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Sample records for spitzer captures cosmic

  1. COSMIC INFRARED BACKGROUND FLUCTUATIONS IN DEEP SPITZER INFRARED ARRAY CAMERA IMAGES: DATA PROCESSING AND ANALYSIS

    International Nuclear Information System (INIS)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2010-01-01

    This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale (∼>30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the ∼1-5 μm mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (∼>1 nW m -2 sr -1 at 3-5 μm), and thus consistent with current γ-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these

  2. Cosmic Infrared Background Fluctuations in Deep Spitzer Infrared Array Camera Images: Data Processing and Analysis

    Science.gov (United States)

    Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

    2010-01-01

    This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer Infrared Array Camera observations. The self-calibration we apply removes a strong instrumental signal from the fluctuations that would otherwise corrupt the results. The procedures and results for masking bright sources and modeling faint sources down to levels set by the instrumental noise are presented. Various tests are performed to demonstrate that the resulting power spectra of these fields are not dominated by instrumental or procedural effects. These tests indicate that the large-scale (gsim30') fluctuations that remain in the deepest fields are not directly related to the galaxies that are bright enough to be individually detected. We provide the parameterization of these power spectra in terms of separate instrument noise, shot noise, and power-law components. We discuss the relationship between fluctuations measured at different wavelengths and depths, and the relations between constraints on the mean intensity of the CIB and its fluctuation spectrum. Consistent with growing evidence that the ~1-5 μm mean intensity of the CIB may not be as far above the integrated emission of resolved galaxies as has been reported in some analyses of DIRBE and IRTS observations, our measurements of spatial fluctuations of the CIB intensity indicate the mean emission from the objects producing the fluctuations is quite low (gsim1 nW m-2 sr-1 at 3-5 μm), and thus consistent with current γ-ray absorption constraints. The source of the fluctuations may be high-z Population III objects, or a more local component of very low luminosity objects with clustering properties that differ from the resolved galaxies. Finally, we discuss the prospects of the upcoming space-based surveys to directly measure the epochs inhabited by the populations producing these source

  3. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Cappelluti, N.; Urry, M. [Yale Center for Astronomy and Astrophysics, P.O. Box 208120, New Haven, CT 06520 (United States); Arendt, R. [University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Kashlinsky, A. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Li, Y.; Hasinger, G. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Helgason, K. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Natarajan, P. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Finoguenov, A. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, D-85741, Garching bei München (Germany)

    2017-09-20

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer -IRAC cosmic infrared background and Chandra -ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ∼12 Ms of Chandra data collected over a total area of 0.3 deg{sup 2}. We report the first (>5 σ ) detection of a cross-power signal on large angular scales >20″ between [0.5–2] keV and the 3.6 and 4.5 μ m bands, at ∼5 σ and 6.3 σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5 σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  4. Probing Large-scale Coherence between Spitzer IR and Chandra X-Ray Source-subtracted Cosmic Backgrounds

    Science.gov (United States)

    Cappelluti, N.; Arendt, R.; Kashlinsky, A.; Li, Y.; Hasinger, G.; Helgason, K.; Urry, M.; Natarajan, P.; Finoguenov, A.

    2017-09-01

    We present new measurements of the large-scale clustering component of the cross-power spectra of the source-subtracted Spitzer-IRAC cosmic infrared background and Chandra-ACIS cosmic X-ray background surface brightness fluctuations Our investigation uses data from the Chandra Deep Field South, Hubble Deep Field North, Extended Groth Strip/AEGIS field, and UDS/SXDF surveys, comprising 1160 Spitzer hours and ˜12 Ms of Chandra data collected over a total area of 0.3 deg2. We report the first (>5σ) detection of a cross-power signal on large angular scales >20″ between [0.5-2] keV and the 3.6 and 4.5 μm bands, at ˜5σ and 6.3σ significance, respectively. The correlation with harder X-ray bands is marginally significant. Comparing the new observations with existing models for the contribution of the known unmasked source population at z < 7, we find an excess of about an order of magnitude at 5σ confidence. We discuss possible interpretations for the origin of this excess in terms of the contribution from accreting early black holes (BHs), including both direct collapse BHs and primordial BHs, as well as from scattering in the interstellar medium and intra-halo light.

  5. NEW MEASUREMENTS OF THE COSMIC INFRARED BACKGROUND FLUCTUATIONS IN DEEP SPITZER/IRAC SURVEY DATA AND THEIR COSMOLOGICAL IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kashlinsky, A. [SSAI, Lanham MD 20706 (United States); Arendt, R. G.; Mather, J.; Moseley, S. H. [Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ashby, M. L. N.; Fazio, G. G., E-mail: alexander.kashlinsky@nasa.gov [Center for Astrophysics, Cambridge, MA 02138 (United States)

    2012-07-01

    We extend previous measurements of cosmic infrared background (CIB) fluctuations to {approx}< 1 Degree-Sign using new data from the Spitzer Extended Deep Survey. Two fields with depths of {approx_equal} 12 hr pixel{sup -1} over three epochs are analyzed at 3.6 and 4.5 {mu}m. Maps of the fields were assembled using a self-calibration method uniquely suitable for probing faint diffuse backgrounds. Resolved sources were removed from the maps to a magnitude limit of mag{sub AB} {approx_equal} 25, as indicated by the level of the remaining shot noise. The maps were then Fourier transformed and their power spectra were evaluated. Instrumental noise was estimated from the time-differenced data, and subtracting this isolates the spatial fluctuations of the actual sky. The power spectra of the source-subtracted fields remain identical (within the observational uncertainties) for the three epochs indicating that zodiacal light contributes negligibly to the fluctuations. Comparing to 8 {mu}m power spectra shows that Galactic cirrus cannot account for the fluctuations. The signal appears isotropically distributed on the sky as required for an extragalactic origin. The CIB fluctuations continue to diverge to >10 times those of known galaxy populations on angular scales out to {approx}< 1 Degree-Sign . The low shot-noise levels remaining in the diffuse maps indicate that the large-scale fluctuations arise from the spatial clustering of faint sources well below the confusion noise. The spatial spectrum of these fluctuations is in reasonable agreement with an origin in populations clustered according to the standard cosmological model ({Lambda}CDM) at epochs coinciding with the first stars era.

  6. Detecting non-relativistic cosmic neutrinos by capture on tritium: phenomenology and physics potential

    Science.gov (United States)

    Long, Andrew J.; Lunardini, Cecilia; Sabancilar, Eray

    2014-08-01

    We study the physics potential of the detection of the Cosmic Neutrino Background via neutrino capture on tritium, taking the proposed PTOLEMY experiment as a case study. With the projected energy resolution of Δ ~ 0.15 eV, the experiment will be sensitive to neutrino masses with degenerate spectrum, m1 simeq m2 simeq m3 = mν gtrsim 0.1 eV. These neutrinos are non-relativistic today; detecting them would be a unique opportunity to probe this unexplored kinematical regime. The signature of neutrino capture is a peak in the electron spectrum that is displaced by 2 mν above the beta decay endpoint. The signal would exceed the background from beta decay if the energy resolution is Δ lesssim 0.7 mν . Interestingly, the total capture rate depends on the origin of the neutrino mass, being ΓD simeq 4 and ΓM simeq 8 events per year (for a 100 g tritium target) for unclustered Dirac and Majorana neutrinos, respectively. An enhancement of the rate of up to Script O(1) is expected due to gravitational clustering, with the unique potential to probe the local overdensity of neutrinos. Turning to more exotic neutrino physics, PTOLEMY could be sensitive to a lepton asymmetry, and reveal the eV-scale sterile neutrino that is favored by short baseline oscillation searches. The experiment would also be sensitive to a neutrino lifetime on the order of the age of the universe and break the degeneracy between neutrino mass and lifetime which affects existing bounds.

  7. Detecting non-relativistic cosmic neutrinos by capture on tritium: phenomenology and physics potential

    Energy Technology Data Exchange (ETDEWEB)

    Long, Andrew J.; Lunardini, Cecilia; Sabancilar, Eray, E-mail: andrewjlong@asu.edu, E-mail: Cecilia.Lunardini@asu.edu, E-mail: Eray.Sabancilar@asu.edu [Physics Department, Arizona State University, Tempe, Arizona 85287 (United States)

    2014-08-01

    We study the physics potential of the detection of the Cosmic Neutrino Background via neutrino capture on tritium, taking the proposed PTOLEMY experiment as a case study. With the projected energy resolution of Δ ∼ 0.15 eV, the experiment will be sensitive to neutrino masses with degenerate spectrum, m{sub 1} ≅ m{sub 2} ≅ m{sub 3} = m{sub ν} ∼> 0.1 eV. These neutrinos are non-relativistic today; detecting them would be a unique opportunity to probe this unexplored kinematical regime. The signature of neutrino capture is a peak in the electron spectrum that is displaced by 2 m{sub ν} above the beta decay endpoint. The signal would exceed the background from beta decay if the energy resolution is Δ ∼< 0.7 m{sub ν} . Interestingly, the total capture rate depends on the origin of the neutrino mass, being Γ{sup D} ≅ 4 and Γ{sup M} ≅ 8 events per year (for a 100 g tritium target) for unclustered Dirac and Majorana neutrinos, respectively. An enhancement of the rate of up to O(1) is expected due to gravitational clustering, with the unique potential to probe the local overdensity of neutrinos. Turning to more exotic neutrino physics, PTOLEMY could be sensitive to a lepton asymmetry, and reveal the eV-scale sterile neutrino that is favored by short baseline oscillation searches. The experiment would also be sensitive to a neutrino lifetime on the order of the age of the universe and break the degeneracy between neutrino mass and lifetime which affects existing bounds.

  8. Electron-capture Isotopes Could Constrain Cosmic-Ray Propagation Models

    Science.gov (United States)

    Benyamin, David; Shaviv, Nir J.; Piran, Tsvi

    2017-12-01

    Electron capture (EC) isotopes are known to provide constraints on the low-energy behavior of cosmic rays (CRs), such as reacceleration. Here, we study the EC isotopes within the framework of the dynamic spiral-arms CR propagation model in which most of the CR sources reside in the galactic spiral arms. The model was previously used to explain the B/C and sub-Fe/Fe ratios. We show that the known inconsistency between the 49Ti/49V and 51V/51Cr ratios remains also in the spiral-arms model. On the other hand, unlike the general wisdom that says the isotope ratios depend primarily on reacceleration, we find here that the ratio also depends on the halo size (Z h) and, in spiral-arms models, also on the time since the last spiral-arm passage ({τ }{arm}). Namely, EC isotopes can, in principle, provide interesting constraints on the diffusion geometry. However, with the present uncertainties in the lab measurements of both the electron attachment rate and the fragmentation cross sections, no meaningful constraint can be placed.

  9. Spitzer Reveals Stellar 'Family Tree'

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] High resolution poster version Generations of stars can be seen in this new infrared portrait from NASA's Spitzer Space Telescope. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Younger stars line the rims of the cavities, and some can be seen as pink dots at the tips of the elephant-trunk-like pillars. The white knotty areas are where the youngest stars are forming. Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. W5 spans an area of sky equivalent to four full moons and is about 6,500 light-years away in the constellation Cassiopeia. The Spitzer picture was taken over a period of 24 hours. Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star-formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars. This image contains some of the best evidence yet for the triggered star-formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities. This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

  10. Spitzer Telemetry Processing System

    Science.gov (United States)

    Stanboli, Alice; Martinez, Elmain M.; McAuley, James M.

    2013-01-01

    The Spitzer Telemetry Processing System (SirtfTlmProc) was designed to address objectives of JPL's Multi-mission Image Processing Lab (MIPL) in processing spacecraft telemetry and distributing the resulting data to the science community. To minimize costs and maximize operability, the software design focused on automated error recovery, performance, and information management. The system processes telemetry from the Spitzer spacecraft and delivers Level 0 products to the Spitzer Science Center. SirtfTlmProc is a unique system with automated error notification and recovery, with a real-time continuous service that can go quiescent after periods of inactivity. The software can process 2 GB of telemetry and deliver Level 0 science products to the end user in four hours. It provides analysis tools so the operator can manage the system and troubleshoot problems. It automates telemetry processing in order to reduce staffing costs.

  11. Spitzer Digs Up Galactic Fossil

    Science.gov (United States)

    2004-01-01

    with stars, infrared images (middle and right), reveal a never-before-seen bundle of stars, called a globular cluster. The left panel is from the California Institute of Technology's Digitized Sky Survey; the middle panel includes images from the NASA-funded Two Micron All-Sky Survey and the University of Wyoming Infrared Observatory (circle inset); and the right panel is from NASA's Spitzer Space Telescope. The Two Micron All-Sky Survey false-color image was obtained using near-infrared wavelengths ranging from 1.3 to 2.2 microns. The University of Wyoming Observatory false-color image was captured on July 31, 2004, at wavelengths ranging from 1.2 to 2.2 microns. The Spitzer false-color image composite was taken on April 21, 2004, by its infrared array camera. It is composed of images obtained at four mid-infrared wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

  12. Efficient Mosaicking of Spitzer Space Telescope Images

    Science.gov (United States)

    Jacob, Joseph; Makovoz, David; Eisenhardt, Peter

    2007-01-01

    A parallel version of the MOPEX software, which generates mosaics of infrared astronomical images acquired by the Spitzer Space Telescope, extends the capabilities of the prior serial version. In the parallel version, both the input image space and the output mosaic space are divided among the available parallel processors. This is the only software that performs the point-source detection and the rejection of spurious imaging effects of cosmic rays required by Spitzer scientists. This software includes components that implement outlier-detection algorithms that can be fine-tuned for a particular set of image data by use of a number of adjustable parameters. This software has been used to construct a mosaic of the Spitzer Infrared Array Camera Shallow Survey, which comprises more than 17,000 exposures in four wavelength bands from 3.6 to 8 m and spans a solid angle of about 9 square degrees. When this software was executed on 32 nodes of the 1,024-processor Cosmos cluster computer at NASA s Jet Propulsion Laboratory, a speedup of 8.3 was achieved over the serial version of MOPEX. The performance is expected to improve dramatically once a true parallel file system is installed on Cosmos.

  13. Spitzer Spies Spectacular Sombrero

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2 NASA's Spitzer Space Telescope set its infrared eyes on one of the most famous objects in the sky, Messier 104, also called the Sombrero galaxy. In this striking infrared picture, Spitzer sees an exciting new view of a galaxy that in visible light has been likened to a 'sombrero,' but here looks more like a 'bulls-eye.' Recent observations using Spitzer's infrared array camera uncovered the bright, smooth ring of dust circling the galaxy, seen in red. In visible light, because this galaxy is seen nearly edge-on, only the near rim of dust can be clearly seen in silhouette. Spitzer's full view shows the disk is warped, which is often the result of a gravitational encounter with another galaxy, and clumpy areas spotted in the far edges of the ring indicate young star-forming regions. Spitzer's infrared view of the starlight from this galaxy, seen in blue, can pierce through obscuring murky dust that dominates in visible light. As a result, the full extent of the bulge of stars and an otherwise hidden disk of stars within the dust ring are easily seen. The Sombrero galaxy is located some 28 million light years away. Viewed from Earth, it is just six degrees south of its equatorial plane. Spitzer detected infrared emission not only from the ring, but from the center of the galaxy too, where there is a huge black hole, believed to be a billion times more massive than our Sun. This picture is composed of four images taken at 3.6 (blue), 4.5 (green), 5.8 (orange), and 8.0 (red) microns. The contribution from starlight (measured at 3.6 microns) has been subtracted from the 5.8 and 8-micron images to enhance the visibility of the dust features. In figure 1, the new picture of Messier 104 combines a recent infrared observation from NASA's Spitzer Space Telescope with a well-known visible light image from the

  14. Scheduling Spitzer: The SIRPASS Story

    Science.gov (United States)

    Mittman, David S.; Hawkins, Robert

    2013-01-01

    NASA's Spitzer Space Telescope was launched on August 25, 2003 from Florida's Cape Canaveral Air Force Base. Drifting in a unique Earth-trailing orbit around the Sun, Spitzer sees an optically invisible universe dominated by dust and stars. Since 1997, the Spitzer Integrated Resource Planning and Scheduling System (SIRPASS) has helped produce spacecraft activity plans for the Spitzer Space Telescope. SIRPASS is used by members of the Observatory Planning and Scheduling Team to plan, schedule and sequence the Telescope from data made available to them from the science and engineering community. Because of the volume of data that needs to be scheduled, SIRPASS offers a variety of automated assistants to aid in this task. This paper will describe the functional elements of the SIRPASS software system -- emphasizing the role that automation plays in the system -- and will highlight lessons learned for the software developer from a decade of Spitzer Space Telescope operations experience.

  15. Parallel MOPEX: Computing Mosaics of Large-Area Spitzer Surveys on a Cluster Computer

    Directory of Open Access Journals (Sweden)

    Joseph C. Jacob

    2007-01-01

    Full Text Available The Spitzer Science Center's MOPEX software is a part of the Spitzer Space Telescope's operational pipeline that enables detection of cosmic ray collisions with the detector array, masking of the corrupted pixels due to these collisions, subsequent mosaicking of image fields, and extraction of point sources to create catalogs of celestial objects. This paper reports on our experiences in parallelizing the parts of MOPEX related to cosmic ray rejection and mosaicking on a 1,024-processor cluster computer at NASA's Jet Propulsion Laboratory. The architecture and performance of the new Parallel MOPEX software are described. This work was done in order to rapidly mosaic the IRAC shallow survey data, covering a region of the sky observed with one of Spitzer's infrared instruments for the study of galaxy clusters, large-scale structure, and brown dwarfs.

  16. Exoplanet Characterization With Spitzer Eclipses

    Science.gov (United States)

    Harrington, Joseph

    We will analyze our existing Spitzer eclipse data for 11 exoplanets (GJ 436b, WASP-8b, WASP-29b, WASP-11b, TrES-1, WASP-34b, WASP-43b, HD 209458b, HAT-P-30b, HAT-P-13b, and WASP-12b) along with all other Spitzer eclipse and transit data for these systems (723 hours of total data). In combination with transit results, these measurements reveal the surface fluxes emitted by the planets' atmospheres in the six Spitzer bandpasses (3.6, 4.5, 5.8, 8.0, 16, and 24 1-4m), as well as orbital eccentricity and in a few cases possibly even precession rate. The fluxes, in turn, can constrain atmospheric composition and thermal profiles. We propose here to analyze data for these planets using Monte Carlo-driven, radiative-transfer, model-fitting codes; to conduct aggregate analyses; and to develop and share statistical modeling tools. Secondary eclipses provide us with a unique way to characterize exoplanetary atmospheres. Since other techniques like spectroscopy divide the planetary signal into many channels, they require very high signal-to-noise ratio (S/N) and are only possible for a few planets. Broadband eclipse photometry is thus the only technique that can measure dozens of atmospheres and identify the mechanisms that cause planets at a given irradiation level to behave so differently from one another. Until JWST becomes available, the broad variety of Spitzer data that we already have in hand, along with observations from the Hubble Space Telescope and possibly SOFIA, are our best way to understand the wide diversity of exoplanetary atmospheres. Since 2010, the team has produced six papers from a new, highly modular pipeline that implements optimal methods for analysis of Spitzer photometric time series, and our efficiency is increasing. The sensitivity needed for these measurements is up to 100 times better than Spitzer's design criteria, so careful treatment of systematic error is critically important and first-order approximations rarely work. The new pipeline

  17. RELICS of the Cosmic Dawn

    Science.gov (United States)

    Bradac, Marusa; Coe, Dan; Huang, Kuang-Han; Salmon, Brett; Hoag, Austin; Bradley, Larry; Ryan, Russell; Dawson, Will; Zitrin, Adi; Jones, Christine; Sharon, Keren; Trentu, Michele; Stark, Daniel; Bouwens, Rychard; Oesch, Pascal; Lam, Daniel; Patricia Carasco Nunez, Daniela; Paterno-Mahler, Rachel; Strait, Victoria

    2017-10-01

    When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and epoch of reionization? Recent observations indicate at least two critical puzzles in these studies. (1) First galaxies might have started forming stars earlier than previously thought (still unclear what is their star formation history and whether these galaxies can reionize the Universe. Accurate knowledge of stellar masses, ages, and star formation rates at this epoch requires measuring both rest-frame UV and optical light, which only Spitzer and HST can probe at z 6-11 for a large enough sample of typical galaxies. To address this cosmic puzzle, we propose Spitzer imaging of the fields behind the most powerful cosmic telescopes selected using HST, Spitzer, and Planck data from the RELICS and SRELICS programs (Reionization Lensing Cluster Survey; 41 clusters, 190 HST orbits, 550 Spitzer hours). This proposal will be a valuable Legacy complement to the existing IRAC deep surveys, and it will open up a new parameter space by probing the ordinary yet magnified population with much improved sample variance. The program will allow us to study stellar properties of a large number, 20 galaxies at z 6-11. Deep Spitzer data will be crucial to unambiguously measure their stellar properties (age, SFR, M*). Finally this proposal is a unique opportunity to establish the presence (or absence) of an unusually early established stellar population, as was recently observed in MACS1149JD at z 9. If confirmed, this result will require a paradigm shift in our understanding of the earliest star formation.

  18. Spitzer - Hot & Colorful Student Activities

    Science.gov (United States)

    McDonald, D.; Rebull, L. M.; DeWolf, C.; Guastella, P.; Johnson, C. H.; Schaefers, J.; Spuck, T.; McDonald, J. G., III; DeWolf, T.; Brock, S.; Boerma, J.; Bemis, G.; Paulsen, K.; Yueh, N.; Peter, A.; Wassmer, W.; Haber, R.; Scaramucci, A.; Butchart, J.; Holcomb, A.; Karns, B.; Kennedy, S.; Siegel, R.; Weiser, S.

    2009-01-01

    In this poster, we present the results of several activities developed for the general science student to explore infrared light. The first activity involved measuring infrared radiation using an updated version of Newton's experiment of splitting white light and finding IR radiation. The second used Leslie's cube to allow students to observe different radiators, while the third used a modern infrared thermometer to measure and identify IR sources in an enclosed box. The last activity involved students making false-color images from narrow-band filter images from data sets from Spitzer Space Telescope, STScI Digitized Sky Survey and other sources. Using computer programs like Adobe Photoshop and free software such as ds9, Spot and Leopard, poster-like images were created by the students. This research is funded by the Spitzer Science Center (SSC) and the National Optical Astronomy Observatory (NOAO). Please see our companion poster, Johnson et al., on the science aspect of this program, and another poster on the educational aspects, Guastella et al.

  19. Spitzer Science Center within an Enterprise Architecture

    Science.gov (United States)

    Handley, T.

    2007-10-01

    The Spitzer Science Center's (SSC) evolutionary development approach, coupled with a flexible, scaleable hardware and software architecture has been key in Spitzer's ability to handle an explosion of data products, evolving data definitions, and changing data quality requirements. Spitzer is generating (depending on the campaign and instrument) about 10 TB of pre-archive data every 14 to 20 days. This generally reduces to between 3 TB and 6 TB of standard products, again depending on the campaign and instrument. This paper will discuss (1) the Spitzer Science Center's responses to evolving data, quality, and processing requirements and (2) how robust or not was the original architecture to allow Spitzer to accommodate on-going change.

  20. Hunting Elusive SPRITEs with Spitzer

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    In recent years, astronomers have developed many wide-field imaging surveys in which the same targets are observed again and again. This new form of observing has allowed us to discover optical and radio transients explosive or irregular events with durations ranging from seconds to years. The dynamic infrared sky, however, has remained largely unexplored until now.Infrared ExplorationExample of a transient: SPIRITS 14ajc was visible when imaged by SPIRITS in 2014 (left) but it wasnt there during previous imaging between 2004 and 2008 (right). The bottom frame shows the difference between the two images. [Adapted from Kasliwal et al. 2017]Why hunt for infrared transients? Optical wavelengths dont allow us to observe events that are obscured, such that their own structure or their surroundings hide them from our view. Both supernovae and luminous red novae (associated with stellar mergers) are discoverable as infrared transients, and there may well be new types of transients in infrared that we havent seen before!To explore this uncharted territory, a team of scientists developed SPIRITS, the Spitzer Infrared Intensive Transients Survey. Begun in 2014, SPIRITS is a five-year long survey that uses the Spitzer Space Telescope to conduct a systematic search for mid-infrared transients in nearby galaxies.In a recent publication led by Mansi Kasliwal (Caltech and the Carnegie Institution for Science), the SPIRITS team has now detailed how their survey works and what theyve discovered in its first year.The light curves of SPRITEs (red stars) lie in the mid-infared luminosity gap between novae (orange) and supernovae (blue). [Kasliwal et al. 2017]Mystery TransientsKasliwal and collaborators used Spitzer to monitor 190 nearby galaxies. In SPIRITS first year, they found over 1958 variable stars and 43 infrared transient sources. Of these 43 transients, 21 were known supernovae, 4 were in the luminosity range of novae, and 4 had optical counterparts. The remaining 14 events

  1. Cosmic strings and cosmic structure

    International Nuclear Information System (INIS)

    Albrecht, A.; Brandenberger, R.; Turok, N.

