the number of MD/MPH and MD/MBA programs available to medical students. However, there is a scarcity of similar programs accessible to trainees during or just after residency training. To assist motivated radiologists interested in leading our profession, opportunities should expand both in formal degree-granting programs and through certificate-sanctioned course series to address relevant issues of leadership and management pertinent to our specialty. Copyright © 2011 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  12. Retrospective report of social withdrawal during adolescence and current maladjustment in young adulthood: cross-cultural comparisons between Australian and South Korean students.

    Science.gov (United States)

    Kim, Jinkwan; Rapee, Ronald M; Ja Oh, Kyung; Moon, Hye-Shin

    2008-10-01

    The current study investigated associations between the frequency of and motivations for social withdrawal during adolescence and emotional distress in young adulthood. Perceived motivations for social withdrawal included unsociability, isolation, shyness, and low mood. Social withdrawal during adolescence was assessed using a retrospective questionnaire completed by Australian and Korean university students. They also completed measures of general self-worth, social relationships, loneliness, social anxiety, and depression at university. Partial correlations and path analyses revealed that different motivations for social withdrawal had different risk status for later adjustment across the two samples. In particular, it appeared that shy and unsociable individuals in Korea showed better social and emotional adjustment than their counterparts in Australia. In contrast, social relationships of sad/depressed and isolated respondents in Korea appeared to be more seriously impaired than their Australian counterparts. These cross-cultural differences are discussed in terms of socio-cultural values and environments unique to the two countries.

  13. The effect of aggression management training programmes for nursing staff and students working in an acute hospital setting. A narrative review of current literature.

    Science.gov (United States)

    Heckemann, B; Zeller, A; Hahn, S; Dassen, T; Schols, J M G A; Halfens, R J G

    2015-01-01

    Patient aggression is a longstanding problem in general hospital nursing. Staff training is recommended to tackle workplace aggression originating from patients or visitors, yet evidence on training effects is scarce. To review and collate current research evidence on the effect of aggression management training for nurses and nursing students working in general hospitals, and to derive recommendations for further research. Systematic, narrative review. Embase, MEDLINE, the Cochrane library, CINAHL, PsycINFO, pubmed, psycArticles, Psychology and Behavioural Sciences Collection were searched for articles evaluating training programs for staff and students in acute hospital adult nursing in a 'before/after' design. Studies published between January 2000 and September 2011 in English, French or German were eligible of inclusion. The methodological quality of included studies was assessed with the 'Quality Assessment Tool for Quantitative Studies'. Main outcomes i.e. attitudes, confidence, skills and knowledge were collated. Nine studies were included. Two had a weak, six a moderate, and one a strong study design. All studies reported increased confidence, improved attitude, skills, and knowledge about risk factors post training. There was no significant change in incidence of patient aggression. Our findings corroborate findings of reviews on training in mental health care, which point to a lack of high quality research. Training does not reduce the incidence of aggressive acts. Aggression needs to be tackled at an organizational level. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Knowledge, attitudes, and practices of argileh (water pipe or hubble-bubble) and cigarette smoking among pregnant women in Lebanon.

    Science.gov (United States)

    Chaaya, M; Jabbour, S; El-Roueiheb, Z; Chemaitelly, H

    2004-12-01

    Currently, little is known about argileh (water pipe or hubble-bubble) and cigarette smoking among pregnant women in the Arab world, despite emerging evidence on the adverse health effects of argileh smoking and well-established knowledge about the health risks of cigarette smoking during pregnancy. The present study assesses pregnant Arab women's knowledge of chemical contents and related harmful effects of argileh and cigarettes, their attitudes towards smoking argileh and cigarettes, and their actual smoking of argileh and cigarettes, both before and during pregnancy. A stratified sample of 864 women from 23 health care centers in Lebanon completed a structured, interviewer-administered questionnaire. Information was collected on basic demographic variables, women's knowledge, attitudes, and cigarette and argileh smoking. Women were partially knowledgeable about the health risks of cigarette smoking, knew little about the harmful ingredients of argileh smoking, and had many misconceptions regarding how argileh worked or how it can produce harm. Attitudes were permissive towards all forms of smoking. Almost one quarter (23%) of participants reported smoking during pregnancy, with 17% smoking only cigarettes, 4% smoking only argileh, and 1.5% smoking both cigarette and argileh. A significant and growing percentage of pregnant Arab women are smoking in Lebanon, with four cigarette smokers for every argileh smoker. Smoking behaviors are empirically linked with important gaps in knowledge and with permissive attitudes. These data may be used to design more effective prevention programs targeting this vulnerable population.

  15. The HST/WFC3 Quicklook Project: A User Interface to Hubble Space Telescope Wide Field Camera 3 Data

    Science.gov (United States)

    Bourque, Matthew; Bajaj, Varun; Bowers, Ariel; Dulude, Michael; Durbin, Meredith; Gosmeyer, Catherine; Gunning, Heather; Khandrika, Harish; Martlin, Catherine; Sunnquist, Ben; Viana, Alex

    2017-06-01

    The Hubble Space Telescope's Wide Field Camera 3 (WFC3) instrument, comprised of two detectors, UVIS (Ultraviolet-Visible) and IR (Infrared), has been acquiring ~ 50-100 images daily since its installation in 2009. The WFC3 Quicklook project provides a means for instrument analysts to store, calibrate, monitor, and interact with these data through the various Quicklook systems: (1) a ~ 175 TB filesystem, which stores the entire WFC3 archive on disk, (2) a MySQL database, which stores image header data, (3) a Python-based automation platform, which currently executes 22 unique calibration/monitoring scripts, (4) a Python-based code library, which provides system functionality such as logging, downloading tools, database connection objects, and filesystem management, and (5) a Python/Flask-based web interface to the Quicklook system. The Quicklook project has enabled large-scale WFC3 analyses and calibrations, such as the monitoring of the health and stability of the WFC3 instrument, the measurement of ~ 20 million WFC3/UVIS Point Spread Functions (PSFs), the creation of WFC3/IR persistence calibration products, and many others.

  16. Review of Current Student-Monitoring Techniques used in eLearning-Focused recommender Systems and Learning analytics. The Experience API & LIME model Case Study

    Directory of Open Access Journals (Sweden)

    Alberto Corbi

    2014-09-01

    Full Text Available Recommender systems require input information in order to properly operate and deliver content or behaviour suggestions to end users. eLearning scenarios are no exception. Users are current students and recommendations can be built upon paths (both formal and informal, relationships, behaviours, friends, followers, actions, grades, tutor interaction, etc. A recommender system must somehow retrieve, categorize and work with all these details. There are several ways to do so: from raw and inelegant database access to more curated web APIs or even via HTML scrapping. New server-centric user-action logging and monitoring standard technologies have been presented in past years by several groups, organizations and standard bodies. The Experience API (xAPI, detailed in this article, is one of these. In the first part of this paper we analyse current learner-monitoring techniques as an initialization phase for eLearning recommender systems. We next review standardization efforts in this area; finally, we focus on xAPI and the potential interaction with the LIME model, which will be also summarized below.

  17. Current Cigarette Smoking, Access, and Purchases from Retail Outlets Among Students Aged 13-15 Years - Global Youth Tobacco Survey, 45 Countries, 2013 and 2014.

    Science.gov (United States)

    D'Angelo, Denise; Ahluwalia, Indu B; Pun, Eugene; Yin, Shaoman; Palipudi, Krishna; Mbulo, Lazarous

    2016-09-02

    Tobacco use is a leading preventable cause of morbidity and mortality, with nearly 6 million deaths caused by tobacco use worldwide every year (1). Cigarette smoking is the most common form of tobacco use in most countries, and the majority of adult smokers initiate smoking before age 18 years (2,3). Limiting access to cigarettes among youths is an effective strategy to curb the tobacco epidemic by preventing smoking initiation and reducing the number of new smokers (3,4). CDC used the Global Youth Tobacco Survey (GYTS) data from 45 countries to examine the prevalence of current cigarette smoking, purchase of cigarettes from retail outlets, and type of cigarette purchases made among school students aged 13-15 years. The results are presented by the six World Health Organization (WHO) regions: African Region (AFR); Eastern Mediterranean Region (EMR); European Region (EUR); Region of the Americas (AMR); South-East Asian Region (SEAR); and Western Pacific Region (WPR). Across all 45 countries, the median overall current cigarette smoking prevalence among students aged 13-15 years was 6.8% (range = 1.7% [Kazakhstan]-28.9% [Timor-Leste]); the median prevalence among boys was 9.7% (2.0% [Kazakhstan]-53.5% [Timor-Leste]), and among girls was 3.5% (0.0% [Bangladesh]-26.3% [Italy]). The proportion of current cigarette smokers aged 13-15 years who reported purchasing cigarettes from a retail outlet such as a store, street vendor, or kiosk during the past 30 days ranged from 14.9% [Latvia] to 95.1% [Montenegro], and in approximately half the countries, exceeded 50%. In the majority of countries assessed in AFR and SEAR, approximately 40% of cigarette smokers aged 13-15 years reported purchasing individual cigarettes. Approximately half of smokers in all but one country assessed in EUR reported purchasing cigarettes in packs. These findings could be used by countries to inform tobacco control strategies in the retail environment to reduce and prevent marketing and sales of

  18. VizieR Online Data Catalog: Hubble Source Catalog (V1 and V2) (Whitmore+, 2016)

    Science.gov (United States)

    Whitmore, B. C.; Allam, S. S.; Budavari, T.; Casertano, S.; Downes, R. A.; Donaldson, T.; Fall, S. M.; Lubow, S. H.; Quick, L.; Strolger, L.-G.; Wallace, G.; White, R. L.

    2016-10-01

    The HSC v1 contains members of the WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR Source Extractor source lists from HLA version DR8 (data release 8). The crossmatching process involves adjusting the relative astrometry of overlapping images so as to minimize positional offsets between closely aligned sources in different images. After correction, the astrometric residuals of crossmatched sources are significantly reduced, to typically less than 10mas. The relative astrometry is supported by using Pan-STARRS, SDSS, and 2MASS as the astrometric backbone for initial corrections. In addition, the catalog includes source nondetections. The crossmatching algorithms and the properties of the initial (Beta 0.1) catalog are described in Budavari & Lubow (2012ApJ...761..188B). The HSC v2 contains members of the WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR Source Extractor source lists from HLA version DR9.1 (data release 9.1). The crossmatching process involves adjusting the relative astrometry of overlapping images so as to minimize positional offsets between closely aligned sources in different images. After correction, the astrometric residuals of crossmatched sources are significantly reduced, to typically less than 10mas. The relative astrometry is supported by using Pan-STARRS, SDSS, and 2MASS as the astrometric backbone for initial corrections. In addition, the catalog includes source nondetections. The crossmatching algorithms and the properties of the initial (Beta 0.1) catalog are described in Budavari & Lubow (2012ApJ...761..188B). Hubble Source Catalog Acknowledgement: Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESAC/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA). (2 data files).

  19. Hubble Space Telescope Wide Field Planetary Camera 2 Observations of Neptune

    Science.gov (United States)

    1995-01-01

    Two groups have recently used the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC 2) to acquire new high-resolution images of the planet Neptune. Members of the WFPC-2 Science Team, lead by John Trauger, acquired the first series of images on 27 through 29 June 1994. These were the highest resolution images of Neptune taken since the Voyager-2 flyby in August of 1989. A more comprehensive program is currently being conducted by Heidi Hammel and Wes Lockwood. These two sets of observations are providing a wealth of new information about the structure, composition, and meteorology of this distant planet's atmosphere.Neptune is currently the most distant planet from the sun, with an orbital radius of 4.5 billion kilometers (2.8 billion miles, or 30 Astronomical Units). Even though its diameter is about four times that of the Earth (49,420 vs. 12,742 km), ground-based telescopes reveal a tiny blue disk that subtends less than 1/1200 of a degree (2.3 arc-seconds). Neptune has therefore been a particularly challenging object to study from the ground because its disk is badly blurred by the Earth's atmosphere. In spite of this, ground-based astronomers had learned a great deal about this planet since its position was first predicted by John C. Adams and Urbain Leverrier in 1845. For example, they had determined that Neptune was composed primarily of hydrogen and helium gas, and that its blue color caused by the presence of trace amounts of the gas methane, which absorbs red light. They had also detected bright cloud features whose brightness changed with time, and tracked these clouds to infer a rotation period between 17 and 22 hours.When the Voyager-2 spacecraft flew past the Neptune in 1989, its instruments revealed a surprising array of meteorological phenomena, including strong winds, bright, high-altitude clouds, and two large dark spots attributed to long-lived giant storm systems. These bright clouds and dark spots were tracked as they moved

  20. Theoretical colours and isochrones for some Hubble Space Telescope colour systems

    Science.gov (United States)

    Edvardsson, B.; Bell, R. A.

    1989-01-01

    Synthetic spectra for effective temperatures of 4000-7250 K, logarithmic surface gravities typical of dwarfs and subgiants, and metallicities from solar values to 0.001 of the solar metallicity were used to derive a grid of synthetic surface brightness magnitudes for 21 of the Hubble Space Telescope Wide Field Camera (WFC) band passes. The absolute magnitudes of these 21 band passes are also obtained for a set of globular cluster isochrones with different helium abundances, metallicities, oxygen abundances, and ages. The usefulness and efficiency of different sets of broad and intermediate bandwidth WFC colors for determining ages and metallicities for globular clusters are evaluated.

  1. The Cardassian expansion revisited: constraints from updated Hubble parameter measurements and type Ia supernova data

    Science.gov (United States)

    Magaña, Juan; Amante, Mario H.; Garcia-Aspeitia, Miguel A.; Motta, V.

    2018-05-01

    Motivated by an updated compilation of observational Hubble data (OHD) that consist of 51 points in the redshift range of 0.07 Ia supernova (SN Ia) using the compressed and full joint-light-analysis (JLA) samples (Betoule et al.). We also perform a joint analysis using the combination OHD plus compressed JLA. Our results show that the OC and MPC models are in agreement with the standard cosmology and naturally introduce a cosmological-constant-like extra term in the canonical Friedmann equation with the capability of accelerating the Universe without dark energy.

  2. Dwarf Galaxies with Gentle Star Formation and the Counts of Galaxies in the Hubble Deep Field

    OpenAIRE

    Campos, Ana

    1997-01-01

    In this paper the counts and colors of the faint galaxies observed in the Hubble Deep Field are fitted by means of simple luminosity evolution models that incorporate a numerous population of fading dwarfs. The observed color distribution of the very faint galaxies now allows us to put constraints on the star formation history in dwarfs. It is shown that the star-forming activity in these small systems has to proceed in a gentle way, i.e., through episodes where each one lasts much longer tha...

  3. Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images

    Science.gov (United States)

    Barrett, Todd K.; Sandler, David G.

    1993-01-01

    An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 micron rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

  4. New Cosmic Horizons: Space Astronomy from the V2 to the Hubble Space Telescope

    Science.gov (United States)

    Leverington, David

    2001-02-01

    Preface; 1. The sounding rocket era; 2. The start of the space race; 3. Initial exploration of the Solar System; 4. Lunar exploration; 5. Mars and Venus; early results; 6. Mars and Venus; the middle period; 7. Venus, Mars and cometary spacecraft post-1980; 8. Early missions to the outer planets; 9. The Voyager missions to the outer planets; 10. The Sun; 11. Early spacecraft observations of non-solar system sources; 12. A period of rapid growth; 13. The high energy astronomy observatory programme; 14. IUE, IRAS and Exosat - spacecraft for the early 1980s; 15. Hiatus; 16. Business as usual; 17. The Hubble Space Telescope.

  5. Infrared observations of giant elliptical galaxies: (V-K) colors and the infrared Hubble diagram

    International Nuclear Information System (INIS)

    Grasdalen, G.L.

    1980-01-01

    The (V-K) colors of giant elliptical galaxies as a function of redshift are discussed. Present data are consistent with mild color evolution at z approximately 0.45. An infrared Hubble (redshift-magnitude) diagram is given. Cosmological models with q 0 =0 and no luminosity evolution are clearly excluded by the present data. A wide variety of models including those with q 0 =0 are permissible if luminosity evolution is included. Instrumental and programmatic implications of these results are summarized. (Auth.)

  6. Gravity waves as a probe of the Hubble expansion rate during an electroweak scale phase transition

    International Nuclear Information System (INIS)

    Chung, Daniel J. H.; Zhou Peng

    2010-01-01

    Just as big bang nucleosynthesis allows us to probe the expansion rate when the temperature of the Universe was around 1 MeV, the measurement of gravity waves from electroweak scale first order phase transitions may allow us to probe the expansion rate when the temperature of the Universe was at the electroweak scale. We compute the simple transformation rule for the gravity wave spectrum under the scaling transformation of the Hubble expansion rate. We then apply this directly to the scenario of quintessence kination domination and show how gravity wave spectra would shift relative to Laser Interferometer Space Antenna and Big Bang Observer projected sensitivities.

  7. UPDATED ANALYSIS OF THE UPWIND INTERPLANETARY HYDROGEN VELOCITY AS OBSERVED BY THE HUBBLE SPACE TELESCOPE DURING SOLAR CYCLE 23

    International Nuclear Information System (INIS)

    Vincent, Frederic E.; Ben-Jaffel, Lotfi; Harris, Walter M.

    2011-01-01

    The interplanetary hydrogen (IPH), a population of neutrals that fill the space between planets inside the heliosphere, carries the signature of the interstellar medium (ISM) and the heliospheric interface. As the incoming ISM-ionized component deflects at the heliopause, charge exchange reactions decelerate the bulk motion of the neutrals that penetrate the heliosphere. Inside the heliosphere, the IPH bulk velocity is further affected by solar gravity, radiation pressure, and ionization processes, with the latter two processes dependent on solar activity. Solar cycle 23 provided the first partial temporal map of the IPH velocity, including measurements from the Hubble Space Telescope (HST) spectrometers (Goddard High Resolution Spectrograph (GHRS) and Space Telescope Imaging Spectrograph (STIS)) and the Solar and Heliospheric Observatory/Solar Wind ANisotropies (SWAN) instrument. We present an updated analysis of IPH velocity measurements from GHRS and STIS and compare these results with those of SWAN and two different time-dependent models. Our reanalysis of STIS data reveals a significant change in IPH velocity relative to earlier reports, because of the contamination by geocoronal oxygen that was not accounted for. While current models of the heliospheric interface predict the observed IPH velocity for solar maximum, they are not consistent with data covering solar minimum. With updates to the HST data points, we now find that all data can be fit by the existing models to within 1σ, with the exception of SWAN observations taken at solar minimum (1997/1998). We conclude that the current data lack the temporal coverage and/or precision necessary to determine the detailed characteristics of the solar cycle dependence. Hence, new observations are merited.

  8. Hubble 3D: A Science and Hollywood Collaboration Made (Nearly) in Heaven

    Science.gov (United States)

    Showstack, Randy

    2010-04-01

    Just 2 days after the 2010 Academy Awards® ceremony in early March bestowed Oscars® for motion picture achievements, NASA deputy administrator Lori Garver touted a new film about the Hubble Space Telescope, Hubble 3D, for best drama, special effects, screenplay, actors and actress, and director and producer. The 43-minute IMAX and Warner Brothers Pictures production, which opened in theaters on 19 March, is an example of the ability of Hollywood and the science community to partner in providing a dynamic educational and entertaining product, according to a number of people associated with the film. Sharing the red carpet at the Smithsonian National Air and Space Museum in Washington, D. C., with astronauts and others to mark the world premiere, Garver said the film shows the drama of the astronauts’ efforts to repair the telescope while traveling 17,000 miles per hour and performing grueling space walks (see Figure 1). “We have literally opened our eyes on the universe through this telescope,” she said. “This is a taxpayer-funded agency, and we are giving back to the public the very story that they paid for.”

  9. The Hubble law and the spiral structures of galaxies from equations of motion in general relativity

    International Nuclear Information System (INIS)

    Sachs, M.

    1975-01-01

    Fully exploiting the Lie group that characterizes the underlying symmetry of general relativity theory, Einstein's tensor formalism factorizes, yielding a generalized (16-component) quaternion field formalism. The associated generalized geodesic equation, taken as the equation of motion of a star, predicts the Hubble law from one approximation for the generally covariant equations of motion, and the spiral structure of galaxies from another approximation. These results depend on the imposition of appropriate boundary conditions. The Hubble law follows when the boundary conditions derive from the oscillating model cosmology, and not from the other cosmological models. The spiral structures of the galaxies follow from the same boundary conditions, but with a different time scale than for the whole universe. The solutions that imply the spiral motion are Fresnel integrals. These predict the star's motion to be along the 'Cornu Spiral'. The part of this spiral in the first quadrant is the imploding phase of the galaxy, corresponding to a motion with continually decreasing radii, approaching the galactic center as time increases. The part of the Cornu Spiral' in the third quadrant is the exploding phase, corresponding to continually increasing radii, as the star moves out from the hub. The spatial origin in the coordinate system of this curve is the inflection point, where the explosion changes to implosion. The two- (or many-) armed spiral galaxies are explained here in terms of two (or many) distinct explosions occurring at displaced times, in the domain of the rotating, planar galaxy. (author)

  10. HUBBLE TARANTULA TREASURY PROJECT. V. THE STAR CLUSTER HODGE 301: THE OLD FACE OF 30 DORADUS

    Energy Technology Data Exchange (ETDEWEB)

    Cignoni, M. [Department of Physics—University of Pisa, Largo Pontecorvo, 3 Pisa, I-56127 (Italy); Sabbi, E.; Marel, R. P. van der; Aloisi, A.; Panagia, N. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218 (United States); Lennon, D. J. [European Space Astronomy Centre, Apdo. de Correo 78, E-28691 Villanueva de la Canada, Madrid (Spain); Tosi, M. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany); Gallagher, J. S. III [Department of Astronomy, University of Wisconsin-Madison, WI 53706 (United States); Marchi, G. de [European Space Research and Technology Centre, Keplerlaan 1, NL-2200 AG Noordwijk (Netherlands); Gouliermis, D. A. [Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Larsen, S. [Department of Astrophysics, Radboud University, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands); Smith, L. J., E-mail: michele.cignoni@unipi.it [European Space Agency and Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2016-12-20

    Based on color–magnitude diagrams (CMDs) from the Hubble Space Telescope  Hubble Tarantula Treasury Project (HTTP) survey, we present the star formation history of Hodge 301, the oldest star cluster in the Tarantula Nebula. The HTTP photometry extends faint enough to reach, for the first time, the cluster pre-main sequence (PMS) turn-on, where the PMS joins the main sequence. Using the location of this feature, along with synthetic CMDs generated with the latest PARSEC models, we find that Hodge 301 is older than previously thought, with an age between 26.5 and 31.5 Myr. From this age, we also estimate that between 38 and 61 Type II supernovae exploded in the region. The same age is derived from the main sequence turn-off, whereas the age derived from the post-main sequence stars is younger and between 20 and 25 Myr. Other relevant parameters are a total stellar mass of ≈8800 ± 800  M {sub ⊙} and average reddening E ( B − V ) ≈ 0.22–0.24 mag, with a differential reddening δE ( B − V ) ≈ 0.04 mag.

  11. SPECTROSCOPIC CONFIRMATION OF FAINT LYMAN BREAK GALAXIES NEAR REDSHIFT FIVE IN THE HUBBLE ULTRA DEEP FIELD

    International Nuclear Information System (INIS)

    Rhoads, James E.; Malhotra, Sangeeta; Cohen, Seth; Grogin, Norman; Hathi, Nimish; Ryan, Russell; Straughn, Amber; Windhorst, Rogier A.; Pirzkal, Norbert; Xu Chun; Koekemoer, Anton; Panagia, Nino; Dickinson, Mark; Ferreras, Ignacio; Gronwall, Caryl; Kuemmel, Martin; Walsh, Jeremy; Meurer, Gerhardt; Pasquali, Anna; Yan, H.-J.

    2009-01-01

    We present the faintest spectroscopically confirmed sample of z ∼ 5 Lyman break galaxies (LBGs) to date. The sample is based on slitless grism spectra of the Hubble Ultra Deep Field region from the Grism ACS Program for Extragalactic Science (GRAPES) and Probing Evolution and Reionization Spectroscopically (PEARS) projects, using the G800L grism on the Hubble Space Telescope Advanced Camera for Surveys. We report here confirmations of 39 galaxies, preselected as candidate LBGs using photometric selection criteria. We compare a 'traditional' V-dropout selection, based on the work of Giavalisco et al., to a more liberal one (with V - i > 0.9), and find that the traditional criteria are about 64% complete and 81% reliable. We also study the Lyα emission properties of our sample. We find that Lyα emission is detected in ∼1/4 of the sample, and that the liberal V-dropout color selection includes ∼55% of previously published line-selected Lyα sources. Finally, we examine our stacked two-dimensional spectra. We demonstrate that strong, spatially extended (∼1'') Lyα emission is not a generic property of these LBGs, but that a modest extension of the Lyα photosphere (compared to the starlight) may be present in those galaxies with prominent Lyα emission.

  12. A HUBBLE DIAGRAM FROM TYPE II SUPERNOVAE BASED SOLELY ON PHOTOMETRY: THE PHOTOMETRIC COLOR METHOD

    International Nuclear Information System (INIS)

    De Jaeger, T.; González-Gaitán, S.; Galbany, L.; Hamuy, M.; Gutiérrez, C. P.; Kuncarayakti, H.; Anderson, J. P.; Phillips, M. M.; Campillay, A.; Castellón, S.; Hsiao, E. Y.; Morrell, N.; Stritzinger, M. D.; Contreras, C.; Bolt, L.; Burns, C. R.; Folatelli, G.; Freedman, W. L.; Krisciunas, K.; Krzeminski, W.

    2015-01-01

    We present a Hubble diagram of SNe II using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I for which optical and near-infrared light curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a color term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) color and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric color method (PCM) with the standardized candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag, which compares with 0.43 mag from the PCM for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data

  13. A HUBBLE DIAGRAM FROM TYPE II SUPERNOVAE BASED SOLELY ON PHOTOMETRY: THE PHOTOMETRIC COLOR METHOD

    Energy Technology Data Exchange (ETDEWEB)

    De Jaeger, T.; González-Gaitán, S.; Galbany, L.; Hamuy, M.; Gutiérrez, C. P.; Kuncarayakti, H. [Millennium Institute of Astrophysics, Santiago (Chile); Anderson, J. P. [European Southern Observatory, Alonso de Córdova 3107, Casilla 19, Santiago (Chile); Phillips, M. M.; Campillay, A.; Castellón, S.; Hsiao, E. Y.; Morrell, N. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Stritzinger, M. D.; Contreras, C. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Bolt, L. [Argelander Institut für Astronomie, Universität Bonn, Auf dem Hgel 71, D-53111 Bonn (Germany); Burns, C. R. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Folatelli, G. [Instituto de Astrofísica de La Plata, CONICET, Paseo del Bosque S/N, B1900FWA, La Plata (Argentina); Freedman, W. L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Krisciunas, K. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Krzeminski, W., E-mail: dthomas@das.uchile.cl [N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa (Poland); and others

    2015-12-20

    We present a Hubble diagram of SNe II using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I for which optical and near-infrared light curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a color term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) color and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric color method (PCM) with the standardized candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag, which compares with 0.43 mag from the PCM for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data.

  14. HUBBLE'S ULTRAVIOLET VIEWS OF NEARBY GALAXIES YIELD CLUES TO EARLY UNIVERSE

    Science.gov (United States)

    2002-01-01

    Astronomers are using these three NASA Hubble Space Telescope images to help tackle the question of why distant galaxies have such odd shapes, appearing markedly different from the typical elliptical and spiral galaxies seen in the nearby universe. Do faraway galaxies look weird because they are truly weird? Or, are they actually normal galaxies that look like oddballs, because astronomers are getting an incomplete picture of them, seeing only the brightest pieces? Light from these galaxies travels great distances (billions of light-years) to reach Earth. During its journey, the light is 'stretched' due to the expansion of space. As a result, the light is no longer visible, but has been shifted to the infrared where present instruments are less sensitive. About the only light astronomers can see comes from regions where hot, young stars reside. These stars emit mostly ultraviolet light. But this light is stretched, appearing as visible light by the time it reaches Earth. Studying these distant galaxies is like trying to put together a puzzle with some of the pieces missing. What, then, do distant galaxies really look like? Astronomers studied 37 nearby galaxies to find out. By viewing these galaxies in ultraviolet light, astronomers can compare their shapes with those of their distant relatives. These three Hubble telescope pictures, taken with the Wide Field and Planetary Camera 2, represent a sampling from that survey. Astronomers observed the galaxies in ultraviolet and visible light to study all the stars that make up these 'cities of stars.' The results of their survey support the idea that astronomers are detecting the 'tip of the iceberg' of very distant galaxies. Based on these Hubble ultraviolet images, not all the faraway galaxies necessarily possess intrinsically odd shapes. The results are being presented today at the 197th meeting of the American Astronomical Society in San Diego, CA. The central region of the 'star-burst' spiral galaxy at far left

  15. Initiating New Science Partnerships in Rural Education: STEM Graduate Students Bring Current Research into 7th-12th Grade Science Classrooms

    Science.gov (United States)

    Radencic, S.; Dawkins, K. S.; Jackson, B. S.; Walker, R. M.; Schmitz, D.; Pierce, D.; Funderburk, W. K.; McNeal, K.

    2014-12-01

    Initiating New Science Partnerships in Rural Education (INSPIRE), a NSF Graduate K-12 (GK-12) program at Mississippi State University, pairs STEM graduate students with local K-12 teachers to bring new inquiry and technology experiences to the classroom (www.gk12.msstate.edu). The graduate fellows prepare lessons for the students incorporating different facets of their research. The lessons vary in degree of difficulty according to the content covered in the classroom and the grade level of the students. The focus of each lesson is directed toward the individual research of the STEM graduate student using inquiry based designed activities. Scientific instruments that are used in STEM research (e.g. SkyMaster weather stations, GPS, portable SEM, Inclinometer, Soil Moisture Probe, Google Earth, ArcGIS Explorer) are also utilized by K-12 students in the activities developed by the graduate students. Creativity and problem solving skills are sparked by curiosity which leads to the discovery of new information. The graduate students work to enhance their ability to effectively communicate their research to members of society through the creation of research linked classroom activities, enabling the 7-12th grade students to connect basic processes used in STEM research with the required state and national science standards. The graduate students become respected role models for the high school students because of their STEM knowledge base and their passion for their research. Sharing enthusiasm for their chosen STEM field, as well as the application techniques to discover new ideas, the graduate students stimulate the interests of the classroom students and model authentic science process skills while highlighting the relevance of STEM research to K-12 student lives. The measurement of the student attitudes about science is gathered from pre and post interest surveys for the past four years. This partnership allows students, teachers, graduate students, and the public to

  16. Quasar Host Galaxies/Neptune Rotation/Galaxy Building Blocks/Hubble Deep Field/Saturn Storm

    Science.gov (United States)

    2001-01-01

    Computerized animations simulate a quasar erupting in the core of a normal spiral galaxy, the collision of two interacting galaxies, and the evolution of the universe. Hubble Space Telescope (HST) images show six quasars' host galaxies (including spirals, ellipticals, and colliding galaxies) and six clumps of galaxies approximately 11 billion light years away. A false color time lapse movie of Neptune displays the planet's 16-hour rotation, and the evolution of a storm on Saturn is seen though a video of the planet's rotation. A zoom sequence starts with a ground-based image of the constellation Ursa major and ends with the Hubble Deep Field through progressively narrower and deeper views.

  17. Hubble Diagram Test of Expanding and Static Cosmological Models: The Case for a Slowly Expanding Flat Universe

    Directory of Open Access Journals (Sweden)

    Laszlo A. Marosi

    2013-01-01

    Full Text Available We present a new redshift (RS versus photon travel time ( test including 171 supernovae RS data points. We extended the Hubble diagram to a range of z = 0,0141–8.1 in the hope that at high RSs, the fitting of the calculated RS/ diagrams to the observed RS data would, as predicted by different cosmological models, set constraints on alternative cosmological models. The Lambda cold dark matter (ΛCDM, the static universe model, and the case for a slowly expanding flat universe (SEU are considered. We show that on the basis of the Hubble diagram test, the static and the slowly expanding models are favored.

  18. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. VIII. A WIDE-AREA, HIGH-RESOLUTION MAP OF DUST EXTINCTION IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Dalcanton, Julianne J.; Fouesneau, Morgan; Weisz, Daniel R.; Williams, Benjamin F. [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Pl #424, New York, NY 10003 (United States); Lang, Dustin [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Leroy, Adam K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Gordon, Karl D.; Gilbert, Karoline M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Sandstrom, Karin [Steward Observatory, University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Dong, Hui; Lauer, Tod R. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Gouliermis, Dimitrios A. [Max Planck Institute für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Guhathakurta, Puragra [Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Schruba, Andreas [California Institute of Technology, Cahill Center for Astrophysics, 1200 E. California Blvd, Pasadena, CA 91125 (United States); Seth, Anil C. [University of Utah, Salt Lake City, UT (United States); Skillman, Evan D., E-mail: jd@astro.washington.edu [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2015-11-20

    We map the distribution of dust in M31 at 25 pc resolution using stellar photometry from the Panchromatic Hubble Andromeda Treasury survey. The map is derived with a new technique that models the near-infrared color–magnitude diagram (CMD) of red giant branch (RGB) stars. The model CMDs combine an unreddened foreground of RGB stars with a reddened background population viewed through a log-normal column density distribution of dust. Fits to the model constrain the median extinction, the width of the extinction distribution, and the fraction of reddened stars in each 25 pc cell. The resulting extinction map has a factor of ≳4 times better resolution than maps of dust emission, while providing a more direct measurement of the dust column. There is superb morphological agreement between the new map and maps of the extinction inferred from dust emission by Draine et al. However, the widely used Draine and Li dust models overpredict the observed extinction by a factor of ∼2.5, suggesting that M31's true dust mass is lower and that dust grains are significantly more emissive than assumed in Draine et al. The observed factor of ∼2.5 discrepancy is consistent with similar findings in the Milky Way by the Plank Collaboration et al., but we find a more complex dependence on parameters from the Draine and Li dust models. We also show that the the discrepancy with the Draine et al. map is lowest where the current interstellar radiation field has a harder spectrum than average. We discuss possible improvements to the CMD dust mapping technique, and explore further applications in both M31 and other galaxies.

  19. INVESTIGATING THE CORE MORPHOLOGY-SEYFERT CLASS RELATIONSHIP WITH HUBBLE SPACE TELESCOPE ARCHIVAL IMAGES OF LOCAL SEYFERT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, M. J.; Hegel, P. R.; Kim, Hwihyun; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Tamura, Kazuyuki [Naruto University of Education, Nakashima, Takashima, Naruto-cho, Naruto-shi 772-8502 (Japan)

    2013-07-01

    The unified model of active galactic nuclei (AGNs) has provided a successful explanation for the observed diversity of AGNs in the local universe. However, recent analysis of multi-wavelength spectral and image data suggests that the unified model is only a partial theory of AGNs, and may need to be augmented to remain consistent with all observations. Recent studies using high spatial resolution ground- and space-based observations of local AGNs show that Seyfert class and the ''core'' (r {approx}< 1 kpc) host-galaxy morphology are correlated. Currently, this relationship has only been established qualitatively, by visual inspection of the core morphologies of low-redshift (z < 0.035) Seyfert host galaxies. We re-establish this empirical relationship in Hubble Space Telescope optical imaging by visual inspection of a catalog of 85 local (D < 63 Mpc) Seyfert galaxies. We also attempt to re-establish the core morphology-Seyfert class relationship using an automated, non-parametric technique that combines both existing classification parameter methods (the adapted CAS and G-M {sub 20}) and a new method which implements the Source Extractor software for feature detection in unsharp-mask images. This new method is designed explicitly to detect dust features in the images. We use our automated approach to classify the morphology of the AGN cores and determine that Sy2 galaxies visually appear, on average, to have more dust features than Sy1. With the exception of this ''dustiness'' however, we do not measure a strong correlation between the dust morphology and the Seyfert class of the host galaxy using quantitative techniques. We discuss the implications of these results in the context of the unified model.

  20. The Relationship of Level of Positive Mental Health with Current Mental Disorders in Predicting Suicidal Behavior and Academic Impairment in College Students

    Science.gov (United States)

    Keyes, Corey L. M.; Eisenberg, Daniel; Perry, Geraldine S.; Dube, Shanta R.; Kroenke, Kurt; Dhingra, Satvinder S.

    2012-01-01

    Objective: To investigate whether level of positive mental health complements mental illness in predicting students at risk for suicidal behavior and impaired academic performance. Participants: A sample of 5,689 college students participated in the 2007 Healthy Minds Study and completed an Internet survey that included the Mental Health…

  1. The Investigation and Analysis of Chinese University Students' Current Situation of Entrepreneurship and the Countermeasures--The Reflection from a Special Investigation in Pearl Delta in China

    Science.gov (United States)

    Lifang, Li

    2012-01-01

    This research has chosen some students and undergraduates from 35 colleges and universities, which are national, local and professional colleges or universities with different entrepreneurship needs and different educational functions in the same area. The research reveals that the undergraduates or students are in strong desire of career…

  2. The Investigation of the Effectiveness of the Criteria for the Construction of a Physics Text for Students with Dyslexia: The Case of the Electric Current

    Science.gov (United States)

    Papalexopoulos, Panagiotis F.; Vavougios, Dionisios; Vlachos, Filippos; Karapetsas, Argiris B.

    2008-01-01

    In this paper we studied the effectiveness of the writing criteria that are proposed to be applied during the construction of physics texts so that students with dyslexia do not confront reading difficulties with them. The effectiveness of the criteria has been assessed by the accomplishment of an investigation among students with and without…

  3. Probing the z > 6 Universe with the First Hubble Frontier Fields Cluster A2744

    Science.gov (United States)

    Atek, Hakim; Richard, Johan; Kneib, Jean-Paul; Clement, Benjamin; Egami, Eiichi; Ebeling, Harald; Jauzac, Mathilde; Jullo, Eric; Laporte, Nicolas; Limousin, Marceau; Natarajan, Priyamvada

    2014-05-01

    The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first combined HST and Spitzer observations of the cluster A-2744. We combine the full near-infrared data with ancillary optical images to search for gravitationally lensed high-redshift (z >~ 6) galaxies. We report the detection of 15 I 814 dropout candidates at z ~ 6-7 and one Y 105 dropout at z ~ 8 in a total survey area of 1.43 arcmin2 in the source plane. The predictions of our lens model also allow us to identify five multiply imaged systems lying at redshifts between z ~ 6 and z ~ 8. Thanks to constraints from the mass distribution in the cluster, we were able to estimate the effective survey volume corrected for completeness and magnification effects. This was in turn used to estimate the rest-frame ultraviolet luminosity function (LF) at z ~ 6-8. Our LF results are generally in agreement with the most recent blank field estimates, confirming the feasibility of surveys through lensing clusters. Although based on a shallower observations than what will be achieved in the final data set including the full Advanced Camera for Survey observations, the LF presented here goes down to M UV ~-18.5, corresponding to 0.2L sstarf at z ~ 7 with one identified object at M UV ~-15 thanks to the highly magnified survey areas. This early study forecasts the power of using massive galaxy clusters as cosmic telescopes and its complementarity to blank fields. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 13495 and 11689. Based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory

  4. Hartmann wavefront sensing of the corrective optics for the Hubble Space Telescope

    Science.gov (United States)

    Davila, Pam S.; Eichhorn, William L.; Wilson, Mark E.

    1994-06-01

    There is no doubt that astronomy with the `new, improved' Hubble Space Telescope will significantly advance our knowledge and understanding of the universe for years to come. The Corrective Optics Space Telescope Axial Replacement (COSTAR) was designed to restore the image quality to nearly diffraction limited performance for three of the first generation instruments; the faint object camera, the faint object spectrograph, and the Goddard high resolution spectrograph. Spectacular images have been obtained from the faint object camera after the installation of the corrective optics during the first servicing mission in December of 1993. About 85% of the light in the central core of the corrected image is contained within a circle with a diameter of 0.2 arcsec. This is a vast improvement over the previous 15 to 17% encircled energies obtained before COSTAR. Clearly COSTAR is a success. One reason for the overwhelming success of COSTAR was the ambitious and comprehensive test program conducted by various groups throughout the program. For optical testing of COSTAR on the ground, engineers at Ball Aerospace designed and built the refractive Hubble simulator to produce known amounts of spherical aberration and astigmatism at specific points in the field of view. The design goal for this refractive aberrated simulator (RAS) was to match the aberrations of the Hubble Space Telescope to within (lambda) /20 rms over the field at a wavelength of 632.8 nm. When the COSTAR optics were combined with the RAS optics, the corrected COSTAR output images were produced. These COSTAR images were recorded with a high resolution 1024 by 1024 array CCD camera, the Ball image analyzer (BIA). The image quality criteria used for assessment of COSTAR performance was encircled energy in the COSTAR focal plane. This test with the BIA was very important because it was a direct measurement of the point spread function. But it was difficult with this test to say anything quantitative about the

  5. Volume 42, Issue5 (May 2005)Articles in the Current Issue:Developmental growth in students' concept of energy: Analysis of selected items from the TIMSS database

    Science.gov (United States)

    Liu, Xiufeng; McKeough, Anne

    2005-05-01

    The aim of this study was to develop a model of students' energy concept development. Applying Case's (1985, 1992) structural theory of cognitive development, we hypothesized that students' concept of energy undergoes a series of transitions, corresponding to systematic increases in working memory capacity. The US national sample from the Third International Mathematics and Science Study (TIMSS) database was used to test our hypothesis. Items relevant to the energy concept in the TIMSS test booklets for three populations were identified. Item difficulty from Rasch modeling was used to test the hypothesized developmental sequence, and percentage of students' correct responses was used to test the correspondence between students' age/grade level and level of the energy concepts. The analysis supported our hypothesized sequence of energy concept development and suggested mixed effects of maturation and schooling on energy concept development. Further, the results suggest that curriculum and instruction design take into consideration the developmental progression of students' concept of energy.

  6. Multi-Epoch Hubble Space Telescope Observations of IZw18 : Characterization of Variable Stars at Ultra-Low Metallicities

    NARCIS (Netherlands)

    Fiorentino, G.; Ramos, R. Contreras; Clementini, G.; Marconi, M.; Musella, I.; Aloisi, A.; Annibali, F.; Saha, A.; Tosi, M.; van der Marel, R. P.

    2010-01-01

    Variable stars have been identified for the first time in the very metal-poor blue compact dwarf galaxy IZw18, using deep multi-band (F606W, F814W) time-series photometry obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope. We detected 34 candidate variable stars in the

  7. STS 31 PAYLOAD HUBBLE SPACE TELESCOPE ENCLOSED IN AN AIR-TIGHT PLASTIC BAG FOR PROTECTION IN VERTICA

    Science.gov (United States)

    1989-01-01

    Preparations are made to enclose the Hubble Space Telescope [HST] inside an air-tight plastic bag in the VPF. Processing of the 94- inch primary mirror telescope for launch on the Discovery in March 1990, involves working within strict controls to prevent contamination.

  8. A natural language query system for Hubble Space Telescope proposal selection

    Science.gov (United States)

    Hornick, Thomas; Cohen, William; Miller, Glenn

    1987-01-01

    The proposal selection process for the Hubble Space Telescope is assisted by a robust and easy to use query program (TACOS). The system parses an English subset language sentence regardless of the order of the keyword phases, allowing the user a greater flexibility than a standard command query language. Capabilities for macro and procedure definition are also integrated. The system was designed for flexibility in both use and maintenance. In addition, TACOS can be applied to any knowledge domain that can be expressed in terms of a single reaction. The system was implemented mostly in Common LISP. The TACOS design is described in detail, with particular attention given to the implementation methods of sentence processing.

  9. Long term trending of engineering data for the Hubble Space Telescope

    Science.gov (United States)

    Cox, Ross M.

    1993-01-01

    A major goal in spacecraft engineering analysis is the detection of component failures before the fact. Trending is the process of monitoring subsystem states to discern unusual behaviors. This involves reducing vast amounts of data about a component or subsystem into a form that helps humans discern underlying patterns and correlations. A long term trending system has been developed for the Hubble Space Telescope. Besides processing the data for 988 distinct telemetry measurements each day, it produces plots of 477 important parameters for the entire 24 hours. Daily updates to the trend files also produce 339 thirty day trend plots each month. The total system combines command procedures to control the execution of the C-based data processing program, user-written FORTRAN routines, and commercial off-the-shelf plotting software. This paper includes a discussion the performance of the trending system and of its limitations.

  10. The Evolution of the Observed Hubble Sequence over the past 6Gyr

    Science.gov (United States)

    Delgado-Serrano, R.; Hammer, F.; Yang, Y. B.; Puech, M.; Flores, H.; Rodrigues, M.

    2011-10-01

    During the past years we have confronted serious problems of methodology concerning the morphological and kinematic classification of distant galaxies. This has forced us to create a new simple and effective morphological classification methodology, in order to guarantee a morpho-kinematic correlation, make the reproducibility easier and restrict the classification subjectivity. Giving the characteristic of our morphological classification, we have thus been able to apply the same methodology, using equivalent observations, to representative samples of local and distant galaxies. It has allowed us to derive, for the first time, the distant Hubble sequence (~6 Gyr ago), and determine a morphological evolution of galaxies over the past 6 Gyr. Our results strongly suggest that more than half of the present-day spirals had peculiar morphologies, 6 Gyr ago.

  11. The white dwarf mass-radius relation with Gaia, Hubble and FUSE

    Science.gov (United States)

    Joyce, Simon R. G.; Barstow, Martin A.; Casewell, Sarah L.; Holberg, Jay B.; Bond, Howard E.

    2018-04-01

    White dwarfs are becoming useful tools for many areas of astronomy. They can be used as accurate chronometers over Gyr timescales. They are also clues to the history of star formation in our galaxy. Many of these studies require accurate estimates of the mass of the white dwarf. The theoretical mass-radius relation is often invoked to provide these mass estimates. While the theoretical mass-radius relation is well developed, observational tests of this relation show a much larger scatter in the results than expected. High precision observational tests to confirm this relation are required. Gaia is providing distance measurements which will remove one of the main source of uncertainty affecting most previous observations. We combine Gaia distances with spectra from the Hubble and FUSE satelites to make precise tests of the white dwarf mass-radius relation.

  12. Large-q correlations from a Hubble-type pion source

    International Nuclear Information System (INIS)

    Barghouty, A.F.; Miller, J.; Frankel, K.A.

    1993-01-01

    In two-pion correlation measurements from relativistic nuclear collisions, the correlation function, C 2 (q), appears to exhibit an oscillatory structure at large (q ≥100 MeV/c) relative momentum. If real, this structure may have consequences for the determination of the space-time extent of the pion source. A qualitatively similar feature is seen in cellular automaton simulations of a Lorentz gas. It has been argued phenomenologically that the q-dependent oscillations can arise from an interplay between successive scattering probabilities and density variations of an exploding pion source. To further illustrate this interplay we consider a Hubble-type free expansion model for the source in which the density is time-folded from an initial Gaussian. This allows the source expansion to enter as a dynamical variable in the source density p[r(t); t] and thus C 2 , along with any signature of the interplay between scattering and source density

  13. Science from a glimpse: Hubble SNAPshot observations of massive galaxy clusters

    Science.gov (United States)

    Repp, A.; Ebeling, H.

    2018-06-01

    Hubble Space Telescope SNAPshot surveys of 86 X-ray selected galaxy clusters at 0.3 0.3. Examining the evolution of the slope of the cluster red sequence, we observe at best a slight decrease with redshift, indicating minimal age contribution since z ˜ 1. Congruent to previous studies' findings, we note that the two BCGs which are significantly bluer (≥5σ) than their clusters' red sequences reside in relaxed clusters and exhibit pronounced internal structure. Thanks to our targets' high X-ray luminosity, the subset of our sample observed with Chandra adds valuable leverage to the X-ray luminosity-optical richness relation, which, albeit with substantial scatter, is now clearly established from groups to extremely massive clusters of galaxies. We conclude that SNAPshot observations of MACS clusters stand to continue to play a vital pathfinder role for astrophysical investigations across the entire electromagnetic spectrum.

  14. Update on the Status of the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope

    Science.gov (United States)

    Hernandez, Svea; Aloisi, A.; Bostroem, K. A.; Cox, C.; Debes, J. H.; DiFelice, A.; Roman-Duval, J.; Hodge, P.; Holland, S.; Lindsay, K.; Lockwood, S. A.; Mason, E.; Oliveira, C. M.; Penton, S. V.; Proffitt, C. R.; Sonnentrucker, P.; Taylor, J. M.; Wheeler, T.

    2013-06-01

    The Space Telescope Imaging Spectrograph (STIS) has been on orbit for approximately 16 years as one of the 2nd generation instruments on the Hubble Space Telescope (HST). Its operations were interrupted by an electronics failure in 2004, but STIS was successfully repaired in May 2009 during Service Mission 4 (SM4) allowing it to resume science observations. The Instrument team continues to monitor its performance and work towards improving the quality of its products. Here we present updated information on the status of the FUV and NUV MAMA and the CCD detectors onboard STIS and describe recent changes to the STIS calibration pipeline. We also discuss the status of efforts to apply a pixel-based correction for charge transfer inefficiency (CTI) effects to STIS CCD data. These techniques show promise for ameliorating the effects of ongoing radiation damage on the quality of STIS CCD data.

  15. Variability search in M 31 using principal component analysis and the Hubble Source Catalogue

    Science.gov (United States)

    Moretti, M. I.; Hatzidimitriou, D.; Karampelas, A.; Sokolovsky, K. V.; Bonanos, A. Z.; Gavras, P.; Yang, M.

    2018-06-01

    Principal component analysis (PCA) is being extensively used in Astronomy but not yet exhaustively exploited for variability search. The aim of this work is to investigate the effectiveness of using the PCA as a method to search for variable stars in large photometric data sets. We apply PCA to variability indices computed for light curves of 18 152 stars in three fields in M 31 extracted from the Hubble Source Catalogue. The projection of the data into the principal components is used as a stellar variability detection and classification tool, capable of distinguishing between RR Lyrae stars, long-period variables (LPVs) and non-variables. This projection recovered more than 90 per cent of the known variables and revealed 38 previously unknown variable stars (about 30 per cent more), all LPVs except for one object of uncertain variability type. We conclude that this methodology can indeed successfully identify candidate variable stars.

  16. CONFRONTING THREE-DIMENSIONAL TIME-DEPENDENT JET SIMULATIONS WITH HUBBLE SPACE TELESCOPE OBSERVATIONS

    International Nuclear Information System (INIS)

    Staff, Jan E.; Niebergal, Brian P.; Ouyed, Rachid; Pudritz, Ralph E.; Cai, Kai

    2010-01-01

    We perform state-of-the-art, three-dimensional, time-dependent simulations of magnetized disk winds, carried out to simulation scales of 60 AU, in order to confront optical Hubble Space Telescope observations of protostellar jets. We 'observe' the optical forbidden line emission produced by shocks within our simulated jets and compare these with actual observations. Our simulations reproduce the rich structure of time-varying jets, including jet rotation far from the source, an inner (up to 400 km s -1 ) and outer (less than 100 km s -1 ) component of the jet, and jet widths of up to 20 AU in agreement with observed jets. These simulations when compared with the data are able to constrain disk wind models. In particular, models featuring a disk magnetic field with a modest radial spatial variation across the disk are favored.

  17. Cosmological Parameters and Hyper-Parameters: The Hubble Constant from Boomerang and Maxima

    Science.gov (United States)

    Lahav, Ofer

    Recently several studies have jointly analysed data from different cosmological probes with the motivation of estimating cosmological parameters. Here we generalise this procedure to allow freedom in the relative weights of various probes. This is done by including in the joint likelihood function a set of `Hyper-Parameters', which are dealt with using Bayesian considerations. The resulting algorithm, which assumes uniform priors on the log of the Hyper-Parameters, is very simple to implement. We illustrate the method by estimating the Hubble constant H0 from different sets of recent CMB experiments (including Saskatoon, Python V, MSAM1, TOCO, Boomerang and Maxima). The approach can be generalised for a combination of cosmic probes, and for other priors on the Hyper-Parameters. Reference: Lahav, Bridle, Hobson, Lasenby & Sodre, 2000, MNRAS, in press (astro-ph/9912105)

  18. Study on Inertia as a Gravity Induced Property of Mass, in an Infinite Hubble Expanding Universe

    Directory of Open Access Journals (Sweden)

    Jeroen van Engelshoven

    2013-01-01

    Full Text Available Mass is experienced to have two intrinsic properties: inertia (resistance to acceleration and gravity (attraction to other masses. In this paper we evaluate the gravitational effect of all masses of the universe on an accelerated mass, starting from linearized general relativity. The gravitational interaction of all masses in a finite static universe model is shown to create a finite resistance to acceleration, which is inertia. Then, we propose a generalization of the linearized theory and evaluate the Hubble expanding universe. It is shown that the gravitational impact of an infinite expanding universe creates finite inertia, according to . The Friedmann critical mass density is found to be valid. The Mach principle is made explicit. The value and sign of the gravitational constant G are found to be of no consequence on an astronomical scale.

  19. Hubble space telescope: The GO and GTO observing programs, version 3.0

    Science.gov (United States)

    Downes, Ron

    1992-01-01

    A portion of the observing time with the Hubble Space Telescope (HST) was awarded by NASA to scientists involved in the development of the HST and its instruments. These scientists are the Guaranteed Time Observers (GTO's). Observing time was also awarded to General Observers (GO's) on the basis of the proposal reviews in 1989 and 1991. The majority of the 1989 programs have been completed during 'Cycle 1', while the 1991 programs will be completed during 'Cycle 2', nominally a 12-month period beginning July 1992. This document presents abstracts of these GO and GTO programs, and detailed listings of the specific targets and exposures contained in them. These programs and exposures are protected by NASA policy, as detailed in the HST Call for Proposals (CP), and are not to be duplicated by new programs.

  20. Dynamical 3-Space: Supernovae and the Hubble Expansion — the Older Universe without Dark Energy

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2007-10-01

    Full Text Available We apply the new dynamics of 3-space to cosmology by deriving a Hubble expansion solution. This dynamics involves two constants; G and — the fine structure constant. This solution gives an excellent parameter-free fit to the recent supernova and gamma- ray burst redshift data without the need for “dark energy” or “dark matter”. The data and theory together imply an older age for the universe of some 14.7Gyrs. The 3-space dynamics has explained the bore hole anomaly, spiral galaxy flat rotation speeds, the masses of black holes in spherical galaxies, gravitational light bending and lensing, all without invoking “dark matter” or “dark energy”. These developments imply that a new understanding of the universe is now available.

  1. Atmospheric and Fundamental Parameters of Stars in Hubble's Next Generation Spectral Library

    Science.gov (United States)

    Heap, Sally

    2010-01-01

    Hubble's Next Generation Spectral Library (NGSL) consists of R approximately 1000 spectra of 374 stars of assorted temperature, gravity, and metallicity. We are presently working to determine the atmospheric and fundamental parameters of the stars from the NGSL spectra themselves via full-spectrum fitting of model spectra to the observed (extinction-corrected) spectrum over the full wavelength range, 0.2-1.0 micron. We use two grids of model spectra for this purpose: the very low-resolution spectral grid from Castelli-Kurucz (2004), and the grid from MARCS (2008). Both the observed spectrum and the MARCS spectra are first degraded in resolution to match the very low resolution of the Castelli-Kurucz models, so that our fitting technique is the same for both model grids. We will present our preliminary results with a comparison with those from the Sloan/Segue Stellar Parameter Pipeline, ELODIE, and MILES, etc.

  2. Gravitational Contraction and Fusion Plasma Burn. Universal Expansion and the Hubble Law

    International Nuclear Information System (INIS)

    Wilhelmsson, Hans

    2002-01-01

    A dynamic approach is developed for the two principle phases of (i) gravitational condensation, and (ii) burning fusion plasma evolution. Comparison is made with conceptual descriptions of star formation and of subsequent decay towards red giant stars, white dwarfs, and other condensed core objects like neutron stars and black holes. The possibility of treating the expansion of the Universe by means of a similar approach is also discussed. The concept of negative diffusion is introduced for the contraction phase of star formation. The coefficients of defining the nonlinear diffusion are determined uniquely by physical conditions and for the case of the expansion of the universe, by the observation of the Hubble law. The contraction and evolution of large scale 3-D stars and 2-D galactic systems can thus be dynamically surveyed. In particular the time-scales can be determined

  3. Hubble Space Telescope Ultraviolet Light Curves Reveal Interesting Properties of CC Sculptoris and RZ Leonis

    Energy Technology Data Exchange (ETDEWEB)

    Szkody, Paula; Mukadam, Anjum S. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Toloza, Odette; Gänsicke, Boris T.; Pala, Anna F. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Dai, Zhibin [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Waagen, Elizabeth O. [AAVSO, 48 Bay State Rd, Cambridge, MA 02138 (United States); Godon, Patrick; Sion, Edward M., E-mail: szkody@astro.washington.edu [Department of Astrophysics and Planetary Science, Villanova University, Villanova, PA 19085 (United States)

    2017-03-01

    Time-tag ultraviolet data obtained on the Hubble Space Telescope in 2013 reveal interesting variability related to the white dwarf spin in the two cataclysmic variables RZ Leo and CC Scl. RZ Leo shows a period at 220 s and its harmonic at 110 s, thus identifying it as a likely Intermediate Polar (IP). The spin signal is not visible in a short single night of ground-based data in 2016, but the shorter exposures in that data set indicate a possible partial eclipse. The much larger UV amplitude of the spin signal in the known IP CC Scl allows the spin of 389 s, previously only seen at outburst, to be visible at quiescence. Spectra created from the peaks and troughs of the spin times indicate a hotter temperature of several thousand degrees during the peak phases, with multiple components contributing to the UV light.

  4. Hubble Space Telescope Photometry of Hodge 301: An ``Old'' Star Cluster in 30 Doradus

    Science.gov (United States)

    Grebel, Eva K.; Chu, You-Hua

    2000-02-01

    We present Hubble Space Telescope Planetary Camera UVI data for Hodge 301, the little-studied cluster 3' northwest of the central ionizing cluster R136 in 30 Doradus. The average reddening of Hodge 301 is found to be =0.28+/-0.05 mag from published infrared and ultraviolet photometry. Using two different sets of evolutionary models, we derive an age of about 20-25 Myr for Hodge 301, which makes it roughly 10 times as old as R136. Hodge 301 is the most prominent representative of the oldest population in the 30 Dor starburst region, a region that has undergone multiple star formation events. This range of ages is an important consideration for the modeling of starburst regions. Hodge 301 shows a widened upper main sequence largely caused by Be stars. We present a list of Be star candidates. The slope of the initial mass function for intermediate-mass, main-sequence stars ranging from 10 to 1.3 Msolar is found to be Γ=-1.4+/-0.1, in good agreement with a Salpeter law. There is no indication for a truncation or change of slope of the initial mass function (IMF) within this mass range. In accordance with the age of Hodge 301, no obvious pre-main-sequence stars are seen down to about 1 Msolar. We estimate that up to 41+/-7 stars with masses more than 12 Msolar may have turned into supernovae since the formation of the cluster. Multiple supernova explosions are the most likely origin of the extremely violent gas motions and the diffuse X-ray emission observed in the cluster surroundings. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555.

  5. Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. IV. Measurement for Sculptor

    Science.gov (United States)

    Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

    2006-03-01

    This article presents a measurement of the proper motion of the Sculptor dwarf spheroidal galaxy determined from images taken with the Hubble Space Telescope using the Space Telescope Imaging Spectrograph in the imaging mode. Each of two distinct fields contains a quasi-stellar object that serves as the ``reference point.'' The measured proper motion of Sculptor, expressed in the equatorial coordinate system, is (μα, μδ)=(9+/-13, 2+/-13) mas century-1. Removing the contributions from the motion of the Sun and the motion of the local standard of rest produces the proper motion in the Galactic rest frame: (μGrfα, μGrfδ)=(-23+/-13, 45+/-13) mas century-1. The implied space velocity with respect to the Galactic center has a radial component of Vr=79+/-6 km s-1 and a tangential component of Vt=198+/-50 km s-1. Integrating the motion of Sculptor in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 68 (31, 83) and 122 (97, 313) kpc, respectively, where the values in the parentheses represent the 95% confidence interval derived from Monte Carlo experiments. The eccentricity of the orbit is 0.29 (0.26, 0.60), and the orbital period is 2.2 (1.5, 4.9) Gyr. Sculptor is on a polar orbit around the Milky Way: the angle of inclination is 86° (83°, 90°). Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  6. UVUDF: Ultraviolet imaging of the Hubble ultra deep field with wide-field camera 3

    Energy Technology Data Exchange (ETDEWEB)

    Teplitz, Harry I.; Rafelski, Marc; Colbert, James W.; Hanish, Daniel J. [Infrared Processing and Analysis Center, MS 100-22, Caltech, Pasadena, CA 91125 (United States); Kurczynski, Peter; Gawiser, Eric [Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States); Bond, Nicholas A.; Gardner, Jonathan P.; De Mello, Duilia F. [Laboratory for Observational Cosmology, Astrophysics Science Division, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Grogin, Norman; Koekemoer, Anton M.; Brown, Thomas M.; Coe, Dan; Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Atek, Hakim [Laboratoire d' Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Finkelstein, Steven L. [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Giavalisco, Mauro [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Gronwall, Caryl [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Lee, Kyoung-Soo [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Ravindranath, Swara, E-mail: hit@ipac.caltech.edu [Inter-University Centre for Astronomy and Astrophysics, Pune (India); and others

    2013-12-01

    We present an overview of a 90 orbit Hubble Space Telescope treasury program to obtain near-ultraviolet imaging of the Hubble Ultra Deep Field using the Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters. This survey is designed to: (1) investigate the episode of peak star formation activity in galaxies at 1 < z < 2.5; (2) probe the evolution of massive galaxies by resolving sub-galactic units (clumps); (3) examine the escape fraction of ionizing radiation from galaxies at z ∼ 2-3; (4) greatly improve the reliability of photometric redshift estimates; and (5) measure the star formation rate efficiency of neutral atomic-dominated hydrogen gas at z ∼ 1-3. In this overview paper, we describe the survey details and data reduction challenges, including both the necessity of specialized calibrations and the effects of charge transfer inefficiency. We provide a stark demonstration of the effects of charge transfer inefficiency on resultant data products, which when uncorrected, result in uncertain photometry, elongation of morphology in the readout direction, and loss of faint sources far from the readout. We agree with the STScI recommendation that future UVIS observations that require very sensitive measurements use the instrument's capability to add background light through a 'post-flash'. Preliminary results on number counts of UV-selected galaxies and morphology of galaxies at z ∼ 1 are presented. We find that the number density of UV dropouts at redshifts 1.7, 2.1, and 2.7 is largely consistent with the number predicted by published luminosity functions. We also confirm that the image mosaics have sufficient sensitivity and resolution to support the analysis of the evolution of star-forming clumps, reaching 28-29th magnitude depth at 5σ in a 0.''2 radius aperture depending on filter and observing epoch.

  7. Hubble Space Telescope Trigonometric Parallax of Polaris B, Companion of the Nearest Cepheid

    Science.gov (United States)

    Bond, Howard E.; Nelan, Edmund P.; Remage Evans, Nancy; Schaefer, Gail H.; Harmer, Dianne

    2018-01-01

    Polaris, the nearest and brightest Cepheid, is a potential anchor point for the Leavitt period–luminosity relation. However, its distance is a matter of contention, with recent advocacy for a parallax of ∼10 mas, in contrast with the Hipparcos measurement of 7.54 ± 0.11 mas. We report an independent trigonometric parallax determination, using the Fine Guidance Sensors (FGS) on the Hubble Space Telescope. Polaris itself is too bright for FGS, so we measured its eighth-magnitude companion Polaris B, relative to a network of background reference stars. We converted the FGS relative parallax to absolute, using estimated distances to the reference stars from ground-based photometry and spectral classification. Our result, 6.26 ± 0.24 mas, is even smaller than that found by Hipparcos. We note other objects for which Hipparcos appears to have overestimated parallaxes, including the well-established case of the Pleiades. We consider possible sources of systematic error in the FGS parallax, but find no evidence they are significant. If our “long” distance is correct, the high luminosity of Polaris indicates that it is pulsating in the second overtone of its fundamental mode. Our results raise several puzzles, including a long pulsation period for Polaris compared to second-overtone pulsators in the Magellanic Clouds, and a conflict between the isochrone age of Polaris B (∼2.1 Gyr) and the much younger age of Polaris A. We discuss possibilities that B is not a physical companion of A, in spite of the strong evidence that it is, or that one of the stars is a merger remnant. These issues may be resolved when Gaia provides parallaxes for both stars. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  8. The Speed of Light and the Hubble parameter: The Mass-Boom Effect

    International Nuclear Information System (INIS)

    Alfonso-Faus, Antonio

    2008-01-01

    We prove here that Newton's universal gravitation and momentum conservation laws together reproduce Weinberg's relation. It is shown that the Hubble parameter H must be built in this relation, or equivalently the age of the Universe t. Using a wave-to-particle interaction technique we then prove that the speed of light c decreases with cosmological time, and that c is proportional to the Hubble parameter H. We see the expansion of the Universe as a local effect due to the LAB value of the speed of light co taken as constant. We present a generalized red shift law and find a predicted acceleration for photons that agrees well with the result from Pioneer 10/11 anomalous acceleration. We finally present a cosmological model coherent with the above results that we call the Mass-Boom. It has a linear increase of mass m with time as a result of the speed of light c linear decrease with time, and the conservation of momentum mc. We obtain the baryonic mass parameter equal to the curvature parameter, Ω m Ω k , so that the model is of the type of the Einstein static, closed, finite, spherical, unlimited, with zero cosmological constant. This model is the cosmological view as seen by photons, neutrinos, tachyons etc. in contrast with the local view, the LAB reference. Neither dark matter nor dark energy is required by this model. With an initial constant speed of light during a short time we get inflation (an exponential expansion). This converts, during the inflation time, the Planck's fluctuation length of 10 -33 cm to the present size of the Universe (about 10 28 cm, constant from then on). Thereafter the Mass-Boom takes care to bring the initial values of the Universe (about 10 15 gr) to the value at the present time of about 10 55 gr

  9. HUBBLE STAYS ON TRAIL OF FADING GAMMA-RAY BURST FIREBALL

    Science.gov (United States)

    2002-01-01

    A Hubble Space Telescope image of the fading fireball from one of the universe's most mysterious phenomena, a gamma-ray burst. Though the visible component has faded to 1/500th its brightness (27.7 magnitude) from the time it was first discovered by ground- based telescopes last March (the actual gamma-ray burst took place on February 28), Hubble continues to clearly see the fireball and discriminated a surrounding nebulosity (at 25th magnitude) which is considered a host galaxy. The continued visibility of the burst, and the rate of its fading, support theories that the light from a gamma-ray burst is an expanding relativistic (moving near the speed of light) fireball, possibly produced by the collision of two dense objects, such as an orbiting pair of neutron stars. If the burst happened nearby, within our own galaxy, the resulting fireball should have had only enough energy to propel it into space for a month. The fact that this fireball is still visible after six months means the explosion was truly titanic and, to match the observed brightness, must have happened at the vast distances of galaxies. The energy released in a burst, which can last from a fraction of a second to a few hundred seconds, is equal to all of the Sun's energy generated over its 10 billion year lifetime. The false-color image was taken Sept. 5, 1997 with the Space Telescope Imaging Spectrograph. Credit: Andrew Fruchter (STScI), Elena Pian (ITSRE-CNR), and NASA

  10. A MULTIWAVELENGTH STUDY OF TADPOLE GALAXIES IN THE HUBBLE ULTRA DEEP FIELD

    International Nuclear Information System (INIS)

    Straughn, Amber N.; Eufrasio, Rafael T.; Gardner, Jonathan P.; Voyer, Elysse N.; Mello, Duilia de; Soto, Emmaris; Petty, Sara; Kassin, Susan; Ravindranath, Swara

    2015-01-01

    Multiwavelength data are essential in order to provide a complete picture of galaxy evolution and to inform studies of galaxies’ morphological properties across cosmic time. Here we present the results of a multiwavelength investigation of the morphologies of “tadpole” galaxies at intermediate redshift (0.314 < z < 3.175) in the Hubble Ultra Deep Field. These galaxies were previously selected from deep Hubble Space Telescope (HST) F775W data based on their distinct asymmetric knot-plus-tail morphologies. Here we use deep Wide Field Camera 3 near-infrared imaging in addition to the HST optical data in order to study the rest-frame UV/optical morphologies of these galaxies across the redshift range 0.3 < z < 3.2. This study reveals that the majority of these galaxies do retain their general asymmetric morphology in the rest-frame optical over this redshift range, if not the distinct “tadpole” shape. The average stellar mass of tadpole galaxies is lower than that of field galaxies, with the effect being slightly greater at higher redshift within the errors. Estimated from spectral energy distribution fits, the average age of tadpole galaxies is younger than that of field galaxies in the lower-redshift bin, and the average metallicity is lower (whereas the specific star formation rate for tadpoles is roughly the same as field galaxies across the redshift range probed here). These average effects combined support the conclusion that this subset of galaxies is in an active phase of assembly, either late-stage merging or cold gas accretion causing localized clumpy star formation

  11. Hubble Space Telescope Observations of cD Galaxies and Their Globular Cluster Systems

    Science.gov (United States)

    Jordán, Andrés; Côté, Patrick; West, Michael J.; Marzke, Ronald O.; Minniti, Dante; Rejkuba, Marina

    2004-01-01

    We have used WFPC2 on the Hubble Space Telescope (HST) to obtain F450W and F814W images of four cD galaxies (NGC 541 in Abell 194, NGC 2832 in Abell 779, NGC 4839 in Abell 1656, and NGC 7768 in Abell 2666) in the range 5400 km s-1cluster (GC) systems reveals no anomalies in terms of specific frequencies, metallicity gradients, average metallicities, or the metallicity offset between the globular clusters and the host galaxy. We show that the latter offset appears roughly constant at Δ[Fe/H]~0.8 dex for early-type galaxies spanning a luminosity range of roughly 4 orders of magnitude. We combine the globular cluster metallicity distributions with an empirical technique described in a series of earlier papers to investigate the form of the protogalactic mass spectrum in these cD galaxies. We find that the observed GC metallicity distributions are consistent with those expected if cD galaxies form through the cannibalism of numerous galaxies and protogalactic fragments that formed their stars and globular clusters before capture and disruption. However, the properties of their GC systems suggest that dynamical friction is not the primary mechanism by which these galaxies are assembled. We argue that cD's instead form rapidly, via hierarchical merging, prior to cluster virialization. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 Based in part on observations obtained at the European Southern Observatory, for VLT program 68.D-0130(A).