    1987-01-01

    The paper concerns the application of the theory of cosmic strings to explain the structure of the Universe. The formation of cosmic strings in the early Universe is outlined, along with the Big Bang theory, Grand Unified theories, and the first three minutes after the Big Bang. A description is given of the shaping of the Universe by cosmic strings, including the evolution of the string. The possibility for direct observation of cosmic strings is discussed. (U.K.)

  2. Lyman Spitzer: Life, Times, and Science

    Indian Academy of Sciences (India)

    Lyman Spitzer was one of the major figures of twentieth centurytheoretical astrophysics. Over more than fifty years,he kept up sustained research of his own, on problems concerningthe interstellar medium, star formation, and galaxies.In addition he was a major influence on observationalprogrammes, and created a thriving ...

  3. Spitzer Parallax of OGLE-2015-BLG-0966

    DEFF Research Database (Denmark)

    Street, R. A.; Udalski, A.; Calchi Novati, S.

    2016-01-01

    We report the detection of a cold Neptune mplanet = 21 ± 2 M⊕ orbiting a 0.38 M⊙ M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real...

  4. Lyman Spitzer: Life, Times, and Science

    Indian Academy of Sciences (India)

    College, Cambridge, in the academic year 1935–36. It was com- mon in those days for promising students from the United States to spend some time in England or Europe – the precise opposite of the situation today! Cambridge exposed Spitzer to the most distinguished astrophysi- cist of that time – Arthur Eddington.

  5. Cosmic particles

    International Nuclear Information System (INIS)

    Fritszh, Harald; Max-Planck-Institut fuer Physik und Astrophysik, Muenchen

    1986-01-01

    The paper on 'Cosmic particles' was presented at the conference on 'The early universe and its evolution', Erice, Italy 1986. The link between ideas in cosmology and in elementary particle physics is examined. The subject is discussed under the following topic headings: cosmic kinetics, cosmic dynamics and general relativity, dynamics of the dust universe, particle physics, unity of quarks and leptons, the hot universe and standard particle physics, creation of matter, and the inflation of the universe. (U.K.)

  6. Spitzer secondary eclipses of Qatar-1b

    Science.gov (United States)

    Garhart, Emily; Deming, Drake; Mandell, Avi; Knutson, Heather; Fortney, Jonathan J.

    2018-02-01

    Aims: Previous secondary eclipse observations of the hot Jupiter Qatar-1b in the Ks band suggest that it may have an unusually high day side temperature, indicative of minimal heat redistribution. There have also been indications that the orbit may be slightly eccentric, possibly forced by another planet in the system. We investigate the day side temperature and orbital eccentricity using secondary eclipse observations with Spitzer. Methods: We observed the secondary eclipse with Spitzer/IRAC in subarray mode, in both 3.6 and 4.5 μm wavelengths. We used pixel-level decorrelation to correct for Spitzer's intra-pixel sensitivity variations and thereby obtain accurate eclipse depths and central phases. Results: Our 3.6 μm eclipse depth is 0.149 ± 0.051% and the 4.5 μm depth is 0.273 ± 0.049%. Fitting a blackbody planet to our data and two recent Ks band eclipse depths indicates a brightness temperature of 1506 ± 71 K. Comparison to model atmospheres for the planet indicates that its degree of longitudinal heat redistribution is intermediate between fully uniform and day-side only. The day side temperature of the planet is unlikely to be as high (1885 K) as indicated by the ground-based eclipses in the Ks band, unless the planet's emergent spectrum deviates strongly from model atmosphere predictions. The average central phase for our Spitzer eclipses is 0.4984 ± 0.0017, yielding e cos ω = -0.0028 ± 0.0027. Our results are consistent with a circular orbit, and we constrain e cos ω much more strongly than has been possible with previous observations. Tables of the lightcurve data are only 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/610/A55

  7. Cosmic impacts, cosmic catastrophes. I

    Science.gov (United States)

    Chapman, Clark R.; Morrison, David

    1989-01-01

    The discovery of cosmic impacts and their effects on the earth's surface are discussed. The manner in which the object impacts with the earth is described. The formation of crytovolcanic structures by craters is examined. Examples of cosmic debris collisions with earth, in particular the Tunguska explosion of 1908 and the Meteor Crater in Arizona, are provided.

  8. Planck, Herschel & Spitzer unveil overdense z>2 regions

    Science.gov (United States)

    Dole, Herve; Chary, Ranga-Ram; Chary, Ranga; Frye, Brenda; Martinache, Clement; Guery, David; Le Floc'h, Emeric; Altieri, Bruno; Flores-Cacho, Ines; Giard, Martin; Hurier, Guillaume; Lagache, Guilaine; Montier, Ludovic; Nesvadba, Nicole; Omont, Alain; Pointecouteau, Etienne; Pierini, Daniele; Puget, Jean-Loup; Scott, Douglas; Soucail, Genevieve

    2014-12-01

    At which cosmic epoch did massive galaxy clusters assemble their baryons? How does star formation occur in the most massive, most rapidly collapsing dark-matter-dense environments in the early Universe? To answer these questions, we take the completely novel approach to select the most extreme z>~2 star-forming overdensities seen over the entire sky. This selection nicely complements the other existing selections for high redshift clusters (i.e., by stellar mass, or by total mass like Sunyaev-Zeldovish (SZ) or X-ray selection). We make use of the Planck all-sky submillimetre survey to systematically identify the rarest, most luminous high-redshift sub-mm sources on the sky, either strongly gravitationally lensed galaxies, or the joint FIR/sub-mm emission from multiple intense starbursts. We observed 228 Planck sources with Herschel/SPIRE and discovered that most of them are overdensities of red galaxies with extremely high star formation rates (typically 7.e3 Msun/yr for a structure). Only Spitzer data can allow a better understanding of these promising Planck+Herschel selected sources, as is shown on a first set of IRAC data on 40 targets in GO9: (i) the good angular resolution and sensitivity of IRAC allows a proper determination of the clustered nature of each Herschel/SPIRE source; (ii) IRAC photometry (often associated with J, K) allows a good estimate of the colors and approximate photometric redshift. Note spectroscopic redshifts are available for two cluster candidates, at z=1.7 and z=2.3, confirming their high redshift nature. The successful GO9 observation of 40 fields showed that about half to be >7sigma overdensities of red IRAC sources. These observations were targeting the whole range of Herschel overdensities and significances. We need to go deeper into the Spitzer sample and acquire complete coverage of the most extreme Herschel overdensities (54 new fields). Such a unique sample has legacy value, and this is the last opportunity prior to JWST

  9. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Cook, David [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Bally, John [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Masci, Frank; Armus, Lee [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Bond, Howard E. [Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Contreras, Carlos [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Dykhoff, Devin A.; Amodeo, Samuel; Carlon, Robert L.; Cass, Alexander C.; Corgan, David T.; Faella, Joseph [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States); Boyer, Martha [NASA Goddard Space Flight Center, MC 665, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Cantiello, Matteo [Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010 (United States); Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2017-04-20

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr{sup −1} to >7 mag yr{sup −1}. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

  10. SPITZER SECONDARY ECLIPSES OF WASP-18b

    International Nuclear Information System (INIS)

    Nymeyer, Sarah; Harrington, Joseph; Hardy, Ryan A.; Stevenson, Kevin B.; Campo, Christopher J.; Blecic, Jasmina; Bowman, William C.; Britt, Christopher B. T.; Cubillos, Patricio; Madhusudhan, Nikku; Collier-Cameron, Andrew; Maxted, Pierre F. L.; Loredo, Thomas J.; Hellier, Coel; Anderson, David R.; Gillon, Michael; Hebb, Leslie; Wheatley, Peter J.; Pollacco, Don

    2011-01-01

    The transiting exoplanet WASP-18b was discovered in 2008 by the Wide Angle Search for Planets project. The Spitzer Exoplanet Target of Opportunity Program observed secondary eclipses of WASP-18b using Spitzer's Infrared Array Camera in the 3.6 μm and 5.8 μm bands on 2008 December 20, and in the 4.5 μm and 8.0 μm bands on 2008 December 24. We report eclipse depths of 0.30% ± 0.02%, 0.39% ± 0.02%, 0.37% ± 0.03%, 0.41% ± 0.02%, and brightness temperatures of 3100 ± 90, 3310 ± 130, 3080 ± 140, and 3120 ± 110 K in order of increasing wavelength. WASP-18b is one of the hottest planets yet discovered—as hot as an M-class star. The planet's pressure-temperature profile most likely features a thermal inversion. The observations also require WASP-18b to have near-zero albedo and almost no redistribution of energy from the day side to the night side of the planet.

  11. Serendipity Observations of Far Infrared Cirrus Emission in the Spitzer Infrared Nearby Galaxies Survey: Analysis of Far-Infrared Correlations

    Science.gov (United States)

    Bot, Caroline; Helou, George; Boulanger, François; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-04-01

    We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

  12. Cosmic impacts, cosmic catastrophes. II

    Science.gov (United States)

    Chapman, Clark R.; Morrison, David

    1990-01-01

    The role of extraterrestrial impacts in shaping the earth's history is discussed, arguing that cosmic impacts represent just one example of a general shift in thinking that has made the idea of catastrophes respectable in science. The origins of this view are presented and current catastrophic theory is discussed in the context of modern debate on the geological formation of the earth. Various conflicting theories are reviewed and prominent participants in the ongoing scientific controversy concerning catastrophism are introduced.

  13. The Cosmic Infrared Background Experiment

    Science.gov (United States)

    Bock, James; Battle, J.; Cooray, A.; Hristov, V.; Kawada, M.; Keating, B.; Lee, D.; Matsumoto, T.; Matsuura, S.; Nam, U.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.; Zemcov, M.

    2009-01-01

    We are developing the Cosmic Infrared Background ExpeRiment (CIBER) to search for signatures of first-light galaxy emission in the extragalactic background. The first generation of stars produce characteristic signatures in the near-infrared extragalactic background, including a redshifted Ly-cutoff feature and a characteristic fluctuation power spectrum, that may be detectable with a specialized instrument. CIBER consists of two wide-field cameras to measure the fluctuation power spectrum, and a low-resolution and a narrow-band spectrometer to measure the absolute background. The cameras will search for fluctuations on angular scales from 7 arcseconds to 2 degrees, where the first-light galaxy spatial power spectrum peaks. The cameras have the necessary combination of sensitivity, wide field of view, spatial resolution, and multiple bands to make a definitive measurement. CIBER will determine if the fluctuations reported by Spitzer arise from first-light galaxies. The cameras observe in a single wide field of view, eliminating systematic errors associated with mosaicing. Two bands are chosen to maximize the first-light signal contrast, at 1.6 um near the expected spectral maximum, and at 1.0 um; the combination is a powerful discriminant against fluctuations arising from local sources. We will observe regions of the sky surveyed by Spitzer and Akari. The low-resolution spectrometer will search for the redshifted Lyman cutoff feature in the 0.7 - 1.8 um spectral region. The narrow-band spectrometer will measure the absolute Zodiacal brightness using the scattered 854.2 nm Ca II Fraunhofer line. The spectrometers will test if reports of a diffuse extragalactic background in the 1 - 2 um band continues into the optical, or is caused by an under estimation of the Zodiacal foreground. We report performance of the assembled and tested instrument as we prepare for a first sounding rocket flight in early 2009. CIBER is funded by the NASA/APRA sub-orbital program.

  14. Spitzer IRS Observations of FU Orionis Objects

    Science.gov (United States)

    Green, J. D.; Hartmann, L.; Calvet, N.; Watson, D. M.; Ibrahimov, M.; Furlan, E.; Sargent, B.; Forrest, W. J.

    2006-09-01

    We present 5-35 μm spectra, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope, of five FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, BBW 76, and V346 Nor. All but V346 Nor reveal amorphous silicate grains in emission at 10 and 20 μm, and show water-vapor absorption bands at 5.8 and 6.8 μm and SiO or possibly methane absorption at 8 μm. These absorption features closely match these bands in model stellar photospheres-signs of the gaseous photospheres of the inner regions of these objects' accretion disks. The continuum emission at 5-8 μm is also consistent with such disks, and, for FU Orionis and BBW 76, longer wavelength emission may be fit by a model that includes moderate disk flaring. V1057 Cyg and V1515 Cyg have much more emission at longer wavelengths than the others, perhaps evidence of a substantial remnant of their natal, infalling envelopes.

  15. From Cosmic Dusk till Dawn with RELICS

    Science.gov (United States)

    Bradac, Marusa

    When did galaxies start forming stars? What is the role of distant galaxies in galaxy formation models and the epoch of reionization? What are the conditions in typical lowmass, star-forming galaxies at z 4? Why is galaxy evolution dependent on environment? Recent observations indicate several critical puzzles in studies that address these questions. Chief among these, galaxies might have started forming stars earlier than previously thought (0.5-11 for a sufficiently large sample of typical galaxies. This program will combine Spitzer imaging from two large programs, Director Discretionary Time (DDT) and the SRELICS program led by the PI.The main challenge in a study such as this is the capability to perform reliable photometry in crowded fields. Our team recently helped develop TPHOT, which is a much improved and much faster version of previously available codes. TPHOT is specifically designed to extract fluxes in crowded fields with very different PSFs. We will combine Spitzer photometry with ground based imaging and spectroscopy to obtain robust measurements of galaxy star formation rates, stellar masses, and stellar ages. This program will be a crucial legacy complement to previous Spitzer/IRAC deep blank field surveys and cluster studies, and will open up new parameter space by probing intrinsically fainter objects than most current surveys with a significantly improved sample variance over deep field surveys. It will allow us to study the properties (e.g. SFRs and stellar masses) of a large number of galaxies (200 at z=6-10), thus meeting our goal of reconstructing the cosmic SFR density with sufficient precision to better understand the role of galaxies in the reionization process. We will measure the presence (or absence) of established stellar populations with Spitzer for the largest sample to date. Furthermore this proposal will allow us to study the SFRs of the intrinsically faint (and magnified) intermediate redshift (z 4) galaxies, as well as the

  16. Capturing Thoughts, Capturing Minds?

    DEFF Research Database (Denmark)

    Nielsen, Janni

    2004-01-01

    Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention...

  17. COLORS OF ELLIPTICALS FROM GALEX TO SPITZER

    International Nuclear Information System (INIS)

    Schombert, James M.

    2016-01-01

    Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.

  18. SPITZER OBSERVATIONS OF YOUNG RED QUASARS

    International Nuclear Information System (INIS)

    Urrutia, Tanya; Lacy, Mark; Spoon, Henrik; Glikman, Eilat; Petric, Andreea; Schulz, Bernhard

    2012-01-01

    We present mid-infrared spectra and photometry of 13 redshift 0.4 < z < 1 dust reddened quasars obtained with Spitzer IRS and MIPS. We compare properties derived from their infrared spectral energy distributions (intrinsic active galactic nucleus (AGN) luminosity and far-infrared luminosity from star formation) to the host luminosities and morphologies from Hubble Space Telescope imaging, and black hole masses estimated from optical and/or near-infrared spectroscopy. Our results are broadly consistent with models in which most dust reddened quasars are an intermediate phase between a merger-driven starburst triggering a completely obscured AGN, and a normal, unreddened quasar. We find that many of our objects have high accretion rates, close to the Eddington limit. These objects tend to fall below the black hole mass-bulge luminosity relation as defined by local galaxies, whereas most of our low accretion rate objects are slightly above the local relation, as typical for normal quasars at these redshifts. Our observations are therefore most readily interpreted in a scenario in which galaxy stellar mass growth occurs first by about a factor of three in each merger/starburst event, followed sometime later by black hole growth by a similar amount. We do not, however, see any direct evidence for quasar feedback affecting star formation in our objects, for example, in the form of a relationship between accretion rate and star formation. Five of our objects, however, do show evidence for outflows in the [O III]5007 Å emission line profile, suggesting that the quasar activity is driving thermal winds in at least some members of our sample.

  19. COLORS OF ELLIPTICALS FROM GALEX TO SPITZER

    Energy Technology Data Exchange (ETDEWEB)

    Schombert, James M., E-mail: jschombe@uoregon.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2016-12-01

    Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.

  20. Capturing Thoughts, Capturing Minds?

    DEFF Research Database (Denmark)

    Nielsen, Janni

    2004-01-01

    Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention...... and probing about her actions and thoughts open for participatory analysis. Keywords usability test, cost effective, unobtrusive, TA, eye and cursor tracking, user experience, participatory analysis...

  1. SEDS: THE SPITZER EXTENDED DEEP SURVEY. SURVEY DESIGN, PHOTOMETRY, AND DEEP IRAC SOURCE COUNTS

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Hernquist, L.; Hora, J. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Arendt, R. [Observational Cosmology Laboratory, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Barmby, P. [University of Western Ontario, London, ON N6A 3K7 (Canada); Barro, G.; Faber, S.; Guhathakurta, P. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064 (United States); Bell, E. F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Bouwens, R. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Cattaneo, A. [Aix Marseille Universite, CNRS, Laboratoire d' Astrophysique de Marseille, UMR 7326, F-13388, Marseille (France); Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218 Hawthorn, VIC 3122 (Australia); Dave, R. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Dunlop, J. S. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Egami, E. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Finlator, K. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, CK-2100 Copenhagen O (Denmark); Grogin, N. A., E-mail: mashby@cfa.harvard.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2013-05-20

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg{sup 2} to a depth of 26 AB mag (3{sigma}) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 {mu}m. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 {+-} 1.0 and 4.4 {+-} 0.8 nW m{sup -2} sr{sup -1} at 3.6 and 4.5 {mu}m to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  2. Investigating Space Weather Events Impacting the Spitzer Space Telescope

    Science.gov (United States)

    Cheng, Leo Y.; Hunt, Joseph C. Jr.; Stowers, Kennis; Lowrance, Patrick; Stewart, Andrzej; Travis, Paul

    2014-01-01

    Our understanding of the dynamical process in the space environment has increased dramatically. A relatively new field of study called "Space Weather" has emerged in the last few decades. Fundamental to the study of space weather is an understanding of how space weather events such as solar flares and coronal mass ejections impact spacecraft in varying orbits and distances around the Sun. Specialized space weather satellite monitoring systems operated by the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) allow scientists to predict space weather events affecting critical systems on and orbiting the Earth. However, the Spitzer Space Telescope is in an orbit far outside the areas covered by those space weather monitoring systems. This poses a challenge for the Spitzer's Mission Operations Team in determining whether space weather events affect Spitzer.

  3. SPITZER IRAC PHOTOMETRY FOR TIME SERIES IN CROWDED FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Novati, S. Calchi; Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W.; Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bryden, G.; Henderson, C. B.; Shvartzvald, Y. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carey, S. [Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Udalski, A.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Collaboration: Spitzer team; OGLE group; and others

    2015-12-01

    We develop a new photometry algorithm that is optimized for the Infrared Array Camera (IRAC) Spitzer time series in crowded fields and that is particularly adapted to faint or heavily blended targets. We apply this to the 170 targets from the 2015 Spitzer microlensing campaign and present the results of three variants of this algorithm in an online catalog. We present detailed accounts of the application of this algorithm to two difficult cases, one very faint and the other very crowded. Several of Spitzer's instrumental characteristics that drive the specific features of this algorithm are shared by Kepler and WFIRST, implying that these features may prove to be a useful starting point for algorithms designed for microlensing campaigns by these other missions.

  4. Cosmic odyssey

    International Nuclear Information System (INIS)

    Heidmann, J.

    1989-01-01

    The immensity of the cosmos, the richness of the universe, the limits of space and time: these are the themes of Cosmic Odyssey, which takes the reader on imaginary journeys through the past, present and future of our universe. After a first look at the starry night sky, the enigmas posed since ancient times by the universe are reviewed. There then follows a broadbrush view of the universe as we understand it today. Following this, a trio of chapters take us to ultimate questions about its nature. The author explores in turn the relativistic universe, the quantum universe and the inflationary universe. Finally the journey returns to questions that touch on our own presence in the universe. Cosmology, the science of understanding the nature of the universe as a whole, has gone through an extraordinary revolution in its approach. This book explains in detail the link between particle physics and cosmology, the very early universe, the significance of Grand Unified Theory and superstrings, the magical qualities of the inflationary universe, and the seemingly bleak scenarios for the farthest future. (author)

  5. Cosmic Discovery

    Science.gov (United States)

    Harwit, Martin

    1984-04-01

    In the remarkable opening section of this book, a well-known Cornell astronomer gives precise thumbnail histories of the 43 basic cosmic discoveries - stars, planets, novae, pulsars, comets, gamma-ray bursts, and the like - that form the core of our knowledge of the universe. Many of them, he points out, were made accidentally and outside the mainstream of astronomical research and funding. This observation leads him to speculate on how many more major phenomena there might be and how they might be most effectively sought out in afield now dominated by large instruments and complex investigative modes and observational conditions. The book also examines discovery in terms of its political, financial, and sociological context - the role of new technologies and of industry and the military in revealing new knowledge; and methods of funding, of peer review, and of allotting time on our largest telescopes. It concludes with specific recommendations for organizing astronomy in ways that will best lead to the discovery of the many - at least sixty - phenomena that Harwit estimates are still waiting to be found.

  6. Measuring anisotropies in the cosmic neutrino background

    Science.gov (United States)

    Lisanti, Mariangela; Safdi, Benjamin R.; Tully, Christopher G.

    2014-10-01

    Neutrino capture on tritium has emerged as a promising method for detecting the cosmic neutrino background (C ν B ). We show that relic neutrinos are captured most readily when their spin vectors are antialigned with the polarization axis of the tritium nuclei and when they approach along the direction of polarization. As a result, C ν B observatories may measure anisotropies in the cosmic neutrino velocity and spin distributions by polarizing the tritium targets. A small dipole anisotropy in the C ν B is expected due to the peculiar velocity of the lab frame with respect to the cosmic frame and due to late-time gravitational effects. The PTOLEMY experiment, a tritium observatory currently under construction, should observe a nearly isotropic background. This would serve as a strong test of the cosmological origin of a potential signal. The polarized-target measurements may also constrain nonstandard neutrino interactions that would induce larger anisotropies and help discriminate between Majorana versus Dirac neutrinos.

  7. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

  8. ExploreNEOs: The Warm Spitzer Near Earth Object Survey

    NARCIS (Netherlands)

    Trilling, D. E.; Hora, J. L.; Mueller, M.; Thomas, C. A.; Harris, A. W.; Hagen, A. R.; Mommert, M.; Benner, L.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo, M.; Emery, J. P.; Fazio, G.; Kistler, J. L.; Mainzer, A.; Morbidelli, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.

    2012-01-01

    We have observed some 600 near Earth objects (NEOs) at 3.6 and 4.5 microns with the Warm Spitzer Space Telescope. We derive the albedo and diameter for each NEO to characterize global properties of the NEO population, among other goals.

  9. Robert Spitzer and psychiatric classification: technical challenges and ethical dilemmas.

    Science.gov (United States)

    Jacob, K S

    2016-01-01

    Dr Robert Leopold Spitzer (May 22, 1932-December 25, 2015), the architect of modern psychiatric diagnostic criteria and classification, died recently at the age of 83 in Seattle. Under his leadership, the American Psychiatric Association's (APA) Diagnostic and Statistical Manuals (DSM) became the international standard.

  10. Cosmic Interactions

    Science.gov (United States)

    2008-01-01

    An image based on data taken with ESO's Very Large Telescope reveals a triplet of galaxies intertwined in a cosmic dance. ESO PR Photo 02/08 ESO PR Photo 02/08 NGC 7173, 7174, and 7176 The three galaxies, catalogued as NGC 7173 (top), 7174 (bottom right) and 7176 (bottom left), are located 106 million light-years away towards the constellation of Piscis Austrinus (the 'Southern Fish'). NGC 7173 and 7176 are elliptical galaxies, while NGC 7174 is a spiral galaxy with quite disturbed dust lanes and a long, twisted tail. This seems to indicate that the two bottom galaxies - whose combined shape bears some resemblance to that of a sleeping baby - are currently interacting, with NGC 7176 providing fresh material to NGC 7174. Matter present in great quantity around the triplet's members also points to the fact that NGC 7176 and NGC 7173 have interacted in the past. Astronomers have suggested that the three galaxies will finally merge into a giant 'island universe', tens to hundreds of times as massive as our own Milky Way. ESO PR Photo 02/08 ESO PR Photo 02b/08 NGC 7173, 7174, and 7176 The triplet is part of a so-called 'Compact Group', as compiled by Canadian astronomer Paul Hickson in the early 1980s. The group, which is the 90th entry in the catalogue and is therefore known as HCG 90, actually contains four major members. One of them - NGC 7192 - lies above the trio, outside of this image, and is another peculiar spiral galaxy. Compact groups are small, relatively isolated, systems of typically four to ten galaxies in close proximity to one another. Another striking example is Robert's Quartet. Compact groups are excellent laboratories for the study of galaxy interactions and their effects, in particular the formation of stars. As the striking image reveals, there are many other galaxies in the field. Some are distant ones, while others seem to be part of the family. Studies made with other telescopes have indeed revealed that the HCG 90 group contains 16 members

  11. ALICE Cosmic Ray Detector

    CERN Multimedia

    Fernandez Tellez, A; Martinez Hernandez, M; Rodriguez Cahuantzi, M

    2013-01-01

    The ALICE underground cavern provides an ideal place for the detection of high energy atmospheric muons coming from cosmic ray showers. ACORDE detects cosmic ray showers by triggering the arrival of muons to the top of the ALICE magnet.

  12. SERENDIPITY OBSERVATIONS OF FAR INFRARED CIRRUS EMISSION IN THE SPITZER INFRARED NEARBY GALAXIES SURVEY: ANALYSIS OF FAR-INFRARED CORRELATIONS

    International Nuclear Information System (INIS)

    Bot, Caroline; Helou, George; Boulanger, Francois; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-01-01

    We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies.

  13. Cosmic Complexity

    Science.gov (United States)

    Mather, John C.

    2012-01-01

    neutrons, liberating a little energy and creating complexity. Then, the expanding universe cooled some more, and neutrons and protons, no longer kept apart by immense temperatures, found themselves unstable and formed helium nuclei. Then, a little more cooling, and atomic nuclei and electrons were no longer kept apart, and the universe became transparent. Then a little more cooling, and the next instability began: gravitation pulled matter together across cosmic distances to form stars and galaxies. This instability is described as a "negative heat capadty" in which extracting energy from a gravitating system makes it hotter -- clearly the 2nd law of thermodynamics does not apply here! (This is the physicist's part of the answer to e e cummings' question: what is the wonder that's keeping the stars apart?) Then, the next instability is that hydrogen and helium nuclei can fuse together to release energy and make stars burn for billions of years. And then at the end of the fuel source, stars become unstable and explode and liberate the chemical elements back into space. And because of that, on planets like Earth, sustained energy flows support the development of additional instabilities and all kinds of complex patterns. Gravitational instability pulls the densest materials into the core of the Earth, leaving a thin skin of water and air, and makes the interior churn incessantly as heat flows outwards. And the heat from the sun, received mostly near the equator and flowing towards the poles, supports the complex atmospheric and oceanic circulations. And because or that, the physical Earth is full of natural chemical laboratories, concentrating elements here, mixing them there, raising and lowering temperatures, ceaselessly experimenting with uncountable events where new instabilities can arise. At least one of them was the new experiment called life. Now that we know that there are at least as many planets as there are stars, it is hard to imagine that nature's ceasess

  14. Cosmic Radiation Detection and Observations

    Science.gov (United States)

    Ramirez Chavez, Juan; Troncoso, Maria

    Cosmic rays consist of high-energy particles accelerated from remote supernova remnant explosions and travel vast distances throughout the universe. Upon arriving at earth, the majority of these particles ionize gases in the upper atmosphere, while others interact with gas molecules in the troposphere and producing secondary cosmic rays, which are the main focus of this research. To observe these secondary cosmic rays, a detector telescope was designed and equipped with two silicon photomultipliers (SiPMs). Each SiPM is coupled to a bundle of 4 wavelength shifting optical fibers that are embedded inside a plastic scintillator sheet. The SiPM signals were amplified using a fast preamplifier with coincidence between detectors established using a binary logic gate. The coincidence events were recorded with two devices; a digital counter and an Arduino micro-controller. For detailed analysis of the SiPM waveforms, a DRS4 sensory digitizer captured the waveforms for offline analysis with the CERN software package Physics Analysis Workstation in a Linux environment. Results from our experiments would be presented. Hartnell College STEM Internship Program.

  15. Nasa Unveils Cosmic Images Book in Braille for Blind Readers

    Science.gov (United States)

    2008-01-01

    BALTIMORE - At a Tuesday ceremony at the National Federation of the Blind, NASA unveiled a new book that brings majestic images taken by its Great Observatories to the fingertips of the blind. "Touch the Invisible Sky" is a 60-page book with color images of nebulae, stars, galaxies and some of the telescopes that captured the original pictures. Each image is embossed with lines, bumps and other textures. These raised patterns translate colors, shapes and other intricate details of the cosmic objects, allowing visually impaired people to experience them. Braille and large-print descriptions accompany each of the book's 28 photographs, making the book's design accessible to readers of all visual abilities. Sample page Sample page The book contains spectacular images from the Hubble Space Telescope, Chandra X-ray Observatory, Spitzer Space Telescope and powerful ground-based telescopes. The celestial objects are presented as they appear through visible-light telescopes and different spectral regions invisible to the naked eye, from radio to infrared, visible, ultraviolet and X-ray light. The book introduces the concept of light and the spectrum and explains how the different observatories complement each others' findings. Readers take a cosmic journey beginning with images of the sun, and travel out into the galaxy to visit relics of exploding and dying stars, as well as the Whirlpool galaxy and colliding Antennae galaxies. People Who Read This Also Read... Chandra Data Reveal Rapidly Whirling Black Holes Jet Power and Black Hole Assortment Revealed in New Chandra Image Action Replay of Powerful Stellar Explosion Black Holes Are The Rhythm at The Heart of Galaxies "Touch the Invisible Sky" was written by astronomy educator and accessibility specialist Noreen Grice of You Can Do Astronomy LLC and the Museum of Science, Boston, with authors Simon Steel, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and Doris Daou, an astronomer

  16. Early 2017 observations of TRAPPIST-1 with Spitzer

    Science.gov (United States)

    Delrez, L.; Gillon, M.; Triaud, A. H. M. J.; Demory, B.-O.; de Wit, J.; Ingalls, J. G.; Agol, E.; Bolmont, E.; Burdanov, A.; Burgasser, A. J.; Carey, S. J.; Jehin, E.; Leconte, J.; Lederer, S.; Queloz, D.; Selsis, F.; Van Grootel, V.

    2018-04-01

    The recently detected TRAPPIST-1 planetary system, with its seven planets transiting a nearby ultracool dwarf star, offers the first opportunity to perform comparative exoplanetology of temperate Earth-sized worlds. To further advance our understanding of these planets' compositions, energy budgets, and dynamics, we are carrying out an intensive photometric monitoring campaign of their transits with the Spitzer Space Telescope. In this context, we present 60 new transits of the TRAPPIST-1 planets observed with Spitzer/Infrared Array Camera (IRAC) in 2017 February and March. We combine these observations with previously published Spitzer transit photometry and perform a global analysis of the resulting extensive data set. This analysis refines the transit parameters and provides revised values for the planets' physical parameters, notably their radii, using updated properties for the star. As part of our study, we also measure precise transit timings that will be used in a companion paper to refine the planets' masses and compositions using the transit timing variations method. TRAPPIST-1 shows a very low level of low-frequency variability in the IRAC 4.5-μm band, with a photometric RMS of only 0.11 per cent at a 123-s cadence. We do not detect any evidence of a (quasi-)periodic signal related to stellar rotation. We also analyse the transit light curves individually, to search for possible variations in the transit parameters of each planet due to stellar variability, and find that the Spitzer transits of the planets are mostly immune to the effects of stellar variations. These results are encouraging for forthcoming transmission spectroscopy observations of the TRAPPIST-1 planets with the James Webb Space Telescope.

  17. SPITZER SPACE TELESCOPE MID-IR LIGHT CURVES OF NEPTUNE

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, John; Rebull, Luisa; Carey, Sean J.; Krick, Jessica; Ingalls, James G.; Lowrance, Patrick; Glaccum, William [Spitzer Science Center (SSC), California Institute of Technology, Pasadena, CA 91125 (United States); Marley, Mark S. [NASA Ames Research Center, Space Sciences and Astrobiology Division, MS245-3, Moffett Field, CA 94035 (United States); Gizis, John E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kirkpatrick, J. Davy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Simon, Amy A. [NASA Goddard Space Flight Center, Solar System Exploration Division (690.0), 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Wong, Michael H. [University of California, Department of Astronomy, Berkeley CA 94720-3411 (United States)

    2016-11-01

    We have used the Spitzer Space Telescope in 2016 February to obtain high cadence, high signal-to-noise, 17 hr duration light curves of Neptune at 3.6 and 4.5 μ m. The light curve duration was chosen to correspond to the rotation period of Neptune. Both light curves are slowly varying with time, with full amplitudes of 1.1 mag at 3.6 μ m and 0.6 mag at 4.5 μ m. We have also extracted sparsely sampled 18 hr light curves of Neptune at W1 (3.4 μ m) and W2 (4.6 μ m) from the Wide-feld Infrared Survey Explorer ( WISE )/ NEOWISE archive at six epochs in 2010–2015. These light curves all show similar shapes and amplitudes compared to the Spitzer light curves but with considerable variation from epoch to epoch. These amplitudes are much larger than those observed with Kepler / K 2 in the visible (amplitude ∼0.02 mag) or at 845 nm with the Hubble Space Telescope ( HST ) in 2015 and at 763 nm in 2016 (amplitude ∼0.2 mag). We interpret the Spitzer and WISE light curves as arising entirely from reflected solar photons, from higher levels in Neptune’s atmosphere than for K 2. Methane gas is the dominant opacity source in Neptune’s atmosphere, and methane absorption bands are present in the HST 763 and 845 nm, WISE W1, and Spitzer 3.6 μ m filters.

  18. Gravitational capture

    International Nuclear Information System (INIS)

    Bondi, H.

    1979-01-01

    In spite of the strength of gravitational focres between celestial bodies, gravitational capture is not a simple concept. The principles of conservation of linear momentum and of conservation of angular momentum, always impose severe constraints, while conservation of energy and the vital distinction between dissipative and non-dissipative systems allows one to rule out capture in a wide variety of cases. In complex systems especially those without dissipation, long dwell time is a more significant concept than permanent capture. (author)

  19. High energy cosmic rays

    CERN Document Server

    Stanev, Todor

    2010-01-01

    Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

  20. Cosmic Accelerators: An Introduction

    International Nuclear Information System (INIS)

    Kanbach, Gottfried

    2005-01-01

    High energy, relativistic, particles are an essential component of the Universe and play a major role in astrophysics. In a few years we will reach the centennial of the discovery of cosmic rays; all through this century the properties, origin, and effects of this radiation have intrigued researchers in astrophysics and elementary particles alike. We briefly review the history, current status, and future perspectives of cosmic ray research. Emphasis will be placed on the multitude of cosmic accelerators, direct observations of these objects, and the effects of cosmic rays in the Galaxy and beyond

  1. Capture reactions

    NARCIS (Netherlands)

    Endt, P.M.

    1956-01-01

    Capture reactions will be considered here from the viewpoint of the nuclear spectroscopist. Especially important to him are the capture of neutrons, protons, and alpha particles, which may proceed through narrow resonances, offering a well defined initial state for the subsequent deexcitation

  2. Maria Montessori's Cosmic Vision, Cosmic Plan, and Cosmic Education

    Science.gov (United States)

    Grazzini, Camillo

    2013-01-01

    This classic position of the breadth of Cosmic Education begins with a way of seeing the human's interaction with the world, continues on to the grandeur in scale of time and space of that vision, then brings the interdependency of life where each growing human becomes a participating adult. Mr. Grazzini confronts the laws of human nature in…

  3. Cosmic-ray exposure records and origins of meteorites

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1985-01-01

    The cosmic-ray records of meteorites can be used to infer much about their origins and recent histories. Some meteorites had simple cosmic-ray exposure histories, while others had complex exposure histories with their cosmogenic products made both before and after a collision in space. The methods used to interpret meteorites' cosmic-ray records, especially identifying simple or complex exposure histories, often are inadequate. Besides spallogenic radionuclides and stable nuclides, measurements of products that have location-sensitive production rates, such as the tracks of heavy cosmic-ray nuclei or neutron-capture nuclides, are very useful in accurately determining a meteorite's history. Samples from different, known locations of a meteorite help in studying the cosmic-ray record. Such extensive sets of meteorite measurements, plus theoretical modeling of complex histories, will improve our ability to predict the production of cosmogenic nuclides in meteorites, to distinguish simple and complex exposure histories, and to better determine exposure ages

  4. Detection prospects of the cosmic neutrino background

    Science.gov (United States)

    Li, Yu-Feng

    2015-04-01

    The existence of the cosmic neutrino background (CνB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CνB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CνB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHECνs) at the Z-resonance, and the atomic de-excitation method are also discussed in this review (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015).

  5. Interactions of cosmic superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Mark G.; /Fermilab

    2007-06-01

    We develop methods by which cosmic superstring interactions can be studied in detail. These include the reconnection probability and emission of radiation such as gravitons or small string loops. Loop corrections to these are discussed, as well as relationships to (p; q)-strings. These tools should allow a phenomenological study of string models in anticipation of upcoming experiments sensitive to cosmic string radiation.

  6. Deepening Cosmic Education

    Science.gov (United States)

    Leonard, Gerard

    2013-01-01

    This article is a special blend of research, theory, and practice, with clear insight into the origins of Cosmic Education and cosmic task, while recalling memories of student explorations in botany, in particular, episodes from Mr. Leonard's teaching. Mr. Leonard speaks of a storytelling curriculum that eloquently puts perspective into dimensions…

  7. Our Cosmic Insignificance

    Science.gov (United States)

    Kahane, Guy

    2014-01-01

    The universe that surrounds us is vast, and we are so very small. When we reflect on the vastness of the universe, our humdrum cosmic location, and the inevitable future demise of humanity, our lives can seem utterly insignificant. Many philosophers assume that such worries about our significance reflect a banal metaethical confusion. They dismiss the very idea of cosmic significance. This, I argue, is a mistake. Worries about cosmic insignificance do not express metaethical worries about objectivity or nihilism, and we can make good sense of the idea of cosmic significance and its absence. It is also possible to explain why the vastness of the universe can make us feel insignificant. This impression does turn out to be mistaken, but not for the reasons typically assumed. In fact, we might be of immense cosmic significance—though we cannot, at this point, tell whether this is the case. PMID:25729095

  8. THE SPITZER -HETDEX EXPLORATORY LARGE-AREA SURVEY

    International Nuclear Information System (INIS)

    Papovich, C.; Shipley, H. V.; Mehrtens, N.; Lanham, C.; DePoy, D. L.; Kawinwanichakij, L.; Lacy, M.; Ciardullo, R.; Gronwall, C.; Finkelstein, S. L.; Drory, N.; Gebhardt, K.; Hill, G. J.; Jogee, S.; Bassett, R.; Behroozi, P.; Blanc, G. A.; Jong, R. S. de; Gawiser, E.; Hopp, U.

    2016-01-01

    We present post-cryogenic Spitzer imaging at 3.6 and 4.5 μ m with the Infrared Array Camera (IRAC) of the Spitzer /HETDEX Exploratory Large-Area (SHELA) survey. SHELA covers ≈24 deg 2 of the Sloan Digital Sky Survey “Stripe 82” region, and falls within the footprints of the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) and the Dark Energy Survey. The HETDEX blind R ∼ 800 spectroscopy will produce ∼200,000 redshifts from the Ly α emission for galaxies in the range 1.9 <  z  < 3.5, and an additional ∼200,000 redshifts from the [O ii] emission for galaxies at z  < 0.5. When combined with deep ugriz images from the Dark Energy Camera, K -band images from NEWFIRM, and other ancillary data, the IRAC photometry from Spitzer will enable a broad range of scientific studies of the relationship between structure formation, galaxy stellar mass, halo mass, the presence of active galactic nuclei, and environment over a co-moving volume of ∼0.5 Gpc 3 at 1.9 <  z  < 3.5. Here, we discuss the properties of the SHELA IRAC data set, including the data acquisition, reduction, validation, and source catalogs. Our tests show that the images and catalogs are 80% (50%) complete to limiting magnitudes of 22.0 (22.6) AB mag in the detection image, which is constructed from the weighted sum of the IRAC 3.6 and 4.5 μ m images. The catalogs reach limiting sensitivities of 1.1  μ Jy at both 3.6 and 4.5 μ m (1 σ , for R = 2″ circular apertures). As a demonstration of the science, we present IRAC number counts, examples of highly temporally variable sources, and galaxy surface density profiles of rich galaxy clusters. In the spirit of the Spitzer Exploratory programs, we provide all of the images and catalogs as part of the publication.

  9. Measurement of the Transverse Spitzer Resistivity during Collisional Magnetic Reconnection

    International Nuclear Information System (INIS)

    Trintchouk, F.; Yamada, M.; Ji, H.; Kulsrud, R.M.; Carter, T.A.

    2000-01-01

    Measurement of the transverse resistivity was carried out in a reconnecting current sheet where the mean free path for the Coulomb collision is smaller than the thickness of the sheet. In a collisional neutral sheet without a guide field, the transverse resistivity is directly related to the reconnection rate. A remarkable agreement is found between the measured resistivity and the classical value derived by L. Spitzer. In his calculation the transverse resistivity for the electrons is higher than the parallel resistivity by a factor of 1.96. The measured values have verified this theory to within 30% errors

  10. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-09-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archived MIPS observations of Phoebe reproduces Cassini results very accurately, thereby validating our method. For all targets, the geometric albedo is found to be low, probably below 10% and clearly below 15%. Irregular satellites are much darker than the large regular satellites. Their albedo is, however, quite similar to that of small bodies in the outer Solar System (such as cometary nuclei, Jupiter Trojans, or TNOs). This is consistent with color measurements as well as dynamical considerations which suggest a common origin of the said populations. There appear to be significant object-to-object albedo differences. Similar albedos found for some members of dynamical clusters support the idea that they may have originated in the breakup of a parent body. For three satellites, thermal data at two wavelengths are available, enabling us to constrain their thermal properties. Sub-solar temperatures are similar to that found from Cassini's Phoebe fly-by. This suggests a rather low thermal inertia, as expected for regolith-covered objects. This work is based on observations made with the Spitzer Space Telescope, which is operated by JPL under a contract with NASA. Support for this work was provided by NASA.

  11. Albedo and Diameter Distributions of Asteroid Families Using the Spitzer Asteroid Catalog

    NARCIS (Netherlands)

    Enga, Marie-Therese; Trilling, D.; Mueller, M.; Wasserman, L.; Sykes, M.; Blaylock, M.; Stansberry, J.; Bhattacharya, B.; Spahr, T.

    2009-01-01

    The Spitzer Asteroid Catalog contains flux measurements of asteroidsserendipitously observed in publicly available Spitzer data. At present,this catalog contains some 10,000 measurements at 24 microns only, andwill ultimately contain 100,000 measurements or more. These measurements, along with with

  12. Multiple asteroid systems : Dimensions and thermal properties from Spitzer Space Telescope and ground-based observations

    NARCIS (Netherlands)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Vieira Martins, R.; Berthier, J.; Vachier, F.; Cruikshank, D. P.; Lim, L. F.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; LaCluyze, A. P.

    2012-01-01

    We collected mid-IR spectra from 5.2 to 38 μm using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric lightcurves were also obtained for 14 of them during the Spitzer observations to provide the context of the

  13. 11. European cosmic ray symposium

    International Nuclear Information System (INIS)

    1989-03-01

    The biannual Symposium includes all aspects of cosmic ray research. The scientific programme was organized under three main headings: Cosmic rays in the heliosphere, Cosmic rays in the interstellar and extragalactic space, Properties of high-energy interactions as studied by cosmic rays. Seven invited talks were indexed seprately for the INIS database. (R.P.)

  14. Light scattering by cosmic particles

    NARCIS (Netherlands)

    Hovenier, J.W.; Min, M.

    2008-01-01

    We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments.

  15. LOCAL BENCHMARKS FOR THE EVOLUTION OF MAJOR-MERGER GALAXIES-SPITZER OBSERVATIONS OF A K-BAND SELECTED SAMPLE

    International Nuclear Information System (INIS)

    Xu, C. Kevin; Cheng Yiwen; Lu Nanyao; Mazzarella, Joseph M.; Cutri, Roc; Domingue, Donovan; Huang Jiasheng; Gao Yu; Sun, W.-H.; Surace, Jason

    2010-01-01

    We present Spitzer observations for a sample of close major-merger galaxy pairs (KPAIR sample) selected from cross-matches between the Two Micron All Sky Survey and Sloan Digital Sky Survey Data Release 3. The goals are to study the star formation activity in these galaxies and to set a local bench mark for the cosmic evolution of close major mergers. The Spitzer KPAIR sample (27 pairs, 54 galaxies) includes all spectroscopically confirmed spiral-spiral (S+S) and spiral-elliptical (S+E) pairs in a parent sample that is complete for primaries brighter than K = 12.5 mag, projected separations of 5 h -1 kpc ≤ s ≤ 20 h -1 kpc, and mass ratios ≤2.5. The Spitzer data, consisting of images in seven bands (3.6, 4.5, 5.8, 8, 24, 70, 160 μm), show very diversified IR emission properties. Compared to single spiral galaxies in a control sample, only spiral galaxies in S+S pairs show significantly enhanced specific star formation rate (sSFR = SFR/M), whereas spiral galaxies in S+E pairs do not. Furthermore, the SFR enhancement of spiral galaxies in S+S pairs is highly mass-dependent. Only those with M ∼> 10 10.5 M sun show significant enhancement. Relatively low-mass (M ∼ 10 10 M sun ) spirals in S+S pairs have about the same SFR/M compared to their counterparts in the control sample, while those with 10 11 M sun have on average a ∼3 times higher SFR/M than single spirals. There is evidence for a correlation between the global star formation activities (but not the nuclear activities) of the component galaxies in massive S+S major-merger pairs (the H olmberg effect ) . There is no significant difference in the SFR/M between the primaries and the secondaries, nor between spirals of SEP KPAIR =2.54 x 10 -4 (M sun yr -1 Mpc -3 ).

  16. Cosmic x ray physics

    Science.gov (United States)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  17. Cosmic Dust Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — Since May 1981, the National Aeronautics and Space Administration (NASA) has used aircraft to collect cosmic dust (CD) particles from Earth's stratosphere. Specially...

  18. A COSMIC VARIANCE COOKBOOK

    International Nuclear Information System (INIS)

    Moster, Benjamin P.; Rix, Hans-Walter; Somerville, Rachel S.; Newman, Jeffrey A.

    2011-01-01

    Deep pencil beam surveys ( 2 ) are of fundamental importance for studying the high-redshift universe. However, inferences about galaxy population properties (e.g., the abundance of objects) are in practice limited by 'cosmic variance'. This is the uncertainty in observational estimates of the number density of galaxies arising from the underlying large-scale density fluctuations. This source of uncertainty can be significant, especially for surveys which cover only small areas and for massive high-redshift galaxies. Cosmic variance for a given galaxy population can be determined using predictions from cold dark matter theory and the galaxy bias. In this paper, we provide tools for experiment design and interpretation. For a given survey geometry, we present the cosmic variance of dark matter as a function of mean redshift z-bar and redshift bin size Δz. Using a halo occupation model to predict galaxy clustering, we derive the galaxy bias as a function of mean redshift for galaxy samples of a given stellar mass range. In the linear regime, the cosmic variance of these galaxy samples is the product of the galaxy bias and the dark matter cosmic variance. We present a simple recipe using a fitting function to compute cosmic variance as a function of the angular dimensions of the field, z-bar , Δz, and stellar mass m * . We also provide tabulated values and a software tool. The accuracy of the resulting cosmic variance estimates (δσ v /σ v ) is shown to be better than 20%. We find that for GOODS at z-bar =2 and with Δz = 0.5, the relative cosmic variance of galaxies with m * >10 11 M sun is ∼38%, while it is ∼27% for GEMS and ∼12% for COSMOS. For galaxies of m * ∼ 10 10 M sun , the relative cosmic variance is ∼19% for GOODS, ∼13% for GEMS, and ∼6% for COSMOS. This implies that cosmic variance is a significant source of uncertainty at z-bar =2 for small fields and massive galaxies, while for larger fields and intermediate mass galaxies, cosmic

  19. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  20. The cosmic infrared background experiment

    Science.gov (United States)

    Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2006-03-01

    The extragalactic background, based on absolute measurements reported by DIRBE and IRTS at 1.2 and 2.2 μm, exceeds the brightness derived from galaxy counts by up to a factor 5. Furthermore, both DIRBE and the IRTS report fluctuations in the near-infrared sky brightness that appear to have an extra-galactic origin, but are larger than expected from local ( z = 1-3) galaxies. These observations have led to speculation that a new class of high-mass stars or mini-quasars may dominate primordial star formation at high-redshift ( z ˜ 10-20), which, in order to explain the excess in the near-infrared background, must be highly luminous but produce a limited amount of metals and X-ray photons. Regardless of the nature of the sources, if a significant component of the near-infrared background comes from first-light galaxies, theoretical models generically predict a prominent near-infrared spectral feature from the redshifted Lyman cutoff, and a distinctive fluctuation power spectrum. We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7″ to 2°, where a first-light galaxy signature is expected to peak, over a range of angular scales poorly covered by previous experiments. CIBER will determine if the fluctuations reported by the IRTS arise from first-light galaxies or have a local origin. In a short rocket flight CIBER has sensitivity to probe fluctuations 100× fainter than IRTS/DIRBE, with sufficient resolution to remove local-galaxy correlations. By jointly observing regions of the sky studied by Spitzer and ASTRO-F, CIBER will build a multi-color view of the near

  1. Unusual Slowly Rotating Brown Dwarfs Discovered through Precision Spitzer Photometry

    Science.gov (United States)

    Heinze, Aren; Metchev, S.