  12. Revisiting the stellar velocity ellipsoid-Hubble-type relation: observations versus simulations

    Science.gov (United States)

    Pinna, F.; Falcón-Barroso, J.; Martig, M.; Martínez-Valpuesta, I.; Méndez-Abreu, J.; van de Ven, G.; Leaman, R.; Lyubenova, M.

    2018-04-01

    The stellar velocity ellipsoid (SVE) in galaxies can provide important information on the processes that participate in the dynamical heating of their disc components (e.g. giant molecular clouds, mergers, spiral density waves, and bars). Earlier findings suggested a strong relation between the shape of the disc SVE and Hubble type, with later-type galaxies displaying more anisotropic ellipsoids and early types being more isotropic. In this paper, we revisit the strength of this relation using an exhaustive compilation of observational results from the literature on this issue. We find no clear correlation between the shape of the disc SVE and morphological type, and show that galaxies with the same Hubble type display a wide range of vertical-to-radial velocity dispersion ratios. The points are distributed around a mean value and scatter of σz/σR = 0.7 ± 0.2. With the aid of numerical simulations, we argue that different mechanisms might influence the shape of the SVE in the same manner and that the same process (e.g. mergers) does not have the same impact in all the galaxies. The complexity of the observational picture is confirmed by these simulations, which suggest that the vertical-to-radial axis ratio of the SVE is not a good indicator of the main source of disc heating. Our analysis of those simulations also indicates that the observed shape of the disc SVE may be affected by several processes simultaneously and that the signatures of some of them (e.g. mergers) fade over time.

  13. A MULTIWAVELENGTH STUDY OF TADPOLE GALAXIES IN THE HUBBLE ULTRA DEEP FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Straughn, Amber N.; Eufrasio, Rafael T.; Gardner, Jonathan P. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Voyer, Elysse N. [Randstad at Google, 1129 San Antonio Road, Palo Alto, CA (United States); Mello, Duilia de; Soto, Emmaris [Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); Petty, Sara [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Kassin, Susan; Ravindranath, Swara [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2015-12-01

    Multiwavelength data are essential in order to provide a complete picture of galaxy evolution and to inform studies of galaxies’ morphological properties across cosmic time. Here we present the results of a multiwavelength investigation of the morphologies of “tadpole” galaxies at intermediate redshift (0.314 < z < 3.175) in the Hubble Ultra Deep Field. These galaxies were previously selected from deep Hubble Space Telescope (HST) F775W data based on their distinct asymmetric knot-plus-tail morphologies. Here we use deep Wide Field Camera 3 near-infrared imaging in addition to the HST optical data in order to study the rest-frame UV/optical morphologies of these galaxies across the redshift range 0.3 < z < 3.2. This study reveals that the majority of these galaxies do retain their general asymmetric morphology in the rest-frame optical over this redshift range, if not the distinct “tadpole” shape. The average stellar mass of tadpole galaxies is lower than that of field galaxies, with the effect being slightly greater at higher redshift within the errors. Estimated from spectral energy distribution fits, the average age of tadpole galaxies is younger than that of field galaxies in the lower-redshift bin, and the average metallicity is lower (whereas the specific star formation rate for tadpoles is roughly the same as field galaxies across the redshift range probed here). These average effects combined support the conclusion that this subset of galaxies is in an active phase of assembly, either late-stage merging or cold gas accretion causing localized clumpy star formation.

  14. Probing the z > 6 universe with the first Hubble frontier fields cluster A2744

    International Nuclear Information System (INIS)

    Atek, Hakim; Kneib, Jean-Paul; Richard, Johan; Clement, Benjamin; Egami, Eiichi; Ebeling, Harald; Jauzac, Mathilde; Jullo, Eric; Limousin, Marceau; Laporte, Nicolas; Natarajan, Priyamvada

    2014-01-01

    The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first combined HST and Spitzer observations of the cluster A-2744. We combine the full near-infrared data with ancillary optical images to search for gravitationally lensed high-redshift (z ≳ 6) galaxies. We report the detection of 15 I 814 dropout candidates at z ∼ 6-7 and one Y 105 dropout at z ∼ 8 in a total survey area of 1.43 arcmin 2 in the source plane. The predictions of our lens model also allow us to identify five multiply imaged systems lying at redshifts between z ∼ 6 and z ∼ 8. Thanks to constraints from the mass distribution in the cluster, we were able to estimate the effective survey volume corrected for completeness and magnification effects. This was in turn used to estimate the rest-frame ultraviolet luminosity function (LF) at z ∼ 6-8. Our LF results are generally in agreement with the most recent blank field estimates, confirming the feasibility of surveys through lensing clusters. Although based on a shallower observations than what will be achieved in the final data set including the full Advanced Camera for Survey observations, the LF presented here goes down to M UV ∼–18.5, corresponding to 0.2L * at z ∼ 7 with one identified object at M UV ∼–15 thanks to the highly magnified survey areas. This early study forecasts the power of using massive galaxy clusters as cosmic telescopes and its complementarity to blank fields.

  15. Probing the z > 6 universe with the first Hubble frontier fields cluster A2744

    Energy Technology Data Exchange (ETDEWEB)

    Atek, Hakim; Kneib, Jean-Paul [Laboratoire d' Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, CH-1290 Versoix (Switzerland); Richard, Johan [CRAL, Observatoire de Lyon, Université Lyon 1, 9 Avenue Ch. André, 69561 Saint Genis Laval Cedex (France); Clement, Benjamin; Egami, Eiichi [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ, 85721 (United States); Ebeling, Harald [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, Hawaii 96822 (United States); Jauzac, Mathilde [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban, 4041 South Africa (South Africa); Jullo, Eric; Limousin, Marceau [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, 13388, Marseille (France); Laporte, Nicolas [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Natarajan, Priyamvada [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States)

    2014-05-01

    The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first combined HST and Spitzer observations of the cluster A-2744. We combine the full near-infrared data with ancillary optical images to search for gravitationally lensed high-redshift (z ≳ 6) galaxies. We report the detection of 15 I {sub 814} dropout candidates at z ∼ 6-7 and one Y {sub 105} dropout at z ∼ 8 in a total survey area of 1.43 arcmin{sup 2} in the source plane. The predictions of our lens model also allow us to identify five multiply imaged systems lying at redshifts between z ∼ 6 and z ∼ 8. Thanks to constraints from the mass distribution in the cluster, we were able to estimate the effective survey volume corrected for completeness and magnification effects. This was in turn used to estimate the rest-frame ultraviolet luminosity function (LF) at z ∼ 6-8. Our LF results are generally in agreement with the most recent blank field estimates, confirming the feasibility of surveys through lensing clusters. Although based on a shallower observations than what will be achieved in the final data set including the full Advanced Camera for Survey observations, the LF presented here goes down to M {sub UV} ∼–18.5, corresponding to 0.2L {sup *} at z ∼ 7 with one identified object at M {sub UV} ∼–15 thanks to the highly magnified survey areas. This early study forecasts the power of using massive galaxy clusters as cosmic telescopes and its complementarity to blank fields.

  16. Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids

    Science.gov (United States)

    Evans, Nancy Remage; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Tingle, Evan; Karovska, Margarita; Pillitteri, Ignazio

    2016-05-01

    We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera 3 (WFC3) of 70 Galactic Cepheids, typically within 1 kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, based on their positions in color-magnitude diagrams, and having separations ⩾ 5'' from the Cepheids. We use follow-up observations of 14 of these candidates with XMM-Newton, and of one of them with ROSAT, to separate X-ray-active young stars (probable physical companions) from field stars (chance alignments). Our preliminary estimate, based on the optical and X-ray observations, is that only 3% of the Cepheids in the sample have wide companions. Our survey easily detects resolved main-sequence companions as faint as spectral type K. Thus the fact that the two most probable companions (those of FF Aql and RV Sco) are earlier than type K is not simply a function of the detection limit. We find no physical companions having separations larger than 4000 au in the X-ray survey. Two Cepheids are exceptions in that they do have young companions at significantly larger separations (δ Cep and S Nor), but both belong to a cluster or a loose association, so our working model is that they are not gravitationally bound binary members, but rather cluster/association members. All of these properties provide constraints on both star formation and subsequent dynamical evolution. The low frequency of true physical companions at separations > 5'' is confirmed by examination of the subset of the nearest Cepheids and also the density of the fields. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  17. The Chrysalis Opens? Photometry from the η Carinae Hubble Space Telescope Treasury Project, 2002-2006

    Science.gov (United States)

    Martin, J. C.; Davidson, Kris; Koppelman, M. D.

    2006-12-01

    During the past decade η Car has brightened markedly, possibly indicating a change of state. Here we summarize photometry gathered by the Hubble Space Telescope (HST) as part of the HST Treasury Project on this object. Our data include Space Telescope Imaging Spectrograph (STIS) CCD acquisition images, Advanced Camera for Surveys HRC images in four filters, and synthetic photometry in flux-calibrated STIS spectra. The HST's spatial resolution allows us to examine the central star separate from the bright circumstellar ejecta. Its apparent brightness continued to increase briskly during 2002-2006, especially after the mid-2003 spectroscopic event. If this trend continues, the central star will soon become brighter than its ejecta, quite different from the state that existed only a few years ago. One precedent may be the rapid change observed in 1938-1953. We conjecture that the star's mass-loss rate has been decreasing throughout the past century. This research was conducted as part of the η Car Hubble Space Telescope Treasury project via grant GO-9973 from the Space Telescope Science Institute. HST is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Some of the data presented in this paper were obtained from the Multimission Archive at the Space Telescope Science Institute (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts.

  18. The New Horizons and Hubble Space Telescope search for rings, dust, and debris in the Pluto-Charon system

    Science.gov (United States)

    Lauer, Tod R.; Throop, Henry B.; Showalter, Mark R.; Weaver, Harold A.; Stern, S. Alan; Spencer, John R.; Buie, Marc W.; Hamilton, Douglas P.; Porter, Simon B.; Verbiscer, Anne J.; Young, Leslie A.; Olkin, Cathy B.; Ennico, Kimberly; New Horizons Science Team

    2018-02-01

    We conducted an extensive search for dust or debris rings in the Pluto-Charon system before, during, and after the New Horizons encounter in July 2015. Methodologies included attempting to detect features by back-scattered light during the approach to Pluto (phase angle α ∼ 15°), in situ detection of impacting particles, a search for stellar occultations near the time of closest approach, and by forward-scattered light imaging during departure (α ∼ 165°). An extensive search using the Hubble Space Telescope (HST) prior to the encounter also contributed to the final ring limits. No rings, debris, or dust features were observed, but our new detection limits provide a substantially improved picture of the environment throughout the Pluto-Charon system. Searches for rings in back-scattered light covered the range 35,000-250,000 km from the system barycenter, a zone that starts interior to the orbit of Styx, the innermost minor satellite, and extends out to four times the orbital radius of Hydra, the outermost known satellite. We obtained our firmest limits using data from the New Horizons LORRI camera in the inner half of this region. Our limits on the normal I/F of an unseen ring depends on the radial scale of the rings: 2 ×10-8 (3σ) for 1500 km wide rings, 1 ×10-8 for 6000 km rings, and 7 ×10-9 for 12,000 km rings. Beyond ∼ 100, 000 km from Pluto, HST observations limit normal I/F to ∼ 8 ×10-8 . Searches for dust features from forward-scattered light extended from the surface of Pluto to the Pluto-Charon Hill sphere (rHill = 6.4 ×106 km). No evidence for rings or dust clouds was detected to normal I/F limits of ∼ 8.9 ×10-7 on ∼ 104 km scales. Four stellar occulation observations also probed the space interior to Hydra, but again no dust or debris was detected. The Student Dust Counter detected one particle impact 3.6 × 106 km from Pluto, but this is consistent with the interplanetary space environment established during the cruise of New

  19. Attitudes of Veterinary Teaching Staff and Exposure of Veterinary Students to Early-Age Desexing, with Review of Current Early-Age Desexing Literature.

    Science.gov (United States)

    Jupe, Alannah; Rand, Jacquie; Morton, John; Fleming, Sophie

    2017-12-25

    Approximately 50% of cats admitted to Australian shelters are kittens, and 26% of dogs are puppies, and, particularly for cats, euthanasia rates are often high. Cats can be pregnant by 4 months of age, yet the traditional desexing age is 5-6 months, and studies in Australasia and Nth America reveal that only a minority of veterinarians routinely perform early age desexing (EAD) of cats or dogs, suggesting they are not graduating with these skills. This study aimed to describe the attitudes of veterinary teaching staff in Australian and New Zealand universities towards EAD, and to determine if these changed from 2008 to 2015. It also aimed to identify students' practical exposure to EAD. Most (64%) of the 25 participants in 2015 did not advocate EAD in their teaching and, in their personal opinion, only 32% advocated it for cats. Concerns related to EAD cited by staff included anesthetic risk, orthopedic problems, hypoglycemia, and, in female dogs, urinary incontinence. Those who advocated EAD cited benefits of population control, ease of surgery and behavioral benefits. Only three of the eight universities provided a majority of students with an opportunity to gain exposure to EAD procedures before graduation, and in two of these, most students had an opportunity to perform EAD. In conclusion, most veterinary students in Australia and New Zealand are not graduating with the knowledge or skills to perform EAD, and have little opportunity while at university to gain practical exposure. Welfare agencies could partner with universities to enable students to experience EAD.

  20. UV Luminosity Functions at z~4, 5, and 6 from the Hubble Ultra Deep Field and Other Deep Hubble Space Telescope ACS Fields: Evolution and Star Formation History

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Franx, Marijn; Ford, Holland

    2007-12-01

    We use the ACS BViz data from the HUDF and all other deep HST ACS fields (including the GOODS fields) to find large samples of star-forming galaxies at z~4 and ~5 and to extend our previous z~6 sample. These samples contain 4671, 1416, and 627 B-, V-, and i-dropouts, respectively, and reach to extremely low luminosities [(0.01-0.04)L*z=3 or MUV~-16 to -17], allowing us to determine the rest-frame UV LF and faint-end slope α at z~4-6 to high accuracy. We find faint-end slopes α=-1.73+/-0.05, -1.66+/-0.09, and -1.74+/-0.16 at z~4, ~5, and ~6, respectively, suggesting that the faint-end slope is very steep and shows little evolution with cosmic time. We find that M*UV brightens considerably in the 0.7 Gyr from z~6 to ~4 (by ~0.7 mag from M*UV=-20.24+/-0.19 to -20.98+/-0.10). The observed increase in the characteristic luminosity over this range is almost identical to that expected for the halo mass function, suggesting that the observed evolution is likely due to the hierarchical coalescence and merging of galaxies. The evolution in φ* is not significant. The UV luminosity density at z~6 is modestly lower than (0.45+/-0.09 times) that at z~4 (integrated to -17.5 mag) although a larger change is seen in the dust-corrected SFR density. We thoroughly examine published LF results and assess the reasons for their wide dispersion. We argue that the results reported here are the most robust available. The extremely steep faint-end slopes α found here suggest that lower luminosity galaxies play a significant role in reionizing the universe. Finally, recent search results for galaxies at z~7-8 are used to extend our estimates of the evolution of M* from z~7-8 to z~4. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 9425, 9575, 9803, 9978, 10189, 10339, 10340, and 10632.

  1. New Target for an Old Method: Hubble Measures Globular Cluster Parallax

    Science.gov (United States)

    Hensley, Kerry

    2018-05-01

    Measuring precise distances to faraway objects has long been a challenge in astrophysics. Now, one of the earliest techniques used to measure the distance to astrophysical objects has been applied to a metal-poor globular cluster for the first time.A Classic TechniqueAn artists impression of the European Space Agencys Gaia spacecraft. Gaia is on track to map the positions and motions of a billion stars. [ESA]Distances to nearby stars are often measured using the parallax technique tracing the tiny apparent motion of a target star against the background of more distant stars as Earth orbits the Sun. This technique has come a long way since it was first used in the 1800s to measure the distance to stars a few tens of light-years away; with the advent of space observatories like Hipparcos and Gaia, parallax can now be used to map the positions of stars out to thousands of light-years.Precise distance measurements arent only important for setting the scale of the universe, however; they can also help us better understand stellar evolution over the course of cosmic history. Stellar evolution models are often anchored to a reference star cluster, the properties of which must be known precisely. These precise properties can be readily determined for young, nearby open clusters using parallax measurements. But stellar evolution models that anchor on themore-distant, ancient, metal-poor globular clusters have been hampered by theless-precise indirect methods used tomeasure distance to these faraway clusters until now.Top: An image of NGC 6397 overlaid with the area scanned by Hubble (dashed green) and the footprint of the camera (solid green). The blue ellipse represents the parallax motion of a star in the cluster, exaggerated by a factor of ten thousand. Bottom: An example scan from this field. [Adapted from Brown et al. 2018]New Measurement to an Old ClusterThomas Brown (Space Telescope Science Institute) and collaborators used the Hubble Space Telescope todetermine the

  2. A 2.4% DETERMINATION OF THE LOCAL VALUE OF THE HUBBLE CONSTANT

    Energy Technology Data Exchange (ETDEWEB)

    Riess, Adam G.; Scolnic, Dan; Jones, David O. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD (United States); Macri, Lucas M.; Hoffmann, Samantha L.; Yuan, Wenlong; Brown, Peter J. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX (United States); Casertano, Stefano [Space Telescope Science Institute, Baltimore, MD (United States); Filippenko, Alexei V.; Tucker, Brad E. [Department of Astronomy, University of California, Berkeley, CA (United States); Reid, Mark J.; Challis, Peter [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Silverman, Jeffrey M. [Department of Astronomy, University of Texas, Austin, TX (United States); Chornock, Ryan [Astrophysical Institute, Department of Physics and Astronomy, Ohio University, Athens, OH (United States); Foley, Ryan J., E-mail: ariess@stsci.edu [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL (United States)

    2016-07-20

    We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ∼300 SNe Ia at z < 0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST -based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST /FGS, HST /WFC3 spatial scanning and/or Hipparcos , and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25 ± 2.51, 72.04 ± 2.67, 76.18 ± 2.37, and 74.50 ± 3.27 km s{sup 1} Mpc{sup 1}, respectively. Our best estimate of H {sub 0} = 73.24 ± 1.74 km s{sup 1} Mpc{sup 1} combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4 σ higher than 66.93 ± 0.62 km s{sup 1} Mpc{sup 1} predicted by ΛCDM with 3 neutrino flavors having a mass of 0.06 eV and the new Planck data, but the discrepancy reduces to 2.1 σ relative to the prediction of 69.3 ± 0.7 km s{sup 1} Mpc{sup 1} based on the

  3. VizieR Online Data Catalog: Hubble Legacy Archive ACS grism data (Kuemmel+, 2011)

    Science.gov (United States)

    Kuemmel, M.; Rosati, P.; Fosbury, R.; Haase, J.; Hook, R. N.; Kuntschner, H.; Lombardi, M.; Micol, A.; Nilsson, K. K.; Stoehr, F.; Walsh, J. R.

    2011-09-01

    A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55-1.00um, with a dispersion of 40Å/pixel and a resolution of ~80Å for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibration, direct image combination, catalogue generation, spectral extraction and collection of metadata. The large number of extracted spectra (73,581) demanded automatic methods for quality control and an automated classification algorithm was trained on the visual inspection of several thousand spectra. The final sample of quality controlled spectra includes 47919 datasets (65% of the total number of extracted spectra) for 32149 unique objects, with a median iAB-band magnitude of 23.7, reaching 26.5 AB for the faintest objects. Each released dataset contains science-ready 1D and 2D spectra, as well as multi-band image cutouts of corresponding sources and a useful preview page summarising the direct and slitless data, astrometric and photometric parameters. This release is part of the continuing effort to enhance the content of the Hubble Legacy Archive (HLA) with highly processed data products which significantly facilitate the scientific exploitation of the Hubble data. In order to characterize the slitless spectra, emission-line flux and equivalent width sensitivity of the ACS data were compared with public ground-based spectra in the GOODS-South field. An example list of emission line galaxies with two or more identified lines is also included, covering the redshift range 0.2-4.6. Almost all redshift determinations outside of the GOODS fields are new. The scope of science projects possible

  4. Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. III. Measurement for Ursa Minor

    Science.gov (United States)

    Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

    2005-07-01

    This article presents a measurement of the proper motion of the Ursa Minor dwarf spheroidal galaxy determined from images taken with the Hubble Space Telescope in two distinct fields. Each field contains a quasi-stellar object that serves as the ``reference point.'' The measured proper motion for Ursa Minor, expressed in the equatorial coordinate system, is (μα,μδ)=(-50+/-17,22+/-16) mas century-1. Removing the contributions of the solar motion and the motion of the local standard of rest yields the proper motion in the Galactic rest frame: (μGrfα,μGrfδ)=(-8+/-17,38+/-16) mas century-1. The implied space velocity with respect to the Galactic center has a radial component of Vr=-75+/-44 km s-1 and a tangential component of Vt=144+/-50 km s-1. Integrating the motion of Ursa Minor in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 40 (10, 76) and 89 (78, 160) kpc, respectively, where the values in the parentheses represent the 95% confidence intervals derived from Monte Carlo experiments. The eccentricity of the orbit is 0.39 (0.09, 0.79), and the orbital period is 1.5 (1.1, 2.7) Gyr. The orbit is retrograde and inclined by 124° (94°, 136°) to the Galactic plane. Ursa Minor is not a likely member of a proposed stream of galaxies on similar orbits around the Milky Way, nor is the plane of its orbit coincident with a recently proposed planar alignment of galaxies around the Milky Way. Comparing the orbits of Ursa Minor and Carina shows no reason for the different star formation histories of these two galaxies. Ursa Minor must contain dark matter to have a high probability of having survived disruption by the Galactic tidal force until the present. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  5. Galaxies at z~7-8: z850-Dropouts in the Hubble Ultra Deep Field

    Science.gov (United States)

    Bouwens, R. J.; Thompson, R. I.; Illingworth, G. D.; Franx, M.; van Dokkum, P. G.; Fan, X.; Dickinson, M. E.; Eisenstein, D. J.; Rieke, M. J.

    2004-12-01

    We have detected likely z~7-8 galaxies in the 144''×144'' Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) observations of the Hubble Ultra Deep Field. Objects are required to be >=3 σ detections in both NICMOS bands, J110 and H160. The selection criteria for this sample are (z850-J110)AB>0.8, (z850-J110)AB>0.66(J110-H160)AB+0.8, (J110-H160)ABdropout galaxies and are clustered within a 1 arcmin2 region. Because all five sources are near the limit of the NICMOS data, we have carefully evaluated their reality. Each of the candidates is visible in different splits of the data and a median stack. We analyzed several noise images and estimate the number of spurious sources to be 1+/-1. A search using an independent reduction of this same data set clearly revealed three of the five candidates and weakly detected a fourth candidate, suggesting that the contamination could be higher. For comparison with predictions from lower redshift samples, we take a conservative approach and adopt four z~7-8 galaxies as our sample. With the same detection criteria on simulated data sets, assuming no evolution from z~3.8, we predict 10 sources at z~7-8, or 14 if we use a more realistic (1+z)-1 size scaling. We estimate that the rest-frame continuum UV (~1800 Å) luminosity density at z~7.5 (integrated down to 0.3L*z=3) is just 0.20+0.12-0.08 times that found at z~3.8 (or 0.20+0.23-0.12 times this quantity including cosmic variance). Effectively this sets an upper limit on the luminosity density down to 0.3L*z=3 and is consistent with significant evolution at the bright end of the luminosity function from z~7.5 to 3.8. Even with the lower UV luminosity density at z~7.5, it appears that galaxies could still play an important role in reionization at these redshifts, although definitive measurements remain to be made. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under

  6. 3D-HST: A Wide-field Grism Spectroscopic Survey with the Hubble Space Telescope

    Science.gov (United States)

    Brammer, Gabriel B.; van Dokkum, Pieter G.; Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Rix, Hans-Walter; Skelton, Rosalind E.; Kriek, Mariska; Nelson, Erica; Schmidt, Kasper B.; Bezanson, Rachel; da Cunha, Elisabete; Erb, Dawn K.; Fan, Xiaohui; Förster Schreiber, Natascha; Illingworth, Garth D.; Labbé, Ivo; Leja, Joel; Lundgren, Britt; Magee, Dan; Marchesini, Danilo; McCarthy, Patrick; Momcheva, Ivelina; Muzzin, Adam; Quadri, Ryan; Steidel, Charles C.; Tal, Tomer; Wake, David; Whitaker, Katherine E.; Williams, Anna

    2012-06-01

    We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for a sample of ~7000 galaxies at 1 < z < 3.5, the epoch when ~60% of all star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. 3D-HST will cover three quarters (625 arcmin2) of the CANDELS Treasury survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of ~5 per resolution element at H 140 ~ 23.1 and a 5σ emission-line sensitivity of ~5 × 10-17 erg s-1 cm-2 for typical objects, improving by a factor of ~2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1 to 1.6 μm at a spatial resolution of ~0farcs13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary reduction and analysis of the grism observations, including emission-line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of σ(z) = 0.0034(1 + z), or σ(v) ≈ 1000 km s-1. We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z = 4.7, quiescent galaxies at z ~ 2, and the most distant T-type brown dwarf star known. The combination of the CANDELS and 3D-HST surveys will provide the definitive imaging and spectroscopic data set for studies of the 1 < z < 3.5 universe until the launch of the James Webb Space

  7. Evolution/Creationism Controversy: Analysis of Past and Current Policies in Public Schools and the Practice of Allowing Students to Opt Out of Learning Evolution Concepts

    Science.gov (United States)

    Speake, Jacquelyn Hoffmann

    2011-07-01

    Recent anti-evolution legislation, in the form of Academic Freedom bills, has been introduced in many state legislatures over the last three years. The language in the proposed Academic Freedom bills may allow different interpretations of what can be taught in the science classrooms, and possibly spur parents to take advantage of their perceived parental rights to request their child be opted-out of class when the scientific theory of evolution is taught. Five research questions guided the analysis of participant responses to questions and perception statements focusing on secondary school administrators' actions, perceptions, and awareness as they relate to their decision to allow or not allow a student to opt out of academics, specifically evolution, through the collection of data using a web-based survey. Opt out policies are typically invoked to excuse students from activities to which they or their parents may have religious objections (Scott & Branch, 2008). Florida statutes allow parents to opt out their child from human sexuality and animal dissection. The population consisted of 281 Florida public secondary school administrators, who were divided into two subgroups based on whether they have allowed or would allow a student to opt out of evolution, or have not allowed or would not allow a student to opt out of class when the scientific theory of evolution is taught. Results found that over 70% of the administrators who completed the survey have allowed or would allow parents to opt out their child from learning about the scientific theory of evolution. There was a significant relationship between the decision to allow opt out and the following variables: (a) Free and Reduced Lunch population, (b) grade level served, (c) support for teaching evolution and alternative theories, and (d) the perception that parent rights supersede state statute requiring students to learn evolution. In Florida, any scientific concept that is based on empirical evidence is

  8. H0, q0 and the local velocity field. [Hubble and deceleration constants in Big Bang expansion

    Science.gov (United States)

    Sandage, A.; Tammann, G. A.

    1982-01-01

    An attempt is made to find a systematic deviation from linearity for distances that are under the control of the Virgo cluster, and to determine the value of the mean random motion about the systematic flow, in order to improve the measurement of the Hubble and the deceleration constants. The velocity-distance relation for large and intermediate distances is studied, and type I supernovae are calibrated relatively as distance indicators and absolutely to obtain a new value for the Hubble constant. Methods of determining the deceleration constant are assessed, including determination from direct measurement, mean luminosity density, virgocentric motion, and the time scale test. The very local velocity field is investigated, and a solution is preferred with a random peculiar radial velocity of very nearby field galaxies of 90-100 km/s, and a Virgocentric motion of the local group of 220 km/s, leading to an underlying expansion rate of 55, in satisfactory agreement with the global value.

  9. The UDF05 Follow-Up of the Hubble Ultra Deep Field. II. Constraints on Reionization from Z-Dropout Galaxies

    Science.gov (United States)

    Oesch, P. A.; Carollo, C. M.; Stiavelli, M.; Trenti, M.; Bergeron, L. E.; Koekemoer, A. M.; Lucas, R. A.; Pavlovsky, C. M.; Beckwith, S. V. W.; Dahlen, T.; Ferguson, H. C.; Gardner, Jonathan P.; Lilly, S. J.; Mobasher, B.; Panagia, N.

    2009-01-01

    We detect three (plus one less certain) z 850-dropout sources in two separate fields (Hubble Ultra Deep Field and NICP34) of our UDF05 Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer images. These z ~ 7 Lyman-break Galaxy (LBG) candidates allow us to constrain the Luminosity Function (LF) of the star-forming galaxy population at those epochs. By assuming a change in only M * and adopting a linear evolution in redshift, anchored to the measured values at z ~ 6, the best-fit evolution coefficient is found to be 0.43 ± 0.19 mag per unit redshift (0.36 ± 0.18, if including all four candidates), which provides a value of M *(z = 7.2) = -19.7 ± 0.3. This implies a drop in the luminosity density in LBGs by a factor of ~2-2.5 over the ~ 170 Myr that separate z ~ 6 and z ~ 7, and a steady evolution for the LBG LF out to z ~ 7, at the same rate that is observed throughout the z ~ 3-6 period. This puts a strong constraint on the star-formation histories of z ~ 6 galaxies, whose ensemble star-formation rate (SFR) density must be lower by a factor of 2 at ~ 170 Myr before the epoch at which they are observed. In particular, a large fraction of stars in the z ~ 6 LBG population must form at redshifts well above z ~ 7. The rate of ionizing photons produced by the LBG population consistently decreases with the decrease in the cosmic SFR density. Extrapolating this steady evolution of the LF out to higher redshifts, we estimate that galaxies would be able to reionize the universe by z ~ 6, provided that the faint-end slope of the z > 7 LF steepens to α ~ -1.9 and that faint galaxies with luminosities below the current detection limits contribute a substantial fraction of the required ionizing photons. This scenario, however, gives an integrated optical depth to electron scattering that is ~2σ below the Wilkinson Microwave Anisotropy Probe-5 measurement. Therefore, altogether, our results indicate that, should galaxies be the primary contributors to

  10. Surface Brightness Profiles of Composite Images of Compact Galaxies at Z approximately equal 4-6 in the Hubble Ultra Deep Field

    National Research Council Canada - National Science Library

    Hathi, N. P; Jansen, R. A; Windhorst, R. A; Cohen, S. H; Keel, W. C; Corbin, M. R; Ryan, Jr, R. E

    2007-01-01

    The Hubble Ultra Deep Field (HUDF) contains a significant number of B-, V-, and iota'-band dropout objects, many of which were recently confirmed to be young star-forming galaxies at Z approximately equal 4-6...

  11. Observations of the Hubble Deep Field with the Infrared Space Observatory .3. Source counts and P(D) analysis

    DEFF Research Database (Denmark)

    Oliver, S.J.; Goldschmidt, P.; Franceschini, A.

    1997-01-01

    We present source counts at 6.7 and 15 mu m from our maps of the Hubble Deep Field (HDF) region, reaching 38.6 mu Jy at 6.7 mu m and 255 mu Jy at 15 mu m. These are the first ever extragalactic number counts to be presented at 6.7 mu m, and are three decades fainter than IRAS at 12 mu m. Both...