    2014-01-01

    Many brown dwarfs exhibit low-amplitude rotationally modulated variability due to photospheric inhomogeneities caused by condensate clouds in their atmospheres. The Spitzer Space Telescope 'Weather on Other Worlds' (WoW) project has monitored 44 brown dwarfs at unprecedented photometric precision from space. We present one of several important new results from WoW: the discovery of brown dwarfs with unexpectedly slow rotation periods. While most brown dwarfs have periods of 2-12 hours, we have identified two with well-constrained periods of 13±1 and >20 hours, respectively, and 2 others that show more tentative evidence of longer than 20-hour periods. By serving as almost non-rotating standards, these objects will allow more accurate calibration of spectroscopic measurements of brown dwarfs' projected rotational velocities. The existence of such slowly-rotating objects also constrains models of brown dwarf formation and angular momentum evolution.

  2. Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer

    Science.gov (United States)

    Hudgins, Douglas M.; Allamandola, L. J.

    2004-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role that carbon-rich plays in the interstellar medium (ISM). Twenty years ago, the possible existence of an abundant population of large, carbon-rich molecules in the ISM was unthinkable. Today, the unmistakable spectroscopic signatures of polycyclic aromatic hydrocarbons (PAHs) - shockingly large molecules by the standards of traditional interstellar chemistry -are recognized throughout the Universe. In this presentation, we will examine the current state of the interstellar PAH model and explore how this data, in conjunction with the unparalleled observational data provided by the Spitzer Space Telescope, can be used to draw ever-deeper insights into the physical and chemical natures of a wide range of astrophysical environments.

  3. Cosmic rays in space

    International Nuclear Information System (INIS)

    Fujitaka, Kazunobu

    2005-01-01

    Cosmos is a mysterious space by which many researchers are fascinated for many years. But, going into space means that we will receive extra exposure due to existence of cosmic rays. Cosmic rays are mainly composed of highly energetic protons. It was born in the last stage of stellar life. Understanding of cosmos will certainly bring right understanding of radiation energy, or energy itself. As no one could see the very early stage of cosmic rays, there is only a speculation. But it is better to speculate something based on certain side evidences, than to give up the whole. Such attitude shall be welcomed in the space researches. Anyway, cosmic rays were born in the last explosion of a star, which is called as Super Nova. After cosmic rays are emitted from the Super Nova, it will reach to the human surroundings. To indicate its intensity, special unit of ''dose rate'' is used. When a man climbs a mountain, cosmic ray intensity surely increases. It doubles as he goes up every 1500m elevation. It was ascertained by our own measurements. Then what happens when the goes up more? At aviation altitude, where airplanes fly, the dose rate will be increased up to 100times the high mountain cases. And what is expected when he goes up further more, up to space orbit altitude? In this case, the dose rate increases up to 10times the airplane cases. Geomagnetism affects the dose rate very much. As primary cosmic ray particles are charged particles, they cannot do well with existence of the magnetic field. In effect, cosmic rays can penetrate into the polar atmosphere along geomagnetic lines of forces which stand almost vertical, but penetration of low energy cosmic rays will be banned when they intend to penetrate crossing the geomagnetic lines of forces in equatorial region. Therefore, exposure due to cosmic rays will become large in polar region, while it remains small in equatorial region. In effect, airplanes which fly over the equator. Only, we have to know that the cosmos

  4. 14th International School of Cosmic Ray Astrophysics

    CERN Document Server

    Stanev, Todor; Wefel, John P; Neutrinos and explosive events in the universe

    2005-01-01

    This volume contains the Lectures and selected participant contributions to the 14th Course of the International School of Cosmic Rays Astrophysics, a NATO Advanced Study Institute. Well known astrophysicists and astronomers discuss different aspects of the generation of high energy signals in powerful astrophysical objects concentrating on the production of neutrinos and gamma rays from high energy particle interactions. Recent results from new experiments and observatories are presented. Topics cover a wide range including the Spitzer infrared observatory, TeV gamma ray observations, dark matter, and neutrino telescopes. The combination of basic knowledge about the production of high energy signals with information about the data analysis of ongoing observations places the book between the usual levels of a textbook and a conference proceedings. It will give the reader a good introduction to the current field of astroparticle physics, and some of the fascinating astrophysics being addressed.

  5. Cosmic questions: an introduction.

    Science.gov (United States)

    Primack, J R; Abrams, N E

    2001-12-01

    This introductory talk at the Cosmic Questions conference sponsored by the AAAS summarizes some earlier pictures of the universe and some pictures based on modern physics and cosmology. The uroboros (snake swallowing its tail) is an example of a traditional picture. The Biblical flat-earth picture was very different from the Greek spherical earth-centered picture, which was the standard view until the end of the Middle Ages. Many people incorrectly assume that the Newtonian picture of stars scattered through otherwise empty space is still the prevailing view. Seeing Earth from space shows the power of a new picture. The Hubble Space Telescope can see all the bright galaxies, all the way to the cosmic Dark Ages. We are at the center of cosmic spheres of time: looking outward is looking backward in time. All the matter and energy in the universe can be represented as a cosmic density pyramid. The laws of physics only allow the material objects in the universe to occupy a wedge-shaped region on a diagram of mass versus size. All sizes--from the smallest size scale, the Planck scale, to the entire visible universe--can be represented on the Cosmic Uroboros. There are interesting connections across this diagram, and the human scale lies in the middle.

  6. Big bang nucleosynthesis and the cosmic neutrino background

    International Nuclear Information System (INIS)

    Cao Yun; Xing Zhizhong

    2013-01-01

    We present a brief overview of the neutrino decoupling and big bang nucleosynthesis in the early universe. The big bang relic neutrinos formed one of the backgrounds of the universe. A few possible ways to directly detect the cosmic neutrino background are briefly introduced, and particular attention is paid to the relic neutrino capture on b-decaying nuclei. (authors)

  7. Cosmic Rays and Climate

    CERN Document Server

    Kirkby, Jasper

    2007-01-01

    Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been controversial—perhaps because the observations had largely involved correlations between climate and the sunspot cycle that had persisted for only a few decades. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Although this remains a mystery, observations suggest that cloud cover may be influenced by cosmic rays, which are modulated by the solar wind and, on longer time scales, by the geomagnetic fiel...

  8. Heterotic cosmic strings

    International Nuclear Information System (INIS)

    Becker, Katrin; Becker, Melanie; Krause, Axel

    2006-01-01

    We show that all three conditions for the cosmological relevance of heterotic cosmic strings, the right tension, stability and a production mechanism at the end of inflation, can be met in the strongly coupled M-theory regime. Whereas cosmic strings generated from weakly coupled heterotic strings have the well-known problems posed by Witten in 1985, we show that strings arising from M5-branes wrapped around 4-cycles (divisors) of a Calabi-Yau in heterotic M-theory compactifications solve these problems in an elegant fashion

  9. Cosmic Sum Rules

    DEFF Research Database (Denmark)

    T. Frandsen, Mads; Masina, Isabella; Sannino, Francesco

    2011-01-01

    We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models.......We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models....

  10. Cosmic ray: Studying the origin

    International Nuclear Information System (INIS)

    Szabelski, J.

    1997-01-01

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10 15 eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O 19 eV (for these are the highest energies observed in nature). (author)

  11. VizieR Online Data Catalog: Spitzer photometric time series of HD 97658 (Van Grootel+, 2014)

    Science.gov (United States)

    Van Grootel, V.; Gillon, M.; Valencia, D.; Madhusudhan, N.; Dragomir, D.; Howe, A. R.; Burrows, A. S.; Demory, B.-O.; Deming, D.; Ehrenreich, D.; Lovis, C.; Mayor, M.; Pepe, F.; Queloz, D.; Scuflaire, R.; Seager, S.; Segransan, D.; Udry, S.

    2017-07-01

    We monitored HD 97658 with Spitzer's IRAC camera on 2013 August 10 from 13:01:00 to 18:27:00 UT, corresponding to a transit window as computed from the MOST transit ephemeris (Dragomir et al. 2013, J/ApJ/772/L2). These Spitzer data were acquired in the context of the Cycle 9 program 90072 (PI: M. Gillon) dedicated to the search for the transits of RV-detected low-mass planets. They consist of 2320 sets of 64 individual subarray images obtained at 4.5 μm with an integration time of 0.08 s. They are available on the Spitzer Heritage Archive database under the form of 2320 Basic Calibrated Data files calibrated by the standard Spitzer reduction pipeline (version S19.1.0). (1 data file).

  12. Galactic propagation of cosmic rays

    International Nuclear Information System (INIS)

    Cesarsky, C.J.

    1982-09-01

    After introducing various phenomenological models of cosmic ray propagation in the galaxy, we examine how some of them fare when compared to the data. We show that a model based on resonant diffusion of cosmic rays off an interstellar spectrum of hydromagnetic waves can account for the presently available evidence on cosmic rays and the interstellar medium

  13. Simulating Cosmic Reionisation

    NARCIS (Netherlands)

    Pawlik, Andreas Heinz

    2009-01-01

    The first stars formed a few hundred million years after the Big Bang, when the Universe was only a small fraction of its present age. Their radiation transformed the previously cold and neutral hydrogen that filled intergalactic space into the hot and ionised cosmic plasma that is observed today.

  14. Cosmic rays and climate

    CERN Multimedia

    2009-01-01

    Inside the new chamber the CLOUD team will be able to recreate the conditions of any part of the atmosphere, from the polar stratosphere to the low level tropics (top). The new chamber safely in position in the East hall. Once carefully cleaned the chamber will be turned sideways onto its legs ready for the beam of 'cosmic rays' (bottom).

  15. Cosmic Rays at Earth

    Science.gov (United States)

    Grieder, P. K. F.

    In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery. Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological

  16. Spitzer identification of potentially active Near-Earth Asteroids

    Science.gov (United States)

    Mommert, Michael; Trilling, David; Hora, Joseph; Smith, Howard; Chesley, Steve; Emery, Josh; Farnocchia, Davide; Fazio, Giovanni; Harris, Alan; Mueller, Migo

    2017-04-01

    The separation between asteroids and comets has become less clear with the discovery of a small group of asteroids that display comet-like activity. While the activity is attributed to different mechanisms, some objects seem to activate close to the Sun. Near-Earth Asteroids (NEAs) come close to the Earth and the Sun, constituting a natural laboratory for the study of thermally induced activity. Two NEA sub-populations are especially suspected of being potentially active: dormant comets and near-Sun asteroids. We propose 12.4 hrs of Spitzer IRAC observations of 3 near-Sun asteroids and one dormant comet (3552) Don Quixote, about which we have already published. Our goals are (1) to search for activity in Don Quixote, which showed CO/CO2 activity during its previous apparition and (2) to search for activity and measure the diameters and albedos of the near-Sun asteroids. In combination with a funded ground-based observing program, our results will provide significant legacy value to the investigation of activity in near-Earth asteroids.

  17. Tracing the cosmic web

    Science.gov (United States)

    Libeskind, Noam I.; van de Weygaert, Rien; Cautun, Marius; Falck, Bridget; Tempel, Elmo; Abel, Tom; Alpaslan, Mehmet; Aragón-Calvo, Miguel A.; Forero-Romero, Jaime E.; Gonzalez, Roberto; Gottlöber, Stefan; Hahn, Oliver; Hellwing, Wojciech A.; Hoffman, Yehuda; Jones, Bernard J. T.; Kitaura, Francisco; Knebe, Alexander; Manti, Serena; Neyrinck, Mark; Nuza, Sebastián E.; Padilla, Nelson; Platen, Erwin; Ramachandra, Nesar; Robotham, Aaron; Saar, Enn; Shandarin, Sergei; Steinmetz, Matthias; Stoica, Radu S.; Sousbie, Thierry; Yepes, Gustavo

    2018-01-01

    The cosmic web is one of the most striking features of the distribution of galaxies and dark matter on the largest scales in the Universe. It is composed of dense regions packed full of galaxies, long filamentary bridges, flattened sheets and vast low-density voids. The study of the cosmic web has focused primarily on the identification of such features, and on understanding the environmental effects on galaxy formation and halo assembly. As such, a variety of different methods have been devised to classify the cosmic web - depending on the data at hand, be it numerical simulations, large sky surveys or other. In this paper, we bring 12 of these methods together and apply them to the same data set in order to understand how they compare. In general, these cosmic-web classifiers have been designed with different cosmological goals in mind, and to study different questions. Therefore, one would not a priori expect agreement between different techniques; however, many of these methods do converge on the identification of specific features. In this paper, we study the agreements and disparities of the different methods. For example, each method finds that knots inhabit higher density regions than filaments, etc. and that voids have the lowest densities. For a given web environment, we find a substantial overlap in the density range assigned by each web classification scheme. We also compare classifications on a halo-by-halo basis; for example, we find that 9 of 12 methods classify around a third of group-mass haloes (i.e. Mhalo ∼ 1013.5 h-1 M⊙) as being in filaments. Lastly, so that any future cosmic-web classification scheme can be compared to the 12 methods used here, we have made all the data used in this paper public.

  18. SPITZER EVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN η CORVI At ∼1 Gyr

    International Nuclear Information System (INIS)

    We have analyzed Spitzer and NASA/IRTF 2-35 μm spectra of the warm, ∼350 K circumstellar dust around the nearby MS star η Corvi (F2V, 1.4 ± 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at ∼3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high-temperature carbonaceous phases. At least 9 × 10 18 kg of 0.1-100 μm warm dust is present in a collisional equilibrium distribution with dn/da ∼ a –3.5 , the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm 3 density and similar to recent estimates of the mass delivered to the Earth at 0.6-0.8 Gyr during the late-heavy bombardment. We conclude that the parent body was a Kuiper Belt body or bodies which captured a large amount of early primitive material in the first megayears of the system's lifetime and preserved it in deep freeze at ∼150 AU. At ∼1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 km s –1 with a rocky planetary body of mass ≤M Earth at ∼3 AU, delivering large amounts of water (>0.1% of M Earth'sOceans ) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.

  19. Spitzer Evidence for a Late Heavy Bombardment and the Formation of Urelites in {eta}Corvi at Approximately 1 Gyr

    Science.gov (United States)

    Lisse, C. M.; Wyatt, M. C.; Chen, C. H.; Morlok, A.; Watson, D. M.; Manj, P.; Sheehan, P.; Currie, T. M.; Thebault, P.; Sitko, M. L.

    2011-01-01

    We have analyzed Spitzer and NASA/IRTF 2 - 35 micrometer spectra of the warm, 350 K circumstellar dust around the nearby MS star eta Corvi (F2V, 1.4 plus or minus 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at 3 AU from the central star, in the system's Terrestrial Habitability Zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high temperature carbonaceous phases. At least 9 x 10(exp 18) kg of 0.1 - 100 micrometer warm dust is present in a collisional equilibrium distribution with dn/da a(exp -3.5), the equivalent of a 130 km radius KBO of 1.0 grams per cubic centimeter density and similar to recent estimates of the mass delivered to the Earth at 0.6 - 0.8 Gyr during the Late Heavy Bombardment. We conclude that the parent body was a Kuiper-Belt body or bodies which captured a large amount of early primitive material in the first Myrs of the system's lifetime and preserved it in deep freeze at approximately 150 AU. At approximately 1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 kilometers per second with a rocky planetary body of mass less than or equal to M(sub Earth at approximately 3 AU, delivering large amounts of water (greater than 0.1 % of M(sub Earth's Oceans)) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.

  20. SPITZER EVIDENCE FOR A LATE-HEAVY BOMBARDMENT AND THE FORMATION OF UREILITES IN {eta} CORVI At {approx}1 Gyr

    Energy Technology Data Exchange (ETDEWEB)

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Morlok, A. [Department of Earth and Planetary Sciences, The Open University, Milton-Keynes (United Kingdom); Watson, D. M.; Manoj, P.; Sheehan, P. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Currie, T. M. [NASA-GSFC, Code 667, Greenbelt, MD 20771 (United States); Thebault, P. [Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Sitko, M. L., E-mail: carey.lisse@jhuapl.edu, E-mail: wyatt@ast.cam.ac.uk, E-mail: cchen@stsci.edu, E-mail: a.morlok@open.ac.uk, E-mail: dmw@pas.rochester.edu, E-mail: manoj@pas.rochester.edu, E-mail: psheeha2@mail.rochester.edu, E-mail: thayne.m.currie@nasa.gov, E-mail: philippe.thebault@obspm.fr, E-mail: sitko@spacescience.org [Space Science Institute, 475 Walnut Street, Suite 205, Boulder, CO 80301 (United States)

    2012-03-10

    We have analyzed Spitzer and NASA/IRTF 2-35 {mu}m spectra of the warm, {approx}350 K circumstellar dust around the nearby MS star {eta} Corvi (F2V, 1.4 {+-} 0.3 Gyr). The spectra show clear evidence for warm, water- and carbon-rich dust at {approx}3 AU from the central star, in the system's terrestrial habitability zone. Spectral features due to ultra-primitive cometary material were found, in addition to features due to impact produced silica and high-temperature carbonaceous phases. At least 9 Multiplication-Sign 10{sup 18} kg of 0.1-100 {mu}m warm dust is present in a collisional equilibrium distribution with dn/da {approx} a{sup -3.5}, the equivalent of a 130 km radius Kuiper Belt object (KBO) of 1.0 g cm{sup 3} density and similar to recent estimates of the mass delivered to the Earth at 0.6-0.8 Gyr during the late-heavy bombardment. We conclude that the parent body was a Kuiper Belt body or bodies which captured a large amount of early primitive material in the first megayears of the system's lifetime and preserved it in deep freeze at {approx}150 AU. At {approx}1.4 Gyr they were prompted by dynamical stirring of their parent Kuiper Belt into spiraling into the inner system, eventually colliding at 5-10 km s{sup -1} with a rocky planetary body of mass {<=}M{sub Earth} at {approx}3 AU, delivering large amounts of water (>0.1% of M{sub Earth'sOceans}) and carbon-rich material. The Spitzer spectrum also closely matches spectra reported for the Ureilite meteorites of the Sudan Almahata Sitta fall in 2008, suggesting that one of the Ureilite parent bodies was a KBO.

  1. Spitzer Observations of Massive, Red Galaxies at High Redshift

    Science.gov (United States)

    Papovich, C.; Moustakas, L. A.; Dickinson, M.; Le Floc'h, E.; Rieke, G. H.; Daddi, E.; Alexander, D. M.; Bauer, F.; Brandt, W. N.; Dahlen, T.; Egami, E.; Eisenhardt, P.; Elbaz, D.; Ferguson, H. C.; Giavalisco, M.; Lucas, R. A.; Mobasher, B.; Pérez-González, P. G.; Stutz, A.; Rieke, M. J.; Yan, H.

    2006-03-01

    We study massive galaxies at z~1-3.5 using HST optical imaging, ground-based near-IR imaging, and Spitzer observations at 3-24 μm. From Ks-selected galaxies in the ~=130 arcmin2 GOODS-S field, we identify 153 distant red galaxies (DRGs) with (J-Ks)Vega>=2.3. This sample is approximately complete in stellar mass for passively evolving galaxies above 1011 Msolar and z~4-6 mag) starbursts (at zmed~1.7). Very few DRGs (=1011 Msolar have specific star formation rates (SFRs per unit mass) including the reradiated far-IR emission that range from 0.2 to 10 Gyr-1. Based on the X-ray luminosities and rest-frame near-IR colors, roughly one-quarter of the DRGs contain AGNs, implying that the growth of supermassive black holes coincides with the formation of massive galaxies. At 1.5=1011 Msolar have an integrated specific SFR comparable to the global value of all galaxies. In contrast, galaxies at z~0.3-0.75 with M>=1011 Msolar have an integrated specific SFR less than the global value and more than an order of magnitude lower than that for massive DRGs. At zcontract 1407; on observations taken with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555 and on observations collected at the Kitt Peak National Observatory (KPNO), National Optical Astronomical Observatory (NOAO), which is operated by AURA, Inc., under cooperative agreement with the National Science Foundation. Observations have also been carried out using the Very Large Telescope at the ESO Paranal Observatory under program ID LP168.A-0485.

  2. FAR-INFRARED PROPERTIES OF SPITZER-SELECTED LUMINOUS STARBURSTS

    International Nuclear Information System (INIS)

    Kovacs, A.; Omont, A.; Fiolet, N.; Beelen, A.; Dole, H.; Lagache, G.; Lonsdale, C.; Polletta, M.; Greve, T. R.; Borys, C.; Dowell, C. D.; Bell, T. A.; Cox, P.; De Breuck, C.; Farrah, D.; Menten, K. M.; Owen, F.

    2010-01-01

    We present SHARC-2 350 μm data on 20 luminous z ∼ 2 starbursts with S 1.2 m m > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S 350 μ m > 25 mJy for 18 of them. With the data, we determine precise dust temperatures and luminosities for these galaxies using both single-temperature fits and models with power-law mass-temperature distributions. We derive appropriate formulae to use when optical depths are non-negligible. Our models provide an excellent fit to the 6 μm-2 mm measurements of local starbursts. We find characteristic single-component temperatures T 1 ≅ 35.5 ± 2.2 K and integrated infrared (IR) luminosities around 10 12.9±0.1 L sun for the SWIRE-selected sources. Molecular gas masses are estimated at ≅4 x 10 10 M sun , assuming κ 850 μ m = 0.15 m 2 kg -1 and a submillimeter-selected galaxy (SMG)-like gas-to-dust mass ratio. The best-fit models imply ∼>2 kpc emission scales. We also note a tight correlation between rest-frame 1.4 GHz radio and IR luminosities confirming star formation as the predominant power source. The far-IR properties of our sample are indistinguishable from the purely submillimeter-selected populations from current surveys. We therefore conclude that our original selection criteria, based on mid-IR colors and 24 μm flux densities, provides an effective means for the study of SMGs at z ∼ 1.5-2.5.

  3. GALACTIC CEPHEIDS WITH SPITZER. II. SEARCH FOR EXTENDED INFRARED EMISSION

    International Nuclear Information System (INIS)

    Barmby, P.; Marengo, M.; Evans, N. R.; Huelsman, D.; Fazio, G. G.; Bono, G.; Su, K. Y. L.; Welch, D. L.

    2011-01-01

    A deep and detailed examination of 29 classical Cepheids with the Spitzer Space Telescope has revealed three stars with strong nearby extended emission detected in multiple bands which appears to be physically associated with the stars. RS Pup was already known to possess extended infrared emission, while the extended emission around the other two stars (S Mus and δ Cep) is newly discovered in our observations. Four other stars (GH Lup, l Car, T Mon, and X Cyg) show tentative evidence for extended infrared emission. An unusual elongated extended object next to SZ Tau appears to be a background or foreground object in a chance alignment with the Cepheid. The inferred mass-loss rate upper limits for S Mus and δ Cep are in the range from 10 -9 to 10 -8 M sun yr -1 , with the upper limit for RS Pup as high as 10 -6 M sun yr -1 . Mass loss during post-main-sequence evolution has been proposed as a resolution to the discrepancy between pulsational and dynamical masses of Cepheid variable stars: dust in the lost material would make itself known by the presence of an infrared bright nebula or unresolved infrared excess. The observed frequency of infrared circumstellar emission (<24%) and the mass-loss rate we estimate for our sources show that dusty mass loss can only account for part of the Cepheid mass-loss discrepancy. Nevertheless, our direct evidence that mass loss is active during the Cepheid phase is an important confirmation that these processes need to be included in evolutionary and pulsation models of these stars and should be taken into account in the calibration of the Cepheid distance scale.

  4. NEOs in the mid-infrared: from Spitzer to JWST

    Science.gov (United States)

    Mueller, Michael; Thomas, Cristina A.

    2016-10-01

    Near-Earth Objects (NEOs) account for a surprisingly large fraction of the Spitzer observing time devoted to Solar System science. As a community, we should think of ways to repeat that success with JWST. JWST is planning an open Early Release Science Program, with the expected deadline for letters of intent in early 2017. We can't wait for next year's DPS to develop ideas. The time is now!In order to stir up the discussion, we will present ideas for NEO observing programs that are well adapted to JWST's capabilities and limitations, based on our recent PASP paper (Thomas et al., 2016). Obvious measurement objectives would include* size and albedo from thermal continuum (MIRI photometry)* thermal inertia for objects with well-known shape and spin state (MIRI)* taxonomy through reflection spectroscopy and emission spectroscopy in the NIR and MIR; NIR colors for faint objects.In all cases, JWST's sensitivity will allow us to go deeper than currently possible by at least an order of magnitude. Meter-sized NEOs similar to 2009 BD or 2011 MD are easy targets for MIRI spectrophotometry!The following limitations must be kept in mind, however: JWST's large size makes it slow to move. Most problematic for NEOs is probably the resulting 'speed limit': non-sidereal tracking is supported up to a rate of 30 mas/s, NEOs can easily move faster than that (ways to relax this constraint are under discussion). The average slew to a new target is budgeted to take 30 min, effectively ruling out programs many-target programs like ExploreNEOs or NEOSurvey (see D. Trilling's paper). Additionally, JWST will only observe close to quadrature, translating to large solar phase angles for NEO observations; this is familiar from other space-based IR facilities.

  5. Dark cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Ping-Kai, E-mail: pingkai.hu@physics.ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Kusenko, Alexander, E-mail: kusenko@ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Takhistov, Volodymyr, E-mail: vtakhist@physics.ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697-4575 (United States)

    2017-05-10

    If dark matter particles have an electric charge, as in models of millicharged dark matter, such particles should be accelerated in the same astrophysical accelerators that produce ordinary cosmic rays, and their spectra should have a predictable rigidity dependence. Depending on the charge, the resulting “dark cosmic rays” can be detected as muon-like or neutrino-like events in Super-Kamiokande, IceCube, and other detectors. We present new limits and propose several new analyses, in particular, for the Super-Kamiokande experiment, which can probe a previously unexplored portion of the millicharged dark matter parameter space. Most of our results are fairly general and apply to a broad class of dark matter models.

  6. Dark cosmic rays

    Directory of Open Access Journals (Sweden)

    Ping-Kai Hu

    2017-05-01

    Full Text Available If dark matter particles have an electric charge, as in models of millicharged dark matter, such particles should be accelerated in the same astrophysical accelerators that produce ordinary cosmic rays, and their spectra should have a predictable rigidity dependence. Depending on the charge, the resulting “dark cosmic rays” can be detected as muon-like or neutrino-like events in Super-Kamiokande, IceCube, and other detectors. We present new limits and propose several new analyses, in particular, for the Super-Kamiokande experiment, which can probe a previously unexplored portion of the millicharged dark matter parameter space. Most of our results are fairly general and apply to a broad class of dark matter models.

  7. Cosmic rays and climate

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    The current understanding of climate change in the industrial age is that it is predominantly caused by anthropogenic greenhouse gases, with relatively small natural contributions due to solar irradiance and volcanoes. However, palaeoclimatic reconstructions show that the climate has frequently varied on 100-year time scales during the Holocene (last 10 kyr) by amounts comparable to the present warming - and yet the mechanism or mechanisms are not understood. Some of these reconstructions show clear associations with solar variability, which is recorded in the light radio-isotope archives that measure past variations of cosmic ray intensity. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Estimated changes of solar irradiance on these time scales appear to be too small to account for the climate observations. This raises the question of whether cosmic rays may directly affect the climate, provi...

  8. Cosmic Rays in Thunderstorms

    Science.gov (United States)

    Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

    2013-04-01

    Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

  9. Carl Sagan's Cosmic Connection

    Science.gov (United States)

    Sagan, Carl; Agel, Jerome

    2000-08-01

    Foreword Freeman Dyson; Personal reflections Ann Druyan; Preface; Part I. Cosmic Perspective: 1. A transitional animal; 2. The Unicorn of Cetus; 3. A message from earth; 4. A message to earth; 5. Experiments in utopias; 6. Chauvinism; 7. Space exploration as a human enterprise I. The scientific interest; 8. Space exploration as a human enterprise II. The public interest; 9. Space exploration as a human enterprise III. The historical interest; Part II. The Solar System: 10. On teaching the first grade; 11. 'The ancient and legendary Gods of old'; 12. The Venus detective story; 13. Venus is hell; 14. Science and 'intelligence'; 15. The moons of Barsoom; 16. The mountains of Mars I. Observations from earth; 17. The mountains of Mars II. Observations from space; 18. The canals of Mars; 19. The lost pictures of Mars; 20. The Ice Age and the cauldron; 21. Beginnings and ends of the Earth; 22. Terraforming the plants; 23. The exploration and utlization of the solar system; Part III. Beyond the Solar System: 24. Some of my best friends are dolphins; 25. 'Hello, central casting? Send me twenty extraterrestrials'; 26. The cosmic connection; 27. Extraterrestrial life: an idea whose time has come; 28. Has the Earth been visited?; 29. A search strategy for detecting extraterrestrial intelligence; 30. If we succeed 31. Cables, drums, and seashells; 32. The night freight to the stars; 33. Astroengineering; 34. Twenty questions: a classification of cosmic civilisations; 35. Galactic cultural exchanges; 36. A passage to elsewhere; 37. Starfolk I. A Fable; 38. Starfolk II. A future; 39. Starfolk III. The cosmic Cheshire cats; Epilog David Morrison; Index.

  10. Cosmic transparency and acceleration

    Science.gov (United States)

    Holanda, R. F. L.; Pereira, S. H.; Jain, Deepak

    2018-01-01

    In this paper, by considering an absorption probability independent of photon wavelength, we show that current type Ia supernovae (SNe Ia) and gamma-ray burst (GRB) observations plus high-redshift measurements of the cosmic microwave background (CMB) radiation temperature support cosmic acceleration regardless of the transparent-universe assumption. Two flat scenarios are considered in our analyses: the Λ CDM model and a kinematic model. We consider τ (z )=2 ln (1 +z )ɛ, where τ (z ) denotes the opacity between an observer at z =0 and a source at z . This choice is equivalent to deforming the cosmic distance duality relation as DLDA-1=(1 +z )2+ɛ and, if the absorption probability is independent of photon wavelength, the CMB temperature evolution law is TCMB(z )=T0(1 +z )1+2 ɛ /3. By marginalizing on the ɛ parameter, our analyses rule out a decelerating universe at 99.99% C.L. for all scenarios considered. Interestingly, by considering only SNe Ia and GRBs observations, we obtain that a decelerated universe—indicated by ΩΛ≤0.33 and q0>0 —is ruled out around 1.5 σ C.L. and 2 σ C.L., respectively, regardless of the transparent-universe assumption.

  11. Cosmic Education: Formation of a Planetary and Cosmic Personality

    Directory of Open Access Journals (Sweden)

    Bazaluk Oleg

    2012-04-01

    Full Text Available The major stages of development of cosmic pedagogy have been researched. Based on the achievements of the modern neurosciences as well as of psychology, cosmology, and philosophy, the authors provide their reasoning for the cosmic education and its outlooks for the educational systems of the world. Through the studies of how important human mind is for the Earth and the cosmos and by researching the evolution of human mind within the structure of the Universe, the authors create a more advanced scientific and philosophic basis for the cosmic education where the subject is a comprehensive process of formation and directed progress of both an individual mind and a conglomerate of minds called the "psychospace". The cosmic education researches the permanent progress of the intelligent matter of the Earth. The purpose of the cosmic education has been determined as formation of a planetary and cosmic personality. According to the authors, a planetary and cosmic personality is a harmony of mind, soul, and body, and such harmony is directed to use the internal creative potential of mind to the benefit of the intelligent matter of the entire Earth and the cosmos. The properties of such a planetary and cosmic personality are being improved continuously; they are a sample (the ideal of the cosmic pedagogy and the image of a human being of the future. Through the usage of the entire potential and art of upbringing and educating, the cosmic pedagogy is called to embody the major properties of the image of a human being of the future in the new generations of minds and to form a planetary and cosmic personality capable of self-actualization to the benefit of the permanent progress of the intelligent matter.

  12. Cosmic ray: Studying the origin

    Energy Technology Data Exchange (ETDEWEB)

    Szabelski, J. [Cosmic Ray Laboratory, Soltan Institute for Nuclear Studies, Lodz (Poland)

    1997-12-31

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10{sup 15} eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O{sup 19} eV (for these are the highest energies observed in nature). (author) 101 refs, 19 figs, 7 tabs

  13. Analysis of Spitzer-IRS spectra of hyperluminous infrared galaxies

    Science.gov (United States)

    Ruiz, A.; Risaliti, G.; Nardini, E.; Panessa, F.; Carrera, F. J.

    2013-01-01

    Context. Hyperluminous infrared galaxies (HLIRG) are the most luminous persistent objects in the Universe. They exhibit extremely high star formation rates, and most of them seem to harbour an active galactic nucleus (AGN). They are unique laboratories for investigating the most extreme star formation and its connection to super-massive black hole growth. Aims: The relative AGN and starburst (SB) contributions to the total output in these objects is still debated. Our aim is to disentangle the AGN and SB emission of a sample of thirteen HLIRG. Methods: We studied the MIR low-resolution spectra of a sample of thirteen HLIRG obtained with the Infrared Spectrograph on board Spitzer. The 5-8 μm range is an optimal window for detecting AGN activity even in a heavily obscured environment. We performed an SB/AGN decomposition of the continuum using templates, which has been successfully applied for ULIRG in previous works. Results: The MIR spectra of all sources is largely dominated by AGN emission. By converting the 6 μm luminosity into IR luminosity, we found that ~80% of the sample shows an IR output dominated by the AGN emission. However, the SB activity is significant in all sources (mean SB contribution ~30%), showing star formation rates ~300-3000 M⊙ yr-1. With X-ray and MIR data we estimated the dust covering factor (CF) of these HLIRG, finding that a significant fraction presents a CF consistent with unity. Along with the high X-ray absorption shown by these sources, this suggests that large amounts of dust and gas enshroud the nucleus of these HLIRG, as also observed in ULIRG. Conclusions: Our results agree with previous studies of the IR SED of HLIRG using radiative transfer models, and we find strong evidence that all HLIRG harbour an AGN. Moreover, this work provides further support for the idea that AGN and SB are both crucial to understanding the properties of HLIRG. Our study of the CF supports the hypothesis that HLIRG can be divided into two

  14. Studies in cosmic rays

    International Nuclear Information System (INIS)

    Bemalkhedkar, M.M.

    1974-03-01

    The investigation of the diurnal variation in the cosmic ray intensity on individual days has revealed a new class of diurnal variation showing a maximum around 09 hour direction in the interplanetary space. It is shown to occur during the recovery phase of Forbush decreases as well as during quiet periods. The rigidity spectrum of the anomalous diurnal variation has an exponent around zero, the same as that for the average diurnal variation exhibiting maximum around 18 hours in the interplanetary space. It is shown that the Forbush decreases associated with the diurnal variation exhibiting morning maximum, are 27 day recurrent in nature and are preceded by east limb solar flares on most of the occasions. A qualitative model of the transient modulation by solar corotating corpuscular streams of enhanced solar wind velocity, emanating from the active regions on the solar disc, is proposed to explain the anomalous diurnal anisotropy in the recovery phase of 27 day recurrent Forbush decreases. From this model, the cosmic ray diffusion coefficients, parallel and perpendicular to the interplanetary magnetic field inside the corotating stream, are derived and compared with the average values. To investigate the possibility of determining the energy spectra of cosmic ray intensity variations from a single station, a continuous record of neutron multiplicity spectrum has been obtained for the period October, 1967 - October, 1971, using the Gulmarg neutron monitor. The average multiplicity spectrum in the Gulmarg neutron monitor shows a mean multiplicity approximately equal to 1.4 for 12 Boron-tri-fluoride counters and is an increasing function of the number of counters used. The mean multiplicity measured in various other neutron monitors, when normalized to the cutoff rigidity of Gulmurg (11.91 GV), shows a systematic increase with the altitude of the station. (author)

  15. Garden of cosmic speculation

    CERN Document Server

    Jencks, Charles

    2005-01-01

    This book tells the story of one of the most important gardens in Europe, created by the architectural critic and designer Charles Jencks and his late wife, the landscape architect and author Maggie Keswick. The Garden of Cosmic Speculation is a landscape that celebrates the new sciences of complexity and chaos theory and consists of a series of metaphors exploring the origins, the destiny and the substance of the Universe. The book is illustrated with year-round photography, bringing the garden's many dimensions vividly to life.

  16. Discovery of cosmic fractals

    CERN Document Server

    Baryshev, Yuri

    2002-01-01

    This is the first book to present the fascinating new results on the largest fractal structures in the universe. It guides the reader, in a simple way, to the frontiers of astronomy, explaining how fractals appear in cosmic physics, from our solar system to the megafractals in deep space. It also offers a personal view of the history of the idea of self-similarity and of cosmological principles, from Plato's ideal architecture of the heavens to Mandelbrot's fractals in the modern physical cosmos. In addition, this invaluable book presents the great fractal debate in astronomy (after Luciano Pi

  17. The Cosmic Background Explorer

    Science.gov (United States)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  18. Cosmic strings and inflation

    International Nuclear Information System (INIS)

    Vishniac, E.T.

    1987-01-01

    We examine the compatibility of inflation with the cosmic string theory for galaxy formation. There is a general conflict between having sufficient string tension to effect galaxy formation, and reheating after inflation to a high enough temperature that strings may form in a thermal phase transition. To escape this conflict, we propose a class of models where the inflation is coupled to the string-producing field. The strings are formed late in inflation as the inflaton rolls towards its zero-temperature value. A large subset of these models have a novel large-scale distribution of galaxies that is fractal, displays biasing without dynamics or feedback mechanisms, and contains voids. (orig.)

  19. DEEP SPITZER 24 μm COSMOS IMAGING. I. THE EVOLUTION OF LUMINOUS DUSTY GALAXIES-CONFRONTING THE MODELS

    International Nuclear Information System (INIS)

    Le Floc'h, Emeric; Ilbert, Olivier; Riguccini, Laurie; Kartaltepe, Jeyhan; Sanders, David; Aussel, Herve; Feruglio, Chiara; Frayer, David T.; Salvato, Mara; Capak, Peter; Scoville, Nick; Arnouts, Stephane; Surace, Jason; Sheth, Kartik; Yan Lin; Rodighiero, Giulia; Heinis, Sebastien; McCracken, Henry Joy; Thompson, David; Koekemoer, Anton

    2009-01-01

    We present the first results obtained from the identification of ∼30,000 sources in the Spitzer/24 μm observations of the COSMOS field at S 24μm ∼> 80 μJy. Using accurate photometric redshifts (σ z ∼ 0.12 at z ∼ 2 for 24 μm sources with i + ∼ 2) contribute only marginally to the cosmic infrared background. Assuming flux-limited selections at optical wavelengths, we also find that the fraction of i + -band sources with 24 μm detection strongly increases up to z ∼ 2 as a consequence of the rapid evolution that star-forming galaxies have undergone with look-back time. Nonetheless, this rising trend shows a clear break at z ∼ 1.3, probably due to k-correction effects implied by the complexity of spectral energy distributions in the mid-infrared. Finally, we compare our results with the predictions from different models of galaxy formation. We note that semianalytical formalisms currently fail to reproduce the redshift distributions observed at 24 μm. Furthermore, the simulated galaxies at S 24μm > 80 μJy exhibit R-K colors much bluer than observed and the predicted K-band fluxes are systematically underestimated at z ∼> 0.5. Unless these discrepancies mainly result from an incorrect treatment of extinction in the models they may reflect an underestimate of the predicted density of high-redshift massive sources with strong ongoing star formation, which would point to more fundamental processes and/or parameters (e.g., initial mass function, critical density to form stars, feedback,...) that are still not fully controlled in the simulations. The most recent backward evolution scenarios reproduce reasonably well the flux/redshift distribution of 24 μm sources up to z ∼ 3, although none of them is able to exactly match our results at all redshifts.

  20. L3 + Cosmics Experiment

    CERN Multimedia

    2002-01-01

    %RE4 %title\\\\ \\\\The L3+C experiment takes advantage of the unique properties of the L3 muon spectrometer to get an accurate measurement of cosmic ray muons 30 m underground. A new muon trigger, readout and DAQ system have been installed, as well as a scintillator array covering the upper surfaces of the L3 magnet for timing purposes. The acceptance amounts to 200 $m^2 sr$. The data are collected independently in parallel with L3 running. In spring 2000 a scintillator array will be installed on the roof of the SX hall in order to estimate the primary energy of air showers associated with events observed in L3+C.\\\\ \\\\The cosmic ray muon momentum spectrum, the zenith angular dependence and the charge ratio are measured with high accuracy between 20 and 2000 GeV/c. The results will provide new information about the primary composition, the shower development in the atmosphere, and the inclusive pion and kaon (production-) cross sections (specifically the "$\\pi$/K ratio") at high energies. These data will also hel...

  1. COSMIC monthly progress report

    Science.gov (United States)

    1994-01-01

    Activities of the Computer Software Management and Information Center (COSMIC) are summarized for the month of May 1994. Tables showing the current inventory of programs available from COSMIC are presented and program processing and evaluation activities are summarized. Nine articles were prepared for publication in the NASA Tech Brief Journal. These articles (included in this report) describe the following software items: (1) WFI - Windowing System for Test and Simulation; (2) HZETRN - A Free Space Radiation Transport and Shielding Program; (3) COMGEN-BEM - Composite Model Generation-Boundary Element Method; (4) IDDS - Interactive Data Display System; (5) CET93/PC - Chemical Equilibrium with Transport Properties, 1993; (6) SDVIC - Sub-pixel Digital Video Image Correlation; (7) TRASYS - Thermal Radiation Analyzer System (HP9000 Series 700/800 Version without NASADIG); (8) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (VAX VMS Version); and (9) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (UNIX Version). Activities in the areas of marketing, customer service, benefits identification, maintenance and support, and dissemination are also described along with a budget summary.

  2. Testing Cosmic Inflation

    Science.gov (United States)

    Chuss, David

    2010-01-01

    The Cosmic Microwave Background (CMB) has provided a wealth of information about the history and physics of the early Universe. Much progress has been made on uncovering the emerging Standard Model of Cosmology by such experiments as COBE and WMAP, and ESA's Planck Surveyor will likely increase our knowledge even more. Despite the success of this model, mysteries remain. Currently understood physics does not offer a compelling explanation for the homogeneity, flatness, and the origin of structure in the Universe. Cosmic Inflation, a brief epoch of exponential expansion, has been posted to explain these observations. If inflation is a reality, it is expected to produce a background spectrum of gravitational waves that will leave a small polarized imprint on the CMB. Discovery of this signal would give the first direct evidence for inflation and provide a window into physics at scales beyond those accessible to terrestrial particle accelerators. I will briefly review aspects of the Standard Model of Cosmology and discuss our current efforts to design and deploy experiments to measure the polarization of the CMB with the precision required to test inflation.

  3. George's cosmic treasure hunt

    CERN Document Server

    Hawking, Lucy; Parsons, Gary

    2009-01-01

    George and Annie explore the galaxy in this cosmic adventure from Stephen Hawking and Lucy Hawking, complete with essays from Professor Hawking about the latest in space travel. George is heartbroken when he learns that his friend Annie and her father are moving to the US. Eric has a new job working for the space program, looking for signs of life in the Universe. Eric leaves George with a gift—a book called The User’s Guide to the Universe. But Annie and Eric haven’t been gone for very long when Annie believes that she is being contacted by aliens, who have a terrible warning for her. George joins her in the US to help her with her quest—and before he knows it, he, Annie, Cosmos, and Annie’s annoying cousin Emmett have been swept up in a cosmic treasure hunt, spanning the whole galaxy and beyond. Lucy Hawking's own experiences in zero-gravity flight and interviews with astronauts at Cape Kennedy and the Johnson Space Center lend the book a sense of realism and excitement that is sure to fire up ima...

  4. Cosmic rays and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Erlykin, A.D. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Sloan, T. [Lancaster University (United Kingdom); Wolfendale, A.W. [Durham University (United Kingdom)

    2010-07-01

    The possible effects of cosmic rays on clouds could contribute to global warming. The argument is that the observed increased solar activity during the last century caused a decrease in the ionization due to cosmic rays since the lower energy cosmic particles are deflected by the magnetic field created by the increasing solar wind. This would lead to a decrease in cloud cover allowing more heating of the earth by the sun. Meteorological data combined to solar activity observations and simulations show that any effect of solar activity on clouds and the climate is likely to be through irradiance rather than cosmic rays. Since solar irradiance transfers 8 orders of magnitude more energy to the atmosphere than cosmic rays it is more plausible that this can produce a real effect. The total contribution of variable solar activity to global warming is shown to be less than 14% of the total temperature rise. (A.C.)

  5. Supernova origin of cosmic rays

    Science.gov (United States)

    Bhat, C. L.; Houston, B. P.

    Evidence has recently been presented from gamma-ray observations for the acceleration of cosmic rays in the Loop I supernova remnant. The cosmic ray intensity thus inferred is in agreement with the predictions of the shock acceleration model of Blandford and Cowie (1980). Here, this model is examined further, specifically by comparing its predictions with the presently available information on the cosmic-ray pre-history as well as with the cosmic ray anisotropy measurements in the energy range 10 to the 9th to 10 to the 15th eV. A cosmic ray conversion efficiency of 10-20 percent is found sufficient to exlain the observations. The present study leads also to the interesting suggestion that the bump observed in the primary energy spectrum at 10 to the 14th to 10 to the 15th eV may be due to an excess contribution from local supernovae.

  6. Cosmic mass spectrometer

    Science.gov (United States)

    Anchordoqui, Luis A.; Barger, Vernon; Weiler, Thomas J.

    2018-03-01

    We argue that if ultrahigh-energy (E ≳1010GeV) cosmic rays are heavy nuclei (as indicated by existing data), then the pointing of cosmic rays to their nearest extragalactic sources is expected for 1010.6 ≲ E /GeV ≲1011. This is because for a nucleus of charge Ze and baryon number A, the bending of the cosmic ray decreases as Z / E with rising energy, so that pointing to nearby sources becomes possible in this particular energy range. In addition, the maximum energy of acceleration capability of the sources grows linearly in Z, while the energy loss per distance traveled decreases with increasing A. Each of these two points tend to favor heavy nuclei at the highest energies. The traditional bi-dimensional analyses, which simultaneously reproduce Auger data on the spectrum and nuclear composition, may not be capable of incorporating the relative importance of all these phenomena. In this paper we propose a multi-dimensional reconstruction of the individual emission spectra (in E, direction, and cross-correlation with nearby putative sources) to study the hypothesis that primaries are heavy nuclei subject to GZK photo-disintegration, and to determine the nature of the extragalactic sources. More specifically, we propose to combine information on nuclear composition and arrival direction to associate a potential clustering of events with a 3-dimensional position in the sky. Actually, both the source distance and maximum emission energy can be obtained through a multi-parameter likelihood analysis to accommodate the observed nuclear composition of each individual event in the cluster. We show that one can track the level of GZK interactions on an statistical basis by comparing the maximum energy at the source of each cluster. We also show that nucleus-emitting-sources exhibit a cepa stratis structure on Earth which could be pealed off by future space-missions, such as POEMMA. Finally, we demonstrate that metal-rich starburst galaxies are highly-plausible candidate

  7. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Harris, A. W.

    2006-01-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a

  8. THE TAURUS SPITZER SURVEY: NEW CANDIDATE TAURUS MEMBERS SELECTED USING SENSITIVE MID-INFRARED PHOTOMETRY

    International Nuclear Information System (INIS)

    Rebull, L. M.; Padgett, D. L.; McCabe, C.-E.; Noriega-Crespo, A.; Carey, S. J.; Brooke, T.; Hillenbrand, L. A.; Stapelfeldt, K. R.; Angione, J. R.; Huard, T.; Terebey, S.; Audard, M.; Baldovin-Saavedra, C.; Monin, J.-L.; Menard, F.; Bouvier, J.; Fukagawa, M.; Guedel, M.; Knapp, G. R.; Allen, L. E.