  12. A Type II Supernova Hubble diagram from the CSP-I, SDSS-II, and SNLS surveys

    OpenAIRE

    de Jaeger, T.; González-Gaitán, S.; Hamuy, M.; Galbany, L.; Anderson, J. P.; Phillips, M. M.; Stritzinger, M. D.; Carlberg, R. G.; Sullivan, M.; Gutiérrez, C. P.; Hook, I. M.; Howell, D. Andrew; Hsiao, E. Y.; Kuncarayakti, H.; Ruhlmann-Kleider, V.

    2016-01-01

    The coming era of large photometric wide-field surveys will increase the detection rate of supernovae by orders of magnitude. Such numbers will restrict spectroscopic follow-up in the vast majority of cases, and hence new methods based solely on photometric data must be developed. Here, we construct a complete Hubble diagram of Type II supernovae (SNe II) combining data from three different samples: the Carnegie Supernova Project-I, the Sloan Digital Sky Survey II SN, and th...

  13. Theoretical colours and isochrones for some Hubble Space Telescope colour systems. II

    Science.gov (United States)

    Paltoglou, G.; Bell, R. A.

    1991-01-01

    A grid of synthetic surface brightness magnitudes for 14 bandpasses of the Hubble Space Telescope Faint Object Camera is presented, as well as a grid of UBV, uvby, and Faint Object Camera surface brightness magnitudes derived from the Gunn-Stryker spectrophotometric atlas. The synthetic colors are used to examine the transformations between the ground-based Johnson UBV and Stromgren uvby systems and the Faint Object Camera UBV and uvby. Two new four-color systems, similar to the Stromgren system, are proposed for the determination of abundance, temperature, and surface gravity. The synthetic colors are also used to calculate color-magnitude isochrones from the list of theoretical tracks provided by VandenBerg and Bell (1990). It is shown that by using the appropriate filters it is possible to minimize the dependence of this color difference on metallicity. The effects of interstellar reddening on various Faint Object Camera colors are analyzed as well as the observational requirements for obtaining data of a given signal-to-noise for each of the 14 bandpasses.

  14. HUBBLE SPACE TELESCOPE SPECTROSCOPY OF BROWN DWARFS DISCOVERED WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER

    International Nuclear Information System (INIS)

    Schneider, Adam C.; Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Mace, Gregory N.; Wright, Edward L.; Eisenhardt, Peter R.; Skrutskie, M. F.; Griffith, Roger L.; Marsh, Kenneth A.

    2015-01-01

    We present a sample of brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE) for which we have obtained Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) near-infrared grism spectroscopy. The sample (22 in total) was observed with the G141 grism covering 1.10–1.70 μm, while 15 were also observed with the G102 grism, which covers 0.90–1.10 μm. The additional wavelength coverage provided by the G102 grism allows us to (1) search for spectroscopic features predicted to emerge at low effective temperatures (e.g.,ammonia bands) and (2) construct a smooth spectral sequence across the T/Y boundary. We find no evidence of absorption due to ammonia in the G102 spectra. Six of these brown dwarfs are new discoveries, three of which are found to have spectral types of T8 or T9. The remaining three, WISE J082507.35+280548.5 (Y0.5), WISE J120604.38+840110.6 (Y0), and WISE J235402.77+024015.0 (Y1), are the 19th, 20th, and 21st spectroscopically confirmed Y dwarfs to date. We also present HST grism spectroscopy and reevaluate the spectral types of five brown dwarfs for which spectral types have been determined previously using other instruments

  15. HUBBLE SPACE TELESCOPE CONSTRAINTS ON THE WINDS AND ASTROSPHERES OF RED GIANT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Brian E. [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States); Müller, Hans-Reinhard [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Harper, Graham M., E-mail: brian.wood@nrl.navy.mil [CASA, University of Colorado, Boulder, CO 80309-0389 (United States)

    2016-10-01

    We report on an ultraviolet spectroscopic survey of red giants observed by the Hubble Space Telescope , focusing on spectra of the Mg ii h and k lines near 2800 Å in order to study stellar chromospheric emission, winds, and astrospheric absorption. We focus on spectral types between K2 III and M5 III, a spectral type range with stars that are noncoronal, but possessing strong, chromospheric winds. We find a very tight relation between Mg ii surface flux and photospheric temperature, supporting the notion that all K2-M5 III stars are emitting at a basal flux level. Wind velocities ( V {sub w} ) are generally found to decrease with spectral type, with V {sub w} decreasing from ∼40 km s{sup −1} at K2 III to ∼20 km s{sup −1} at M5 III. We find two new detections of astrospheric absorption, for σ Pup (K5 III) and γ Eri (M1 III). This absorption signature had previously only been detected for α Tau (K5 III). For the three astrospheric detections, the temperature of the wind after the termination shock (TS) correlates with V {sub w} , but is lower than predicted by the Rankine–Hugoniot shock jump conditions, consistent with the idea that red giant TSs are radiative shocks rather than simple hydrodynamic shocks. A full hydrodynamic simulation of the γ Eri astrosphere is provided to explore this further.

  16. PANCHROMATIC HUBBLE ANDROMEDA TREASURY. XII. MAPPING STELLAR METALLICITY DISTRIBUTIONS IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Gregersen, Dylan; Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Williams, Benjamin F.; Dalcanton, Julianne J.; Johnson, L. C.; Lewis, Alexia R. [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Lang, Dustin [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Girardi, Leó [Osservatorio Astronomico di Padova—INAF, Vicolo dell’Osservatori 5, I-35122 Padova (Italy); Skillman, Evan D. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Bell, Eric [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Dolphin, Andrew E. [Raytheon, 1151 E. Hermans Road, Tucson, AZ 85706 (United States); Fouesneau, Morgan [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Guhathakurta, Puragra; Hamren, Katherine M. [UCO/Lick Observatory, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Kalirai, Jason [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Monachesi, Antonela [MPA, Garching (Germany); Olsen, Knut, E-mail: dylan.gregersen@utah.edu, E-mail: aseth@astro.utah.edu [NOAO, Tucson, AZ 85719 (United States)

    2015-12-15

    We present a study of spatial variations in the metallicity of old red giant branch stars in the Andromeda galaxy. Photometric metallicity estimates are derived by interpolating isochrones for over seven million stars in the Panchromatic Hubble Andromeda Treasury (PHAT) survey. This is the first systematic study of stellar metallicities over the inner 20 kpc of Andromeda’s galactic disk. We see a clear metallicity gradient of −0.020 ± 0.004 dex kpc{sup −1} from ∼4–20 kpc assuming a constant red giant branch age. This metallicity gradient is derived after correcting for the effects of photometric bias and completeness and dust extinction, and is quite insensitive to these effects. The unknown age gradient in M31's disk creates the dominant systematic uncertainty in our derived metallicity gradient. However, spectroscopic analyses of galaxies similar to M31 show that they typically have small age gradients that make this systematic error comparable to the 1σ error on our metallicity gradient measurement. In addition to the metallicity gradient, we observe an asymmetric local enhancement in metallicity at radii of 3–6 kpc that appears to be associated with Andromeda’s elongated bar. This same region also appears to have an enhanced stellar density and velocity dispersion.

  17. Infall of nearby galaxies into the Virgo cluster as traced with Hubble space telescope

    Energy Technology Data Exchange (ETDEWEB)

    Karachentsev, Igor D. [Special Astrophysical Observatory RAS, Nizhnij Arkhyz, Karachai-Cherkessian Republic 369167 (Russian Federation); Tully, R. Brent; Wu, Po-Feng [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Shaya, Edward J. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dolphin, Andrew E., E-mail: ikar@sao.ru [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States)

    2014-02-10

    We measured the tip of the red giant branch distances to nine galaxies in the direction to the Virgo cluster using the Advanced Camera for Surveys on the Hubble Space Telescope. These distances put seven galaxies (GR 34, UGC 7512, NGC 4517, IC 3583, NGC 4600, VCC 2037, and KDG 215) in front of Virgo and two galaxies (IC 3023 and KDG 177) likely inside the cluster. Distances and radial velocities of the galaxies situated between us and the Virgo core clearly exhibit the infall phenomenon toward the cluster. In the case of spherically symmetric radial infall, we estimate the radius of the 'zero-velocity surface' to be (7.2 ± 0.7) Mpc, which yields a total mass of the Virgo cluster of (8.0 ± 2.3) × 10{sup 14} M {sub ☉}, in good agreement with its virial mass estimates. We conclude that the Virgo outskirts do not contain significant amounts of dark matter beyond their virial radius.

  18. Hubble Space Telescope observations of cool white dwarf stars: Detection of new species of heavy elements

    Science.gov (United States)

    Shipman, Harry; Barnhill, Maurice; Provencal, Judi; Roby, Scott; Bues, Irmela; Cordova, France; Hammond, Gordon; Hintzen, Paul; Koester, Detlev; Liebert, James

    1995-01-01

    Observations of cool white dwarf stars with the Hubble Space Telescope (HST) has uncovered a number of spectral features from previouslly unobserved species. In this paper we present the data on four cool white dwarfs. We present identifications, equivalent width measurements, and brief summaries of the significance of our findings. The four stars observed are GD 40 (DBZ3, G 74-7 (DAZ), L 745-46A (DZ), and LDS 749B (DBA). Many additional species of heavey elements were detected in GD 40 and G 74-7. In L 745-46A, while the detections are limited to Fe 1, Fe II, and Mg II, the quality of the Mg II h and K line profiles should permit a test of the line broadening theories, which are so crucial to abundance determinations. The clear detection of Mg II h and k in LDS 749 B should, once an abundance determination is made, provide a clear test of the hypothesis that the DBA stars are the result of accretion from the interstellar medium. This star contains no other clear features other than a tantalizing hint of C II 1335 with a P Cygni profile, and some expected He 1 lines.

  19. LQG and maximum entropy control design for the Hubble Space Telescope

    Science.gov (United States)

    Collins, Emmanuel G., Jr.; Richter, Stephen

    Solar array vibrations are responsible for serious pointing control problems on the Hubble Space Telescope (HST). The original HST control law was not designed to attenuate these disturbances because they were not perceived to be a problem prior to launch. However, significant solar array vibrations do occur due to large changes in the thermal environment as the HST orbits the earth. Using classical techniques, Marshall Space Flight Center in conjunction with Lockheed Missiles and Space Company developed modified HST controllers that were able to suppress the influence of the vibrations of the solar arrays on the line-of-sight (LOS) performance. Substantial LOS improvement was observed when two of these controllers were implemented on orbit. This paper describes the development of modified HST controllers by using modern control techniques, particularly linear-quadratic-gaussian (LQG) design and Maximum Entropy robust control design, a generalization of LQG that incorporates robustness constraints with respect to modal errors. The fundamental issues are discussed candidly and controllers designed using these modern techniques are described.

  20. YOUNG PLANETARY NEBULAE: HUBBLE SPACE TELESCOPE IMAGING AND A NEW MORPHOLOGICAL CLASSIFICATION SYSTEM

    International Nuclear Information System (INIS)

    Sahai, Raghvendra; Villar, Gregory G.; Morris, Mark R.

    2011-01-01

    Using Hubble Space Telescope images of 119 young planetary nebulae (PNs), most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of PNs. Unlike previous classification studies, we have focused primarily on young PNs rather than all PNs, because the former best show the influences or symmetries imposed on them by the dominant physical processes operating at the first and primary stage of the shaping process. Older PNs develop instabilities, interact with the ambient interstellar medium, and are subject to the passage of photoionization fronts, all of which obscure the underlying symmetries and geometries imposed early on. Our classification system is designed to suffer minimal prejudice regarding the underlying physical causes of the different shapes and structures seen in our PN sample, however, in many cases, physical causes are readily suggested by the geometry, along with the kinematics that have been measured in some systems. Secondary characteristics in our system, such as ansae, indicate the impact of a jet upon a slower-moving, prior wind; a waist is the signature of a strong equatorial concentration of matter, whether it be outflowing or in a bound Keplerian disk, and point symmetry indicates a secular trend, presumably precession, in the orientation of the central driver of a rapid, collimated outflow.

  1. FOMALHAUT b: INDEPENDENT ANALYSIS OF THE HUBBLE SPACE TELESCOPE PUBLIC ARCHIVE DATA

    International Nuclear Information System (INIS)

    Galicher, Raphaël; Marois, Christian; Zuckerman, B.; Macintosh, Bruce

    2013-01-01

    The nature and even the existence of a putative planet-mass companion ( F omalhaut b ) to Fomalhaut has been debated since 2008. In the present paper, we reanalyze the multi-epoch ACS/STIS/WFC3 Hubble Space Telescope (HST) optical/near-infrared images on which the discovery and some other claims were based. We confirm that the HST images do reveal an object in orbit around Fomalhaut, but the detailed results from our analysis differ in some ways from previous discussions. In particular, we do not confirm flux variability over a two-year interval at 0.6 μm wavelength and we detect Fomalhaut b for the first time at the short wavelength of 0.43 μm. We find that the HST image of Fomalhaut b at 0.8 μm may be extended beyond the point-spread function. We cannot determine from our astrometry if Fomalhaut b will cross or not the dust ring. The optical through mid-infrared spectral energy distribution (SED) of Fomalhaut b cannot be explained as due to direct or scattered radiation from a massive planet. We consider two models to explain the SED: (1) a large circumplanetary disk around an unseen planet and (2) the aftermath of a collision during the past 50-150 yr of two Kuiper-Belt-like objects of radii ∼50 km.

  2. HUBBLE SPACE TELESCOPE SPECTROSCOPY OF BROWN DWARFS DISCOVERED WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Adam C.; Cushing, Michael C. [Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States); Kirkpatrick, J. Davy; Gelino, Christopher R. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Mace, Gregory N.; Wright, Edward L. [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Eisenhardt, Peter R. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Skrutskie, M. F. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Griffith, Roger L. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Marsh, Kenneth A., E-mail: Adam.Schneider@Utoledo.edu [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom)

    2015-05-10

    We present a sample of brown dwarfs identified with the Wide-field Infrared Survey Explorer (WISE) for which we have obtained Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) near-infrared grism spectroscopy. The sample (22 in total) was observed with the G141 grism covering 1.10–1.70 μm, while 15 were also observed with the G102 grism, which covers 0.90–1.10 μm. The additional wavelength coverage provided by the G102 grism allows us to (1) search for spectroscopic features predicted to emerge at low effective temperatures (e.g.,ammonia bands) and (2) construct a smooth spectral sequence across the T/Y boundary. We find no evidence of absorption due to ammonia in the G102 spectra. Six of these brown dwarfs are new discoveries, three of which are found to have spectral types of T8 or T9. The remaining three, WISE J082507.35+280548.5 (Y0.5), WISE J120604.38+840110.6 (Y0), and WISE J235402.77+024015.0 (Y1), are the 19th, 20th, and 21st spectroscopically confirmed Y dwarfs to date. We also present HST grism spectroscopy and reevaluate the spectral types of five brown dwarfs for which spectral types have been determined previously using other instruments.

  3. PANCHROMATIC HUBBLE ANDROMEDA TREASURY. XVI. STAR CLUSTER FORMATION EFFICIENCY AND THE CLUSTERED FRACTION OF YOUNG STARS

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L. Clifton; Sandstrom, Karin [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Dalcanton, Julianne J.; Beerman, Lori C.; Lewis, Alexia R.; Weisz, Daniel R.; Williams, Benjamin F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Fouesneau, Morgan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Bell, Eric F. [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Larsen, Søren S. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Skillman, Evan D., E-mail: lcj@ucsd.edu [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2016-08-10

    We use the Panchromatic Hubble Andromeda Treasury survey data set to perform spatially resolved measurements of star cluster formation efficiency (Γ), the fraction of stellar mass formed in long-lived star clusters. We use robust star formation history and cluster parameter constraints, obtained through color–magnitude diagram analysis of resolved stellar populations, to study Andromeda’s cluster and field populations over the last ∼300 Myr. We measure Γ of 4%–8% for young, 10–100 Myr-old populations in M31. We find that cluster formation efficiency varies systematically across the M31 disk, consistent with variations in mid-plane pressure. These Γ measurements expand the range of well-studied galactic environments, providing precise constraints in an H i-dominated, low-intensity star formation environment. Spatially resolved results from M31 are broadly consistent with previous trends observed on galaxy-integrated scales, where Γ increases with increasing star formation rate surface density (Σ{sub SFR}). However, we can explain observed scatter in the relation and attain better agreement between observations and theoretical models if we account for environmental variations in gas depletion time ( τ {sub dep}) when modeling Γ, accounting for the qualitative shift in star formation behavior when transitioning from a H{sub 2}-dominated to a H i-dominated interstellar medium. We also demonstrate that Γ measurements in high Σ{sub SFR} starburst systems are well-explained by τ {sub dep}-dependent fiducial Γ models.

  4. THE PECULIAR EXTINCTION LAW OF SN 2014J MEASURED WITH THE HUBBLE SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Amanullah, R.; Goobar, A.; Johansson, J.; Petrushevska, T. [Oskar Klein Centre, Physics Department, Stockholm University, SE-106 91 Stockholm (Sweden); Banerjee, D. P. K.; Venkataraman, V.; Joshi, V.; Ashok, N. M. [Physical Research Laboratory, Ahmedabad 380009 (India); Cao, Y.; Kulkarni, S. R. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Kasliwal, M. M. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Nugent, P. E. [Department of Astronomy, University of California Berkeley, B-20 Hearst Field, Annex # 3411, Berkeley, CA 94720-3411 (United States); Stanishev, V., E-mail: rahman@fysik.su.se [CENTRA—Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal)

    2014-06-20

    The wavelength dependence of the extinction of Type Ia SN 2014J in the nearby galaxy M82 has been measured using UV to near-IR photometry obtained with the Hubble Space Telescope, the Nordic Optical Telescope, and the Mount Abu Infrared Telescope. This is the first time that the reddening of an SN Ia is characterized over the full wavelength range of 0.2-2 μm. A total-to-selective extinction, R{sub V} ≥ 3.1, is ruled out with high significance. The best fit at maximum using a Galactic type extinction law yields R{sub V} = 1.4 ± 0.1. The observed reddening of SN 2014J is also compatible with a power-law extinction, A {sub λ}/A{sub V} = (λ/λ {sub V}) {sup p} as expected from multiple scattering of light, with p = –2.1 ± 0.1. After correcting for differences in reddening, SN 2014J appears to be very similar to SN 2011fe over the 14 broadband filter light curves used in our study.

  5. Karl Schwarzschild Lecture: The Ups and Downs of the Hubble Constant (With 12 Figures)

    Science.gov (United States)

    Tammann, G. Andreas

    2006-01-01

    A brief history of the determination of the Hubble constant H_0 is given. Early attempts following Lemaitre (1927) gave much too high values due to errors of the magnitude scale, Malmquist bias and calibration problems. By 1962 most authors agreed that 75< H_0 <130. After 1975 a dichotomy arose with values near 100 and others around 55. The former came from apparent-magnitude-limited samples and were affected by Malmquist bias. New distance indicators were introduced; they were sometimes claimed to yield high values of H_0, but the most recent data lead to H_0 in the 60's, yet with remaining difficulties as to the zero-point of the respective distance indicators. SNe Ia with their large range and very small luminosity dispersion (avoiding Malmquist bias) offer a unique opportunity to determine the large-scale value of H_0. Their maximum luminosity can be well calibrated from 10 SNe Ia in local parent galaxies whose Cepheids have been observed with HST. An unforeseen difficulty - affecting all Cepheid distances - is that their P-L relation varies from galaxy to galaxy, presumably in function of metallicity. A proposed solution is summarized here. The conclusion is that H_0 = 63.2 +/- 1.3 (random) +/- 5.3 (systematic) on all scales. The expansion age becomes then (with Omega_m=0.3, Omega_Lambda=0.7) 15.1 Gyr.

  6. DISENTANGLING AGN AND STAR FORMATION ACTIVITY AT HIGH REDSHIFT USING HUBBLE SPACE TELESCOPE GRISM SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Bridge, Joanna S.; Zeimann, Gregory R.; Trump, Jonathan R.; Gronwall, Caryl; Ciardullo, Robin; Fox, Derek; Schneider, Donald P., E-mail: jsbridge@psu.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2016-08-01

    Differentiating between active galactic nucleus (AGN) activity and star formation in z ∼ 2 galaxies is difficult because traditional methods, such as line-ratio diagnostics, change with redshift, while multi-wavelength methods (X-ray, radio, IR) are sensitive to only the brightest AGNs. We have developed a new method for spatially resolving emission lines using the Hubble Space Telescope /Wide Field Camera 3 G141 grism spectra and quantifying AGN activity through the spatial gradient of the [O iii]/H β line ratio. Through detailed simulations, we show that our novel line-ratio gradient approach identifies ∼40% more low-mass and obscured AGNs than obtained by classical methods. Based on our simulations, we developed a relationship that maps the stellar mass, star formation rate, and measured [O iii]/H β gradient to the AGN Eddington ratio. We apply our technique to previously studied stacked samples of galaxies at z ∼ 2 and find that our results are consistent with these studies. This gradient method will also be able to inform other areas of galaxy evolution science, such as inside-out quenching and metallicity gradients, and will be widely applicable to future spatially resolved James Webb Space Telescope data.

  7. HUBBLE SPACE TELESCOPE EMISSION-LINE GALAXIES AT z ∼ 2: THE MYSTERY OF NEON

    Energy Technology Data Exchange (ETDEWEB)

    Zeimann, Gregory R.; Ciardullo, Robin; Gebhardt, Henry; Gronwall, Caryl; Hagen, Alex; Trump, Jonathan R.; Bridge, Joanna S.; Luo, Bin; Schneider, Donald P., E-mail: grzeimann@psu.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2015-01-01

    We use near-infrared grism spectroscopy from the Hubble Space Telescope to examine the strength of [Ne III] λ3869 relative to Hβ, [O II] λ3727, and [O III] λ5007 in 236 low-mass (7.5 ≲ log (M {sub *}/M {sub ☉}) ≲ 10.5) star-forming galaxies in the redshift range 1.90 < z < 2.35. By stacking the data by stellar mass, we show that the [Ne III]/[O II] ratios of the z ∼ 2 universe are marginally higher than those seen in a comparable set of local Sloan Digital Sky Survey galaxies, and that [Ne III]/[O III] is enhanced by ∼0.2 dex. We consider the possible explanations for this ∼4σ result, including higher oxygen depletion out of the gas phase, denser H II regions, higher production of {sup 22}Ne via Wolf-Rayet stars, and the existence of a larger population of X-ray obscured active galactic nuclei at z ∼ 2 compared to z ∼ 0. None of these simple scenarios, alone, are favored to explain the observed line ratios. We conclude by suggesting several avenues of future observations to further explore the mystery of enhanced [Ne III] emission.

  8. THE GHOSTS SURVEY. I. HUBBLE SPACE TELESCOPE ADVANCED CAMERA FOR SURVEYS DATA

    International Nuclear Information System (INIS)

    Radburn-Smith, D. J.; Dalcanton, J. J.; De Jong, R. S.; Streich, D.; Vlajic, M.; Seth, A. C.; Bailin, J.; Bell, E. F.; Brown, T. M.; Ferguson, H. C.; Goudfrooij, P.; Holfeltz, S.; Bullock, J. S.; Courteau, S.; Sick, J.; Holwerda, B. W.; Purcell, C.; Zucker, D. B.

    2011-01-01

    We present an overview of the GHOSTS survey, the largest study to date of the resolved stellar populations in the outskirts of disk galaxies. The sample consists of 14 disk galaxies within 17 Mpc, whose outer disks and halos are imaged with the Hubble Space Telescope Advanced Camera for Surveys (ACS). In the first paper of this series, we describe the sample, explore the benefits of using resolved stellar populations, and discuss our ACS F606W and F814W photometry. We use artificial star tests to assess completeness and use overlapping regions to estimate photometric uncertainties. The median depth of the survey at 50% completeness is 2.7 mag below the tip of the red giant branch (TRGB). We comprehensively explore and parameterize contamination from unresolved background galaxies and foreground stars using archival fields of high-redshift ACS observations. Left uncorrected, these would account for 10 0.65xF814W-19.0 detections per mag per arcsec 2 . We therefore identify several selection criteria that typically remove 95% of the contaminants. Even with these culls, background galaxies are a significant limitation to the surface brightness detection limit which, for this survey, is typically V ∼ 30 mag arcsec -2 . The resulting photometric catalogs are publicly available and contain some 3.1 million stars across 76 ACS fields, predominantly of low extinction. The uniform magnitudes of TRGB stars in these fields enable galaxy distance estimates with 2%-7% accuracy.

  9. Hubble Space Telescope Imaging of the Mass-losing Supergiant VY Canis Majoris

    Science.gov (United States)

    Kastner, Joel H.; Weintraub, David A.

    1998-04-01

    The highly luminous M supergiant VY CMa is a massive star that appears to be in its final death throes, losing mass at high rate en route to exploding as a supernova. Subarcsecond-resolution optical images of VY CMa, obtained with the Faint Object Camera (FOC) aboard the Hubble Space Telescope, vividly demonstrate that mass loss from VY CMa is highly anisotropic. In the FOC images, the optical ``star'' VY CMa constitutes the bright, well-resolved core of an elongated reflection nebula. The imaged nebula is ~3" (~4500 AU) in extent and is clumpy and highly asymmetric. The images indicate that the bright core, which lies near one edge of the nebula, is pure scattered starlight. We conclude that at optical wavelengths VY CMa is obscured from view along our line of sight by its own dusty envelope. The presence of the extended reflection nebula then suggests that this envelope is highly flattened and/or that the star is surrounded by a massive circumstellar disk. Such axisymmetric circumstellar density structure should have profound effects on post-red supergiant mass loss from VY CMa and, ultimately, on the shaping of the remnant of the supernova that will terminate its post-main-sequence evolution.

  10. Isochrone Fitting of Hubble Photometry in UV–VIS–IR Bands

    Science.gov (United States)

    Barker, Hallie; Paust, Nathaniel E. Q.

    2018-03-01

    We present new isochrone fits to color–magnitude diagrams from Hubble Space Telescope Wide Field Camera 3 and Advanced Camera for Surveys photometry of the globular clusters M13 and M80 in five bands from the ultraviolet to near-infrared. Isochrone fits to the photometry using the Dartmouth Stellar Evolution Program (DSEP), the PAdova and TRieste Stellar Evolution Code (PARSEC), and MESA Isochrones and Stellar Tracks (MIST) are examined to study the isochrone morphology. Additionally, cluster ages, extinctions, and distances are found from the visible-infrared color–magnitude diagrams. We conduct careful qualitative analysis on the inconsistencies of the fits across twelve color combinations of the five observed bands, and find that the (F606W‑F814W) color generally produces very good fits, but that there are large discrepancies when the data is fit using colors including UV bands for all three models. We also find that the best fits in the UV are achieved using MIST isochrones, but that they require metallicities that are lower than the other two models, as well published spectroscopic values. Finally, we directly compare DSEP and PARSEC by performing isochrone-isochrone fitting, and find that, for globular cluster aged populations, similar appearing PARSEC isochrones are on average 1.5 Gyr younger than DSEP isochrones. We find that the two models become less discrepant at lower metallicities.

  11. The Carnegie Hubble Program: The Infrared Leavitt Law in IC 1613

    Science.gov (United States)

    Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andrew J.; Persson, S. E.; Seibert, Mark; Rigby, Jane R.; Melbourne, Jason

    2013-01-01

    We have observed the dwarf galaxy IC 1613 at multiple epochs in the midinfrared using Spitzer and the in the near-infrared using the new FourStar near-IR camera on Magellan. We have constructed Cepheid period luminosity relations in the J, H, Ks, [3.6] and [4.5] bands and have used the run of their apparent distance moduli as a function of wavelength to derive the line of sight reddening and distance to IC 1613. Using a nineband fit, we find E(BV ) = 0.050.01 mag and an extinction corrected distance modulus of 0 = 24.29 0.03statistical 0.03systematic mag. By comparing our multiband and [3.6] distance moduli to results from the tip of the red giant branch and red clump distance indicators, we find that metallicity has no measurable effect on Cepheid distances at 3.6 m in the metallicity range 1.0 [Fe/H] 0.2, hence derivations of the Hubble constant at this wavelength require no correction for metallicity.

  12. SOLAR-LIKE OSCILLATIONS IN A METAL-POOR GLOBULAR CLUSTER WITH THE HUBBLE SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Stello, Dennis; Gilliland, Ronald L.

    2009-01-01

    We present analyses of variability in the red giant stars in the metal-poor globular cluster NGC 6397, based on data obtained with the Hubble Space Telescope. We use a nonstandard data reduction approach to turn a 23 day observing run originally aimed at imaging the white dwarf population, into time-series photometry of the cluster's highly saturated red giant stars. With this technique we obtain noise levels in the final power spectra down to 50 parts per million, which allows us to search for low-amplitude solar-like oscillations. We compare the observed excess power seen in the power spectra with estimates of the typical frequency range, frequency spacing, and amplitude from scaling the solar oscillations. We see evidence that the detected variability is consistent with solar-like oscillations in at least one and perhaps up to four stars. With metallicities 2 orders of magnitude lower than those of the Sun, these stars present so far the best evidence of solar-like oscillations in such a low-metallicity environment.

  13. Bayesian `hyper-parameters' approach to joint estimation: the Hubble constant from CMB measurements

    Science.gov (United States)

    Lahav, O.; Bridle, S. L.; Hobson, M. P.; Lasenby, A. N.; Sodré, L.

    2000-07-01

    Recently several studies have jointly analysed data from different cosmological probes with the motivation of estimating cosmological parameters. Here we generalize this procedure to allow freedom in the relative weights of various probes. This is done by including in the joint χ2 function a set of `hyper-parameters', which are dealt with using Bayesian considerations. The resulting algorithm, which assumes uniform priors on the log of the hyper-parameters, is very simple: instead of minimizing \\sum \\chi_j2 (where \\chi_j2 is per data set j) we propose to minimize \\sum Nj (\\chi_j2) (where Nj is the number of data points per data set j). We illustrate the method by estimating the Hubble constant H0 from different sets of recent cosmic microwave background (CMB) experiments (including Saskatoon, Python V, MSAM1, TOCO and Boomerang). The approach can be generalized for combinations of cosmic probes, and for other priors on the hyper-parameters.

  14. HUBBLE SPACE TELESCOPE OBSERVATIONS OF MAIN-BELT COMET (596) SCHEILA

    International Nuclear Information System (INIS)

    Jewitt, David; Weaver, Harold; Mutchler, Max; Larson, Stephen; Agarwal, Jessica

    2011-01-01

    We present Hubble Space Telescope Observations of (596) Scheila during its recent dust outburst. The nucleus remained point-like with absolute magnitude H V = 8.85 ± 0.02 in our data, equal to the pre-outburst value, with no secondary fragments of diameter ≥100 m (for assumed albedos 0.04). We find a coma having a peak scattering cross section ∼2.2x10 4 km 2 , corresponding to a mass in micron-sized particles of ∼4x10 7 kg. The particles are deflected by solar radiation pressure on projected spatial scales ∼2x10 4 km, in the sunward direction, and swept from the vicinity of the nucleus on timescales of weeks. The coma fades by ∼30% between observations on UT 2010 December 27 and 2011 January 4. The observed mass loss is inconsistent with an origin either by rotational instability of the nucleus or by electrostatic ejection of regolith charged by sunlight. Dust ejection could be caused by the sudden but unexplained exposure of buried ice. However, the data are most simply explained by the impact, at ∼5 km s -1 , of a previously unknown asteroid ∼35 m in diameter.

  15. Discovery of an Unusual Optical Transient with the Hubble Space Telescope

    Energy Technology Data Exchange (ETDEWEB)

    The Supernova Cosmology Project; Barbary, Kyle; Dawson, Kyle S.; Tokita, Kouichi; Aldering, Greg; Amanullah, Rahman; Connolly, Natalia V.; Doi, Mamoru; Faccioli, Lorenzo; Fadeyev, Vitaliy; Fruchter, Andrew S.; Goldhaber, Gerson; Goobar, Ariel; Gude, Alexander; Huang, Xiaosheng; Ihara, Yutaka; Konishi, Kohki; Kowalski, Marek; Lidman, Chris; Meyers, Josh; Morokuma, Tomoki; Nugent, Peter; Perlmutter, Saul; Rubin, David; Schlegel, David; Spadafora, Anthony L.; Suzuki, Nao; Swift, Hannah K.; Takanashi, Naohiro; Thomas, Rollin C.; Yasuda, Naoki

    2008-09-08

    We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~;;100 days, reached a peak magnitude of ~;;21.0 in both i_775 and z_850, and then declined over a similar timescale. There is no host galaxy or progenitor star detected at the location of the transient to a 3 sigma upper limit of i_775 = 26.4 and z_850 = 26.1, giving a corresponding lower limit on the flux increase of a factor of ~;;120. Multiple spectra show five broad absorption bands between 4100 AA and 6500 AA and a mostly featureless continuum longward of 6500 AA. The shape of the lightcurve is inconsistent with microlensing. The transient's spectrum, in addition to being inconsistent with all known supernova types, is not matched to any spectrum in the Sloan Digital Sky Survey (SDSS) database. We suggest that the transient may be one of a new class.

  16. HUBBLE SPACE TELESCOPE EMISSION-LINE GALAXIES AT z ∼ 2: THE MYSTERY OF NEON

    International Nuclear Information System (INIS)

    Zeimann, Gregory R.; Ciardullo, Robin; Gebhardt, Henry; Gronwall, Caryl; Hagen, Alex; Trump, Jonathan R.; Bridge, Joanna S.; Luo, Bin; Schneider, Donald P.