    2010-01-01

    We report on the properties of pre-main-sequence objects in the Taurus molecular clouds as observed in seven mid- and far-infrared bands with the Spitzer Space Telescope. There are 215 previously identified members of the Taurus star-forming region in our ∼44 deg 2 map; these members exhibit a range of Spitzer colors that we take to define young stars still surrounded by circumstellar dust (noting that ∼20% of the bona fide Taurus members exhibit no detectable dust excesses). We looked for new objects in the survey field with similar Spitzer properties, aided by extensive optical, X-ray, and ultraviolet imaging, and found 148 new candidate members of Taurus. We have obtained follow-up spectroscopy for about half the candidate sample, thus far confirming 34 new members, three probable new members, and 10 possible new members, an increase of 15%-20% in Taurus members. Of the objects for which we have spectroscopy, seven are now confirmed extragalactic objects, and one is a background Be star. The remaining 93 candidate objects await additional analysis and/or data to be confirmed or rejected as Taurus members. Most of the new members are Class II M stars and are located along the same cloud filaments as the previously identified Taurus members. Among non-members with Spitzer colors similar to young, dusty stars are evolved Be stars, planetary nebulae, carbon stars, galaxies, and active galactic nuclei.

  9. The Accuracy of the Warm Spitzer Near-Earth Object Survey

    NARCIS (Netherlands)

    Harris, Alan W.; Mommert, M.; Hora, J. L.; Mueller, M.; Trilling, D. E.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Delbo', M.; Emery, J. P.; Fazio, G. G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    We report on observations of near-Earth objects (NEOs) performed with IRAC as part of our on-going (2009-2011) Warm Spitzer NEO survey ("ExploreNEOs"), the primary aim of which is to provide sizes and albedos of some 700 NEOs. The emphasis of the work described here is an assessment of the overall

  10. Spitzer Observations of OGLE-2015-BLG-1212 Reveal a New Path toward Breaking Strong Microlens Degeneracies

    DEFF Research Database (Denmark)

    Bozza, V.; Shvartzvald, Y.; Udalski, A.

    2016-01-01

    Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter s...

  11. HST and Spitzer point source and dust lane detection in powerful narrow-line radio galaxies

    Science.gov (United States)

    Ramírez, E. A.; Tadhunter, C. N.; Dicken, D.; Rose, M.; Axon, D. J.; Sparks, W.

    2014-10-01

    We present the analysis of infrared HST and Spitzer data for a sample of 13 FRII powerful radio galaxies at 0.03 scale toroidal structure when this is viewed edge-on (Barthel 1989, Antonucci 1993). Our high resolution infrared observations provide new information about the optical extinction, orientation, and direct AGN detection of the inner kpc-scale region of the AGN.

  12. Random walks, Brownian motion, and interacting particle systems: a festschrift in honor of Frank Spitzer

    National Research Council Canada - National Science Library

    Durrett, Richard; Kesten, Harry; Spitzer, Frank

    1991-01-01

    ..., made the transparency used in the printing process. STUDENTS OF FRANK SPITZERSTUDENTS OF FRANK SPITZER 1957 J. W. Lamperti, On the asymptotic behavior of recurrent and almostrecurrent events. 1964 W. W. Whitman, Some strong laws for random walks and Brownian motion. 1965 J. C. Mineka, The existence and uniqueness of positive solutions to the Wien...

  13. Thermal properties of Trans-Neptunian objects and Centaurs from combined Herschel and Spitzer observations

    NARCIS (Netherlands)

    Santos-Sanz, P.; Lellouch, E.; Mommert, M.; Fornasier, S.; Stansberry, J.; Mueller, Th.; Kiss, C.; Vilenius, E.; Mueller, M.; Harris, A. W.; Delsanti, A.; Groussin, O.

    2012-01-01

    We present a study of the thermal properties of about 70 trans-Neptunian objects (TNOs) and Centaurs observed with Herschel Space Observatory [8] (either PACS or PACS and SPIRE) and Spitzer Space Telescope [12] (MIPS). We apply radiometric modeling techniques (NEATM [2]) to the measured fluxes to

  14. Thermal Properties Of Trans-neptunian Objects And Centaurs From Combined Herschel And Spitzer Observations

    NARCIS (Netherlands)

    Lellouch, Emmanuel; Santos-Sanz, P.; Mommert, M.; Fornasier, S.; Stansberry, J.; Müller, T.; Duffard, R.; Ortiz, J.; Kiss, C.; Vilenius, E.; Mueller, M.; Lacerda, P.; Harris, A.; TNOs are Cool Team, [No Value

    2012-01-01

    We present a study of the thermal properties of about 70 trans-Neptunian objects (TNOs) and Centaurs observed with Herschel Space Observatory (either PACS or PACS/SPIRE) and Spitzer (MIPS). The combined wavelength range is 24-160 μm and additionally up to 500 μm for a few targets. We apply

  15. Dust evolution in protoplanetary disks around Herbig Ae/Be stars—the Spitzer view

    NARCIS (Netherlands)

    Juhász, A.; Bouwman, J.; Henning, T.; Acke, B.; van den Ancker, M.E.; Meeus, G.; Dominik, C.; Min, M.; Tielens, A.G.G.M.; Waters, L.B.F.M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  16. Waters, dust evolution in protoplanetary disks around herbig ae/be stars—the spitzer view

    NARCIS (Netherlands)

    Juhász, A.; Bouwman, J.; Henning, Th.; Acke, B.; Van Den Ancker, M.; Meeus, G.; Dominik, C.; Min, M.|info:eu-repo/dai/nl/277318416; Tielens, A. G. G. M.; Waters, L.B.F.M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  17. Dust Evolution in Protoplanetary Disks Around Herbig Ae/Be Stars—the Spitzer View

    NARCIS (Netherlands)

    Juhasz, A.; Bouwman, J.; Henning, Th.; Acke, B.; van den Ancker, M. E.; Meeus, G.; Dominik, C.; Min, M.; Tielens, A. G. G. M.; Waters, L. B. F. M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the

  18. The Spitzer IRS infrared spectrum and abundances of the planetary nebula IC 2448

    NARCIS (Netherlands)

    Guiles, S.; Bernard-Salas, J.; Pottasch, S. R.; Roellig, T. L.

    2007-01-01

    We present the mid-infrared spectrum of the planetary nebula IC 2448. In order to determine the chemical composition of the nebula, we use the infrared line fluxes from the Spitzer spectrum along with optical line fluxes from the literature and ultraviolet line fluxes from archival IUE spectra. We

  19. Visible photometry of NEOs in support of a Warm Spitzer program

    Science.gov (United States)

    Trilling, David E.; Jones, Sarah; Penprase, Bryan; Emery, Josh; Harris, Alan; Spahr, Tim; Delbo, Marco

    2009-08-01

    Near Earth Objects (NEOs) may act as dynamical and compositional tracers of the history of near-Earth space. However, despite their scientific importance, key characteristics of the NEO population -- such as the size distribution, mix of albedos and mineralogies, and contributions from so-called dead or dormant comets -- remain largely unexplored; some 99% of all presently known NEOs are essentially uncharacterized. We have been awarded 500 hours of Warm Spitzer time to study some 700 NEOs. The Spitzer data will allow us to measure thermal fluxes and, in combination with optical data, derive albedos and diameters for a large fraction of all known NEOs. Remarkably, the primary uncertainty in our Spitzer results will derive from a lack of good optical photometry for our targets. Fortunately, our targets are generally bright, and obtaining good V band measurements of them requires only a modest amount of time on modest aperture telescopes. We propose here for 36 hours of SMARTS 1.3-m time or 54 hours of SMARTS 0.9-m time to obtain visible photometry of the 72 southern moderately bright ``B'' semester targets in our Warm Spitzer program. These program is ideal for queue/service observing because each observation requires only ~30 minutes and our targets are all over the sky.

  20. Bulk Densities of Binary Asteroids from the Warm Spitzer NEO Survey

    NARCIS (Netherlands)

    Kistler, John; Trilling, D. E.; Mueller, M.; Hora, J. L.; Harris, A. W.; Bhattacharya, B.; Bottke, W. F.; Chesley, S.; Emery, J. P.; Fazo, G.; Mainzer, A.; Penprase, B.; Smith, H. A.; Spahr, T. B.; Stansberry, J. A.; Thomas, C. A.

    2010-01-01

    The Warm Spitzer NEO survey, ExploreNEOs, will observe approximately 700 Near Earth Asteroids. Several of these objects are known to be binary asteroid systems. Binary systems are interesting due to the unique opportunity they present for determining the masses and densities of their constituent

  1. Spitzer Photometry of WISE-selected Brown Dwarf and Hyper-luminous Infrared Galaxy Candidates

    Science.gov (United States)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen; Yan, Lin

    2012-11-01

    We present Spitzer 3.6 and 4.5 μm photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 μm ~ 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (>20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of ~7.33 × 105 objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 μm photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  2. Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates

    Science.gov (United States)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; hide

    2012-01-01

    We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  3. Our cosmic habitat

    CERN Document Server

    Rees, Martin

    2001-01-01

    Our universe seems strangely 'biophilic,' or hospitable to life. Is this providence or coincidence? According to Martin Rees, the answer depends on the answer to another question, the one posed by Einstein's famous remark: 'What interests me most is whether God could have made the world differently.' This highly engaging book centres on the fascinating consequences of the answer being 'yes'. Rees explores the notion that our universe is just part of a vast 'multiverse,' or ensemble of universes, in which most of the other universes are lifeless. What we call the laws of nature would then be local by laws, imposed in the aftermath of our own Big Bang. In this scenario, our cosmic habitat would be a special, possibly unique universe where the prevailing laws of physics allowed life to emerge.

  4. Cosmic magnetic fields

    CERN Document Server

    Sánchez Almeida, Jorge

    2018-01-01

    Magnetic fields pervade the universe and play an important role in many astrophysical processes. However, they require specialised observational tools, and are challenging to model and understand. This volume provides a unified view of magnetic fields across astrophysical and cosmological contexts, drawing together disparate topics that are rarely covered together. Written by the lecturers of the XXV Canary Islands Winter School, it offers a self-contained introduction to cosmic magnetic fields on a range of scales. The connections between the behaviours of magnetic fields in these varying contexts are particularly emphasised, from the relatively small and close ranges of the Sun, planets and stars, to galaxies and clusters of galaxies, as well as on cosmological scales. Aimed at young researchers and graduate students, this up-to-date review uniquely brings together a subject often tackled by disconnected communities, conveying the latest advances as well as highlighting the limits of our current understandi...

  5. Cosmic ray synergies

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    In laboratories, cosmic rays have been the subject of scientific research for many years. A more recent development is their appearance in schools, as educational tools. A recent workshop at CERN, organised by ASPERA in collaboration with EPPOG and EPPCN, had the goal of bringing together ideas and initiatives with a view to setting up a future common project.   Presentation at the workshop on 15 October. In research, as in education, you can sometimes get things done more rapidly and easily by joining forces. For roughly the past decade, physicists have been taking their particle detectors to secondary schools. “The challenge now is to bring all of these existing projects together in a network,” says Arnaud Marsollier, in charge of communication for the ASPERA network and organiser of the workshop. The workshop held on Friday, 15 October was attended by representatives of major European educational projects and members of the European Particle Physics Communication Network...

  6. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  7. Microphysics of cosmic plasmas

    CERN Document Server

    Bykov, Andrei; Cargill, Peter; Dendy, Richard; Wit, Thierry; Raymond, John

    2014-01-01

    This title presents a review of the detailed aspects of the physical processes that underlie the observed properties, structures and dynamics of cosmic plasmas. An assessment of the status of understanding of microscale processes in all astrophysical collisionless plasmas is provided. The topics discussed include  turbulence in astrophysical and solar system plasmas as a phenomenological description of their dynamic properties on all scales; observational, theoretical and modelling aspects of collisionless magnetic reconnection; the formation and dynamics of shock waves; and a review and assessment of microprocesses, such as the hierarchy of plasma instabilities, non-local and non-diffusive transport processes and ionisation and radiation processes.  In addition, some of the lessons that have been learned from the extensive existing knowledge of laboratory plasmas as applied to astrophysical problems are also covered.   This volume is aimed at graduate students and researchers active in the areas of cosmi...

  8. Overproduction of cosmic superstrings

    International Nuclear Information System (INIS)

    Barnaby, Neil; Berndsen, Aaron; Cline, James M.; Stoica, Horace

    2005-01-01

    We show that the naive application of the Kibble mechanism seriously underestimates the initial density of cosmic superstrings that can be formed during the annihilation of D-branes in the early universe, as in models of brane-antibrane inflation. We study the formation of defects in effective field theories of the string theory tachyon both analytically, by solving the equation of motion of the tachyon field near the core of the defect, and numerically, by evolving the tachyon field on a lattice. We find that defects generically form with correlation lengths of order M s -1 rather than H -1 . Hence, defects localized in extra dimensions may be formed at the end of inflation. This implies that brane-antibrane inflation models where inflation is driven by branes which wrap the compact manifold may have problems with overclosure by cosmological relics, such as domain walls and monopoles

  9. Cosmic Ray Antimatter

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Over the last decade, space-born experiments have delivered new measurements of high energy cosmic-ray (CR) antiprotons and positrons, opening new frontiers in energy reach and precision. While being a promising discovery tool for new physics or exotic astrophysical phenomena, an irreducible background of antimatter comes from CR collisions with interstellar matter in the Galaxy. Understanding this irreducible source or constraining it from first principles is an interesting challenge: a game of hide-and-seek where the objective is to identify the laws of basic particle physics among the forest of astrophysical uncertainties. I describe an attempt to obtain such understanding, combining information from a zoo of CR species including massive nuclei and relativistic radioisotopes. I show that: (i) CR antiprotons most likely come from CR-gas collisions; (ii) positron data is consistent with, and suggestive of the same astrophysical production mechanism responsible for antiprotons and dominated by proton-proton c...

  10. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  11. What is cosmic radiation?

    International Nuclear Information System (INIS)

    2004-01-01

    The earth was indeed receiving ionizing radiations from the heavens. This cosmic radiation consists of particles travelling near the speed of light. It consists of two components, the first of which is permanent and of galactic origin, while the other is more sporadic, depending on the sun's activities. Natural land-based sources expose each of us to an average total dose of 2.4 mSv per year (source UNSCEAR). In addition, the human activities using ionizing radiation contribute to an average annual exposure of 1.4 mSv, originating primarily with medical activities ( radiodiagnostic and radiation therapy). Members of flights crew are subject to exposure. The total dose of cosmic radiation received is is directly proportional with the duration of exposure, and thus with the duration of the flight. Measurement taken on board aircraft during the 1990's showed that flight personnel (on long haul flights) receive an average dose of approximately the same magnitude as the one due to exposure to natural radioactivity in France. The damage caused by ionizing radiation depends on the quantity of energy released by radiation into the cells of each organ or tissue of the human body(exposure dose). For a given quantity of absorbed energy (dose expressed in Gray), the damage will vary according to the nature of the radiation and the affected organ. These effects are of two types: acute effects and deferred effects. Two measurements are essential for radiation protection: the measurements of the dose of radiation absorbed by the body and the assessment of the risk associated with the absorbed dose. Two units were thus created: the gray and the sievert. (N.C.)

  12. THE COSMIC ORIGINS SPECTROGRAPH

    Energy Technology Data Exchange (ETDEWEB)

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John [Department of Astrophysical and Planetary Sciences, University of Colorado, 391-UCB, Boulder, CO 80309 (United States); Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin [Center for Astrophysics and Space Astronomy, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Ebbets, Dennis [Ball Aerospace and Technologies Corp., 1600 Commerce Street, Boulder, CO 80301 (United States); Heap, Sara H. [NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771 (United States); Leitherer, Claus; Sembach, Kenneth [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, Boulder, CO 80309-0440 (United States); Savage, Blair D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Siegmund, Oswald H. W. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Spencer, John; Alan Stern, S. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Welsh, Barry [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  13. Primary cosmic radiation

    International Nuclear Information System (INIS)

    Anderson, H.R.

    1972-01-01

    The term cosmic radiation means the charged particle flux that reaches the earth from outside its magnetosphere with energies above the solar wind energy of a few keV. There are two sources of flux. Sporadically the sun produces such particles, generally within the energy range 1--200 MeV, and these solar cosmic rays arrive at the earth for a period ranging from hours to days. There may be a small, rather constant flux from the sun also, but the bulk of the steady flux originates outside the earth's orbit. Although some have conjectured that part of this latter flux may be accelerated in the outer portions of the solar system where the outward flowing interplanetary medium meets the interstellar medium, it is generally thought that most or all of it arises in unique systems such as supernovae, and is distributed throughout the galaxy. These galactic particles range in energy from a few MeV to at least 10 13 MeV and consist primarily of protons with significant numbers of heavier nuclei, positrons and electrons. They are supposed to fill our galaxy, or at least the disc, more or less uniformly. However, the flux with energies below a few GeV that reaches earth's orbit is modulated by the interplanetary medium so that the number at earth varies inversely with solar activity and is always somewhat below the interstellar flux. A discussion is presented of primary galactic radiation at earth, its modulation by solar activity, and its interaction with the geomagnetic field. (U.S.)

  14. The Cosmic Origins Spectrograph

    Science.gov (United States)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20120013029'); toggleEditAbsImage('author_20120013029_show'); toggleEditAbsImage('author_20120013029_hide'); "> hide

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  15. New Results from Spitzer's Journey Through The Earth's Resonant Ring: 2004-2006

    Science.gov (United States)

    Jayaraman, Sumita; Grogan, K.; Bhattacharya, B.; Reach, W. T.

    2006-09-01

    The Spitzer Space Telescope, in its solar orbit, has been drifting away from the Earth - enabling it to trace a path through the Earth's Resonant Ring, specifically, traverse through the resonant dust cloud that follows the Earth. The dust cloud causes the mid-infrared flux in the sky to be higher in the trailing direction when viewed from the Earth. After launch, Spitzer has slowly entered into the dust cloud and has crossed over the peak dust density of the trailing dust cloud. This causes a change in the trailing/leading asymmetry in the background flux. Eventually the leading flux will be higher as Spitzer views the cloud from the opposite side at the end of the mission. We have designed a zodiacal background monitoring program for the ecliptic and north and south ecliptic poles to obtain absolutely calibrated data in the MIPS total power mode. This program includes observations from 2004 to 2006 and will continue into the next observation cycle. We present new results measuring the change in the zodiacal background radiation at 24 microns in combination with science calibration observation observations from IRAC during this period. Further comparison of the multi-wavelength measurements to models shows the detailed ring structure and the provide estimates of the ring dust density in the Resonant Ring. We would like to thank NASA/JPL for funding this program through the Spitzer GO Cycle. We would also like to thank the Spitzer Science Center for helping us to schedule the individual solar system observations after the MIPS campaign dates are fixed and contributing the IRAC calibration observations.

  16. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    We present a detailed analysis of the motion of test particle in the gravitational field of cosmic strings in different situations using the Hamilton–Jacobi (H–J) formalism. We have discussed the trajectories near static cosmic string, cosmic string in Brans–Dicke theory and cosmic string in dilaton gravity.

  17. Interaction of cosmic strings with gravitational waves

    International Nuclear Information System (INIS)

    Frolov, V.P.; Garfinkle, D.

    1990-01-01

    We find solutions of Einstein's equation representing a gravitational wave interacting with a cosmic-string traveling wave. The motion of test cosmic strings in the gravitational field of a cosmic-string traveling wave is also examined. A solution representing traveling waves on several parallel cosmic strings is also found

  18. Spherical Orbifolds for Cosmic Topology

    International Nuclear Information System (INIS)

    Kramer, Peter

    2012-01-01

    Harmonic analysis is a tool to infer cosmic topology from the measured astrophysical cosmic microwave background CMB radiation. For overall positive curvature, Platonic spherical manifolds are candidates for this analysis. We combine the specific point symmetry of the Platonic manifolds with their deck transformations. This analysis in topology leads from manifolds to orbifolds. We discuss the deck transformations of the orbifolds and give eigenmodes for the harmonic analysis as linear combinations of Wigner polynomials on the 3-sphere. These provide new tools for detecting cosmic topology from the CMB radiation.

  19. Experimental aspects of cosmic rays

    CERN Document Server

    Sommers, P

    2006-01-01

    High-energy cosmic rays are detected as extensive air showers, and properties of the primary cosmic rays are deduced from measurements of those air showers. The physics of air showers is reviewed here in order to explain how the measurement techniques work. The Pierre Auger Cosmic Ray Observatory (near this school in Malargue) is used to illustrate the experimental methods. The Auger Observatory combines a surface array of water Cherenkov detectors with atmospheric uorescence detectors. This `hybrid' measurement technique provides high resolution and measurement cross-checks. In conjunction with a complementary site in the northern hemisphere, the Auger Observatory expects to map the arrival directions over the full sky as well as measuring the cosmic-ray energy spectrum and statistical properties of the mass distribution.

  20. Cosmic rays, clouds, and climate.

    Science.gov (United States)

    Carslaw, K S; Harrison, R G; Kirkby, J

    2002-11-29

    It has been proposed that Earth's climate could be affected by changes in cloudiness caused by variations in the intensity of galactic cosmic rays in the atmosphere. This proposal stems from an observed correlation between cosmic ray intensity and Earth's average cloud cover over the course of one solar cycle. Some scientists question the reliability of the observations, whereas others, who accept them as reliable, suggest that the correlation may be caused by other physical phenomena with decadal periods or by a response to volcanic activity or El Niño. Nevertheless, the observation has raised the intriguing possibility that a cosmic ray-cloud interaction may help explain how a relatively small change in solar output can produce much larger changes in Earth's climate. Physical mechanisms have been proposed to explain how cosmic rays could affect clouds, but they need to be investigated further if the observation is to become more than just another correlation among geophysical variables.

  1. Cosmic microwave background, where next?

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Ground-based, balloon-borne and space-based experiments will observe the Cosmic Microwave Background in greater details to address open questions about the origin and the evolution of the Universe. In particular, detailed observations the polarization pattern of the Cosmic Microwave Background radiation have the potential to directly probe physics at the GUT scale and illuminate aspects of the physics of the very early Universe.

  2. Cosmic rays and Earth's climate

    DEFF Research Database (Denmark)

    Svensmark, Henrik

    2000-01-01

    During the last solar cycle the Earth's cloud cover underwent a modulation in phase with the cosmic ray flux. Assuming that there is a causal relationship between the two, it is expected and found that the Earth's temperature follows more closely decade variations in cosmic ray flux than other...... solar activity parameters. If the relationship is real the state of the Heliosphere affects the Earth's climate....

  3. The Cosmic Century

    Science.gov (United States)

    Longair, Malcolm S.

    2013-04-01

    Part I. Stars and Stellar Evolution up to the Second World War: 1. The legacy of the nineteenth century; 2. The classification of stellar spectra; 3. Stellar structure and evolution; 4. The end points of stellar evolution; Part II. The Large-Scale Structure of the Universe, 1900-1939: 5. The Galaxy and the nature of spiral nebulae; 6. The origins of astrophysical cosmology; Part III. The Opening up of the Electromagnetic Spectrum: 7. The opening up of the electromagnetic spectrum and the new astronomies; Part IV. The Astrophysics of Stars and Galaxies since 1945: 8. Stars and stellar evolution; 9. The physics of the interstellar medium; 10. The physics of galaxies and clusters of galaxies; 11. High-energy astrophysics; Part V. Astrophysical Cosmology since 1945: 12. Astrophysical cosmology; 13. The determination of cosmological parameters; 14. The evolution of galaxies and active galaxies with cosmic epoch; 15. The origin of galaxies and the large-scale structure of the Universe; 16. The very early Universe; References; Name index; Object index; Subject index.

  4. Nonthermal cosmic neutrino background

    Science.gov (United States)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  5. Illustrated cosmic monopole

    CERN Document Server

    Seagrave, Wyken

    2015-01-01

    Truly bizarre, utterly unique I've never read a novel quite like this before. The author takes you on an exciting adventure full of unforgettable and vivid imagery. Solidly written with each character's personality shining through. If you find physics fascinating you will not be disappointed by the author's keen intellect and clear understanding of this most challenging (for me anyway) scientific subject. This is not a novel I will forget anytime soon, I would highly recommend it. Andrewly Very imaginative tale Anybody interested in a very imaginative and engrossing sci fi story needs to check this one out. I have been reading sci fi for decades and this story has elements that surprise me which is very unusual considering the number of novels and stories I have over the years. ric freeman Summary of the story The cosmic monopole has been wandering the Universe since it was created in the Big Bang. Its existence is fundamental to the way the Universe works. It is finally trapped by the powerful magnetic f...

  6. New Software for Ensemble Creation in the Spitzer-Space-Telescope Operations Database

    Science.gov (United States)

    Laher, Russ; Rector, John

    2004-01-01

    Some of the computer pipelines used to process digital astronomical images from NASA's Spitzer Space Telescope require multiple input images, in order to generate high-level science and calibration products. The images are grouped into ensembles according to well documented ensemble-creation rules by making explicit associations in the operations Informix database at the Spitzer Science Center (SSC). The advantage of this approach is that a simple database query can retrieve the required ensemble of pipeline input images. New and improved software for ensemble creation has been developed. The new software is much faster than the existing software because it uses pre-compiled database stored-procedures written in Informix SPL (SQL programming language). The new software is also more flexible because the ensemble creation rules are now stored in and read from newly defined database tables. This table-driven approach was implemented so that ensemble rules can be inserted, updated, or deleted without modifying software.