    2015-01-01

    We use near-infrared grism spectroscopy from the Hubble Space Telescope to examine the strength of [Ne III] λ3869 relative to Hβ, [O II] λ3727, and [O III] λ5007 in 236 low-mass (7.5 ≲ log (M * /M ☉ ) ≲ 10.5) star-forming galaxies in the redshift range 1.90 < z < 2.35. By stacking the data by stellar mass, we show that the [Ne III]/[O II] ratios of the z ∼ 2 universe are marginally higher than those seen in a comparable set of local Sloan Digital Sky Survey galaxies, and that [Ne III]/[O III] is enhanced by ∼0.2 dex. We consider the possible explanations for this ∼4σ result, including higher oxygen depletion out of the gas phase, denser H II regions, higher production of 22 Ne via Wolf-Rayet stars, and the existence of a larger population of X-ray obscured active galactic nuclei at z ∼ 2 compared to z ∼ 0. None of these simple scenarios, alone, are favored to explain the observed line ratios. We conclude by suggesting several avenues of future observations to further explore the mystery of enhanced [Ne III] emission

  17. DISENTANGLING AGN AND STAR FORMATION ACTIVITY AT HIGH REDSHIFT USING HUBBLE SPACE TELESCOPE GRISM SPECTROSCOPY

    International Nuclear Information System (INIS)

    Bridge, Joanna S.; Zeimann, Gregory R.; Trump, Jonathan R.; Gronwall, Caryl; Ciardullo, Robin; Fox, Derek; Schneider, Donald P.

    2016-01-01

    Differentiating between active galactic nucleus (AGN) activity and star formation in z ∼ 2 galaxies is difficult because traditional methods, such as line-ratio diagnostics, change with redshift, while multi-wavelength methods (X-ray, radio, IR) are sensitive to only the brightest AGNs. We have developed a new method for spatially resolving emission lines using the Hubble Space Telescope /Wide Field Camera 3 G141 grism spectra and quantifying AGN activity through the spatial gradient of the [O iii]/H β line ratio. Through detailed simulations, we show that our novel line-ratio gradient approach identifies ∼40% more low-mass and obscured AGNs than obtained by classical methods. Based on our simulations, we developed a relationship that maps the stellar mass, star formation rate, and measured [O iii]/H β gradient to the AGN Eddington ratio. We apply our technique to previously studied stacked samples of galaxies at z ∼ 2 and find that our results are consistent with these studies. This gradient method will also be able to inform other areas of galaxy evolution science, such as inside-out quenching and metallicity gradients, and will be widely applicable to future spatially resolved James Webb Space Telescope data.

  18. A Butterfly in the Making: Revealing the Near-Infrared Structure of Hubble 12

    Science.gov (United States)

    Hora, Joseph L.; Latter, William B.

    1996-01-01

    We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at lambda = 2.12, 2.16, and 2.26 micron. The lambda = 2.12 Am image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equatorial region. The images show an elliptical region of emission, which may indicate a ring or a cylindrical source structure. This structure is possibly related to the mechanism that is producing the bipolar flow. The spectra show the nature of several distinct components. The central object is dominated by recombination lines of H I and He I. The core is not a significant source of molecular hydrogen emission. The east position in the equatorial region is rich in lines of ultraviolet-excited fluorescent H2. A spectrum of part of the central region shows strong [Fe II] emission, which might indicate the presence of shocks.

  19. Attitudes of Veterinary Teaching Staff and Exposure of Veterinary Students to Early-Age Desexing, with Review of Current Early-Age Desexing Literature

    Directory of Open Access Journals (Sweden)

    Alannah Jupe

    2017-12-01

    Full Text Available Approximately 50% of cats admitted to Australian shelters are kittens, and 26% of dogs are puppies, and, particularly for cats, euthanasia rates are often high. Cats can be pregnant by 4 months of age, yet the traditional desexing age is 5–6 months, and studies in Australasia and Nth America reveal that only a minority of veterinarians routinely perform early age desexing (EAD of cats or dogs, suggesting they are not graduating with these skills. This study aimed to describe the attitudes of veterinary teaching staff in Australian and New Zealand universities towards EAD, and to determine if these changed from 2008 to 2015. It also aimed to identify students’ practical exposure to EAD. Most (64% of the 25 participants in 2015 did not advocate EAD in their teaching and, in their personal opinion, only 32% advocated it for cats. Concerns related to EAD cited by staff included anesthetic risk, orthopedic problems, hypoglycemia, and, in female dogs, urinary incontinence. Those who advocated EAD cited benefits of population control, ease of surgery and behavioral benefits. Only three of the eight universities provided a majority of students with an opportunity to gain exposure to EAD procedures before graduation, and in two of these, most students had an opportunity to perform EAD. In conclusion, most veterinary students in Australia and New Zealand are not graduating with the knowledge or skills to perform EAD, and have little opportunity while at university to gain practical exposure. Welfare agencies could partner with universities to enable students to experience EAD.

  20. CONSTRAINING DUST AND COLOR VARIATIONS OF HIGH-z SNe USING NICMOS ON THE HUBBLE SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Nobili, S.; Amanullah, R.; Goobar, A.

    2009-01-01

    We present data from the Supernova Cosmology Project for five high redshift Type Ia supernovae (SNe Ia) that were obtained using the NICMOS infrared camera on the Hubble Space Telescope. We add two SNe from this sample to a rest-frame I-band Hubble diagram, doubling the number of high redshift supernovae on this diagram. This I-band Hubble diagram is consistent with a flat universe (Ω M , Ω Λ ) = (0.29, 0.71). A homogeneous distribution of large grain dust in the intergalactic medium (replenishing dust) is incompatible with the data and is excluded at the 5σ confidence level, if the SN host galaxy reddening is corrected assuming R V = 1.75. We use both optical and infrared observations to compare photometric properties of distant SNe Ia with those of nearby objects. We find generally good agreement with the expected color evolution for all SNe except the highest redshift SN in our sample (SN 1997ek at z = 0.863) which shows a peculiar color behavior. We also present spectra obtained from ground-based telescopes for type identification and determination of redshift.

  1. Weak currents

    International Nuclear Information System (INIS)

    Leite Lopes, J.

    1976-01-01

    A survey of the fundamental ideas on weak currents such as CVC and PCAC and a presentation of the Cabibbo current and the neutral weak currents according to the Salam-Weinberg model and the Glashow-Iliopoulos-Miami model are given [fr

  2. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2012-01-01

    In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.

  3. Images From Hubbles's ACS Tell A Tale Of Two Record-Breaking Galaxy Clusters

    Science.gov (United States)

    2004-01-01

    Looking back in time nearly 9 billion years, an international team of astronomers found mature galaxies in a young universe. The galaxies are members of a cluster of galaxies that existed when the universe was only 5 billion years old, or about 35 percent of its present age. This compelling evidence that galaxies must have started forming just after the big bang was bolstered by observations made by the same team of astronomers when they peered even farther back in time. The team found embryonic galaxies a mere 1.5 billion years after the birth of the cosmos, or 10 percent of the universe's present age. The "baby galaxies" reside in a still-developing cluster, the most distant proto-cluster ever found. The Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope was used to make observations of the massive cluster, RDCS 1252.9-2927, and the proto-cluster, TN J1338-1942. Observations by NASA's Chandra X-ray Observatory yielded the mass and heavy element content of RDCS 1252, the most massive known cluster for that epoch. These observations are part of a coordinated effort by the ACS science team to track the formation and evolution of clusters of galaxies over a broad range of cosmic time. The ACS was built especially for studies of such distant objects. These findings further support observations and theories that galaxies formed relatively early in the history of the cosmos. The existence of such massive clusters in the early universe agrees with a cosmological model wherein clusters form from the merger of many sub-clusters in a universe dominated by cold dark matter. The precise nature of cold dark matter, however, is still not known. The first Hubble study estimated that galaxies in RDCS 1252 formed the bulk of their stars more than 11 billion years ago (at redshifts greater than 3). The results were published in the Oct. 20, 2003 issue of the Astrophysical Journal. The paper's lead author is John Blakeslee of the Johns Hopkins University in

  4. 大学生饮酒及限酒策略现状%Current situation of college students' drinking and alcohol limit strategies

    Institute of Scientific and Technical Information of China (English)

    谯燕群; 李均; 许小明; 张成剑

    2017-01-01

    饮酒在各大高校比较盛行,为了大学生身体素质的提高和健康形象的提升,减少或避免酒精带来的不良影响,大学生限酒很有必要.目前已采取几项限酒策略,这些限酒策略已取得不错的效果,但仍有比较高的饮酒率,还需采取更多的策略来降低其使用率,最终减少对人类健康的危害.本文从大学生饮酒的流行状况及国内外针对大学生饮酒所采取的措施进行综述.%Drinking is popular in colleges.In order to improve college students' physical quality and healthy image,reduce or avoid the adverse effects of alcohol,it is very necessary to limit alcohol in campuses.Several alcohol limit strategies have been adopted at present and have made good effects,but there is still a relatively high rate of alcohol consumption.More strategies are needed to decline the consumption rate and ultimately reduce the risk to human health.This review discusses the prevalence of drinking alcohol among college students and alcohol limit measures at home and abroad.

  5. The evolution of C/O in dwarf galaxies from Hubble Space Telescope FOS observations

    Science.gov (United States)

    Garnett, D. R.; Skillman, E. D.; Dufour, R. J.; Peimbert, M.; Torres-Peimbert, S.; Terlevich, R.; Terlevich, E.; Shields, G. A.

    1995-01-01

    We present UV observations of seven H II regions in low-luminosity dwarf irregular galaxies and the Magellanic Clouds obtained with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) in order to measure the C/O abundance ratio in the interstellar medium (ISM) of those galaxies. We measure both O III 1666 A and C III 1909 A in our spectra, enabling us to determine C(+2)/O(+2) with relatively small uncertainties. The results from our HST observations show a continuous increase in C/O with increasing O/H, consistent with a power law having an index of 0.43 +/- 0.09 over the range -4.7 to -3.6 in log (O/H). One possible interpretation of this trend is that the most metal-poor galaxies are the youngest and dominated by the products of early enrichment by massive stars, while more metal-rich galaxies show increasing, delayed contributions of carbon from intermediate-mass stars. Our results also suggest that it may not be appropiate to combine abundances in irregular galaxies with those in spiral galaxies to study the evolution of chemical abundances. Our measured C/O ratios in the most metal-poor galaxies are consistent with predictions of nucleosynthesis from massive stars for Weaver & Woosley's best estimate for the 12C(alpha, gamma) 16O nuclear reaction rate, assuming negligible contanmination from carbon produced in intermediate-mass stars in these galaxies. We detect a weak N III 1750 A multiplet in SMC N88A and obtain interesting upper limits for two other objects. Our 2 sigma uppr limits on the 1750 A feature indicate that the N(+2)/O(+2) ratios in these objects are not significantly larger than the N(+)/O(+) ratios measured from optical spectra. This behavior is consistent with predictions of photionization models, although better detections of N III are needed to confirm the results.

  6. Young Galaxy Candidates in the Hubble Frontier Fields. III. MACS J0717.5+3745

    Science.gov (United States)

    Laporte, N.; Infante, L.; Troncoso Iribarren, P.; Zheng, W.; Molino, A.; Bauer, F. E.; Bina, D.; Broadhurst, Tom; Chilingarian, I.; Huang, X.; Garcia, S.; Kim, S.; Marques-Chaves, R.; Moustakas, J.; Pelló, R.; Pérez-Fournon, I.; Shu, X.; Streblyanska, A.; Zitrin, A.

    2016-04-01

    In this paper we present the results of our search for and study of z≳ 6 galaxy candidates behind the third Frontier Fields (FFs) cluster, MACS J0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman break technique, for which the clear non-detection in optical make the extreme mid-z interlopers hypothesis unlikely. We also take benefit from z≳ 6 samples selected using the previous FF data sets of Abell 2744 and MACS 0416 to improve the constraints on the properties of very high redshift objects. We compute the redshift and the physical properties such emission lines properties, star formation rate, reddening, and stellar mass for all FF objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV luminosity function with redshift seems more compatible with an evolution of density. Moreover, no robust z≥slant 8.5 object is selected behind the cluster field and few z˜ 9 candidates have been selected in the two previous data sets from this legacy survey, suggesting a strong evolution in the number density of galaxies between z˜ 8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L > 0.03 {L}\\star , and confirm the strong decrease observed between z˜ 8 and 9.

  7. Hubble Tarantula Treasury Project - VI. Identification of Pre-Main-Sequence Stars using Machine Learning techniques

    Science.gov (United States)

    Ksoll, Victor F.; Gouliermis, Dimitrios A.; Klessen, Ralf S.; Grebel, Eva K.; Sabbi, Elena; Anderson, Jay; Lennon, Daniel J.; Cignoni, Michele; de Marchi, Guido; Smith, Linda J.; Tosi, Monica; van der Marel, Roeland P.

    2018-05-01

    The Hubble Tarantula Treasury Project (HTTP) has provided an unprecedented photometric coverage of the entire star-burst region of 30 Doradus down to the half Solar mass limit. We use the deep stellar catalogue of HTTP to identify all the pre-main-sequence (PMS) stars of the region, i.e., stars that have not started their lives on the main-sequence yet. The photometric distinction of these stars from the more evolved populations is not a trivial task due to several factors that alter their colour-magnitude diagram positions. The identification of PMS stars requires, thus, sophisticated statistical methods. We employ Machine Learning Classification techniques on the HTTP survey of more than 800,000 sources to identify the PMS stellar content of the observed field. Our methodology consists of 1) carefully selecting the most probable low-mass PMS stellar population of the star-forming cluster NGC2070, 2) using this sample to train classification algorithms to build a predictive model for PMS stars, and 3) applying this model in order to identify the most probable PMS content across the entire Tarantula Nebula. We employ Decision Tree, Random Forest and Support Vector Machine classifiers to categorise the stars as PMS and Non-PMS. The Random Forest and Support Vector Machine provided the most accurate models, predicting about 20,000 sources with a candidateship probability higher than 50 percent, and almost 10,000 PMS candidates with a probability higher than 95 percent. This is the richest and most accurate photometric catalogue of extragalactic PMS candidates across the extent of a whole star-forming complex.

  8. Lyman Break Galaxies in the Hubble Ultra Deep Field through Deep U-Band Imaging

    Science.gov (United States)

    Rafelski, Marc; Wolfe, A. M.; Cooke, J.; Chen, H. W.; Armandroff, T. E.; Wirth, G. D.

    2009-12-01

    We introduce an extremely deep U-band image taken of the Hubble Ultra Deep Field (HUDF), with a one sigma depth of 30.7 mag arcsec-2 and a detection limiting magnitude of 28 mag arcsec-2. The observations were carried out on the Keck I telescope using the LRIS-B detector. The U-band image substantially improves the accuracy of photometric redshift measurements of faint galaxies in the HUDF at z=[2.5,3.5]. The U-band for these galaxies is attenuated by lyman limit absorption, allowing for more reliable selections of candidate Lyman Break Galaxies (LBGs) than from photometric redshifts without U-band. We present a reliable sample of 300 LBGs at z=[2.5,3.5] in the HUDF. Accurate redshifts of faint galaxies at z=[2.5,3.5] are needed to obtain empirical constraints on the star formation efficiency of neutral gas at high redshift. Wolfe & Chen (2006) showed that the star formation rate (SFR) density in damped Ly-alpha absorption systems (DLAs) at z=[2.5,3.5] is significantly lower than predicted by the Kennicutt-Schmidt law for nearby galaxies. One caveat to this result that we wish to test is whether LBGs are embedded in DLAs. If in-situ star formation is occurring in DLAs, we would see it as extended low surface brightness emission around LBGs. We shall use the more accurate photometric redshifts to create a sample of LBGs around which we will look for extended emission in the more sensitive and higher resolution HUDF images. The absence of extended emission would put limits on the SFR density of DLAs associated with LBGs at high redshift. On the other hand, detection of faint emission on scales large compared to the bright LBG cores would indicate the presence of in situ star formation in those DLAs. Such gas would presumably fuel the higher star formation rates present in the LBG cores.

  9. Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder

    Science.gov (United States)

    Feeney, Stephen M.; Mortlock, Daniel J.; Dalmasso, Niccolò

    2018-05-01

    Estimates of the Hubble constant, H0, from the local distance ladder and from the cosmic microwave background (CMB) are discrepant at the ˜3σ level, indicating a potential issue with the standard Λ cold dark matter (ΛCDM) cosmology. A probabilistic (i.e. Bayesian) interpretation of this tension requires a model comparison calculation, which in turn depends strongly on the tails of the H0 likelihoods. Evaluating the tails of the local H0 likelihood requires the use of non-Gaussian distributions to faithfully represent anchor likelihoods and outliers, and simultaneous fitting of the complete distance-ladder data set to ensure correct uncertainty propagation. We have hence developed a Bayesian hierarchical model of the full distance ladder that does not rely on Gaussian distributions and allows outliers to be modelled without arbitrary data cuts. Marginalizing over the full ˜3000-parameter joint posterior distribution, we find H0 = (72.72 ± 1.67) km s-1 Mpc-1 when applied to the outlier-cleaned Riess et al. data, and (73.15 ± 1.78) km s-1 Mpc-1 with supernova outliers reintroduced (the pre-cut Cepheid data set is not available). Using our precise evaluation of the tails of the H0 likelihood, we apply Bayesian model comparison to assess the evidence for deviation from ΛCDM given the distance-ladder and CMB data. The odds against ΛCDM are at worst ˜10:1 when considering the Planck 2015 XIII data, regardless of outlier treatment, considerably less dramatic than naïvely implied by the 2.8σ discrepancy. These odds become ˜60:1 when an approximation to the more-discrepant Planck Intermediate XLVI likelihood is included.

  10. HUBBLE SPACE TELESCOPE AND GROUND-BASED OBSERVATIONS OF V455 ANDROMEDAE POST-OUTBURST

    Energy Technology Data Exchange (ETDEWEB)

    Szkody, Paula; Mukadam, Anjum S.; Brown, Justin; Funkhouser, Kelsey [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Gänsicke, Boris T. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Henden, Arne [AAVSO, 49 Bay State Road, Cambridge, MA 02138 (United States); Sion, Edward M. [Department of Astronomy and Astrophysics, Villanova University, Villanova, PA 19085 (United States); Townsley, Dean M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Christian, Damian [Department of Physics and Astronomy, California State University, Northridge, CA 91330 (United States); Falcon, Ross E. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Pyrzas, Stylianos, E-mail: szkody@astro.washington.edu, E-mail: anjum@astro.washington.edu, E-mail: boris.gaensicke@warwick.ac.uk, E-mail: arne@aavso.org, E-mail: edward.sion@villanova.edu, E-mail: Dean.M.Townsley@ua.edu, E-mail: damian.christian@csun.edu, E-mail: cylver@astro.as.utexas.edu, E-mail: stylianos.pyrzas@gmail.com [Instituto de Astronomia, Universidad Catolica del Norte, Avenida Angamos 0619, Antofagasta (Chile)

    2013-09-20

    Hubble Space Telescope spectra obtained in 2010 and 2011, 3 and 4 yr after the large amplitude dwarf nova outburst of V455 And, were combined with optical photometry and spectra to study the cooling of the white dwarf, its spin, and possible pulsation periods after the outburst. The modeling of the ultraviolet (UV) spectra shows that the white dwarf temperature remains ∼600 K hotter than its quiescent value at 3 yr post-outburst, and still a few hundred degrees hotter at 4 yr post-outburst. The white dwarf spin at 67.6 s and its second harmonic at 33.8 s are visible in the optical within a month of outburst and are obvious in the later UV observations in the shortest wavelength continuum and the UV emission lines, indicating an origin in high-temperature regions near the accretion curtains. The UV light curves folded on the spin period show a double-humped modulation consistent with two-pole accretion. The optical photometry 2 yr after outburst shows a group of frequencies present at shorter periods (250-263 s) than the periods ascribed to pulsation at quiescence, and these gradually shift toward the quiescent frequencies (300-360 s) as time progresses past outburst. The most surprising result is that the frequencies near this period in the UV data are only prominent in the emission lines, not the UV continuum, implying an origin away from the white dwarf photosphere. Thus, the connection of this group of periods with non-radial pulsations of the white dwarf remains elusive.

  11. Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. V. Final Measurement for Fornax

    Science.gov (United States)

    Piatek, Slawomir; Pryor, Carlton; Bristow, Paul; Olszewski, Edward W.; Harris, Hugh C.; Mateo, Mario; Minniti, Dante; Tinney, Christopher G.

    2007-03-01

    The measured proper motion of Fornax, expressed in the equatorial coordinate system, is (μα,μδ)=(47.6+/-4.6,-36.0+/-4.1) mas century-1. This proper motion is a weighted mean of four independent measurements for three distinct fields. Each measurement uses a quasi-stellar object as a reference point. Removing the contribution of the motion of the Sun and of the local standard of rest to the measured proper motion produces a Galactic rest-frame proper motion of (μGrfα,μGrfδ)=(24.4+/-4.6,-14.3+/-4.1) mas century-1. The implied space velocity with respect to the Galactic center has a radial component of Vr=-31.8+/-1.7 km s-1 and a tangential component of Vt=196+/-29 km s-1. Integrating the motion of Fornax in a realistic potential for the Milky Way produces orbital elements. The perigalacticon and apogalacticon are 118 (66, 137) and 152 (144, 242) kpc, respectively, where the values in the parentheses represent the 95% confidence intervals derived from Monte Carlo experiments. The eccentricity of the orbit is 0.13 (0.11, 0.38), and the orbital period is 3.2 (2.5, 4.6) Gyr. The orbit is retrograde and inclined by 101° (94°, 107°) to the Galactic plane. Fornax could be a member of a proposed ``stream'' of galaxies and globular clusters; however, the membership of another proposed galaxy in the stream, Sculptor, has been previously ruled out. Fornax is in the Kroupa-Theis-Boily plane, which contains 11 of the Galactic satellite galaxies, but its orbit will take it out of that plane. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  12. HUBBLE AND KECK TELESCOPE OBSERVATIONS OF ACTIVE ASTEROID 288P/300163 (2006 VW139)

    International Nuclear Information System (INIS)

    Agarwal, Jessica; Jewitt, David; Weaver, Harold; Mutchler, Max; Larson, Stephen

    2016-01-01

    We present Hubble Space Telescope (HST) and Keck 10 m telescope observations of active asteroid 288P/300163 (2006 VW139) taken to examine ejected dust. The nucleus is a C-type object with absolute magnitude H V = 17.0 ± 0.1 and estimated diameter ∼2.6 km (for assumed visual geometric albedo p V = 0.04). Variations in the brightness of the nucleus at the 10%–15% level are significant in both 2011 December and 2012 October but we possess too few data to distinguish variations caused by activity from those caused by rotation. The dust scattering cross-section in 2011 December is ∼40 km 2 , corresponding to a dust mass ∼9 × 10 6 kg (88 μm mean particle radius assumed). The FWHM of the debris sheet varies from ∼100 km near the nucleus to ∼1000 km 30″ (40,000 km) east of it. Dust dynamical models indicate ejection speeds between 0.06 and 0.3 m s −1 , particle sizes between 10 and 300 μm and an inverse square-root relation between particle size and velocity. Overall, the data are most simply explained by prolonged, low velocity ejection of dust, starting in or before 2011 July and continuing until at least 2011 October. These properties are consistent with the sublimation of near-surface ice aided by centrifugal forces. The high spatial resolution of our HST images (52 km pixel −1 ) reveals details that remained hidden in previous ground-based observations, such as the extraordinarily small vertical extent of the dust sheet, ejection speeds well below the nucleus escape speed, and the possibility of a binary nucleus

  13. HUBBLE AND KECK TELESCOPE OBSERVATIONS OF ACTIVE ASTEROID 288P/300163 (2006 VW139)

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Jessica [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Jewitt, David [Department Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Box 951567 Los Angeles, CA 90095-1567 (United States); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Mutchler, Max [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larson, Stephen, E-mail: agarwal@mps.mpg.de [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd. Tucson AZ 85721-0092 (United States)

    2016-01-15

    We present Hubble Space Telescope (HST) and Keck 10 m telescope observations of active asteroid 288P/300163 (2006 VW139) taken to examine ejected dust. The nucleus is a C-type object with absolute magnitude H{sub V} = 17.0 ± 0.1 and estimated diameter ∼2.6 km (for assumed visual geometric albedo p{sub V} = 0.04). Variations in the brightness of the nucleus at the 10%–15% level are significant in both 2011 December and 2012 October but we possess too few data to distinguish variations caused by activity from those caused by rotation. The dust scattering cross-section in 2011 December is ∼40 km{sup 2}, corresponding to a dust mass ∼9 × 10{sup 6} kg (88 μm mean particle radius assumed). The FWHM of the debris sheet varies from ∼100 km near the nucleus to ∼1000 km 30″ (40,000 km) east of it. Dust dynamical models indicate ejection speeds between 0.06 and 0.3 m s{sup −1}, particle sizes between 10 and 300 μm and an inverse square-root relation between particle size and velocity. Overall, the data are most simply explained by prolonged, low velocity ejection of dust, starting in or before 2011 July and continuing until at least 2011 October. These properties are consistent with the sublimation of near-surface ice aided by centrifugal forces. The high spatial resolution of our HST images (52 km pixel{sup −1}) reveals details that remained hidden in previous ground-based observations, such as the extraordinarily small vertical extent of the dust sheet, ejection speeds well below the nucleus escape speed, and the possibility of a binary nucleus.

  14. ASASSN-15LH: A SUPERLUMINOUS ULTRAVIOLET REBRIGHTENING OBSERVED BY SWIFT AND HUBBLE

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Peter J.; Yang, Yi; Wang, Lifan [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Cooke, Jeff; Mould, Jeremy [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn VIC 3122 (Australia); Olaes, Melanie; Quimby, Robert M. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Baade, Dietrich [European Organisation for Astronomical Research in the Southern Hemisphere (ESO), Karl-Schwarzschild-Str. 2, D-85748 Garching b. München (Germany); Gehrels, Neil [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hoeflich, Peter [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Maund, Justyn [Department of Physics and Astronomy F39 Hicks Building, Hounsfield Road Sheffield, S3 7RH (United Kingdom); Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

    2016-09-01

    We present and discuss ultraviolet and optical photometry from the Ultraviolet/Optical Telescope, X-ray limits from the X-Ray Telescope on Swift, and imaging polarimetry and ultraviolet/optical spectroscopy with the Hubble Space Telescope , all from observations of ASASSN-15lh. It has been classified as a hydrogen-poor superluminous supernova (SLSN I), making it more luminous than any other supernova observed. ASASSN-15lh is not detected in the X-rays in individual or co-added observations. From the polarimetry we determine that the explosion was only mildly asymmetric. We find the flux of ASASSN-15lh to increase strongly into the ultraviolet, with an ultraviolet luminosity 100 times greater than the hydrogen-rich, ultraviolet-bright SLSN II SN 2008es. We find that objects as bright as ASASSN-15lh are easily detectable beyond redshifts of ∼4 with the single-visit depths planned for the Large Synoptic Survey Telescope. Deep near-infrared surveys could detect such objects past a redshift of ∼20, enabling a probe of the earliest star formation. A late rebrightening—most prominent at shorter wavelengths—is seen about two months after the peak brightness, which is itself as bright as an SLSN. The ultraviolet spectra during the rebrightening are dominated by the continuum without the broad absorption or emission lines seen in SLSNe or tidal disruption events (TDEs) and the early optical spectra of ASASSN-15lh. Our spectra show no strong hydrogen emission, showing only Ly α absorption near the redshift previously found by optical absorption lines of the presumed host. The properties of ASASSN-15lh are extreme when compared to either SLSNe or TDEs.

  15. The panchromatic Hubble Andromeda Treasury. V. Ages and masses of the year 1 stellar clusters

    International Nuclear Information System (INIS)

    Fouesneau, Morgan; Johnson, L. Clifton; Weisz, Daniel R.; Dalcanton, Julianne J.; Williams, Benjamin F.; Bell, Eric F.; Bianchi, Luciana; Caldwell, Nelson; Gouliermis, Dimitrios A.; Guhathakurta, Puragra; Kalirai, Jason; Larsen, Søren S.; Rix, Hans-Walter; Seth, Anil C.; Skillman, Evan D.

    2014-01-01

    We present ages and masses for 601 star clusters in M31 from the analysis of the six filter integrated light measurements from near-ultraviolet to near-infrared wavelengths, made as part of the Panchromatic Hubble Andromeda Treasury (PHAT). We derive the ages and masses using a probabilistic technique, which accounts for the effects of stochastic sampling of the stellar initial mass function. Tests on synthetic data show that this method, in conjunction with the exquisite sensitivity of the PHAT observations and their broad wavelength baseline, provides robust age and mass recovery for clusters ranging from ∼10 2 to 2 × 10 6 M ☉ . We find that the cluster age distribution is consistent with being uniform over the past 100 Myr, which suggests a weak effect of cluster disruption within M31. The age distribution of older (>100 Myr) clusters falls toward old ages, consistent with a power-law decline of index –1, likely from a combination of fading and disruption of the clusters. We find that the mass distribution of the whole sample can be well described by a single power law with a spectral index of –1.9 ± 0.1 over the range of 10 3 -3 × 10 5 M ☉ . However, if we subdivide the sample by galactocentric radius, we find that the age distributions remain unchanged. However, the mass spectral index varies significantly, showing best-fit values between –2.2 and –1.8, with the shallower slope in the highest star formation intensity regions. We explore the robustness of our study to potential systematics and conclude that the cluster mass function may vary with respect to environment.

  16. HUBBLE SPACE TELESCOPE NICMOS POLARIZATION OBSERVATIONS OF THREE EDGE-ON MASSIVE YOUNG STELLAR OBJECTS

    International Nuclear Information System (INIS)

    Simpson, Janet P.; Colgan, Sean W. J.; Erickson, Edwin F.; Burton, Michael G.; Cotera, Angela S.; Hines, Dean C.; Whitney, Barbara A.

    2009-01-01

    Massive young stellar objects (YSOs), like low-mass YSOs, appear to be surrounded by optically thick envelopes and/or disks and have regions, often bipolar, that are seen in polarized scattered light at near-infrared wavelengths. We are using the 0.''2 spatial resolution of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on Hubble Space Telescope to examine the structure of the disks and outflow regions of massive YSOs in star-forming regions within a few kpc of the Sun. Here we report on 2 μm polarimetry of NGC 6334 V and S255 IRS1. NGC 6334 V consists of a double-lobed bright reflection nebula seen against a dark region, probably an optically thick molecular cloud. Our polarization measurements show that the illuminating star lies ∼2'' south of the line connecting the two lobes; we do not detect this star at 2 μm, but there are a small radio source and a mid-infrared source at this location. S255 IRS1 consists of two YSOs (NIRS1 and NIRS3) with overlapping scattered light lobes and luminosities corresponding to early B stars. Included in IRS1 is a cluster of stars from whose polarization we determine the local magnetic field direction. Neither of the YSOs has its scattered light lobes aligned with this magnetic field. The line connecting the scattered light lobes of NIRS1 is twisted symmetrically around the star; the best explanation is that the star is part of a close binary and the outflow axis of NIRS1 is precessing as a result of non-coplanar disk and orbit. The star NIRS3 is also offset from the line connecting its two scattered light lobes. We suggest that all three YSOs show evidence of episodic ejection of material as they accrete from dense, optically thick envelopes.

  17. The Hubble Frontier Fields: Engaging Multiple Audiences in Exploring the Cosmic Frontier

    Science.gov (United States)

    Lawton, Brandon L.; Smith, Denise A.; Summers, Frank; Ryer, Holly; Slivinski, Carolyn; Lotz, Jennifer M.

    2017-06-01

    The Hubble Frontier Fields is a multi-cycle program of six deep-field observations of strong-lensing galaxy clusters taken in parallel with six deep “blank fields.” The three-year long collaborative program began in late 2013 and is led by observations from NASA’s Great Observatories. The observations, now complete, allow astronomers to look deeper into the universe than ever before, and potentially uncover galaxies that are as much as 100 times fainter than what the telescopes can typically observe. The Frontier Fields science program is ideal for informing audiences about scientific advances and topics in STEM. The study of galaxy properties, statistics, optics, and Einstein’s theory of general relativity naturally leverages off of the science returns of the Frontier Fields program. As a result, the Space Telescope Science Institute’s Office of Public Outreach (OPO) has engaged multiple audiences over the past three years to follow the progress of the Frontier Fields.For over two decades, the STScI outreach program has sought to bring the wonders of the universe to the public and engage audiences in the adventure of scientific discovery. In addition, we are leveraging the reach of the new NASA’s Universe of Learning education program to bring the science of the Frontier Fields to informal education audiences. The main underpinnings of the STScI outreach program and the Universe of Learning education program are scientist-educator development teams, partnerships, and an embedded program evaluation component. OPO is leveraging the infrastructure of these education and outreach programs to bring the Frontier Fields science program to the education community and the public in a cost-effective way.This talk will feature highlights over the past three years of the program. We will highlight OPO’s strategies and infrastructure that allows for the quick delivery of groundbreaking science to the education community and public.

  18. HUBBLE SPACE TELESCOPE SNAPSHOT SEARCH FOR PLANETARY NEBULAE IN GLOBULAR CLUSTERS OF THE LOCAL GROUP

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Howard E., E-mail: heb11@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2015-04-15

    Single stars in ancient globular clusters (GCs) are believed incapable of producing planetary nebulae (PNs), because their post-asymptotic-giant-branch evolutionary timescales are slower than the dissipation timescales for PNs. Nevertheless, four PNs are known in Galactic GCs. Their existence likely requires more exotic evolutionary channels, including stellar mergers and common-envelope binary interactions. I carried out a snapshot imaging search with the Hubble Space Telescope (HST) for PNs in bright Local Group GCs outside the Milky Way. I used a filter covering the 5007 Å nebular emission line of [O iii], and another one in the nearby continuum, to image 66 GCs. Inclusion of archival HST frames brought the total number of extragalactic GCs imaged at 5007 Å to 75, whose total luminosity slightly exceeds that of the entire Galactic GC system. I found no convincing PNs in these clusters, aside from one PN in a young M31 cluster misclassified as a GC, and two PNs at such large angular separations from an M31 GC that membership is doubtful. In a ground-based spectroscopic survey of 274 old GCs in M31, Jacoby et al. found three candidate PNs. My HST images of one of them suggest that the [O iii] emission actually arises from ambient interstellar medium rather than a PN; for the other two candidates, there are broadband archival UV HST images that show bright, blue point sources that are probably the PNs. In a literature search, I also identified five further PN candidates lying near old GCs in M31, for which follow-up observations are necessary to confirm their membership. The rates of incidence of PNs are similar, and small but nonzero, throughout the GCs of the Local Group.

  19. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Adamo, Angela [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schaerer, Daniel [Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse (France); Verhamme, Anne; Orlitová, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Otí-Floranes, Héctor [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M.; Pardy, Stephen [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Atek, Hakim [Laboratoire dAstrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095, CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Herenz, E. Christian, E-mail: matthew@astro.su.se [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

    2014-02-10

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f{sub esc}{sup Lyα} of 80%; such objects have not previously been reported at low-z.

  20. Accretion Disk Reverberation with Hubble Space Telescope Observations of NGC 4593: Evidence for Diffuse Continuum Lags

    Science.gov (United States)

    Cackett, Edward M.; Chiang, Chia-Ying; McHardy, Ian; Edelson, Rick; Goad, Michael R.; Horne, Keith; Korista, Kirk T.

    2018-04-01

    The Seyfert 1 galaxy NGC 4593 was monitored spectroscopically with the Hubble Space Telescope as part of a reverberation mapping campaign that also included Swift, Kepler, and ground-based photometric monitoring. During 2016 July 12–August 6, we obtained 26 spectra across a nearly continuous wavelength range of ∼1150–10000 Å. These were combined with Swift data to produce a UV/optical “lag spectrum,” which shows the interband lag relative to the Swift UVW2 band as a function of wavelength. The broad shape of the lag spectrum appears to follow the τ ∝ λ 4/3 relation seen previously in photometric interband lag measurements of other active galactic nuclei (AGNs). This shape is consistent with the standard thin disk model, but the magnitude of the lags implies a disk that is a factor of ∼3 larger than predicted, again consistent with what has been previously seen in other AGNs. In all cases these large disk sizes, which are also implied by independent gravitational microlensing of higher-mass AGNs, cannot be simply reconciled with the standard model. However, the most striking feature in this higher-resolution lag spectrum is a clear excess around the 3646 Å Balmer jump. This strongly suggests that diffuse emission from gas in the much larger broad-line region (BLR) must also contribute significantly to the interband lags. While the relative contributions of the disk and BLR cannot be uniquely determined in these initial measurements, it is clear that both will need to be considered to comprehensively model and understand AGN lag spectra.

  1. EVIDENCE FOR TYPE Ia SUPERNOVA DIVERSITY FROM ULTRAVIOLET OBSERVATIONS WITH THE HUBBLE SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaofeng [Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084 (China); Wang Lifan [Physics and Astronomy Department, Texas A and M University, College Station, TX 77843 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Baron, Eddie [Department of Physics, University of Oklahoma, Norman, OK 73019 (United States); Kromer, Markus [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching (Germany); Jack, Dennis [Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg (Germany); Zhang Tianmeng [National Astronomical Observatory of China, Chinese Academy of Sciences, Beijing 100012 (China); Aldering, Greg [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Antilogus, Pierre [Laboratoire de Physique Nucleaire des Hautes Energies, Paris (France); Arnett, W. David [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Baade, Dietrich [European Southern Observatory, 85748 Garching (Germany); Barris, Brian J. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Benetti, Stefano; Cappellaro, Enrico [Osservatorio Astronomico di Padova, 35122 Padova (Italy); Bouchet, Patrice [CEA/DSM/DAPNIA/Service d' Astrophysique, 91191 Gif-sur-Yvette Cedex (France); Burrows, Adam S. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Canal, Ramon [Department d' Astronomia i Meterorologia, Universidad de Barcelona, Barcelona 8007 (Spain); Carlberg, Raymond G. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3J3 (Canada); Di Carlo, Elisa [INAF, Osservatorio Astronomico di Teramo, 64100 Teramo (Italy); Challis, Peter J., E-mail: wang_xf@mail.tsinghua.edu.cn [Harvard/Smithsonian Center Astrophysics, Cambridge, MA 02138 (United States); and others

    2012-04-20

    We present ultraviolet (UV) spectroscopy and photometry of four Type Ia supernovae (SNe 2004dt, 2004ef, 2005M, and 2005cf) obtained with the UV prism of the Advanced Camera for Surveys on the Hubble Space Telescope. This data set provides unique spectral time series down to 2000 A. Significant diversity is seen in the near-maximum-light spectra ({approx}2000-3500 A) for this small sample. The corresponding photometric data, together with archival data from Swift Ultraviolet/Optical Telescope observations, provide further evidence of increased dispersion in the UV emission with respect to the optical. The peak luminosities measured in the uvw1/F250W filter are found to correlate with the B-band light-curve shape parameter {Delta}m{sub 15}(B), but with much larger scatter relative to the correlation in the broadband B band (e.g., {approx}0.4 mag versus {approx}0.2 mag for those with 0.8 mag < {Delta}m{sub 15}(B) < 1.7 mag). SN 2004dt is found as an outlier of this correlation (at > 3{sigma}), being brighter than normal SNe Ia such as SN 2005cf by {approx}0.9 mag and {approx}2.0 mag in the uvw1/F250W and uvm2/F220W filters, respectively. We show that different progenitor metallicity or line-expansion velocities alone cannot explain such a large discrepancy. Viewing-angle effects, such as due to an asymmetric explosion, may have a significant influence on the flux emitted in the UV region. Detailed modeling is needed to disentangle and quantify the above effects.

  2. THE CARNEGIE SUPERNOVA PROJECT: FIRST NEAR-INFRARED HUBBLE DIAGRAM TO z ∼ 0.7

    International Nuclear Information System (INIS)

    Freedman, Wendy L.; Burns, Christopher R.; Wyatt, Pamela; Persson, S. E.; Madore, Barry F.; Kelson, Daniel D.; Murphy, D. C.; Sturch, Laura; Phillips, M. M.; Contreras, Carlos; Folatelli, Gaston; Gonzalez, E. Sergio; Morrell, Nidia; Roth, Miguel; Stritzinger, Maximilian; Hamuy, Mario; Hsiao, Eric; Suntzeff, Nick B.; Astier, P.; Balland, C.

    2009-01-01

    The Carnegie Supernova Project (CSP) is designed to measure the luminosity distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set observational constraints on the dark energy contribution to the total energy content of the universe. The CSP differs from other projects to date in its goal of providing an I-band rest-frame Hubble diagram. Here, we present the first results from near-infrared observations obtained using the Magellan Baade telescope for SNe Ia with 0.1 m = 0.27 ± 0.02(statistical) and Ω DE = 0.76 ± 0.13(statistical) ± 0.09(systematic), for the matter and dark energy densities, respectively. If we parameterize the data in terms of an equation of state, w (with no time dependence), assume a flat geometry, and combine with baryon acoustic oscillations, we find that w = -1.05 ± 0.13(statistical) ± 0.09(systematic). The largest source of systematic uncertainty on w arises from uncertainties in the photometric calibration, signaling the importance of securing more accurate photometric calibrations for future supernova cosmology programs. Finally, we conclude that either the dust affecting the luminosities of SNe Ia has a different extinction law (R V = 1.8) than that in the Milky Way (where R V = 3.1), or that there is an additional intrinsic color term with luminosity for SNe Ia, independent of the decline rate. Understanding and disentangling these effects is critical for minimizing the systematic uncertainties in future SN Ia cosmology studies.

  3. A Hubble Space Telescope imaging study of four FeLoBAL quasar host galaxies

    Science.gov (United States)

    Lawther, D.; Vestergaard, M.; Fan, X.

    2018-04-01

    We study the host galaxies of four Iron Low-Ionization Broad Absorption-line Quasars (FeLoBALs), using Hubble Space Telescope imaging data, investigating the possibility that they represent a transition between an obscured active galactic nucleus (AGN) and an ordinary optical quasar. In this scenario, the FeLoBALs represent the early stage of merger-triggered accretion, in which case their host galaxies are expected to show signs of an ongoing or recent merger. Using PSF subtraction techniques, we decompose the images into host galaxy and AGN components at rest-frame ultraviolet and optical wavelengths. The ultraviolet is sensitive to young stars, while the optical probes stellar mass. In the ultraviolet we image at the BAL absorption trough wavelengths so as to decrease the contrast between the quasar and host galaxy emission. We securely detect an extended source for two of the four FeLoBALs in the rest-frame optical; a third host galaxy is marginally detected. In the rest-frame UV we detect no host emission; this constrains the level of unobscured star formation. Thus, the host galaxies have observed properties that are consistent with those of non-BAL quasars with the same nuclear luminosity, i.e. quiescent or moderately star-forming elliptical galaxies. However, we cannot exclude starbursting hosts that have the stellar UV emission obscured by modest amounts of dust reddening. Thus, our findings also allow the merger-induced young quasar scenario. For three objects, we identify possible close companion galaxies that may be gravitationally interacting with the quasar hosts.

  4. HUBBLE'S 100,000TH EXPOSURE CAPTURES IMAGE OF DISTANT QUASAR

    Science.gov (United States)

    2002-01-01

    The Hubble Space Telescope achieved its 100,000th exposure June 22 with a snapshot of a quasar that is about 9 billion light-years from Earth. The Wide Field and Planetary Camera 2 clicked this image of the quasar, the bright object in the center of the photo. The fainter object just above it is an elliptical galaxy. Although the two objects appear to be close to each other, they are actually separated by about 2 billion light-years. Located about 7 billion light-years away, the galaxy is almost directly in front of the quasar. Astronomer Charles Steidel of the California Institute of Technology in Pasadena, Calif., indirectly discovered the galaxy when he examined the quasar's light, which contained information about the galaxy's chemical composition. The reason, Steidel found, was that the galaxy was absorbing the light at certain frequencies. The astronomer is examining other background quasars to determine which kinds of galaxies absorb light at the same frequencies. Steidel also was somewhat surprised to discover that the galaxy is an elliptical, rather than a spiral. Elliptical galaxies are generally believed to contain very little gas. However, this elliptical has a gaseous 'halo' and contains no visible stars. Part of the halo is directly in front of the quasar. The bright object to the right of the quasar is a foreground star. The quasar and star are separated by billions of light-years. The quasar looks as bright as the star because it produces a tremendous amount of light from a compact source. The 'disturbed-looking' double spiral galaxy above the quasar also is in the foreground. Credit: Charles Steidel (California Institute of Technology, Pasadena, CA) and NASA. Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from ftp.stsci.edu in /pubinfo.

  5. Characterizing the Evolution of Circumstellar Systems with the Hubble Space Telescope and the Gemini Planet Imager

    Science.gov (United States)

    Wolff, Schuyler; Schuyler G. Wolff

    2018-01-01

    The study of circumstellar disks at a variety of evolutionary stages is essential to understand the physical processes leading to planet formation. The recent development of high contrast instruments designed to directly image the structures surrounding nearby stars, such as the Gemini Planet Imager (GPI) and coronagraphic data from the Hubble Space Telescope (HST) have made detailed studies of circumstellar systems possible. In my thesis work I detail the observation and characterization of three systems. GPI polarization data for the transition disk, PDS 66 shows a double ring and gap structure with a temporally variable azimuthal asymmetry. This evolved morphology could indicate shadowing from some feature in the innermost regions of the disk, a gap-clearing planet, or a localized change in the dust properties of the disk. Millimeter continuum data of the DH Tau system places limits on the dust mass that is contributing to the strong accretion signature on the wide-separation planetary mass companion, DH Tau b. The lower than expected dust mass constrains the possible formation mechanism, with core accretion followed by dynamical scattering being the most likely. Finally, I present HST scattered light observations of the flared, edge-on protoplanetary disk ESO H$\\alpha$ 569. I combine these data with a spectral energy distribution to model the key structural parameters such as the geometry (disk outer radius, vertical scale height, radial flaring profile), total mass, and dust grain properties in the disk using the radiative transfer code MCFOST. In order to conduct this work, I developed a new tool set to optimize the fitting of disk parameters using the MCMC code \\texttt{emcee} to efficiently explore the high dimensional parameter space. This approach allows us to self-consistently and simultaneously fit a wide variety of observables in order to place constraints on the physical properties of a given disk, while also rigorously assessing the uncertainties in

  6. The Hubble Space Telescope Medium Deep Survey Cluster Sample: Methodology and Data

    Science.gov (United States)

    Ostrander, E. J.; Nichol, R. C.; Ratnatunga, K. U.; Griffiths, R. E.

    1998-12-01

    We present a new, objectively selected, sample of galaxy overdensities detected in the Hubble Space Telescope Medium Deep Survey (MDS). These clusters/groups were found using an automated procedure that involved searching for statistically significant galaxy overdensities. The contrast of the clusters against the field galaxy population is increased when morphological data are used to search around bulge-dominated galaxies. In total, we present 92 overdensities above a probability threshold of 99.5%. We show, via extensive Monte Carlo simulations, that at least 60% of these overdensities are likely to be real clusters and groups and not random line-of-sight superpositions of galaxies. For each overdensity in the MDS cluster sample, we provide a richness and the average of the bulge-to-total ratio of galaxies within each system. This MDS cluster sample potentially contains some of the most distant clusters/groups ever detected, with about 25% of the overdensities having estimated redshifts z > ~0.9. We have made this sample publicly available to facilitate spectroscopic confirmation of these clusters and help more detailed studies of cluster and galaxy evolution. We also report the serendipitous discovery of a new cluster close on the sky to the rich optical cluster Cl l0016+16 at z = 0.546. This new overdensity, HST 001831+16208, may be coincident with both an X-ray source and a radio source. HST 001831+16208 is the third cluster/group discovered near to Cl 0016+16 and appears to strengthen the claims of Connolly et al. of superclustering at high redshift.

  7. Photometric and structural properties of NGC 6544: A combined VVV-Hubble space telescope study

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Roger E.; Mauro, Francesco; Geisler, Doug [Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Moni Bidin, Christian [Instituto de Astronomía, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Dotter, Aaron [Research School of Astronomy and Astrophysics, The Australian National University, Canberra ACT 2611 (Australia); Bonatto, Charles [Departamento de Astronomia, Universidade Federal de Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre 91501-970, RS (Brazil)

    2014-07-01

    We combine archival Hubble Space Telescope imaging with wide-field near-infrared photometry to study the neglected metal-poor Galactic globular cluster NGC 6544. A high spatial resolution map of differential reddening over the inner portion of the cluster is constructed, revealing variations of up to half of the total reddening, and the resulting corrected color-magnitude diagrams reveal a sparse blue horizontal branch and centrally concentrated blue straggler population, verified via relative proper motions. Using the corrected photometry to investigate the cluster distance, reddening, and age via direct comparison to well-calibrated photometry of clusters with similar metallicities, we estimate (m – M){sub 0} = 11.96, E(B – V) = 0.79, and an age coeval with M13 to within the relevant uncertainties. Although our data are insufficient to place tight constraints on the reddening law toward NGC 6544, we find no strong evidence that it is non-standard at optical or near-infrared wavelengths. We also provide near-infrared fiducial sequences extending nearly 2 mag below the cluster main sequence turnoff, generated from a statistically decontaminated sample of cluster stars. Lastly, we redetermine the cluster center and construct a radial number density profile which is well fit by an atypically flat power law with a slope of about 1.7. We discuss this result, together with a flattened main sequence luminosity function and inverted mass function, in the context of mass segregation and tidal stripping via interactions with Milky Way potential.

  8. HUBBLE SPACE TELESCOPE IMAGING OF Lyα EMISSION AT z ∼ 4.4

    International Nuclear Information System (INIS)

    Finkelstein, Steven L.; Finkelstein, Keely D.; Cohen, Seth H.; Windhorst, Rogier A.; Malhotra, Sangeeta; Rhoads, James E.; Ryan, Russell E.; Hathi, Nimish P.; McCarthy, Patrick J.; Anderson, Jay; Grogin, Norman A.; Koekemoer, Anton M.; Mutchler, Max; Bond, Howard E.; O'Connell, Robert W.; Balick, Bruce; Calzetti, Daniela; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.

    2011-01-01

    We present the highest redshift detections of resolved Lyα emission, using Hubble Space Telescope (HST)/Advanced Camera for Surveys F658N narrowband-imaging data taken in parallel with the Wide Field Camera 3 Early Release Science program in the GOODS Chandra Deep Field-South. We detect Lyα emission from three spectroscopically confirmed z = 4.4 Lyα emitting galaxies (LAEs), more than doubling the sample of LAEs with resolved Lyα emission. Comparing the light distribution between the rest-frame ultraviolet continuum and narrowband images, we investigate the escape of Lyα photons at high redshift. While our data do not support a positional offset between the Lyα and rest-frame ultraviolet (UV) continuum emission, the half-light radius in one out of the three galaxies is significantly (>1σ) larger in Lyα than in the rest-frame UV continuum. Stacking the three LAEs in both the narrowband and UV continuum images, we find that the Lyα light appears larger than the rest-frame UV at 4.2σ significance. This Lyα flux detected with HST is a factor of 4-10 less than observed in similar filters from the ground. These results together imply that the Lyα emission is not strictly confined to its indigenous star-forming regions. Rather, for at least one object the Lyα emission is more extended, with the missing HST flux possibly existing in a diffuse outer halo. This suggests that the radiative transfer of Lyα photons in high-redshift LAEs is complicated, with the interstellar-medium geometry and/or outflows playing a significant role in galaxies at these redshifts.

  9. HUBBLE SPACE TELESCOPE WFC3 EARLY RELEASE SCIENCE: EMISSION-LINE GALAXIES FROM INFRARED GRISM OBSERVATIONS

    International Nuclear Information System (INIS)

    Straughn, Amber N.; Gardner, Jonathan P.; Kuntschner, Harald; Kuemmel, Martin; Walsh, Jeremy R.; Cohen, Seth H.; Windhorst, Rogier A.; Malhotra, Sangeeta; Rhoads, James; O'Connell, Robert W.; Pirzkal, Norbert; Bond, Howard E.; Meurer, Gerhardt; McCarthy, Patrick J.; Hathi, Nimish P.; Balick, Bruce; Calzetti, Daniela; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.

    2011-01-01

    We present grism spectra of emission-line galaxies (ELGs) from 0.6 to 1.6 μm from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95 μm grism data in GOODS-South from the PEARS program, extending the wavelength coverage well past the G800L red cutoff. The Early Release Science (ERS) grism field was observed at a depth of two orbits per grism, yielding spectra of hundreds of faint objects, a subset of which is presented here. ELGs are studied via the Hα, [O III], and [O II] emission lines detected in the redshift ranges 0.2 ∼ B(F098M) ≅ 25 mag. Seventeen GOODS-South galaxies that previously only had photometric redshifts now have new grism-spectroscopic redshifts, in some cases with large corrections to the photometric redshifts (Δz ≅ 0.3-0.5). Additionally, one galaxy had no previously measured redshift but now has a secure grism-spectroscopic redshift, for a total of 18 new GOODS-South spectroscopic redshifts. The faintest source in our sample has a magnitude m AB(F098M) = 26.9 mag. The ERS grism data also reflect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample as a function of redshift, consistent with downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes and redshifts to z ∼> 2.

  10. THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. VIII. PRELIMINARY PUBLIC CATALOG RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Soto, M.; Bellini, A.; Anderson, J.; Van der Marel, R. P.; Brown, T. M. [Space Telescope Science Institute, San Martin Drive 3700, Baltimore, MD 21218 (United States); Piotto, G.; Granata, V.; Ortolani, S.; Nardiello, D. [Dipartimento di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova (Italy); Bedin, L. R. [INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT, 2611 (Australia); Cool, A. M. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); King, I. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sarajedini, A. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Cassisi, S. [Osservatorio Astronomico di Teramo, Via Mentore Maggini s.n.c., I-64100 Teramo (Italy); Aparicio, A.; Hidalgo, S., E-mail: mario.soto@uda.cl [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain)

    2017-01-01

    The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GO-13297) has been specifically designed to complement the existing F606W and F814W observations of the Advanced Camera for Surveys (ACS) Globular Cluster Survey (GO-10775) by observing the most accessible 47 of the previous survey’s 65 clusters in three WFC3/UVIS filters F275W, F336W, and F438W. The new survey also adds super-solar metallicity open cluster NGC 6791 to increase the metallicity diversity. The combined survey provides a homogeneous 5-band data set that can be used to pursue a broad range of scientific investigations. In particular, the chosen UV filters allow the identification of multiple stellar populations by targeting the regions of the spectrum that are sensitive to abundance variations in C, N, and O. In order to provide the community with uniform preliminary catalogs, we have devised an automated procedure that performs high-quality photometry on the new UV observations (along with similar observations of seven other programs in the archive). This procedure finds and measures the potential sources on each individual exposure using library point-spread functions and cross-correlates these observations with the original ACS-Survey catalog. The catalog of 57 clusters we publish here will be useful to identify stars in the different stellar populations, in particular for spectroscopic follow-up. Eventually, we will construct a more sophisticated catalog and artificial-star tests based on an optimal reduction of the UV survey data, but the catalogs presented here give the community the chance to make early use of this HST Treasury survey.

  11. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    International Nuclear Information System (INIS)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger; Adamo, Angela; Schaerer, Daniel; Verhamme, Anne; Orlitová, Ivana; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor; Cannon, John M.; Pardy, Stephen; Atek, Hakim; Kunth, Daniel; Laursen, Peter; Herenz, E. Christian

    2014-01-01

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f esc Lyα of 80%; such objects have not previously been reported at low-z.

  12. Current Implementation of and Opinions and Concerns Regarding Suicide Education for Social Work Undergraduate Students in Japan: A Cross-Sectional Study

    Science.gov (United States)

    Kodaka, Manami; Hikitsuchi, Emi; Takai, Michiko; Okada, Sumie; Watanabe, Yasue; Fukushima, Kiyoko; Yamada, Mitsuhiko; Inagaki, Masatoshi; Takeshima, Tadashi; Matsumoto, Toshihiko

    2018-01-01

    This study explored the current implementation status of and opinions and concerns regarding suicide education at schools of social work in Japan. We conducted a survey of faculty members who taught at least one of the social work subjects. About half the respondents had given a lecture of some kind on suicide, and more than 80% agreed that…

  13. Retrospective Report of Social Withdrawal during Adolescence and Current Maladjustment in Young Adulthood: Cross-Cultural Comparisons between Australian and South Korean Students

    Science.gov (United States)

    Kim, Jinkwan; Rapee, Ronald M.; Ja Oh, Kyung; Moon, Hye-Shin

    2008-01-01

    The current study investigated associations between the frequency of and motivations for social withdrawal during adolescence and emotional distresses in young adulthood. Perceived motivations for social withdrawal included unsociability, isolation, shyness, and low mood. Social withdrawal during adolescence was assessed using a retrospective…

  14. Statistics of the Hubble diagram. I. Determination of q2 and luminosity evolution with application to quasars

    International Nuclear Information System (INIS)

    Turner, E.L.

    1979-01-01

    A rank statistic version of the magnitude-redshift q 0 test is developed. It may be applied to the Hubble diagram of objects with an arbitrary and unknown luminosity function; in particular, the objects need not be ''standard candles.'' Only the single restriction that the objects' luminosity function does not vary in functional form is placed on the sources' intrinsic properties. Density and/or luminosity evolution are taken into account. Corrections for sample selection biases are incorporated into the analysis. Tests for the presence of luminosity evolution are given. Methods for determining either q 0 or the luminosity evolution when the other is a priori known are described.Application of these techniques to a sample of 119 3CR and 4C quasars leads to the following results: The radio Hubble diagram is consistent with all values of q 0 , suggesting that the quasar radio luminosity function is a featureless power law. The optical Hubble diagram indicates one of these possibilities: (1) the value of q 0 is in the range 2--32, probably near 5; (2) the value of q 0 is more reasonable and there is strong optical luminosity evolution [e.g., if q/sub o/ approx. = 0.05, then the characteristic optical luminosity scales like approx. (1 + Z)/sup 7/3/]; or (3) the data are a low-probability (< or =0.05) statistical fluctuation. The second interpretation is probably the most sensible one.Generalizations of the rank statistic magnitude-redshift test are suggested for application to a variety of extragalactic and stellar problems. Specific examples of applications to unorthodox cosmologies are given. Even for the unfavorable (very broad luminosity function) case of the optical quasar data, the rank statistic analysis is sensitive to relative variations in the distance-modulus-redshift relation as small as approx.0.4 mag for 1/2 < or = Z < or = 2

  15. Discovery of z ~ 8 Galaxies in the Hubble Ultra Deep Field from Ultra-Deep WFC3/IR Observations

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Oesch, P. A.; Stiavelli, M.; van Dokkum, P.; Trenti, M.; Magee, D.; Labbé, I.; Franx, M.; Carollo, C. M.; Gonzalez, V.

    2010-02-01

    We utilize the newly acquired, ultra-deep WFC3/IR observations over the Hubble Ultra Deep Field (HUDF) to search for star-forming galaxies at z ~ 8-8.5, only 600 million years from recombination, using a Y 105-dropout selection. The new 4.7 arcmin2 WFC3/IR observations reach to ~28.8 AB mag (5σ) in the Y 105 J 125 H 160 bands. These remarkable data reach ~1.5 AB mag deeper than the previous data over the HUDF, and now are an excellent match to the HUDF optical ACS data. For our search criteria, we use a two-color Lyman break selection technique to identify z ~ 8-8.5Y 105-dropouts. We find five likely z ~ 8-8.5 candidates. The sources have H 160-band magnitudes of ~28.3 AB mag and very blue UV-continuum slopes, with a median estimated β of lsim-2.5 (where f λ vprop λβ). This suggests that z ~ 8 galaxies are not only essentially dust free but also may have very young ages or low metallicities. The observed number of Y 105-dropout candidates is smaller than the 20 ± 6 sources expected assuming no evolution from z ~ 6, but is consistent with the five expected extrapolating the Bouwens et al. luminosity function (LF) results to z ~ 8. These results provide evidence that the evolution in the LF seen from z ~ 7 to z ~ 3 continues to z ~ 8. The remarkable improvement in the sensitivity of WFC3/IR has enabled Hubble Space Telescope to cross a threshold, revealing star-forming galaxies at z~ 8-9. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11563, 9797.

  16. Galaxy Size Evolution at High Redshift and Surface Brightness Selection Effects: Constraints from the Hubble Ultra Deep Field

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Blakeslee, J. P.; Broadhurst, T. J.; Franx, M.

    2004-08-01

    We use the exceptional depth of the Ultra Deep Field (UDF) and UDF-parallel Advanced Camera for Surveys fields to study the sizes of high-redshift (z~2-6) galaxies and address long-standing questions about possible biases in the cosmic star formation rate due to surface brightness dimming. Contrasting B-, V-, and i-dropout samples culled from the deeper data with those obtained from the shallower Great Observatories Origins Deep Survey fields, we demonstrate that the shallower data are essentially complete at bright magnitudes to z~0.4", >~3 kpc) low surface brightness galaxies are rare. A simple comparison of the half-light radii of the Hubble Deep Field-North + Hubble Deep Field-South U-dropouts with B-, V-, and i-dropouts from the UDF shows that the sizes follow a (1+z)-1.05+/-0.21 scaling toward high redshift. A more rigorous measurement compares different scalings of our U-dropout sample with the mean profiles for a set of intermediate-magnitude (26.0dropouts from the UDF. The best fit is found with a (1+z)-0.94+0.19-0.25 size scaling (for fixed luminosity). This result is then verified by repeating this experiment with different size measures, low-redshift samples, and magnitude ranges. Very similar scalings are found for all comparisons. A robust measurement of size evolution is thereby demonstrated for galaxies from z~6 to 2.5 using data from the UDF. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  17. The Carnegie-Chicago Hubble Program: Discovery of the Most Distant Ultra-faint Dwarf Galaxy in the Local Universe

    Science.gov (United States)

    Lee, Myung Gyoon; Jang, In Sung; Beaton, Rachael; Seibert, Mark; Bono, Giuseppe; Madore, Barry

    2017-02-01

    Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies, and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of a UFD, Fornax UFD1, in the outskirts of NGC 1316, a giant galaxy in the Fornax cluster. The new galaxy is located at a projected radius of 55 kpc in the south-east of NGC 1316. This UFD is found as a small group of resolved stars in the Hubble Space Telescope images of a halo field of NGC 1316, obtained as part of the Carnegie-Chicago Hubble Program. Resolved stars in this galaxy are consistent with being mostly metal-poor red giant branch (RGB) stars. Applying the tip of the RGB method to the mean magnitude of the two brightest RGB stars, we estimate the distance to this galaxy, 19.0 ± 1.3 Mpc. Fornax UFD1 is probably a member of the Fornax cluster. The color-magnitude diagram of these stars is matched by a 12 Gyr isochrone with low metallicity ([Fe/H] ≈ -2.4). Total magnitude and effective radius of Fornax UFD1 are MV ≈ -7.6 ± 0.2 mag and reff = 146 ± 9 pc, which are similar to those of Virgo UFD1 that was discovered recently in the intracluster field of Virgo by Jang & Lee. Fornax UFD1 is the most distant known UFD that is confirmed by resolved stars. This indicates that UFDs are ubiquitous and that more UFDs remain to be discovered in the Fornax cluster. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs #10505 and #13691.

  18. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  19. The Black Hole Mass-Bulge Luminosity Relationship for Active Galactic Nuclei From Reverberation Mapping and Hubble Space Telescope Imaging

    DEFF Research Database (Denmark)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.

    2009-01-01

    We investigate the relationship between black hole mass and bulge luminosity for active galactic nuclei (AGNs) with reverberation-based black hole mass measurements and bulge luminosities from two-dimensional decompositions of Hubble Space Telescope host galaxy images. We find that the slope...... of the relationship for AGNs is 0.76-0.85 with an uncertainty of ~0.1, somewhat shallower than the M BH vprop L 1.0±0.1 relationship that has been fit to nearby quiescent galaxies with dynamical black hole mass measurements. This difference is somewhat perplexing, as the AGN black hole masses include an overall...

  20. The universe in a mirror the saga of the Hubble Space Telescope and the visionaries who built it

    CERN Document Server

    Zimmerman, Robert

    2008-01-01

    The Hubble Space Telescope has produced the most stunning images of the cosmos humanity has ever seen. It has transformed our understanding of the universe around us, revealing new information about its age and evolution, the life cycle of stars, and the very existence of black holes, among other startling discoveries. But it took an amazing amount of work and perseverance to get the first space telescope up and running. The Universe in a Mirror tells the story of this telescope and the visionaries responsible for its extraordinary accomplishments. Robert Zimmerman takes readers beh

  1. Observations of the Hubble Deep Field with the Infrared Space Observatory .1. Data reduction, maps and sky coverage

    DEFF Research Database (Denmark)

    Serjeant, S.B.G.; Eaton, N.; Oliver, S.J.

    1997-01-01

    We present deep imaging at 6.7 and 15 mu m from the CAM instrument on the Infrared Space Observatory (ISO), centred on the Hubble Deep Field (HDF). These are the deepest integrations published to date at these wavelengths in any region of sky. We discuss the observational strategy and the data...... reduction. The observed source density appears to approach the CAM confusion limit at 15 mu m, and fluctuations in the 6.7-mu m sky background may be identifiable with similar spatial fluctuations in the HDF galaxy counts. ISO appears to be detecting comparable field galaxy populations to the HDF, and our...

  2. Thermally Induced Vibrations of the Hubble Space Telescope's Solar Array 3 in a Test Simulated Space Environment

    Science.gov (United States)

    Early, Derrick A.; Haile, William B.; Turczyn, Mark T.; Griffin, Thomas J. (Technical Monitor)

    2001-01-01

    NASA Goddard Space Flight Center and the European Space Agency (ESA) conducted a disturbance verification test on a flight Solar Array 3 (SA3) for the Hubble Space Telescope using the ESA Large Space Simulator (LSS) in Noordwijk, the Netherlands. The LSS cyclically illuminated the SA3 to simulate orbital temperature changes in a vacuum environment. Data acquisition systems measured signals from force transducers and accelerometers resulting from thermally induced vibrations of the SAI The LSS with its seismic mass boundary provided an excellent background environment for this test. This paper discusses the analysis performed on the measured transient SA3 responses and provides a summary of the results.

  3. HUBBLE-BUBBLE 1. A computer program for the analysis of non-equilibrium flows of water

    International Nuclear Information System (INIS)

    Mather, D.J.

    1978-02-01

    A description is given of the computer program HUBBLE-BUBBLE I which simulates the non-equilibrium flow of water and steam in a pipe. The code is designed to examine the transient flow developing in a pipe containing hot compressed water following the rupture of a retaining diaphragm. Allowance is made for an area change in the pipe. Particular attention is paid to the non-equilibrium development of vapour bubbles and to the transition from a bubble-liquid regime to a droplet-vapour regime. The mathematical and computational model is described together with a summary of the FORTRAN subroutines and listing of data input. (UK)

  4. Cosmological model-independent test of ΛCDM with two-point diagnostic by the observational Hubble parameter data

    Science.gov (United States)

    Cao, Shu-Lei; Duan, Xiao-Wei; Meng, Xiao-Lei; Zhang, Tong-Jie

    2018-04-01

    Aiming at exploring the nature of dark energy (DE), we use forty-three observational Hubble parameter data (OHD) in the redshift range 0 measurements. The binning methods turn out to be promising and considered to be robust. By applying the two-point diagnostic to the binned data, we find that although the best-fit values of Omh^2 fluctuate as the continuous redshift intervals change, on average, they are continuous with being constant within 1 σ confidence interval. Therefore, we conclude that the ΛCDM model cannot be ruled out.

  5. Results of a technical analysis of the Hubble Space Telescope nickel-cadmium and nickel-hydrogen batteries

    Science.gov (United States)

    Manzo, Michelle A.

    1991-01-01

    The Hubble Space Telescope (HST) Program Office requested the expertise of the NASA Aerospace Flight Battery Systems Steering Committee (NAFBSSC) in the conduct of an independent assessment of the HST's battery system to assist in their decision of whether to fly nickel-cadmium or nickel-hydrogen batteries on the telescope. In response, a subcommittee to the NAFBSSC was organized with membership comprised of experts with background in the nickel-cadmium/nickel-hydrogen secondary battery/power systems areas. The work and recommendations of that subcommittee are presented.

  6. Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition

    OpenAIRE

    Burgasser, Adam J.; Gagliuffi, Daniella C. Bardalez; Gizis, John E.

    2010-01-01

    We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS show opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-lig...