  7. SPITZER PARALLAX OF OGLE-2015-BLG-0966: A COLD NEPTUNE IN THE GALACTIC DISK

    Energy Technology Data Exchange (ETDEWEB)

    Street, R. A.; Bachelet, E. [LCOGT, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Novati, S. Calchi [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Hundertmark, M. P. G.; Jørgensen, U. G. [Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350—Copenhagen K (Denmark); Zhu, W.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Yee, J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tsapras, Y. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg (Germany); Bennett, D. P. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Dominik, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Andersen, M. I. [Niels Bohr Institute and Dark Cosmology Centre, University of Copenhagen, Juliane Mariesvej 30, DK-2100—Copenhagen Ø (Denmark); Bozza, V. [Dipartimento di Fisica “E.R. Caianiello,” Università di Salerno, Via Giovanni Paolo II 132, I-84084, Fisciano (Italy); Bramich, D. M. [Qatar Environment and Energy Research Institute, Qatar Foundation, P.O. Box 5825, Doha (Qatar); Collaboration: RoboNet Project and MiNDSTEp Consortium; OGLE Project; Spitzer Team; MOA Collaboration; KMTNet Modeling Team; and others

    2016-03-10

    We report the detection of a cold Neptune m{sub planet} = 21 ± 2 M{sub ⊕} orbiting a 0.38 M{sub ⊙} M dwarf lying 2.5–3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real-time protocols described by Yee et al., which aim to maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey and follow up teams successfully combined their efforts within the framework of these protocols to detect this planet. This is the second planet in the Spitzer Galactic distribution sample. Both are in the near to mid-disk and are clearly not in the Galactic bulge.

  8. Nearest Cosmic Mirage

    Science.gov (United States)

    2003-07-01

    Discovery of quadruply lensed quasar with Einstein ring Summary Using the ESO 3.6-m telescope at La Silla (Chile), an international team of astronomers [1] has discovered a complex cosmic mirage in the southern constellation Crater (The Cup). This "gravitational lens" system consists of (at least) four images of the same quasar as well as a ring-shaped image of the galaxy in which the quasar resides - known as an "Einstein ring". The more nearby lensing galaxy that causes this intriguing optical illusion is also well visible. The team obtained spectra of these objects with the new EMMI camera mounted on the ESO 3.5-m New Technology Telescope (NTT), also at the La Silla observatory. They find that the lensed quasar [2] is located at a distance of 6,300 million light-years (its "redshift" is z = 0.66 [3]) while the lensing elliptical galaxy is rougly halfway between the quasar and us, at a distance of 3,500 million light-years (z = 0.3). The system has been designated RXS J1131-1231 - it is the closest gravitationally lensed quasar discovered so far . PR Photo 20a/03 : Image of the gravitational lens system RXS J1131-1231 (ESO 3.6m Telescope). PR Photo 20b/03 : Spectra of two lensed images of the source quasar and the lensing galaxy. Cosmic mirages The physical principle behind a "gravitational lens" (also known as a "cosmic mirage") has been known since 1916 as a consequence of Albert Einstein's Theory of General Relativity . The gravitational field of a massive object curves the local geometry of the Universe, so light rays passing close to the object are bent (like a "straight line" on the surface of the Earth is necessarily curved because of the curvature of the Earth's surface). This effect was first observed by astronomers in 1919 during a total solar eclipse. Accurate positional measurements of stars seen in the dark sky near the eclipsed Sun indicated an apparent displacement in the direction opposite to the Sun, about as much as predicted by Einstein

  9. Cosmic Dawn Intensity Mapper

    Science.gov (United States)

    Cooray, Asantha

    2018-01-01

    Cosmic Dawn Intensity Mapper (CDIM) is a 1.0m-class infrared telescope capable of three-dimensional spectro-imaging observations over the wavelength range of 0.75 to 7.5 microns, at a spectral resolving power at or better than 300. This will be achieved with linear variablefilters (LVFs) and a large field-of-view (FoV). The survey strategy using spacecraft operations following a shift and stare mode will result in more than 1300 independent narrow-band spectral images of the sky at a given location. Currently prioritized science programs, taking over three-years of a five-year mission, will be accomplished with a two-tiered wedding-cake survey with the shallowest spanning close to 300 sq. degrees and the deepest tier of about 25 sq. degrees.The remaining two-years could be used for additional survey programs (the wide tier can be expanded to 1000 sq. degrees) or for use by the astronomical community through a General Observing (GO) campaign. CDIM survey data will allow us to (i) establish the initial mass function of stars in galaxies present during reionization, (ii) definitively address AGN/quasar contribution to the reionization photon budget; (iii) establish the environmental dependence of star-formation during reionization through clustering and other environmental measurements; (iv) establish the metal abundance of first-light galaxies during reionization over two decades of stellar mass; (v) measure 3D intensity fluctuations during reionization in both Ly-alpha and H-alpha; and (vi) combine intensity fluctuations with 21-cm data to establish the topology of reionization bubbles.

  10. Video Screen Capture Basics

    Science.gov (United States)

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  11. SPITZER INFRARED SPECTROMETER 16 μm OBSERVATIONS OF THE GOODS FIELDS

    International Nuclear Information System (INIS)

    Teplitz, Harry I.; Chary, Ranga; Elbaz, David; Le Floc'h, Emeric; Dickinson, Mark; Bridge, Carrie; Howell, Justin H.; Siana, Brian; Colbert, James; Scarlata, Claudia; Frayer, David T.; Koo, David C.; Phillips, Andrew; Papovich, Casey; Spinrad, Hyron; Stern, Daniel

    2011-01-01

    We present Spitzer 16 μm imaging of the Great Observatories Origins Deep Survey (GOODS) fields. We survey 150 arcmin 2 in each of the two GOODS fields (North and South), to an average 3σ depth of 40 and 65 μJy, respectively. We detect ∼1300 sources in both fields combined. We validate the photometry using the 3-24 μm spectral energy distribution of stars in the fields compared to Spitzer spectroscopic templates. Comparison with ISOCAM and AKARI observations in the same fields shows reasonable agreement, though the uncertainties are large. We provide a catalog of photometry, with sources cross-correlated with available Spitzer, Chandra, and Hubble Space Telescope data. Galaxy number counts show good agreement with previous results from ISOCAM and AKARI with improved uncertainties. We examine the 16-24 μm flux ratio and find that for most sources it lies within the expected locus for starbursts and infrared luminous galaxies. A color cut of S 16 /S 24 >1.4 selects mostly sources which lie at 1.1 -2 sr -1 .

  12. Physical Properties of Asteroid (10302) 1989 ML, a Potential Spacecraft Target, from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Harris, A. W.

    2006-09-01

    We report on results from recent Spitzer observations of near-Earth asteroid (10302) 1989 ML, which is among the lowest-ranking objects in terms of the specific momentum Δv required to reach it from Earth. It was originally considered as a target for Hayabusa and is now under consideration as a target of the planned ESA mission Don Quijote. Unfortunately, little is known about the physical properties of 1989 ML, in particular its size and albedo are unknown. Its exhibits an X type reflection spectrum, so depending on its albedo, 1989 ML may be an E, M, or P type asteroid. Provisional results from thermal-infrared observations carried out with Spitzer indicate that the albedo of 1989 ML is compatible with an M- or E-type classification. We will discuss our results and their implications for the physical properties and the rotation period of 1989 ML, and its importance as a potential spacecraft target. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  13. MEASURING ORGANIC MOLECULAR EMISSION IN DISKS WITH LOW-RESOLUTION SPITZER SPECTROSCOPY

    International Nuclear Information System (INIS)

    Teske, Johanna K.; Najita, Joan R.; Carr, John S.; Pascucci, Ilaria; Apai, Daniel; Henning, Thomas

    2011-01-01

    We explore the extent to which Spitzer Infrared Spectrograph (IRS) spectra taken at low spectral resolution can be used in quantitative studies of organic molecular emission from disks surrounding low-mass young stars. We use Spitzer IRS spectra taken in both the high- and low-resolution modules for the same sources to investigate whether it is possible to define line indices that can measure trends in the strength of the molecular features in low-resolution data. We find that trends in the HCN emission strength seen in the high-resolution data can be recovered in low-resolution data. In examining the factors that influence the HCN emission strength, we find that the low-resolution HCN flux is modestly correlated with stellar accretion rate and X-ray luminosity. Correlations of this kind are perhaps expected based on recent observational and theoretical studies of inner disk atmospheres. Our results demonstrate the potential of using the large number of low-resolution disk spectra that reside in the Spitzer archive to study the factors that influence the strength of molecular emission from disks. Such studies would complement results for the much smaller number of circumstellar disks that have been observed at high resolution with IRS.

  14. Spitzer and Variable Young Stars: Shining a Spotlight on Circumstellar Disks

    Science.gov (United States)

    Cody, Ann Marie; CSI 2264 Team

    2014-01-01

    Since its launch in 2003, the Spitzer Space Telescope has helped to uncover hundreds of disk bearing young stars in clusters by detecting their infrared excesses. Study of the spectral energy distributions of these objects has shed light on disk evolution, dispersal, and the relationship to planet formation. With the start of the Warm Spitzer Mission, mid-infrared time series observations have opened up a new window into the dynamic nature of these systems. Not only are young stellar objects (YSOs) highly variable, but so are their disks! I will review recent findings on mid-infrared variability in young stars, highlighting the Young Stellar Object Variability project and the joint Spitzer/CoRoT Coordinated Synoptic Investigation of NGC 2264. These efforts have resulted in a comprehensive census and categorization of YSO flux behavior at 0.5 through 4.5 microns, on timescales from hours to months. We now have evidence for multiple simultaneous variability mechanisms, supporting the picture of a highly dynamic star-disk system.

  15. SPITZER IRS SPECTRA OF DEBRIS DISKS IN THE SCORPIUS–CENTAURUS OB ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Jang-Condell, Hannah [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Chen, Christine H.; Mittal, Tushar; Lisse, Carey M. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Rd., Mumbai 400005 (India); Watson, Dan [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Nesvold, Erika; Kuchner, Marc [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2015-08-01

    We analyze spectra obtained with the Spitzer Infrared Spectrograph (IRS) of 110 B-, A-, F-, and G-type stars with optically thin infrared excess in the Scorpius–Centaurus OB association. The ages of these stars range from 11 to 17 Myr. We fit the infrared excesses observed in these sources by Spitzer IRS and the Multiband Imaging Photometer for Spitzer (MIPS) to simple dust models according to Mie theory. We find that nearly all of the objects in our study can be fit by one or two belts of dust. Dust around lower mass stars appears to be closer in than around higher mass stars, particularly for the warm dust component in the two-belt systems, suggesting a mass-dependent evolution of debris disks around young stars. For those objects with stellar companions, all dust distances are consistent with truncation of the debris disk by the binary companion. The gaps between several of the two-belt systems can place limits on the planets that might lie between the belts, potentially constraining the mass and locations of planets that may be forming around these stars.

  16. Cosmic logic: a computational model

    International Nuclear Information System (INIS)

    Vanchurin, Vitaly

    2016-01-01

    We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or Gödel number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies that it is impossible to construct CM machines to compute probabilities on the set of all CO machines using cut-off prescriptions. The cut-off measures can still be used if the set is reduced to include only machines which halt after a finite and predetermined number of steps

  17. Acceleration, transport and fractionation of anomalous cosmic rays

    International Nuclear Information System (INIS)

    Jokipii, J.R.

    2000-01-01

    The effects acceleration and transport on the charge and elemental composition of anomalous cosmic rays is discussed in the context of the model of acceleration at the solar-wind termination shock. Since the transport coefficients depend on the mass and charge of the particles, changes of composition are expected, both in the acceleration and the transport process. These effects are shown for different species. Special attention will be given to the production of multiply-charged ionic species from the originally singly-charged species, as a result of the acceleration at the termination shock and subsequent propagation. Good agreement is found with these observations, suggesting that the models are capturing much of the basic physics. In particular, the energy where the singly-charged anomalous cosmic rays give way to multiply-charged particles is very sharp and at very nearly the same energy for all species observed, and also in the model

  18. Radiative electron capture

    International Nuclear Information System (INIS)

    Biggerstaff, J.A.; Appleton, B.R.; Datz, S.; Moak, C.D.; Neelavathi, V.N.; Noggle, T.S.; Ritchie, R.H.; VerBeek, H.

    1975-01-01

    Some data are presented for radiative electron capture by fast moving ions. The radiative electron capture spectrum is shown for O 8+ in Ag, along with the energy dependence of the capture cross-section. A discrepancy between earlier data, theoretical prediction, and the present data is pointed out. (3 figs) (U.S.)

  19. Capture Their Attention: Capturing Lessons Using Screen Capture Software

    Science.gov (United States)

    Drumheller, Kristina; Lawler, Gregg

    2011-01-01

    When students miss classes for university activities such as athletic and academic events, they inevitably miss important class material. Students can get notes from their peers or visit professors to find out what they missed, but when students miss new and challenging material these steps are sometimes not enough. Screen capture and recording…

  20. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start......Satellite observations have shown that the Earth’s cloud cover is strongly correlated with the galactic cosmic ray flux. While this correlation is indicative of a possible physical connection, there is currently no confirmation that a physical mechanism exists. We are therefore setting up...... an experiment in order to investigate the underlying microphysical processes. The results of this experiment will help to understand whether ionization from cosmic rays, and by implication the related processes in the universe, has a direct influence on Earth’s atmosphere and climate. Since any physical...

  1. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability......A correlation between a global average of low cloud cover and the flux of cosmic rays incident in the atmosphere has been observed during the last solar cycle. The ionising potential of Earth bound cosmic rays are modulated by the state of the heliosphere, while clouds play an important role...... in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...

  2. Cosmic Ray Energetics and Mass

    CERN Multimedia

    Baylon cardiel, J L; Wallace, K C; Anderson, T B; Copley, M

    The cosmic-ray energetics and mass (CREAM) investigation is designed to measure cosmic-ray composition to the supernova energy scale of 10$^{15}$ eV in a series of ultra long duration balloon (ULDB) flights. The first flight is planned to be launched from Antarctica in December 2004. The goal is to observe cosmic-ray spectral features and/or abundance changes that might signify a limit to supernova acceleration. The particle ($\\{Z}$) measurements will be made with a timing-based charge detector and a pixelated silicon charge detector to minimize the effect of backscatter from the calorimeter. The particle energy measurements will be made with a transition radiation detector (TRD) for $\\{Z}$ > 3 and a sampling tungsten/scintillator calorimeter for $\\{Z}$ $\\geq$1 particles, allowing inflight cross calibration of the two detectors. The status of the payload construction and flight preparation are reported in this paper.

  3. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    between cosmic ray flux and low cloud top temperature. The temperature of a cloud depends on the radiation properties determined by its droplet distribution. Low clouds are warm (> 273 K) and therefore consist of liquid water droplets. At typical atmospheric supersaturations (similar to1%) a liquid cloud...... that a mechanism to explain the cosmic ray-cloud link might be found through the role of atmospheric ionisation in aerosol production and/or growth. Observations of local aerosol increases in low cloud due to ship exhaust indicate that a small perturbation in atmospheric aerosol can have a major impact on low...... cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability...

  4. Cosmic rays and particle physics

    CERN Document Server

    Gaisser, Thomas K; Resconi, Elisa

    2016-01-01

    Fully updated for the second edition, this book introduces the growing and dynamic field of particle astrophysics. It provides an overview of high-energy nuclei, photons and neutrinos, including their origins, their propagation in the cosmos, their detection on Earth and their relation to each other. Coverage is expanded to include new content on high energy physics, the propagation of protons and nuclei in cosmic background radiation, neutrino astronomy, high-energy and ultra-high-energy cosmic rays, sources and acceleration mechanisms, and atmospheric muons and neutrinos. Readers are able to master the fundamentals of particle astrophysics within the context of the most recent developments in the field. This book will benefit graduate students and established researchers alike, equipping them with the knowledge and tools needed to design and interpret their own experiments and, ultimately, to address a number of questions concerning the nature and origins of cosmic particles that have arisen in recent resea...

  5. Enhancing the Legacy of Spitzer and Herschel with the MOSFIRE Deep Evolution Field Survey

    Science.gov (United States)

    Reddy, Naveen

    The next frontier for comprehensive galaxy surveys is the epoch at z~1.5-3.5, the peak of star formation and black hole activity. Despite the new windows that Spitzer and Herschel have opened up into the stellar and dust emission of distant galaxies and AGN during this key epoch, these studies have been limited by the lack of spectroscopic redshifts and the unknown physical conditions (e.g., metallicities, ionization) within the targeted galaxies. To realize the full potential of Spitzer and Herschel, we require a large spectroscopic survey that will: (a) efficiently assemble spectroscopic redshifts for large samples of galaxies at z=1.4-3.8; (b) yield the physical conditions, including the ionization and metallicities of these galaxies; and (c) easily obtain spectroscopic redshifts even for very dusty/confused galaxies. To this end, our team has been allocated a large program of 47 Keck nights with the multi-object near-IR spectrograph MOSFIRE to carry out the MOSFIRE Deep Evolution Field Survey (MOSDEF) in three of the Hubble CANDELS fields. MOSDEF will obtain rest-optical spectra of ~1500 galaxies at redshifts z=1.4-3.8, targeting many of the optical nebular emission lines and continuum features (e.g., [OII], [OIII], H-beta, H-alpha, [NII], [SII], 4000 Angstrom break, Ca H and K, and Mbg) that until now have been inaccessible for large samples of distant galaxies, but which are routinely used to measure the SFRs, dust attenuation, metal and gas content, and ionization and dynamical properties in nearby galaxies. MOSDEF spectroscopy provides a critical supporting role for the analysis of Spitzer and Herschel observations of distant galaxies. With this transformative dataset, we will perform the following analyses. First, we will use Spitzer and Herschel imaging, aided with spectroscopic redshifts from MOSDEF, to construct individual and mean dust SEDs for galaxies at redshifts 1.4formation and destruction processes. Our study will greatly enhance the scientific

  6. The Cosmic Shoreline

    Science.gov (United States)

    Zahnle, Kevin J.; Catling, D. C.

    2013-01-01

    in 2004 when there were just two transiting exoplanets to consider. The trend was well-defined by late 2007. Figure 1 shows how matters stood in Dec 2012 with approx.240 exoplanets. The figure shows that the boundary between planets with and without active volatiles - the cosmic shoreline, as it were - is both well-defined and follows a power law.

  7. Cosmic Humanity: Utopia, Realities, Prospects

    Directory of Open Access Journals (Sweden)

    Sergey Krichevsky

    2017-07-01

    Full Text Available The philosophical foundations of the theory and practice of the creation of cosmic humanity as a process of the evolution of human civilization, the emergence into space, with the prospect of resettlement outside the Earth are considered. There is a connection between myths, fantasies, ideas, concepts and projects aimed at the exploration of outer space, the creation of cosmic humanity. A new and voluminous definition of cosmic humanity in the evolutionary paradigm is given. Cosmic humanity is (essence and 4 stages of evolution: 1. Humanity living on Earth, sensing, knowing, understanding its cosmic origin, relationship with the cosmos and cosmic destiny. 2. Humanity living on Earth, leading aerospace activity for the purposes of exploration and use of aerospace space (Heaven, Space for survival and development. 3. Humanity living on Earth and outside the Earth — in the solar system, preserving the Earth and mastering the Cosmos for survival and development. 4. Humanity, settled and living in the Cosmos. Now humanity is in the process of transition from the second to the third stage. In the process of this evolution, a complex transformation of man and society takes place. The problem-semantic field of cosmic humanity is described and its general model is presented. The meta-goal-setting is the justification of cosmic humanity with the application of the anthropic principle and its “active” super (post anthropic supplement: “Cosmic humanity has an evolutionary purpose to actively manage evolution: change man, humanity and the universe.” The evolution of the “cosmic dream”, goals and technologies of space activities is formalized in the form of a conceptual model. Challenges and negative trends are considered in connection with the crisis of space activity, criticism and attempts to limit the flights of people into space. The prototype of cosmic humanity, its basis and acting model is the cosmonauts’ community. The main

  8. The Cosmic Infrared Background Experiment

    OpenAIRE

    Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2005-01-01

    We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7 arcseconds to 2 degrees over a range of angular sca...

  9. Cosmic Rays and Global Warming

    OpenAIRE

    Sloan, T.; Wolfendale, A W

    2007-01-01

    It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variatio...

  10. Evolution of cosmic string networks

    International Nuclear Information System (INIS)

    Albrecht, A.; Turok, N.; Princeton Univ., NJ

    1989-06-01

    We summarize our new results on cosmic strings. These results include: the application of non-equilibrium statistical mechanics to cosmic string evolution, a simple ''one scale'' model for the long strings which has a great deal of predictive power, results from large scale numerical simulations, and a discussion of the observational consequences of our results. An upper bond on Gμ of approximately 10 -7 emerges from the millisecond pulsar gravity wave bound. We discuss how numerical uncertainties affect this. Any changes which weaken the bound would probably also give the long strings the dominant role in producing observational consequences. 22 refs

  11. Cosmic string in gravity's rainbow

    Science.gov (United States)

    Momeni, Davood; Upadhyay, Sudhaker; Myrzakulov, Yerlan; Myrzakulov, Ratbay

    2017-09-01

    In this paper, we study the various cylindrical solutions (cosmic strings) in gravity's rainbow scenario. In particular, we calculate the gravitational field equations corresponding to energy-dependent background. Further, we discuss the possible Kasner, quasi-Kasner and non-Kasner exact solutions of the field equations. In this framework, we find that quasi-Kasner solutions cannot be realized in gravity's rainbow. Assuming only time-dependent metric functions, we also analyse the time-dependent vacuum cosmic strings in gravity's rainbow, which are completely different than the other GR solutions.

  12. Dust in cosmic plasma environments

    International Nuclear Information System (INIS)

    Mendis, D.A.

    1979-01-01

    Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments - including planetary magnetospheres, the heliosphere and the interstellar medium - are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed. (Auth.)

  13. Closing CMS to hunt cosmic rays

    CERN Multimedia

    Claudia Marcelloni

    2006-01-01

    Every second the Earth is bombarded by billions of cosmic rays and occasionally one of these cosmic particles will collide with the Earth's atmosphere generating a shower of particles known as an 'air shower'. This is similiar to the collisions and subsequent particle showers observed in accelerators such as the LHC. Here the CMS detector is closed so that systems can be tested using muon cosmic rays in the 'Cosmic Challenge'.

  14. Chandra Discovers Cosmic Cannonball

    Science.gov (United States)

    2007-11-01

    One of the fastest moving stars ever seen has been discovered with NASA's Chandra X-ray Observatory. This cosmic cannonball is challenging theories to explain its blistering speed. Astronomers used Chandra to observe a neutron star, known as RX J0822-4300, over a period of about five years. During that span, three Chandra observations clearly show the neutron star moving away from the center of the Puppis A supernova remnant. This remnant is the stellar debris field created during the same explosion in which the neutron star was created about 3700 years ago. Chandra X-ray Image of RX J0822-4300 in Puppis A Chandra X-ray Image of RX J0822-4300 in Puppis A By combining how far it has moved across the sky with its distance from Earth, astronomers determined the neutron star is moving at over 3 million miles per hour. At this rate, RX J0822-4300 is destined to escape from the Milky Way after millions of years, even though it has only traveled about 20 light years so far. "This star is moving at 3 million miles an hour, but it's so far away that the apparent motion we see in five years is less than the height of the numerals in the date on a penny, seen from the length of a football field," said Frank Winkler of Middlebury College in Vermont. "It's remarkable, and a real testament to the power of Chandra, that such a tiny motion can be measured." Labeled Image of RX J0822-4300 in Puppis A Labeled Image of RX J0822-4300 in Puppis A "Just after it was born, this neutron star got a one-way ticket out of the Galaxy," said co-author Robert Petre of NASA's Goddard Space Flight Center in Greenbelt, Md. "Astronomers have seen other stars being flung out of the Milky Way, but few as fast as this." So-called hypervelocity stars have been previously discovered shooting out of the Milky Way with speeds around one million miles per hour. One key difference between RX J0822-4300 and these other reported galactic escapees is the source of their speed. The hypervelocity stars are

  15. Voids and the Cosmic Web: cosmic depression & spatial complexity

    NARCIS (Netherlands)

    van de Weygaert, Rien; Shandarin, S.; Saar, E.; Einasto, J.