  7. Neutrino mass from cosmology: impact of high-accuracy measurement of the Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, Toyokazu [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Ichikawa, Kazuhide [Department of Micro Engineering, Kyoto University, Kyoto 606-8501 (Japan); Takahashi, Tomo [Department of Physics, Saga University, Saga 840-8502 (Japan); Greenhill, Lincoln, E-mail: sekiguti@icrr.u-tokyo.ac.jp, E-mail: kazuhide@me.kyoto-u.ac.jp, E-mail: tomot@cc.saga-u.ac.jp, E-mail: greenhill@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2010-03-01

    Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave background (CMB) anisotropies, the Hubble constant H{sub 0}, and the length scale for baryon acoustic oscillations (BAO) to investigate the constraint on the neutrino mass, m{sub ν}. We analyze data from multiple existing CMB studies (WMAP5, ACBAR, CBI, BOOMERANG, and QUAD), recent measurement of H{sub 0} (SHOES), with about two times lower uncertainty (5 %) than previous estimates, and recent treatments of BAO from the Sloan Digital Sky Survey (SDSS). We obtained an upper limit of m{sub ν} < 0.2eV (95 % C.L.), for a flat ΛCDM model. This is a 40 % reduction in the limit derived from previous H{sub 0} estimates and one-third lower than can be achieved with extant CMB and BAO data. We also analyze the impact of smaller uncertainty on measurements of H{sub 0} as may be anticipated in the near term, in combination with CMB data from the Planck mission, and BAO data from the SDSS/BOSS program. We demonstrate the possibility of a 5σ detection for a fiducial neutrino mass of 0.1 eV or a 95 % upper limit of 0.04 eV for a fiducial of m{sub ν} = 0 eV. These constraints are about 50 % better than those achieved without external constraint. We further investigate the impact on modeling where the dark-energy equation of state is constant but not necessarily -1, or where a non-flat universe is allowed. In these cases, the next-generation accuracies of Planck, BOSS, and 1 % measurement of H{sub 0} would all be required to obtain the limit m{sub ν} < 0.05−0.06 eV (95 % C.L.) for the fiducial of m{sub ν} = 0 eV. The independence of systematics argues for pursuit of both BAO and H{sub 0} measurements.

  8. HUBBLE SPACE TELESCOPE OBSERVATIONS OF ACTIVE ASTEROID 324P/La SAGRA

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David; Li, Jing [Department of Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States); Agarwal, Jessica [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723 (United States); Mutchler, Max [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larson, Stephen, E-mail: jewitt@ucla.edu [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Boulevard, Tucson, AZ 85721-0092 (United States)

    2016-09-01

    Hubble Space Telescope observations of active asteroid 324P/La Sagra near perihelion show continued mass loss consistent with the sublimation of near-surface ice. Isophotes of the coma measured from a vantage point below the orbital plane are best matched by steady emission of particles having a nominal size  of  a  ∼ 100 μ m. The inferred rate of mass loss, dM{sub d} / dt  ∼ 0.2 kg s{sup −1}, can be supplied by sublimation of water ice in thermal equilibrium with sunlight from an area as small as 930 m{sup 2}, corresponding to about 0.2% of the nucleus surface. Observations taken from a vantage point only 0.°6 from the orbital plane of 324P set a limit to the velocity of ejection of dust in the direction perpendicular to the plane, V {sub ⊥} < 1 m s{sup −1}. Short-term photometric variations of the near-nucleus region, if related to rotation of the underlying nucleus, rule-out periods ≤3.8 hr and suggest that rotation probably does not play a central role in driving the observed mass loss. We estimate that, in the previous orbit, 324P lost about 4 × 10{sup 7} kg in dust particles, corresponding to 6 × 10{sup −5} of the mass of a 550 m spherical nucleus of assumed density ρ  = 1000 kg m{sup −3}. If continued, mass loss at this rate would limit the lifetime of 324P to ∼1.6 × 10{sup 4} orbits (about 10{sup 5} years). To survive for the 100–400 Myr timescales corresponding to dynamical and collisional stability requires a duty cycle of 2 × 10{sup −4} ≤  f{sub d}  ≤ 8 × 10{sup −4}. Unless its time in orbit is overestimated by many orders of magnitude, 324P is revealed as a briefly active member of a vast population of otherwise dormant ice-containing asteroids.

  9. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. I. BRIGHT UV STARS IN THE BULGE OF M31

    International Nuclear Information System (INIS)

    Rosenfield, Philip; Johnson, L. Clifton; Dalcanton, Julianne J.; Williams, Benjamin F.; Gilbert, Karoline M.; Girardi, Léo; Bressan, Alessandro; Lang, Dustin; Guhathakurta, Puragra; Dorman, Claire E.; Howley, Kirsten M.; Lauer, Tod R.; Olsen, Knut A. G.; Bell, Eric F.; Bianchi, Luciana; Caldwell, Nelson; Dolphin, Andrew; Kalirai, Jason; Larsen, Søren S.; Rix, Hans-Walter

    2012-01-01

    As part of the Panchromatic Hubble Andromeda Treasury multi-cycle program, we observed a 12' × 6.'5 area of the bulge of M31 with the WFC3/UVIS filters F275W and F336W. From these data we have assembled a sample of ∼4000 UV-bright, old stars, vastly larger than previously available. We use updated Padova stellar evolutionary tracks to classify these hot stars into three classes: Post-AGB stars (P-AGB), Post-Early AGB (PE-AGB) stars, and AGB-manqué stars. P-AGB stars are the end result of the asymptotic giant branch (AGB) phase and are expected in a wide range of stellar populations, whereas PE-AGB and AGB-manqué (together referred to as the hot post-horizontal branch; HP-HB) stars are the result of insufficient envelope masses to allow a full AGB phase, and are expected to be particularly prominent at high helium or α abundances when the mass loss on the red giant branch is high. Our data support previous claims that most UV-bright sources in the bulge are likely hot (extreme) horizontal branch (EHB) stars and their progeny. We construct the first radial profiles of these stellar populations and show that they are highly centrally concentrated, even more so than the integrated UV or optical light. However, we find that this UV-bright population does not dominate the total UV luminosity at any radius, as we are detecting only the progeny of the EHB stars that are the likely source of the UV excess. We calculate that only a few percent of main-sequence stars in the central bulge can have gone through the HP-HB phase and that this percentage decreases strongly with distance from the center. We also find that the surface density of hot UV-bright stars has the same radial variation as that of low-mass X-ray binaries. We discuss age, metallicity, and abundance variations as possible explanations for the observed radial variation in the UV-bright population.

  10. Measuring metallicities with Hubble space telescope/wide-field camera 3 photometry

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Teresa L.; Holtzman, Jon A. [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Anthony-Twarog, Barbara J.; Twarog, Bruce [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045-7582 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Saha, Abhijit [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States); Walker, Alistair, E-mail: rosst@nmsu.edu, E-mail: holtz@nmsu.edu, E-mail: bjat@ku.edu, E-mail: btwarog@ku.edu, E-mail: heb11@psu.edu, E-mail: awalker@ctio.noao.edu [Cerro Tololo Inter-American Observatory (CTIO), National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)

    2014-01-01

    We quantified and calibrated the metallicity and temperature sensitivities of colors derived from nine Wide-Field Camera 3 filters on board the Hubble Space Telescope using Dartmouth isochrones and Kurucz atmosphere models. The theoretical isochrone colors were tested and calibrated against observations of five well studied galactic clusters, M92, NGC 6752, NGC 104, NGC 5927, and NGC 6791, all of which have spectroscopically determined metallicities spanning –2.30 < [Fe/H] <+0.4. We found empirical corrections to the Dartmouth isochrone grid for each of the following color-magnitude diagrams (CMDs): (F555W-F814W, F814W), (F336W-F555W, F814W), (F390M-F555W, F814W), and (F390W-F555W, F814W). Using empirical corrections, we tested the accuracy and spread of the photometric metallicities assigned from CMDs and color-color diagrams (which are necessary to break the age-metallicity degeneracy). Testing three color-color diagrams [(F336W-F555W),(F390M-F555W),(F390W-F555W), versus (F555W-F814W)], we found the colors (F390M-F555W) and (F390W-F555W) to be the best suited to measure photometric metallicities. The color (F390W-F555W) requires much less integration time, but generally produces wider metallicity distributions and, at very low metallicity, the metallicity distribution function (MDF) from (F390W-F555W) is ∼60% wider than that from (F390M-F555W). Using the calibrated isochrones, we recovered the overall cluster metallicity to within ∼0.1 dex in [Fe/H] when using CMDs (i.e., when the distance, reddening, and ages are approximately known). The measured MDF from color-color diagrams shows that this method measures metallicities of stellar clusters of unknown age and metallicity with an accuracy of ∼0.2-0.5 dex using F336W-F555W, ∼0.15-0.25 dex using F390M-F555W, and ∼0.2-0.4 dex with F390W-F555W, with the larger uncertainty pertaining to the lowest metallicity range.

  11. Star Formation at z ~ 6: The Hubble Ultra Deep Parallel Fields

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Thompson, R. I.; Blakeslee, J. P.; Dickinson, M. E.; Broadhurst, T. J.; Eisenstein, D. J.; Fan, X.; Franx, M.; Meurer, G.; van Dokkum, P.

    2004-05-01

    We report on the i-dropouts detected in two exceptionally deep Advanced Camera for Surveys fields (B435, V606, i775, and z850 with 10σ limits of 28.8, 29.0, 28.5, and 27.8, respectively) taken in parallel with the Ultra Deep Field Near-Infrared Camera and Multi-Object Spectrometer observations. Using an i-z>1.4 cut, we find 30 i-dropouts over 21 arcmin2 down to z850,AB=28.1, or 1.4 i-dropouts arcmin-2, with significant field-to-field variation (as expected from cosmic variance). This extends i-dropout searches some ~0.9 mag further down the luminosity function than was possible in the Great Observatories Origins Deep Survey (GOODS) fields, yielding a ~7 times increase in surface density. An estimate of the size evolution for UV-bright objects is obtained by comparing the composite radial flux profile of the bright i-dropouts (z850,ABdropouts. The best fit is found with a (1+z)-1.57+0.50-0.53 scaling in size (for fixed luminosity), extending lower redshift (1dropouts from both GOODS fields, we make incompleteness estimates and construct a z~6 luminosity function (LF) in the rest-frame continuum UV (~1350 Å) over a 3.5 mag baseline, finding a shape consistent with that found at lower redshift. To evaluate the evolution in the LF from z~3.8, we make comparisons against different scalings of a lower redshift B-dropout sample. Although a strong degeneracy is found between luminosity and density evolution, our best-fit model scales as (1+z)-2.8 in number and (1+z)0.1 in luminosity, suggesting a rest-frame continuum UV luminosity density at z~6 that is just 0.38+0.09-0.07 times that at z~3.8. Our inclusion of the size evolution makes the present estimate lower than previous z~6 estimates. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with program 9803.

  12. Constraints on z~10 Galaxies from the Deepest Hubble Space Telescope NICMOS Fields

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Thompson, R. I.; Franx, M.

    2005-05-01

    We use all available fields with deep NICMOS imaging to search for J110-dropouts (H160,AB1.8. Eleven such sources were found in all search fields using this criterion. Eight of these are clearly ruled out as credible z~10 sources, either as a result of detections (>2 σ) blueward of J110 or their colors redward of the break (H160-K~1.5) (redder than >~98% of lower redshift dropouts). The nature of the three remaining sources could not be determined from the data. This number appears consistent with the expected contamination from low-redshift interlopers. Analysis of the stacked images for the three candidates also suggests some contamination. Regardless of their true redshifts, the actual number of z~10 sources must be three or fewer. To assess the significance of these results, two lower redshift samples (a z~3.8 B-dropout and z~6 i-dropout sample) were projected to z~7-13 using a (1+z)-1 size scaling (for fixed luminosity). They were added to the image frames and the selection was repeated, giving 15.6 and 4.8 J110-dropouts, respectively. This suggests that to the limit of this probe (~0.3L*z=3), there has been evolution from z~3.8 and possibly from z~6. This is consistent with the strong evolution already noted at z~6 and z~7.5 relative to z~3-4. Even assuming that three sources from this probe are at z~10, the rest-frame continuum UV (~1500 Å) luminosity density at z~10 (integrated down to 0.3L*z=3) is just 0.19+0.13-0.09 times that at z~3.8 (or 0.19+0.15-0.10 times, including the small effect from cosmic variance). However, if none of our sources are at z~10, this ratio has a 1 σ upper limit of 0.07. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  13. 3D-HST: A WIDE-FIELD GRISM SPECTROSCOPIC SURVEY WITH THE HUBBLE SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Brammer, Gabriel B.; Van Dokkum, Pieter G.; Skelton, Rosalind E.; Nelson, Erica; Bezanson, Rachel; Leja, Joel; Lundgren, Britt; Franx, Marijn; Fumagalli, Mattia; Patel, Shannon; Labbé, Ivo; Rix, Hans-Walter; Schmidt, Kasper B.; Da Cunha, Elisabete; Kriek, Mariska; Erb, Dawn K.; Fan, Xiaohui; Förster Schreiber, Natascha; Illingworth, Garth D.; Magee, Dan

    2012-01-01

    We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the physical processes that shape galaxies in the distant universe. 3D-HST provides rest-frame optical spectra for a sample of ∼7000 galaxies at 1 2 ) of the CANDELS Treasury survey area with two orbits of primary WFC3/G141 grism coverage and two to four orbits with the ACS/G800L grism in parallel. In the IR, these exposure times yield a continuum signal-to-noise ratio of ∼5 per resolution element at H 140 ∼ 23.1 and a 5σ emission-line sensitivity of ∼5 × 10 –17 erg s –1 cm –2 for typical objects, improving by a factor of ∼2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1 to 1.6 μm at a spatial resolution of ∼0.''13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present an overview of the preliminary reduction and analysis of the grism observations, including emission-line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of σ(z) = 0.0034(1 + z), or σ(v) ≈ 1000 km s –1 . We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z = 4.7, quiescent galaxies at z ∼ 2, and the most distant T-type brown dwarf star known. The combination of the CANDELS and 3D-HST surveys will provide the definitive imaging and spectroscopic data set for studies of the 1 < z < 3.5 universe until the launch of the James Webb Space Telescope.

  14. THE UV CONTINUUM OF z > 1 STAR-FORMING GALAXIES IN THE HUBBLE ULTRAVIOLET ULTRADEEP FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kurczynski, Peter; Gawiser, Eric [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Rafelski, Marc [NASA Postdoctoral Program Fellow, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Teplitz, Harry I. [Infrared Processing and Analysis Center, MS 100-22, Caltech, Pasadena, CA 91125 (United States); Acquaviva, Viviana [New York City College of Technology, Brooklyn, NY 11201 (United States); Brown, Thomas M.; Coe, Dan; Grogin, Norman A.; Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); De Mello, Duilia F. [Laboratory for Observational Cosmology, Astrophysics Science Division, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Finkelstein, Steven L. [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Lee, Kyoung-soo [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Scarlata, Claudia [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Siana, Brian D. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)

    2014-09-20

    We estimate the UV continuum slope, β, for 923 galaxies in the range 1 < z < 8 in the Hubble Ultradeep Field (HUDF). These data include 460 galaxies at 1 < z < 2 down to an absolute magnitude M{sub UV}=−14(∼0.006 L{sub z=1}{sup ∗};0.02 L{sub z=0}{sup ∗}), comparable to dwarf galaxies in the local universe. We combine deep HST/UVIS photometry in F225W, F275W, F336W wavebands (UVUDF) with recent data from HST/WFC3/IR (HUDF12). Galaxies in the range 1 < z < 2 are significantly bluer than local dwarf galaxies. We find their mean (median) values <β > = – 1.382(– 1.830) ± 0.002 (random) ± 0.1 (systematic). We find comparable scatter in β (standard deviation = 0.43) to local dwarf galaxies and 30% larger scatter than z > 2 galaxies. We study the trends of β with redshift and absolute magnitude for binned sub-samples and find a modest color-magnitude relation, dβ/dM = –0.11 ± 0.01, and no evolution in dβ/dM with redshift. A modest increase in dust reddening with redshift and luminosity, ΔE(B – V) ∼ 0.1, and a comparable increase in the dispersion of dust reddening at z < 2, appears likely to explain the observed trends. At z > 2, we find trends that are consistent with previous works; combining our data with the literature in the range 1 < z < 8, we find a color evolution with redshift, dβ/dz = –0.09 ± 0.01 for low luminosity (0.05 L{sub z=3}{sup ∗}), and dβ/dz = –0.06 ± 0.01 for medium luminosity (0.25 L{sub z=3}{sup ∗}) galaxies.

  15. Impacts on Hubble Space Telescope solar arrays: discrimination between natural and man-made particles.

    Science.gov (United States)

    Kearsley, A. T.; Drolshagen, G.; McDonnell, J. A. M.; Mandeville, J.-C.; Moussi, A.

    A Post-Flight Investigation was initiated by the European Space Agency to analyze impact fluxes on solar arrays of the Hubble Space Telescope (HST), exposed to space for 8.25 years at approximately 600 km altitude. The solar cells were deployed during servicing mission SM-1 (December 1993), and retrieved by shuttle orbiter Columbia in March 2002 (SM-3B). A sub-panel of 2 m2 was cut from the --V2 wing and cells were selected for in-depth analysis. Twelve cells (9.6x10-3 m2) were surveyed for flux of all craters of sizes greater than 5 microns Dco; six at the NHM, and six at ONERA. Cumulative flux plots reveal slightly greater abundance of very small craters than in a comparable survey of SM-1 cells. Analytical scanning electron microscopy was used to locate impact features and to analyse residues at the NHM. 103 features of 3 -- 4000 micron conchoidal detachment diameter (Dco) were located on a total of 17 solar cells. 78 features show identifiable residue: 36 are Space Debris impacts and 42 Micrometeoroid impacts. Of the remaining 25: 4 contain residue of ambiguous origin, 1 is a minor manufacturing flaw, 1 is obscured by contamination, and 19 are unresolved, lacking recognizable residue. Space debris impacts on the SM-3B cells are all less than 80 microns Dco, dominated by Al- rich residue, probably of solid rocket motor origin, some may be unburnt fuel. Three craters may be sodium metal droplet impacts. No residues from paint pigment, aluminium or ferrous alloys, or copper- and tin-bearing metal were found. All craters larger than 100 microns are of micrometeoroid origin, or unresolved. Most residues are magnesium-iron silicate or iron sulfide. A few craters show vesicular Mg, S, Fe and Ni residue. A single Fe Ni metal residue was found, as well as enigmatic Mg- and S-bearing residues, all considered of micrometeoroid origin. A few Fe-, O- and C-bearing residues were classified as of ambiguous origin. The quality and quantity of residue is clearly linked to the

  16. Ultraviolet spectropolarimetry of high-redshift quasars with the Hubble Space Telescope

    Science.gov (United States)

    Impey, C. D.; Malkan, Matthew A.; Webb, Wayne; Petry, C. E.

    1995-01-01

    Ultraviolet spectropolarimetry of three bright high-redshift low-polarization quasars (LPQs) was obtained with the Faint Object Spectrograph of the Hubble Space Telescope (HST). Two of the quasars, PG 1634+706 and PG 2302+029, had polarizations p approximately = 0.5%-1.0% throughout the ultraviolet, and showed no significant variation of polarization amplitude or position angle with wavelength. PG 2302+029 was also marginally (2.4 sigma) circularly polarized in the optical continuum. For the highest redshift quasar, PG 1222+228 (Ton 1530), the polarization was measured down to rest wavelengths below 800 A. Although the continuum of PG 1222+228 was weakened by Lyman limit absorption from an intergalactic gas cloud, the polarization increased sharply from 1% to about 4.5%, a change of 4 sigma significance. This abrupt rise in polarization does not appear attributable to any known instrumental artifact. These UV polarizations were only slightly less than those previously observed for these same objects in the optical. The polarization spectra were flat with a typical slope of the polarized flux pF(sub nu) proportional to nu(exp -0.8 +/- 0.5). Unlike the case of several high luminosity Seyfert 1 nuclei studied previously, polarization caused by scattering from dust grains does not provide the best fit to the polarization spectra of these luminous quasars. These observed spectra are consistent with a wavelength-independent polarization proportional to the total nonstellar light or, possibly, to the contribution of the blue thermal component. The polarization spectra have insufficient signal-to-noise to locate the scatterers with respect to the continuum source and the much larger broad line region. A decrease in amplitude and rotation of the position angle of the polarization vector at the shortest wavelengths, which could result from general relativistic effects near a spinning black hole, was not observed. In fact, in PG 1222+228, the polarization was observed to

  17. Current Extensions on PULSE

    Directory of Open Access Journals (Sweden)

    Sanda Dragos

    2010-09-01

    Full Text Available Using a learning management system (LMS is a common practise nowadays. Such instruments are used in educational institutions to enhance and support the teaching act as well as in industry for training purposes. In a computer science department of an university such instrument tends to be a basic requirement. That is because not only it allows a better management of courses and a better communication between students and professors, but can also serve as a perfect instrument for presenting teaching related materials for computer science subjects. During the years I have created and used several such instruments: a System with Interactive ackNowledgement and Evaluation of students work during laboratory sessions (SINE, a Php Utility used in Laboratories for Student Evaluation (PULSE, and PULSE Extended. The aim of this paper is to present the current enhancements of PULSE.

  18. Spin current

    CERN Document Server

    Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi

    2017-01-01

    Since the discovery of the giant magnetoresistance effect in magnetic multilayers in 1988, a new branch of physics and technology, called spin-electronics or spintronics, has emerged, where the flow of electrical charge as well as the flow of electron spin, the so-called “spin current,” are manipulated and controlled together. The physics of magnetism and the application of spin current have progressed in tandem with the nanofabrication technology of magnets and the engineering of interfaces and thin films. This book aims to provide an introduction and guide to the new physics and applications of spin current, with an emphasis on the interaction between spin and charge currents in magnetic nanostructures.

  19. Neutral currents

    International Nuclear Information System (INIS)

    Paschos, E.A.

    1977-01-01

    It is stated that over the past few years considerable progress has been made in the field of weak interactions. The existence of neutral currents involving leptons and hadrons has been established and some of the questions concerning their detailed structure have been answered. This imposes constraints on the gauge theories and has eliminated large classes of models. New questions have also been raised, one of which concerns the conservation laws obeyed by neutral currents. The wide range of investigations is impressive and is expected to continue with new results from particle, nuclear, and atomic physics. Headings include - various aspects of a gauge theory (choice of group, the symmetry breaking scheme, representation assignments for fermion fields); space-time structure; isospin structure; leptonic neutral currents; and atomic experiments. (U.K.)

  20. Constraints on Λ(t)CDM models as holographic and agegraphic dark energy with the observational Hubble parameter data

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Zhong-Xu; Liu, Wen-Biao [Department of Physics, Institute of Theoretical Physics, Beijing Normal University, Beijing, 100875 (China); Zhang, Tong-Jie, E-mail: zzx@mail.bnu.edu.cn, E-mail: tjzhang@bnu.edu.cn, E-mail: wbliu@bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing, 100875 (China)

    2011-08-01

    The newly released observational H(z) data (OHD) is used to constrain Λ(t)CDM models as holographic and agegraphic dark energy. By the use of the length scale and time scale as the IR cut-off including Hubble horizon (HH), future event horizon (FEH), age of the universe (AU), and conformal time (CT), we achieve four different Λ(t)CDM models which can describe the present cosmological acceleration respectively. In order to get a comparison between such Λ(t)CDM models and standard ΛCDM model, we use the information criteria (IC), Om(z) diagnostic, and statefinder diagnostic to measure the deviations. Furthermore, by simulating a larger Hubble parameter data sample in the redshift range of 0.1 < z < 2.0, we get the improved constraints and more sufficient comparison. We show that OHD is not only able to play almost the same role in constraining cosmological parameters as SNe Ia does but also provides the effective measurement of the deviation of the DE models from standard ΛCDM model. In the holographic and agegraphic scenarios, the results indicate that the FEH is more preferable than HH scenario. However, both two time scenarios show better approximations to ΛCDM model than the length scenarios.

  1. A TYPE Ia SUPERNOVA AT REDSHIFT 1.55 IN HUBBLE SPACE TELESCOPE INFRARED OBSERVATIONS FROM CANDELS

    International Nuclear Information System (INIS)

    Rodney, Steven A.; Riess, Adam G.; Jones, David O.; Dahlen, Tomas; Ferguson, Henry C.; Casertano, Stefano; Grogin, Norman A.; Strolger, Louis-Gregory; Hjorth, Jens; Frederiksen, Teddy F.; Weiner, Benjamin J.; Mobasher, Bahram; Challis, Peter; Kirshner, Robert P.; Faber, S. M.; Filippenko, Alexei V.; Garnavich, Peter; Hayden, Brian; Graur, Or; Jha, Saurabh W.

    2012-01-01

    We report the discovery of a Type Ia supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SN Ia with direct spectroscopic evidence for classification. It is also the first SN Ia at z > 1 found and followed in the infrared, providing a full light curve in rest-frame optical bands. The classification and redshift are securely defined from a combination of multi-band and multi-epoch photometry of the SN, ground-based spectroscopy of the host galaxy, and WFC3-IR grism spectroscopy of both the SN and host. This object is the first of a projected sample at z > 1.5 that will be discovered by the CANDELS and CLASH programs. The full CANDELS+CLASH SN Ia sample will enable unique tests for evolutionary effects that could arise due to differences in SN Ia progenitor systems as a function of redshift. This high-z sample will also allow measurement of the SN Ia rate out to z ≈ 2, providing a complementary constraint on SN Ia progenitor models.

  2. Spectroscopic Properties of Star-Forming Host Galaxies and Type Ia Supernova Hubble Residuals in a Nearly Unbiased Sample

    Energy Technology Data Exchange (ETDEWEB)

    D' Andrea, Chris B. [Univ. of Pennsylvania, Philadelphia, PA (United States); et al.

    2011-12-20

    We examine the correlation between supernova host galaxy properties and their residuals on the Hubble diagram. We use supernovae discovered during the Sloan Digital Sky Survey II - Supernova Survey, and focus on objects at a redshift of z < 0.15, where the selection effects of the survey are known to yield a complete Type Ia supernova sample. To minimize the bias in our analysis with respect to measured host-galaxy properties, spectra were obtained for nearly all hosts, spanning a range in magnitude of -23 < M_r < -17. In contrast to previous works that use photometric estimates of host mass as a proxy for global metallicity, we analyze host-galaxy spectra to obtain gas-phase metallicities and star-formation rates from host galaxies with active star formation. From a final sample of ~ 40 emission-line galaxies, we find that light-curve corrected Type Ia supernovae are ~ 0.1 magnitudes brighter in high-metallicity hosts than in low-metallicity hosts. We also find a significant (> 3{\\sigma}) correlation between the Hubble residuals of Type Ia supernovae and the specific star-formation rate of the host galaxy. We comment on the importance of supernova/host-galaxy correlations as a source of systematic bias in future deep supernova surveys.

  3. Low-redshift effects of local structure on the Hubble parameter in presence of a cosmological constant

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Antonio Enea [University of Crete, Department of Physics and CCTP, Heraklion (Greece); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Vallejo, Sergio Andres [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia)

    2016-04-15

    In order to estimate the effects of a local structure on the Hubble parameter we calculate the low-redshift expansion for H(z) and (δH)/(H) for an observer at the center of a spherically symmetric matter distribution in the presence of a cosmological constant. We then test the accuracy of the formulas comparing them with fully relativistic non-perturbative numerical calculations for different cases for the density profile. The low-redshift expansion we obtain gives results more precise than perturbation theory since it is based on the use of an exact solution of Einstein's field equations. For larger density contrasts the low-redshift formulas accuracy improves respect to the perturbation theory accuracy because the latter is based on the assumption of a small density contrast, while the former does not rely on such an assumption. The formulas can be used to take into account the effects on the Hubble expansion parameter due to the monopole component of the local structure. If the H(z) observations will show deviations from the ΛCDM prediction compatible with the formulas we have derived, this could be considered an independent evidence of the existence of a local inhomogeneity, and the formulas could be used to determine the characteristics of this local structure. (orig.)

  4. SN 2016jhj at redshift 0.34: extending the Type II supernova Hubble diagram using the standard candle method

    Science.gov (United States)

    de Jaeger, T.; Galbany, L.; Filippenko, A. V.; González-Gaitán, S.; Yasuda, N.; Maeda, K.; Tanaka, M.; Morokuma, T.; Moriya, T. J.; Tominaga, N.; Nomoto, K.; Komiyama, Y.; Anderson, J. P.; Brink, T. G.; Carlberg, R. G.; Folatelli, G.; Hamuy, M.; Pignata, G.; Zheng, W.

    2017-12-01

    Although Type Ia supernova cosmology has now reached a mature state, it is important to develop as many independent methods as possible to understand the true nature of dark energy. Recent studies have shown that Type II supernovae (SNe II) offer such a path and could be used as alternative distance indicators. However, the majority of these studies were unable to extend the Hubble diagram above redshift z = 0.3 because of observational limitations. Here, we show that we are now ready to move beyond low redshifts and attempt high-redshift (z ≳ 0.3) SN II cosmology as a result of new-generation deep surveys such as the Subaru/Hyper Suprime-Cam survey. Applying the 'standard candle method' to SN 2016jhj (z = 0.3398 ± 0.0002; discovered by HSC) together with a low-redshift sample, we are able to construct the highest-redshift SN II Hubble diagram to date with an observed dispersion of 0.27 mag (i.e. 12-13 per cent in distance). This work demonstrates the bright future of SN II cosmology in the coming era of large, wide-field surveys like that of the Large Synoptic Survey Telescope.

  5. The MUSE Hubble Ultra Deep Field Survey. IX. Evolution of galaxy merger fraction since z ≈ 6

    Science.gov (United States)

    Ventou, E.; Contini, T.; Bouché, N.; Epinat, B.; Brinchmann, J.; Bacon, R.; Inami, H.; Lam, D.; Drake, A.; Garel, T.; Michel-Dansac, L.; Pello, R.; Steinmetz, M.; Weilbacher, P. M.; Wisotzki, L.; Carollo, M.

    2017-11-01

    We provide, for the first time, robust observational constraints on the galaxy major merger fraction up to z ≈ 6 using spectroscopic close pair counts. Deep Multi Unit Spectroscopic Explorer (MUSE) observations in the Hubble Ultra Deep Field (HUDF) and Hubble Deep Field South (HDF-S) are used to identify 113 secure close pairs of galaxies among a parent sample of 1801 galaxies spread over a large redshift range (0.2 separation limit of 109.5 M⊙ or the median value of stellar mass computed in each redshift bin. Overall, the major close pair fraction for low-mass and massive galaxies follows the same trend. These new, homogeneous, and robust estimates of the major merger fraction since z ≈ 6 are in good agreement with recent predictions of cosmological numerical simulations. Based on observations made with ESO telescopes at the La Silla-Paranal Observatory under programmes 094.A-0289(B), 095.A-0010(A), 096.A-0045(A) and 096.A-0045(B).

  6. Neutral currents

    International Nuclear Information System (INIS)

    Aubert, B.

    1994-11-01

    The evidence for the existence of weak neutral current has been a very controverted topics in the early 1970's, as well as the muon did in the 1930's. The history is very rich considering the evolution of the experimental techniques in high energy particle physics. The history of the discovery and the study of weak neutral current is reviewed. Later the quest of the intermediate vector boson continues with the decision of the community to build a large proton antiproton collider. (K.A.). 14 refs., 1 fig

  7. Current Observational Constraints to Holographic Dark Energy Model with New Infrared cut-off via Markov Chain Monte Carlo Method

    OpenAIRE

    Wang, Yuting; Xu, Lixin

    2010-01-01

    In this paper, the holographic dark energy model with new infrared (IR) cut-off for both the flat case and the non-flat case are confronted with the combined constraints of current cosmological observations: type Ia Supernovae, Baryon Acoustic Oscillations, current Cosmic Microwave Background, and the observational hubble data. By utilizing the Markov Chain Monte Carlo (MCMC) method, we obtain the best fit values of the parameters with $1\\sigma, 2\\sigma$ errors in the flat model: $\\Omega_{b}h...

  8. Current algebra

    International Nuclear Information System (INIS)

    Jacob, M.

    1967-01-01

    The first three chapters of these lecture notes are devoted to generalities concerning current algebra. The weak currents are defined, and their main properties given (V-A hypothesis, conserved vector current, selection rules, partially conserved axial current,...). The SU (3) x SU (3) algebra of Gell-Mann is introduced, and the general properties of the non-leptonic weak Hamiltonian are discussed. Chapters 4 to 9 are devoted to some important applications of the algebra. First one proves the Adler- Weisberger formula, in two different ways, by either the infinite momentum frame, or the near-by singularities method. In the others chapters, the latter method is the only one used. The following topics are successively dealt with: semi leptonic decays of K mesons and hyperons, Kroll- Ruderman theorem, non leptonic decays of K mesons and hyperons ( ΔI = 1/2 rule), low energy theorems concerning processes with emission (or absorption) of a pion or a photon, super-convergence sum rules, and finally, neutrino reactions. (author) [fr

  9. Current Titles

    Energy Technology Data Exchange (ETDEWEB)

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  10. Current scenario

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Current scenario. India , like other parts of the world, is also facing the problem of increase in the incidence of drug resistance in tuberculosis. Multi-drug resistance (MDR, resistance to RIF & INH) and extensively drug resistant strains (X-DR, resistance to RIF, INH, FQs ...

  11. Dissecting the Gravitational Lens B1608 656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State

    Energy Technology Data Exchange (ETDEWEB)

    Suyu, S.H.; /Argelander Inst. Astron.; Marshall, P.J.; /KIPAC, Menlo Park /UC, Santa Barbara; Auger, M.W.; /UC, Santa Barbara /UC, Davis; Hilbert, S.; /Argelander Inst. Astron. /Garching, Max Planck Inst.; Blandford, R.D.; /KIPAC, Menlo Park; Koopmans, L.V.E.; /Kapteyn Astron. Inst., Groningen; Fassnacht, C.D.; /UC, Davis; Treu, T.; /UC, Santa Barbara

    2009-12-11

    Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the 'time-delay distance' to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep Hubble Space Telescope (HST) observations, (2) a new velocity dispersion measurement of 260 {+-} 15 km s{sup -1} for the primary lens galaxy, and (3) an updated study of the lens environment. Our analysis of the HST images takes into account the extended source surface brightness, and the dust extinction and optical emission by the interacting lens galaxies. When modeling the stellar dynamics of the primary lens galaxy, the lensing effect, and the environment of the lens, we explicitly include the total mass distribution profile logarithmic slope {gamma}{prime} and the external convergence {kappa}{sub ext}; we marginalize over these parameters, assigning well-motivated priors for them, and so turn the major systematic errors into statistical ones. The HST images provide one such prior, constraining the lens mass density profile logarithmic slope to be {gamma}{prime} = 2.08 {+-} 0.03; a combination of numerical simulations and photometric observations of the B1608+656 field provides an estimate of the prior for {kappa}{sub ext}: 0.10{sub -0.05}{sup +0.08}. This latter distribution dominates the final uncertainty on H{sub 0}. Fixing the cosmological parameters at {Omega}{sub m} = 0.3, {Omega}{sub {Lambda}} = 0.7, and w = -1 in order to compare with previous work on this system, we find H{sub 0} = 70.6{sub -3.1}{sup +3.1} km s{sup -1} Mpc{sup -1}. The new data provide an increase in precision of more than a factor of two, even including the marginalization over {kappa}{sub ext}. Relaxing the prior probability density function for the cosmological parameters to that derived from the WMAP 5-year data set, we find that the B1608+656 data set breaks the degeneracy

  12. INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Deming, Drake; Wilkins, Ashlee [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); McCullough, Peter; Crouzet, Nicolas [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Agol, Eric; Dobbs-Dixon, Ian [NASA Astrobiology Institute' s Virtual Planetary Laboratory (United States); Madhusudhan, Nikku [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Desert, Jean-Michel; Knutson, Heather A.; Line, Michael [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Haynes, Korey [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Magic, Zazralt [Max-Planck-Institut fuer Astrophysik, D-85741 Garching (Germany); Mandell, Avi M.; Clampin, Mark [NASA' s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ranjan, Sukrit; Charbonneau, David [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Seager, Sara, E-mail: ddeming@astro.umd.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

    2013-09-10

    Exoplanetary transmission spectroscopy in the near-infrared using the Hubble Space Telescope (HST) NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with HST/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant planets HD 209458b and XO-1b in transit, using spatial scanning mode for maximum photon-collecting efficiency. We introduce an analysis technique that derives the exoplanetary transmission spectrum without the necessity of explicitly decorrelating instrumental effects, and achieves nearly photon-limited precision even at the high flux levels collected in spatial scan mode. Our errors are within 6% (XO-1) and 26% (HD 209458b) of the photon-limit at a resolving power of {lambda}/{delta}{lambda} {approx} 70, and are better than 0.01% per spectral channel. Both planets exhibit water absorption of approximately 200 ppm at the water peak near 1.38 {mu}m. Our result for XO-1b contradicts the much larger absorption derived from NICMOS spectroscopy. The weak water absorption we measure for HD 209458b is reminiscent of the weakness of sodium absorption in the first transmission spectroscopy of an exoplanet atmosphere by Charbonneau et al. Model atmospheres having uniformly distributed extra opacity of 0.012 cm{sup 2} g{sup -1} account approximately for both our water measurement and the sodium absorption. Our results for HD 209458b support the picture advocated by Pont et al. in which weak molecular absorptions are superposed on a transmission spectrum that is dominated by continuous opacity due to haze and/or dust. However, the extra opacity needed for HD 209458b is grayer than for HD 189733b, with a weaker Rayleigh component.

  13. NEW CONSTRAINTS ON THE FAINT END OF THE UV LUMINOSITY FUNCTION AT z ∼ 7-8 USING THE GRAVITATIONAL LENSING OF THE HUBBLE FRONTIER FIELDS CLUSTER A2744

    International Nuclear Information System (INIS)

    Atek, Hakim; Kneib, Jean-Paul; Richard, Johan; Clement, Benjamin; Jauzac, Mathilde; Schaerer, Daniel; Limousin, Marceau; Jullo, Eric; Natarajan, Priyamvada; Egami, Eiichi; Ebeling, Harald

    2015-01-01

    Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster A2744, we report the detection of 50 galaxy candidates at z ∼ 7 and eight candidates at z ∼ 8 in a total survey area of 0.96 arcmin 2 in the source plane. Three of these galaxies are multiply imaged by the lensing cluster. Using an updated model of the mass distribution in the cluster we were able to calculate the magnification factor and the effective survey volume for each galaxy in order to compute the ultraviolet galaxy luminosity function (LF) at both redshifts 7 and 8. Our new measurements reliably extend the z ∼ 7 UV LF down to an absolute magnitude of M UV ∼ –15.5. We find a characteristic magnitude of M UV ⋆ =−20.90 −0.73 +0.90  mag and a faint-end slope α=−2.01 −0.28 +0.20 , close to previous determinations in blank fields. We show here for the first time that this slope remains steep down to very faint luminosities of 0.01 L * . Although prone to large uncertainties, our results at z ∼ 8 also seem to confirm a steep faint-end slope below 0.1 L * . The HFF program is therefore providing an extremely efficient way to study the faintest galaxy populations at z > 7 that would otherwise be inaccessible with current instrumentation. The full sample of six galaxy clusters will provide even better constraints on the buildup of galaxies at early epochs and their contribution to cosmic reionization

  14. NEW CONSTRAINTS ON THE FAINT END OF THE UV LUMINOSITY FUNCTION AT z ∼ 7-8 USING THE GRAVITATIONAL LENSING OF THE HUBBLE FRONTIER FIELDS CLUSTER A2744

    Energy Technology Data Exchange (ETDEWEB)

    Atek, Hakim; Kneib, Jean-Paul [Laboratoire d' Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, CH-1290 Versoix (Switzerland); Richard, Johan; Clement, Benjamin [CRAL, Observatoire de Lyon, Université Lyon 1, 9 Avenue Ch. André, F-69561 Saint Genis Laval Cedex (France); Jauzac, Mathilde [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Schaerer, Daniel [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland); Limousin, Marceau; Jullo, Eric [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Natarajan, Priyamvada [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Egami, Eiichi [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Ebeling, Harald [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2015-02-10

    Exploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant universe far beyond the limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster A2744, we report the detection of 50 galaxy candidates at z ∼ 7 and eight candidates at z ∼ 8 in a total survey area of 0.96 arcmin{sup 2} in the source plane. Three of these galaxies are multiply imaged by the lensing cluster. Using an updated model of the mass distribution in the cluster we were able to calculate the magnification factor and the effective survey volume for each galaxy in order to compute the ultraviolet galaxy luminosity function (LF) at both redshifts 7 and 8. Our new measurements reliably extend the z ∼ 7 UV LF down to an absolute magnitude of M {sub UV} ∼ –15.5. We find a characteristic magnitude of M{sub UV}{sup ⋆}=−20.90{sub −0.73}{sup +0.90} mag and a faint-end slope α=−2.01{sub −0.28}{sup +0.20}, close to previous determinations in blank fields. We show here for the first time that this slope remains steep down to very faint luminosities of 0.01 L {sup *}. Although prone to large uncertainties, our results at z ∼ 8 also seem to confirm a steep faint-end slope below 0.1 L {sup *}. The HFF program is therefore providing an extremely efficient way to study the faintest galaxy populations at z > 7 that would otherwise be inaccessible with current instrumentation. The full sample of six galaxy clusters will provide even better constraints on the buildup of galaxies at early epochs and their contribution to cosmic reionization.

  15. Current awareness.

    Science.gov (United States)

    Compagno, C; Brambilla, L; Capitanio, D; Boschi, F; Ranzi, B M; Porro, D

    2001-05-01

    In order to keep subscribers up-to-date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly-published material on yeasts. Each bibliography is divided into 10 sections. 1 Books, Reviews & Symposia; 2 General; 3 Biochemistry; 4 Biotechnology; 5 Cell Biology; 6 Gene Expression; 7 Genetics; 8 Physiology; 9 Medical Mycology; 10 Recombinant DNA Technology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. (4 weeks journals - search completed 7th Mar. 2001)

  16. Current titles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Gretchen Hermes at (510) 486-5006 or address below for a User`s Guide. Copies of available papers can be ordered from: Theda Crawford National Center for Electron Microscopy, Lawrence Berkeley Laboratory, One Cyclotron Rd., MS72, Berkeley, California, USA 94720.

  17. Current ornithology

    CERN Document Server

    1983-01-01

    The appearance of the first volume of a projected series is the occasion for comment on scope, aims, and genesis of the work. The scope of Current Ornithology is all of the biology of birds. Ornithology, as a whole-organism science, is concerned with birds at every level of bi­ ological organization, from the molecular to the community, at least from the Jurassic to the present time, and over every scholarly discipline in which bird biology is done; to say this is merely to expand a dic­ tionary definition of "ornithology. " The aim of the work, to be realized over several volumes, is to present reviews or position statements con­ cerning the active fields of ornithological research. The reviews will be relatively short, and often will be done from the viewpoint of a readily­ identified group or school. Such a work could have come into being at any time within the past fifty years, but that Current Ornithology appears now is a result of events that are only seven to eight years old. One important event wa...

  18. New Constraints on ΩM, ΩΛ, and w from an Independent Set of 11 High-Redshift Supernovae Observed with the Hubble Space Telescope

    Science.gov (United States)

    Knop, R. A.; Aldering, G.; Amanullah, R.; Astier, P.; Blanc, G.; Burns, M. S.; Conley, A.; Deustua, S. E.; Doi, M.; Ellis, R.; Fabbro, S.; Folatelli, G.; Fruchter, A. S.; Garavini, G.; Garmond, S.; Garton, K.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I.; Howell, D. A.; Kim, A. G.; Lee, B. C.; Lidman, C.; Mendez, J.; Nobili, S.; Nugent, P. E.; Pain, R.; Panagia, N.; Pennypacker, C. R.; Perlmutter, S.; Quimby, R.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Sainton, G.; Schaefer, B.; Schahmaneche, K.; Smith, E.; Spadafora, A. L.; Stanishev, V.; Sullivan, M.; Walton, N. A.; Wang, L.; Wood-Vasey, W. M.; Yasuda, N.

    2003-11-01

    We report measurements of ΩM, ΩΛ, and w from 11 supernovae (SNe) at z=0.36-0.86 with high-quality light curves measured using WFPC2 on the Hubble Space Telescope (HST). This is an independent set of high-redshift SNe that confirms previous SN evidence for an accelerating universe. The high-quality light curves available from photometry on WFPC2 make it possible for these 11 SNe alone to provide measurements of the cosmological parameters comparable in statistical weight to the previous results. Combined with earlier Supernova Cosmology Project data, the new SNe yield a measurement of the mass density ΩM=0.25+0.07-0.06(statistical)+/-0.04 (identified systematics), or equivalently, a cosmological constant of ΩΛ=0.75+0.06-0.07(statistical)+/-0.04 (identified systematics), under the assumptions of a flat universe and that the dark energy equation-of-state parameter has a constant value w=-1. When the SN results are combined with independent flat-universe measurements of ΩM from cosmic microwave background and galaxy redshift distortion data, they provide a measurement of w=-1.05+0.15-0.20(statistical)+/-0.09 (identified systematic), if w is assumed to be constant in time. In addition to high-precision light-curve measurements, the new data offer greatly improved color measurements of the high-redshift SNe and hence improved host galaxy extinction estimates. These extinction measurements show no anomalous negative E(B-V) at high redshift. The precision of the measurements is such that it is possible to perform a host galaxy extinction correction directly for individual SNe without any assumptions or priors on the parent E(B-V) distribution. Our cosmological fits using full extinction corrections confirm that dark energy is required with P(ΩΛ>0)>0.99, a result consistent with previous and current SN analyses that rely on the identification of a low-extinction subset or prior assumptions concerning the intrinsic extinction distribution. Based in part on

  19. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    NARCIS (Netherlands)

    Adamo, A.; Ryon, J.E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D.O.; Calzetti, D.; Lee, J.C.; Whitmore, B.C.; Elmegreen, B.G.; Ubeda, L.; Smith, L.J.; Bright, S.N.; Runnholm, A.; Andrews, J.E.; Fumagalli, M.; Gouliermis, D.A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T.M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G.C.; Dale, D.A.; de Mink, S.E.; Dobbs, C.; Elmegreen, D.M.; Evans, A.S.; Gallagher III, J.S.; Grebel, E.K.; Herrero, A.; Hunter, D.A.; Johnson, K.E.; Kennicutt, R.C.; Krumholz, M.R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M.W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S.D.; Zackrisson, E.

    2017-01-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify

  20. CANDELS : THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY-THE HUBBLE SPACE TELESCOPE OBSERVATIONS, IMAGING DATA PRODUCTS, AND MOSAICS

    NARCIS (Netherlands)

    Koekemoer, Anton M.; Faber, S. M.; Ferguson, Henry C.; Grogin, Norman A.; Kocevski, Dale D.; Koo, David C.; Lai, Kamson; Lotz, Jennifer M.; Lucas, Ray A.; McGrath, Elizabeth J.; Ogaz, Sara; Rajan, Abhijith; Riess, Adam G.; Rodney, Steve A.; Strolger, Louis; Casertano, Stefano; Castellano, Marco; Dahlen, Tomas; Dickinson, Mark; Dolch, Timothy; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Guo, Yicheng; Hathi, Nimish P.; Huang, Kuang-Han; van der Wel, Arjen; Yan, Hao-Jing; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Cassata, Paolo; Challis, Peter J.; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; Conselice, Christopher J.; Cooray, Asantha Roshan; Croton, Darren J.; Daddi, Emanuele; Dave, Romeel; de Mello, Duilia F.; de Ravel, Loic; Dekel, Avishai; Donley, Jennifer L.; Dunlop, James S.; Dutton, Aaron A.; Elbaz, David; Fazio, Giovanni G.; Filippenko, Alexei V.; Finkelstein, Steven L.; Frazer, Chris; Gardner, Jonathan P.; Garnavich, Peter M.; Gawiser, Eric; Gruetzbauch, Ruth; Hartley, Will G.; Haeussler, Boris; Herrington, Jessica; Hopkins, Philip F.; Huang, Jia-Sheng; Jha, Saurabh W.; Johnson, Andrew; Kartaltepe, Jeyhan S.; Khostovan, Ali A.; Kirshner, Robert P.; Lani, Caterina; Lee, Kyoung-Soo; Li, Weidong; Madau, Piero; McCarthy, Patrick J.; McIntosh, Daniel H.; McLure, Ross J.; McPartland, Conor; Mobasher, Bahram; Moreira, Heidi; Mortlock, Alice; Moustakas, Leonidas A.; Mozena, Mark; Nandra, Kirpal; Newman, Jeffrey A.; Nielsen, Jennifer L.; Niemi, Sami; Noeske, Kai G.; Papovich, Casey J.; Pentericci, Laura; Pope, Alexandra; Primack, Joel R.; Ravindranath, Swara; Reddy, Naveen A.; Renzini, Alvio; Rix, Hans-Walter; Robaina, Aday R.; Rosario, David J.; Rosati, Piero; Salimbeni, Sara; Scarlata, Claudia; Siana, Brian; Simard, Luc; Smidt, Joseph; Snyder, Diana; Somerville, Rachel S.; Spinrad, Hyron; Straughn, Amber N.; Telford, Olivia; Teplitz, Harry I.; Trump, Jonathan R.; Vargas, Carlos; Villforth, Carolin; Wagner, Cory R.; Wandro, Pat; Wechsler, Risa H.; Weiner, Benjamin J.; Wiklind, Tommy; Wild, Vivienne; Wilson, Grant; Wuyts, Stijn; Yun, Min S.

    2011-01-01

    This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z approximate to 1.5-8, and to study

  1. Dissecting the Gravitational lens B1608+656 : II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Auger, M. W.; Hilbert, S.; Blandford, R. D.; Koopmans, L. V. E.; Fassnacht, C. D.; Treu, T.

    2010-01-01

    Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep

  2. Space Telescope and Optical Reverberation Mapping Project.I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope

    NARCIS (Netherlands)

    De Rosa, G.; Peterson, B.M.; Ely, J.; Kriss, G.A.; Crenshaw, D.M.; Horne, K.; Korista, K.T.; Netzer, H.; Pogge, R.W.; Arévalo, P.; Barth, A.J.; Bentz, M.C.; Brandt, W.N.; Breeveld, A.A.; Brewer, B.J.; Dalla Bontà, E.; De Lorenzo-Cáceres, A.; Denney, K.D.; Dietrich, M.; Edelson, R.; Evans, P.A.; Fausnaugh, M.M.; Gehrels, N.; Gelbord, J.M.; Goad, M.R.; Grier, C.J.; Grupe, D.; Hall, P.B.; Kaastra, J.; Kelly, B.C.; Kennea, J.A.; Kochanek, C.S.; Lira, P.; Mathur, S.; McHardy, I.M.; Nousek, J.A.; Pancoast, A.; Papadakis, I.; Pei, L.; Schimoia, J.S.; Siegel, M.; Starkey, D.; Treu, T.; Uttley, P.; Vaughan, S.; Vestergaard, M.; Villforth, C.; Yan, H.; Young, S.; Zu, Y.

    2015-01-01

    We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and

  3. Correcting a statistical artifact in the estimation of the Hubble; constant based on Type Ia Supernovae results in a change in estimate; of 1.2%

    DEFF Research Database (Denmark)

    Petersen, JH; Holst, KK; Budtz-Jørgensen, Esben

    2010-01-01

    The Hubble constant enters big bang cosmology by quantifying the expansion rate of the universe. Existing statistical methods used to estimate Hubble’s constant only partially take into account random measurement errors. As a consequence, estimates of Hubble’s constant are statistically...

  4. A determination of H-0 with the class gravitational lens B1608+656. II. Mass models and the Hubble constant from lensing

    NARCIS (Netherlands)

    Koopmans, LVE; Fassnacht, CD

    1999-01-01

    We present mass models of the four-image gravitational lens system B1608 + 656, based on information obtained through VLBA imaging, VLA monitoring, and Hubble Space Telescope (HST) WFPC2 and NICMOS imaging. We have determined a mass model for the lens galaxies that reproduces (1) all image positions

  5. Automated Morphological Classification in Deep Hubble Space Telescope UBVI Fields: Rapidly and Passively Evolving Faint Galaxy Populations

    Science.gov (United States)

    Odewahn, Stephen C.; Windhorst, Rogier A.; Driver, Simon P.; Keel, William C.

    1996-11-01

    We analyze deep Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) images in U, B, V, I using artificial neural network (ANN) classifiers, which are based on galaxy surface brightness and light profile (but not on color nor on scale length, rhl). The ANN distinguishes quite well between E/S0, Sabc, and Sd/Irr+M galaxies (M for merging systems) for BJ ~ 24 mag. The faint blue galaxy counts in the B band are dominated by Sd/Irr+M galaxies and can be explained by a moderately steep local luminosity function (LF) undergoing strong luminosity evolution. We suggest that these faint late-type objects (24 mag <~ BJ <~ 28 mag) are a combination of low-luminosity lower redshift dwarf galaxies, plus compact star-forming galaxies and merging systems at z ~= 1--3, possibly the building blocks of the luminous early-type galaxies seen today.

  6. TOWARD A NEW GEOMETRIC DISTANCE TO THE ACTIVE GALAXY NGC 4258. III. FINAL RESULTS AND THE HUBBLE CONSTANT

    International Nuclear Information System (INIS)

    Humphreys, E. M. L.; Reid, M. J.; Moran, J. M.; Greenhill, L. J.; Argon, A. L.

    2013-01-01

    We report a new geometric maser distance estimate to the active galaxy NGC 4258. The data for the new model are maser line-of-sight (LOS) velocities and sky positions from 18 epochs of very long baseline interferometry observations, and LOS accelerations measured from a 10 yr monitoring program of the 22 GHz maser emission of NGC 4258. The new model includes both disk warping and confocal elliptical maser orbits with differential precession. The distance to NGC 4258 is 7.60 ± 0.17 ± 0.15 Mpc, a 3% uncertainty including formal fitting and systematic terms. The resulting Hubble constant, based on the use of the Cepheid variables in NGC 4258 to recalibrate the Cepheid distance scale, is H 0 = 72.0 ± 3.0 km s –1 Mpc –1

  7. Astrometry with Hubble Space Telescope Fine Guidance Sensor 3: The Parallax of the Cataclysmic Variable RW Triangulum

    Science.gov (United States)

    McArthur, B. E.; Benedict, G. F.; Lee, J.; Lu, C.-L.; van Altena, W. F.; Deliyannis, C. P.; Girard, T.; Fredrick, L. W.; Nelan, E.; Duncombe, R. L.; Hemenway, P. D.; Jefferys, W. H.; Shelus, P. J.; Franz, O. G.; Wasserman, L. H.

    1999-07-01

    RW Triangulum (RW Tri) is a 13th magnitude nova-like cataclysmic variable star with an orbital period of 0.2319 days (5.56 hr). Infrared observations of RW Tri indicate that its secondary is most likely a late-K dwarf (Dhillon). Past analyses predicted a distance of 270 pc, derived from a blackbody fit to the spectrum of the central part of the disk (Rutten, van Paradijs, & Tinbergen). Recently completed Hubble Space Telescope Fine Guidance Sensor interferometric observations allow us to determine the first trigonometric parallax to RW Tri. This determination puts the distance of RW Tri at 341-31+38, one of the most distant objects with a direct parallax measurement. We compare our result with methods previously employed to estimate distances to cataclysmic variables.

  8. Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Microanalysis and Recognition of Micrometeoroid Compositions

    Science.gov (United States)

    Kearsley, A. T.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.; Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V. V.; Colaux, J. L.; hide

    2014-01-01

    Postflight surveys of the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope have located hundreds of features on the 2.2 by 0.8 m curved plate, evidence of hypervelocity impact by small particles during 16 years of exposure to space in low Earth orbit (LEO). The radiator has a 100 - 200 micron surface layer of white paint, overlying 4 mm thick Al alloy, which was not fully penetrated by any impact. Over 460 WFPC2 samples were extracted by coring at JSC. About half were sent to NHM in a collaborative program with NASA, ESA and IBC. The structural and compositional heterogeneity at micrometer scale required microanalysis by electron and ion beam microscopes to determine the nature of the impactors (artificial orbital debris, or natural micrometeoroids, MM). Examples of MM impacts are described elsewhere. Here we describe the development of novel electron beam analysis protocols, required to recognize the subtle traces of MM residues.

  9. Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters

    Science.gov (United States)

    Robertson, Brant E.; Ellis, Richard S.; Dunlop, James S.; McLure, Ross J.; Stark, Dan P.; McLeod, Derek

    2014-12-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ~35% at redshift z ~ 7 to >~ 65% at z ~ 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.

  10. Micrometeoroid Impacts on the Hubble Sace Telescope Wide Field and Planetary Camera 2: Ion Beam Analysis of Subtle Impactor Traces

    Science.gov (United States)

    Grime, G. W.; Webb, R. P.; Jeynes, C.; Palitsin, V. V.; Colaux, J. L.; Kearsley, A. T.; Ross, D. K.; Anz-Meador, P.; Liou, J. C.; Opiela, J.; hide

    2014-01-01

    Recognition of origin for particles responsible for impact damage on spacecraft such as the Hubble Space Telescope (HST) relies upon postflight analysis of returned materials. A unique opportunity arose in 2009 with collection of the Wide Field and Planetary Camera 2 (WFPC2) from HST by shuttle mission STS-125. A preliminary optical survey confirmed that there were hundreds of impact features on the radiator surface. Following extensive discussion between NASA, ESA, NHM and IBC, a collaborative research program was initiated, employing scanning electron microscopy (SEM) and ion beam analysis (IBA) to determine the nature of the impacting grains. Even though some WFPC2 impact features are large, and easily seen without the use of a microscope, impactor remnants may be hard to find.

  11. Characterizing Io’s Pele, Tvashtar and Pillan plumes: Lessons learned from Hubble

    Science.gov (United States)

    Jessup, Kandis Lea; Spencer, John R.

    2012-03-01

    Hubble Space Telescope/Wide Field and Planetary Camera 2 (HST/WFPC2) images of Io obtained between 1995 and 2007 between 0.24 and 0.42 μm led to the detection of the Pele plume in reflected sunlight in 1995 and 1999; imaging of the Pele plume via absorption of jovian light in 1996 and 1999; detection of the Prometheus-type Pillan plume in reflected sunlight in 1997; and detection of the 2007 Pele-type Tvashtar plume eruption in reflected sunlight and via absorption of jovian light. Based on a detailed analysis of these observations we characterize and compare the gas and dust properties of each of the detected plumes. In each case, the brightness of the plumes in reflected sunlight is less at 0.26 μm than at 0.33 μm. Mie scattering analysis of the wavelength dependence of each plume’s reflectance signature suggests that range of particle sizes within the plumes is quite narrow. Assuming a normal distribution of particle sizes, the range of mean particle sizes is ∼0.035-0.12 μm for the 1997 Pillan eruption, ∼0.05-0.08 μm for the 1999 Pele and 2007 Tvasthar plumes, and ∼0.05-0.11 μm for the 1995 Pele plume, and in each case the standard deviation in the particle size distribution is Pele eruption released ∼109 g of SO2 dust, the 1997 Pillan eruption released ∼1010 g of SO2 dust, and the 1995 Pele plume may have released ∼1010 g of SO2 dust. Analysis of the plume absorption signatures recorded in the F255W filter bandpass (0.24-0.28 μm) indicates that the opacity of the 2007 Tvashtar plume was 2× that of the 1996 and 1999 Pele plume eruptions. While the sulfur dust density estimated for the Tvashtar from the reflected sunlight data could have produced 61% of the observed plume opacity, Pele F255W plume opacity could have resulted from the SO2 dust detected in the eruption. Accounting for the remaining F255W opacity level of the Pele and Tvasthar plumes based on SO2 and S2 gas absorption, the SO2 and S2 gas density inferred for each plume is

  12. Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results

    Science.gov (United States)

    Gardner, J. P.; Straughn, Amber N.; Meurer, Gerhardt R.; Pirzkal, Norbert; Cohen, Seth H.; Malhotra, Sangeeta; Rhoads, james; Windhorst, Rogier A.; Gardner, Jonathan P.; Hathi, Nimish P.; hide

    2007-01-01

    The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) grism PEARS (Probing Evolution And Reionization Spectroscopically) survey provides a large dataset of low-resolution spectra from thousands of galaxies in the GOODS North and South fields. One important subset of objects in these data are emission-line galaxies (ELGs), and we have investigated several different methods aimed at systematically selecting these galaxies. Here we present a new methodology and results of a search for these ELGs in the PEARS observations of the Hubble Ultra Deep Field (HUDF) using a 2D detection method that utilizes the observation that many emission lines originate from clumpy knots within galaxies. This 2D line-finding method proves to be useful in detecting emission lines from compact knots within galaxies that might not otherwise be detected using more traditional 1D line-finding techniques. We find in total 96 emission lines in the HUDF, originating from 81 distinct "knots" within 63 individual galaxies. We find in general that [0 1111 emitters are the most common, comprising 44% of the sample, and on average have high equivalent widths (70% of [0 1111 emitters having rest-frame EW> 100A). There are 12 galaxies with multiple emitting knots; several show evidence of variations in H-alpha flux in the knots, suggesting that the differing star formation properties across a single galaxy can in general be probed at redshifts approximately greater than 0.2 - 0.4. The most prevalent morphologies are large face-on spirals and clumpy interacting systems, many being unique detections owing to the 2D method described here, thus highlighting the strength of this technique.

  13. THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. III. A QUINTUPLE STELLAR POPULATION IN NGC 2808

    International Nuclear Information System (INIS)

    Milone, A. P.; Marino, A. F.; Jerjen, H.; Piotto, G.; Renzini, A.; Bedin, L. R.; Anderson, J.; Bellini, A.; Cassisi, S.; Pietrinferni, A.; D’Antona, F.; Ventura, P.

    2015-01-01

    In this study we present the first results from multi-wavelength Hubble Space Telescope (HST) observations of the Galactic globular cluster (GC) NGC 2808 as an extension of the Hubble Space Telescope UV Legacy Survey of Galactic GCs (GO-13297 and previous proprietary and HST archive data). Our analysis allowed us to disclose a multiple-stellar-population phenomenon in NGC 2808 even more complex than previously thought. We have separated at least five different populations along the main sequence and the red giant branch (RGB), which we name A, B, C, D, and E (though an even finer subdivision may be suggested by the data). We identified the RGB bump in four out of the five RGBs. To explore the origin of this complex color–magnitude diagram, we have combined our multi-wavelength HST photometry with synthetic spectra, generated by assuming different chemical compositions. The comparison of observed colors with synthetic spectra suggests that the five stellar populations have different contents of light elements and helium. Specifically, if we assume that NGC 2808 is homogeneous in [Fe/H] (as suggested by spectroscopy for Populations B, C, D, E, but lacking for Population A) and that population A has a primordial helium abundance, we find that populations B, C, D, E are enhanced in helium by ΔY ∼ 0.03, 0.03, 0.08, 0.13, respectively. We obtain similar results by comparing the magnitude of the RGB bumps with models. Planned spectroscopic observations will test whether Population A also has the same metallicity, or whether its photometric differences with Population B can be ascribed to small [Fe/H] and [O/H] differences rather than to helium

  14. A Hubble Space Telescope Survey of the Disk Cluster Population of M31. II. Advanced Camera for Surveys Pointings

    Science.gov (United States)

    Krienke, O. K.; Hodge, P. W.

    2008-01-01

    This paper reports on a survey of star clusters in M31 based on archival images from the Hubble Space Telescope. Paper I reported results from images obtained with the Wide Field Planetary Camera 2 (WFPC2) and this paper reports results from the Advanced Camera for Surveys (ACS). The ACS survey has yielded a total of 339 star clusters, 52 of which—mostly globular clusters—were found to have been cataloged previously. As for the previous survey, the luminosity function of the clusters drops steeply for absolute magnitudes fainter than MV = -3 the implied cluster mass function has a turnover for masses less than a few hundred solar masses. The color-integrated magnitude diagram of clusters shows three significant features: (1) a group of very red, luminous objects: the globular clusters, (2) a wide range in color for the fainter clusters, representing a considerable range in age and reddening, and (3) a maximum density of clusters centered approximately at V = 21, B - V = 0.30, V - I = 0.50, where there are intermediate-age, intermediate-mass clusters with ages close to 500 million years and masses of about 2000 solar masses. We give a brief qualitative interpretation of the distribution of clusters in the CMDs in terms of their formation and destruction rates. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for research in astronomy, Inc., under NASA contract NAS 5-26555.

  15. Type-Ia supernova rates to redshift 2.4 from clash: The cluster lensing and supernova survey with Hubble

    International Nuclear Information System (INIS)

    Graur, O.; Rodney, S. A.; Riess, A. G.; Medezinski, E.; Maoz, D.; Jha, S. W.; Holoien, T. W.-S.; McCully, C.; Patel, B.; Postman, M.; Dahlen, T.; Strolger, L.-G.; Coe, D.; Bradley, L.; Koekemoer, A.; Benítez, N.; Molino, A.; Jouvel, S.; Nonino, M.; Balestra, I.

    2014-01-01

    We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, ∼13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z > 1.2. We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit on the SN Ia rate in the range 1.8 < z < 2.4. The results are consistent with the rates measured by the HST/GOODS and Subaru Deep Field SN surveys. We model these results together with previous measurements at z < 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of −1.00 −0.06(0.10) +0.06(0.09) (statistical) −0.08 +0.12 (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at >99% significance level.

  16. Type-Ia Supernova Rates to Redshift 2.4 from Clash: The Cluster Lensing and Supernova Survey with Hubble

    Science.gov (United States)

    Graur, O.; Rodney, S. A.; Maoz, D.; Riess, A. G.; Jha, S. W.; Postman, M.; Dahlen, T.; Holoien, T. W.-S.; McCully, C.; Patel, B.; hide

    2014-01-01

    We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, approximately 13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z greater than 1.2.We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit on the SN Ia rate in the range z greater than 1.8 and less than 2.4. The results are consistent with the rates measured by the HST/ GOODS and Subaru Deep Field SN surveys.We model these results together with previous measurements at z less than 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of 1.00 (+0.06(0.09))/(-0.06(0.10)) (statistical) (+0.12/-0.08) (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at greater than 99% significance level.

  17. THE UDF05 FOLLOW-UP OF THE HUBBLE ULTRA DEEP FIELD. III. THE LUMINOSITY FUNCTION AT z ∼ 6

    International Nuclear Information System (INIS)

    Su Jian; Stiavelli, Massimo; Bergeron, Eddie; Bradley, Larry; Dahlen, Tomas; Ferguson, Henry C.; Koekemoer, Anton; Lucas, Ray A.; Panagia, Nino; Pavlovsky, Cheryl; Oesch, Pascal; Carollo, Marcella; Lilly, Simon; Trenti, Michele; Giavalisco, Mauro; Mobasher, Bahram

    2011-01-01

    In this paper, we present a derivation of the rest-frame 1400 A luminosity function (LF) at redshift six from a new application of the maximum likelihood method by exploring the five deepest Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) fields, i.e., the Hubble Ultra Deep Field, two UDF05 fields, and two Great Observatories Origins Deep Survey fields. We work on the latest improved data products, which makes our results more robust than those of previous studies. We use unbinned data and thereby make optimal use of the information contained in the data set. We focus on the analysis to a magnitude limit where the completeness is larger than 50% to avoid possibly large errors in the faint end slope that are difficult to quantify. We also take into account scattering in and out of the dropout sample due to photometric errors by defining for each object a probability that it belongs to the dropout sample. We find the best-fit Schechter parameters to the z ∼ 6 LF are α = 1.87 ± 0.14, M * = -20.25 ± 0.23, and φ * = 1.77 +0.62 -0.49 x 10 -3 Mpc -3 . Such a steep slope suggests that galaxies, especially the faint ones, are possibly the main sources of ionizing photons in the universe at redshift six. We also combine results from all stu