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do theyrepresent a key constituent of the Cosmic Web, they also are one of the cleanest probesand measures of global cosmological parameters. The shape and evolution of voids are highly sensitive tothe

  16. The Spine of the Cosmic Web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; Platen, Erwin; Weygaert, Rien van de; Szalay, Alexander S.

    2008-01-01

    We present a new concept, the Spine of the Cosmic Web, for the topological analysis of the Cosmic Web and the identification of its filaments and walls. Based on the watershed segmentation of the cosmic density field, the method invokes the local properties of the regions adjacent to the critical

  17. A Demonstration Device for Cosmic Rays Telescopes

    Science.gov (United States)

    Esposito, Salvatore

    2018-01-01

    We describe a hands-on accurate demonstrator for cosmic rays realized by six high school students. The main aim is to show the relevance and the functioning of the principal parts of a cosmic ray telescope (muon detector), with the help of two large sized wooden artefacts. The first one points out how cosmic rays can be tracked in a muon…

  18. Cosmic Censorship for Gowdy Spacetimes.

    Science.gov (United States)

    Ringström, Hans

    2010-01-01

    Due to the complexity of Einstein's equations, it is often natural to study a question of interest in the framework of a restricted class of solutions. One way to impose a restriction is to consider solutions satisfying a given symmetry condition. There are many possible choices, but the present article is concerned with one particular choice, which we shall refer to as Gowdy symmetry. We begin by explaining the origin and meaning of this symmetry type, which has been used as a simplifying assumption in various contexts, some of which we shall mention. Nevertheless, the subject of interest here is strong cosmic censorship. Consequently, after having described what the Gowdy class of spacetimes is, we describe, as seen from the perspective of a mathematician, what is meant by strong cosmic censorship. The existing results on cosmic censorship are based on a detailed analysis of the asymptotic behavior of solutions. This analysis is in part motivated by conjectures, such as the BKL conjecture, which we shall therefore briefly describe. However, the emphasis of the article is on the mathematical analysis of the asymptotics, due to its central importance in the proof and in the hope that it might be of relevance more generally. The article ends with a description of the results that have been obtained concerning strong cosmic censorship in the class of Gowdy spacetimes.

  19. Cosmology with the cosmic web

    Science.gov (United States)

    Forero-Romero, J. E.

    2017-07-01

    This talk summarizes different algorithms that can be used to trace the cosmic web both in simulations and observations. We present different applications in galaxy formation and cosmology. To finalize, we show how the Dark Energy Spectroscopic Instrument (DESI) could be a good place to apply these techniques.

  20. Davis Meeting on Cosmic Inflation

    CERN Document Server

    Kaloper, N; Knox, L; Cosmic Inflation

    2003-01-01

    The Davis Meeting on Cosmic Inflation marked an exciting milestone on the road to precision cosmology. This is the index page for the proceedings of the conference. Individual proceedings contributions, when they appear on this archive, are linked from this page.

  1. Meteors, meteorites and cosmic dust

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1987-01-01

    The problem of meteorite origin and meteorite composition is discussed. Nowadays, most scientists suppose that the giant Oort cloud consisting of ice comet nuclei is the sourse of the meteor matter. A principle unity of the matter of meteorites falling to the Earth and cosmic dust is noted as well as that of meteorite bodies evaporating in the atmosphere and bearing meteors and bodies

  2. Art and the Cosmic Connection

    Science.gov (United States)

    Cobb, Whitney H.; Aiello, Monica Petty; Macdonald, Reeves; Asplund, Shari

    2014-01-01

    The interdisciplinary unit described in this article utilizes "Art and the Cosmic Connection," a free program conceived of by artists Monica and Tyler Aiello and developed by the artists, scientists, and educators through NASA's Discovery and New Frontiers Programs, to inspire learners to explore mysterious worlds in our solar…

  3. Evolution of the cosmic web

    NARCIS (Netherlands)

    Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.; Frenk, Carlos S.

    The cosmic web is the largest scale manifestation of the anisotropic gravitational collapse of matter. It represents the transitional stage between linear and non-linear structures and contains easily accessible information about the early phases of structure formation processes. Here we investigate

  4. Prospectives on Direct Detection of the Cosmic Neutrino Background

    Science.gov (United States)

    Li, Yu-Feng

    2017-09-01

    The cosmic neutrino background (CνB) is a fundamental prediction of the hot Big Bang cosmology. Although cosmological observations provide indirect evidence for the existence of the CνB, we still lack a direct detection in a laboratory. In this work we present the current possible detection methods of the CνB. The method of CνB captures on the radioactive decaying nuclei is particularly emphasized in light of the PTOLEMY project. We stress that such direct measurements might not be hopeless in the long term.

  5. Spatial capture-recapture

    Science.gov (United States)

    Royle, J. Andrew; Chandler, Richard B.; Sollmann, Rahel; Gardner, Beth

    2013-01-01

    Spatial Capture-Recapture provides a revolutionary extension of traditional capture-recapture methods for studying animal populations using data from live trapping, camera trapping, DNA sampling, acoustic sampling, and related field methods. This book is a conceptual and methodological synthesis of spatial capture-recapture modeling. As a comprehensive how-to manual, this reference contains detailed examples of a wide range of relevant spatial capture-recapture models for inference about population size and spatial and temporal variation in demographic parameters. Practicing field biologists studying animal populations will find this book to be a useful resource, as will graduate students and professionals in ecology, conservation biology, and fisheries and wildlife management.

  6. SPITZER TRANSITS OF THE SUPER-EARTH GJ1214b AND IMPLICATIONS FOR ITS ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Fraine, Jonathan D.; Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Gillon, Michaeel; Jehin, Emmanueel [Institute d' Astrophysique et de Geophysique, Universite de Liege, Liege (Belgium); Demory, Brice-Olivier; Benneke, Bjoern; Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Knutson, Heather [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Desert, Jean-Michel, E-mail: jfraine@astro.umd.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2013-03-10

    We observed the transiting super-Earth exoplanet GJ1214b using warm Spitzer at 4.5 {mu}m wavelength during a 20 day quasi-continuous sequence in 2011 May. The goals of our long observation were to accurately define the infrared transit radius of this nearby super-Earth, to search for the secondary eclipse, and to search for other transiting planets in the habitable zone of GJ1214. We here report results from the transit monitoring of GJ1214b, including a reanalysis of previous transit observations by Desert et al. In total, we analyze 14 transits of GJ1214b at 4.5 {mu}m, 3 transits at 3.6 {mu}m, and 7 new ground-based transits in the I+z band. Our new Spitzer data by themselves eliminate cloudless solar composition atmospheres for GJ1214b, and methane-rich models from Howe and Burrows. Using our new Spitzer measurements to anchor the observed transit radii of GJ1214b at long wavelengths, and adding new measurements in I+z, we evaluate models from Benneke and Seager and Howe and Burrows using a {chi}{sup 2} analysis. We find that the best-fit model exhibits an increase in transit radius at short wavelengths due to Rayleigh scattering. Pure water atmospheres are also possible. However, a flat line (no atmosphere detected) remains among the best of the statistically acceptable models, and better than pure water atmospheres. We explore the effect of systematic differences among results from different observational groups, and we find that the Howe and Burrows tholin-haze model remains the best fit, even when systematic differences among observers are considered.

  7. Spitzer/IRS Observations Of Multiple Main-Belt And Binary Near-Earth Asteroids

    Science.gov (United States)

    Enriquez, J. Emilio; Marchis, F.; Emery, J. P.; Im, S.

    2010-10-01

    Since the discovery of Ida's companion in 1993, 195 companions of asteroids have been discovered. To understand the formation process of these interesting bodies, their physical properties such as their bulk density, size, shape, and surface roughness need to be determined. During the Spitzer Cycle-4, we obtained IRS thermal emission spectra (5-42 um) of 23 known binary systems. The majority of asteroids are from the main-belt (16), while the rest are NEOs (7). After extracting the thermal spectra, we used a modified Standard Thermal Model (STM) to calculate their equivalent diameter (from 0.8 km to 237 km), their albedo (from 0.04 for C-type to 0.394 for a V-type) and their beaming factor related to the surface roughness and thermal inertia. We derive their emissivity spectra, which is useful to detect silicate features. Combining these measurements with 3D-models of these multiple asteroid systems obtained by lightcurve inversion, we should be able to derive an accurate estimate of their bulk-density and contrast them with their taxonomic classes. Preliminary studies by Marchis et al. (2008)1, suggested a relationship between bulk density and the taxonomic class of asteroids, which varies from 0.9 g/cc for C-complex to 2.4 g/cc for S-complex asteroids. The National Science Foundation supported this research under award number AAG-0807468. It was conducted with the Spitzer space telescope, which is operated by JPL under a contract with NASA. 1 Marchis et al. , 2008, "Mid-infrared Spectra of Binary Asteroids With Spitzer/IRS", 40th DPS Meeting, Bulletin of the American Astronomical Society, 40, 508

  8. Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-based Observations

    Science.gov (United States)

    Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Matins, R. Vieira; Berthier, J.; Vachier, F.; hide

    2012-01-01

    We collected mid-IR spectra from 5.2 to 38 microns using the Spitzer Space Telescope Infrared Spectrograph of 28 asteroids representative of all established types of binary groups. Photometric light curves were also obtained for 14 of them during the Spitzer observations to provide the context of the observations and reliable estimates of their absolute magnitudes. The extracted mid-IR spectra were analyzed using a modified standard thermal model (STM) and a thermophysical model (TPM) that takes into account the shape and geometry of the large primary at the time of the Spitzer observation. We derived a reliable estimate of the size, albedo, and beaming factor for each of these asteroids, representing three main taxonomic groups: C, S, and X. For large (volume-equivalent system diameter Deq > 130 km) binary asteroids, the TPM analysis indicates a low thermal inertia (Lambda thermally insulating regolith. The smaller (surface-equivalent system diameter Deff < 17 km) asteroids also show some emission lines of minerals, but they are significantly weaker, consistent with regoliths with coarser grains, than those of the large binary asteroids. The average bulk densities of these multiple asteroids vary from 0.7-1.7 g/cu cm (P-, C-type) to approx. 2 g/cu cm (S-type). The highest density is estimated for the M-type (22) Kalliope (3.2 +/- 0.9 g/cu cm). The spectral energy distributions (SEDs) and emissivity spectra, made available as a supplement document, could help to constrain the surface compositions of these asteroids.

  9. Observations of V592 Cassiopeiae with the Spitzer Space Telescope - Dust in the Mid-Infrared

    OpenAIRE

    Hoard, D. W.; Kafka, Stella; Wachter, Stefanie; Howell, Steve B.; Brinkworth, Carolyn S.; Ciardi, David R.; Szkody, Paula; Belle, Kunegunda; Froning, Cynthia; van Belle, Gerard

    2008-01-01

    We present the ultraviolet-optical-infrared spectral energy distribution of the low inclination novalike cataclysmic variable (CV) V592 Cassiopeiae, including new mid-infrared observations from 3.5 to 24 μm obtained with the Spitzer Space Telescope. At wavelengths shortward of 8 μm, the spectral energy distribution of V592 Cas is dominated by the steady state accretion disk, but there is flux density in excess of the summed stellar components and accretion disk at longer wavelengths. Reproduc...

  10. Spitzer 3.6 and 5.8 micron Monitoring of the Seyfert 1 NGC 4051

    Science.gov (United States)

    Gorjian, Varoujan; Adkins, J.; Borders, K.; Kelly, S.; Martin, C.; Mendez, B.; Paradis, J.; Perreira, V.; Pittman, P.; Sepulveda, B.; NGC 4051 Monitoring Group

    2009-01-01

    We used the Spitzer Space Telescope Infrared Array Camera (IRAC) to monitor the Seyfert 1 active galactic nucleus NGC 4051. We took data at 3.6 and 5.8 microns every day for 10 days in June 2008. We also observed in the optical at B, V, and R bands starting a month before the IRAC observations with various ground based observatories, though we were unable to achieve daily coverage. We will present the IR and optical light curves and will search for correlated variability that may be evidence of dust reverberation. For the education and public outreach component of this program please see Sepulveda et al.

  11. REPEATABILITY OF SPITZER/IRAC EXOPLANETARY ECLIPSES WITH INDEPENDENT COMPONENT ANALYSIS

    International Nuclear Information System (INIS)

    Morello, G.; Waldmann, I. P.; Tinetti, G.

    2016-01-01

    The research of effective and reliable detrending methods for Spitzer data is of paramount importance for the characterization of exoplanetary atmospheres. To date, the totality of exoplanetary observations in the mid- and far-infrared, at wavelengths >3 μm, have been taken with Spitzer. In some cases, in past years, repeated observations and multiple reanalyses of the same data sets led to discrepant results, raising questions about the accuracy and reproducibility of such measurements. Morello et al. (2014, 2015) proposed a blind-source separation method based on the Independent Component Analysis of pixel time series (pixel-ICA) to analyze InfraRed Array Camera (IRAC) data, obtaining coherent results when applied to repeated transit observations previously debated in the literature. Here we introduce a variant to the pixel-ICA through the use of wavelet transform, wavelet pixel-ICA, which extends its applicability to low-signal-to-noise-ratio cases. We describe the method and discuss the results obtained over 12 eclipses of the exoplanet XO3b observed during the “Warm Spitzer” era in the 4.5 μm band. The final results are reported, in part, also in Ingalls et al. (2016), together with results obtained with other detrending methods, and over 10 synthetic eclipses that were analyzed for the “IRAC Data Challenge 2015.” Our results are consistent within 1σ with the ones reported in Wong et al. (2014) and with most of the results reported in Ingalls et al. (2016), which appeared on arXiv while this paper was under review. Based on many statistical tests discussed in Ingalls et al. (2016), the wavelet pixel-ICA method performs as well as or better than other state-of-art methods recently developed by other teams to analyze Spitzer/IRAC data, and, in particular, it appears to be the most repeatable and the most reliable, while reaching the photon noise limit, at least for the particular data set analyzed. Another strength of the ICA approach is its highest

  12. CAPTURED India Country Evaluation

    NARCIS (Netherlands)

    O'Donoghue, R.; Brouwers, J.H.A.M.

    2012-01-01

    This report provides the findings of the India Country Evaluation and is produced as part of the overall CAPTURED End Evaluation. After five years of support by the CAPTURED project the End Evaluation has assessed that results are commendable. I-AIM was able to design an approach in which health

  13. 'Ouvertures' in muon capture

    International Nuclear Information System (INIS)

    Deutsch, J.P.

    1978-01-01

    Attention is called to some open problems in the field of muon capture namely; the conserved isovector current hypothesis, the axial current in muon capture, vector-axial vector versus scalar-tensor coupling, and polarization of the muon neutrino. Some novel approaches to these problems are proposed which it is hoped may prove of help in tackling them. (U.K.)

  14. Carbon Capture and Storage

    NARCIS (Netherlands)

    Benson, S.M.; Bennaceur, K.; Cook, P.; Davison, J.; Coninck, H. de; Farhat, K.; Ramirez, C.A.; Simbeck, D.; Surles, T.; Verma, P.; Wright, I.

    2012-01-01

    Emissions of carbon dioxide, the most important long-lived anthropogenic greenhouse gas, can be reduced by Carbon Capture and Storage (CCS). CCS involves the integration of four elements: CO 2 capture, compression of the CO2 from a gas to a liquid or a denser gas, transportation of pressurized CO 2

  15. Electron capture and loss

    International Nuclear Information System (INIS)

    Horsdal Pedersen, E.

    1978-01-01

    Two limiting cases of electron capture leading to the formation of heavy ions with inner-shell vacancies are discussed. The first case is electron capture by fast (v>v 0 ) light ions in heavy targets. This process results, with a large probability, in the formation of inner-shell vacancies in the target. The second case is electron capture by, highly heavy charged ions in light targets, resulting in fast beam particles with K-shell vacancies which decay by means of polarised x rays. It is possible to get a quantitative understanding of the importance of capture from inner shells of the target in fast collisions between light projectiles and heavy targets and of the polarisation of x rays following electron capture by heavy, highly charged particles in light targets by a consideration of the matrix element in the Brinkman-Kramers approximation. (JIW)

  16. Direct thermal neutron capture

    International Nuclear Information System (INIS)

    Raman, S.; Kahane, S.; Lynn, J.E.

    1987-01-01

    We discuss the direct-capture theory pertaining to primary electric dipole (E1) transitions following slow-neutron capture. For light nuclides that we have studied (including 9 Be, 12 C, 13 C, 24 Mg, 25 Mg, 26 Mg, 32 S, 33 S, 34 S, 40 Ca, and 44 Ca), estimates of direct-capture cross sections using optical-model potentials with physically realistic parameters, are in reasonable agreement with the data. Minor disagreements that exist are consistent with extrapolations to light nuclides of generally accepted formulations of compound-nucleus capture. We also discuss the channel-capture approximation which is, in general, a good representation of these cross sections in heavier nuclei particularly if the scattering lengths are not different from the corresponding potential radii. We also draw attention to cases where the use of this formula leads to inaccurate predictions. 9 refs., 1 fig., 2 tab

  17. The impact of endorsing Spitzer's proposed criteria for PTSD in the forthcoming DSM-V on male and female Veterans.

    Science.gov (United States)

    Miller, Lyndsey N; Chard, Kathleen M; Schumm, Jeremiah A; O'Brien, Carol

    2011-06-01

    This study explored differences between Spitzer's proposed model of posttraumatic stress disorder (PTSD) and the current DSM-IV diagnostic classification scheme in 353 Veterans. The majority of Veterans (89%) diagnosed with PTSD as specified in the DSM-IV also met Spitzer's proposed criteria. Veterans who met both DSM-IV and Spitzer's proposed criteria had significantly higher Clinician Administered PTSD Scale severity scores than Veterans only meeting DSM-IV criteria. Logistic regression indicated that being African American and having no comorbid diagnosis of major depressive disorder or history of a substance use disorder were found to predict those Veterans who met current, but not proposed criteria. These findings have important implications regarding proposed changes to the diagnostic classification criteria for PTSD in the forthcoming DSM-V. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Investigating the Evolution of the Mass-Metallicity-SFR Relation at z<1.6 with Deep GALEX and Spitzer Imaging

    Science.gov (United States)

    Rigby, Jane

    The gas-phase metallicity of galaxies is a fossil tracer of what has happened physically in and around galaxies: gas inflows, star formation, mergers, and ``feedback'' from star formation. Therefore, measuring the dependence of metallicity on stellar mass, star formation rate (SFR), and redshift is a key test of galaxy evolution models. While metallicity studies have attempted to extend to higher redshifts, most of these studies have failed to study low-mass galaxies. This population is of great interest as stellar feedback effects, which are responsible for distributing the metals in galaxies, are expected to play a significant role in their evolution. Moreover, low-mass galaxies are the dominant population in the early universe, and are thought to produce most of the ionizing photons to reionize the universe. Here we propose to study the physical properties and evolution of emission-line selected galaxies at zstar-forming galaxies, the mass-metallicity and mass-metallicity-SFR relation over the past 8 billions years or 60% of cosmic time. Our second science objective is to determine the evolution of the stellar mass-SFR relation over the same cosmic period with a much larger sample, 9,000 emission-line galaxies. We will then use our determination of these relations to compare and constrain predictions from galaxy formation models that consider the balance between star formation and gas flows. To accomplish these goals, we will merge a unique combination of deep archival imaging from GALEX (ultraviolet) and Spitzer (infrared), existing ground-based optical through near-infrared imaging, and existing optical and near-infrared spectroscopy. The latter is a strength of our program, as we have more deep follow-up spectroscopy ( 1000) on low-mass and high specific SFR galaxies than any other metallicity study. These observations will allow us to acquire robust measures of stellar masses, dust attenuation, dust-corrected SFRs, and oxygen abundances. In particular, the

  19. Evolution of the Cosmic Web

    Science.gov (United States)

    Einasto, J.

    2017-07-01

    In the evolution of the cosmic web dark energy plays an important role. To understand the role of dark energy we investigate the evolution of superclusters in four cosmological models: standard model SCDM, conventional model LCDM, open model OCDM, and a hyper-dark-energy model HCDM. Numerical simulations of the evolution are performed in a box of size 1024 Mpc/h. Model superclusters are compared with superclusters found for Sloan Digital Sky Survey (SDSS). Superclusters are searched using density fields. LCDM superclusters have properties, very close to properties of observed SDSS superclusters. Standard model SCDM has about 2 times more superclusters than other models, but SCDM superclusters are smaller and have lower luminosities. Superclusters as principal structural elements of the cosmic web are present at all cosmological epochs.

  20. Cosmic Revelation: Making Astroparticles Visible

    Science.gov (United States)

    Roth, T. O.; Haungs, A.; Schieler, H.; Weindl, A.

    2010-06-01

    Cosmic Revelation is a prime example of a successful art and science project connecting art and astroparticle physics. One of the main reasons for its success might be that the collaboration between the KArlsruhe Shower Core and Array DEtector (KASCADE) experiment and Tim Otto Roth is both a minimalist light art project and a scientific experiment. In a field of 16 flashing mirror sculptures connected to the KASCADE detector field at KIT (Karlsruhe Institute of Technology, Germany) the impact of high energy cosmic rays on Earth can be experienced directly. In just one year the project has developed from the initial concept to its first presentation in a public space in autumn 2008. We explain how the project developed, and also highlight the practical and conceptual conditions for its realisation.

  1. Vector superconductivity in cosmic strings

    International Nuclear Information System (INIS)

    Dvali, G.R.; Mahajan, S.M.

    1992-03-01

    We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

  2. Charged Cosmic Rays and Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kachelrieß, M.

    2013-04-15

    High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test “vanilla” models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at “Neutrino 2012”.

  3. Cosmic Visions Dark Energy: Technology

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Slosar, Anze [Brookhaven National Lab. (BNL), Upton, NY (United States); Heitmann, Katrin [Brookhaven National Lab. (BNL), Upton, NY (United States); Hirata, Chris [Brookhaven National Lab. (BNL), Upton, NY (United States); Honscheid, Klaus [Brookhaven National Lab. (BNL), Upton, NY (United States); Roodman, Aaron [Brookhaven National Lab. (BNL), Upton, NY (United States); Seljak, Uros [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-05-02

    A strong instrumentation and detector R&D program has enabled the current generation of cosmic frontier surveys. A small investment in R&D will continue to pay dividends and enable new probes to investigate the accelerated expansion of the universe. Instrumentation and detector R&D provide critical training opportunities for future generations of experimentalists, skills that are important across the entire DOE HEP program.

  4. Cosmic Visions Dark Energy: Technology

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Heitmann, Katrin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hirata, Chris [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Roodman, Aaron [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Seljak, Uroš [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Slosar, Anže [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Trodden, Mark [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-04-26

    A strong instrumentation and detector R&D program has enabled the current generation of cosmic frontier surveys. A small investment in R&D will continue to pay dividends and enable new probes to investigate the accelerated expansion of the universe. Instrumentation and detector R&D provide critical training opportunities for future generations of experimentalists, skills that are important across the entire Department of Energy High Energy Physics program.

  5. Albedo Corrections for High Albedo Near Earth Objects Observed With Spitzer

    Science.gov (United States)

    Gustafsson, Annika; Trilling, David E.; Mommert, Michael; Hora, Joseph L.

    2017-10-01

    Thermal infrared observations are the most effective way to measure asteroid diameter and albedo. Major surveys like NEOWISE and NEOSurvey return a small fraction of objects with albedo values higher than that believed to exist in the near-Earth object (NEO) population. About 10% of Spitzer-observed NEOs have nominal albedo solutions greater than 0.5. There are many possible causes for these unrealistically high albedos, including thermal lightcurves (leading to a mis-estimate of asteroid diameter) or inaccurate absolute visual magnitudes (either from poor photometry or lightcurve effects). We present here the results of a ground-based optical photometric study of 36 high albedo NEOs from NEOSurvey (Trilling et al. 2016) using measurements from the Discovery Channel Telescope. Our findings indicate that uncertainty in the diameter has the most impact on the derived albedo of our targets, while the uncertainty in the H-magnitude and slope parameter have smaller effects. We supply corrected albedos for our target list, as well as a systematic offset dependent on the solar phase angle of the object (Mommert el al. 2017). These corrected albedo values will help constrain the albedo range in the population to better reflect its physical characteristics. This work is based in part on the observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  6. PLANETARY NEBULAE DETECTED IN THE SPITZER SPACE TELESCOPE GLIMPSE II LEGACY SURVEY

    International Nuclear Information System (INIS)

    Zhang Yong; Sun Kwok

    2009-01-01

    We report the result of a search for the infrared counterparts of 37 planetary nebulae (PNs) and PN candidates in the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire II (GLIMPSE II) survey. The photometry and images of these PNs at 3.6, 4.5, 5.8, 8.0, and 24 μm, taken through the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS), are presented. Most of these nebulae are very red and compact in the IRAC bands, and are found to be bright and extended in the 24 μm band. The infrared morphology of these objects are compared with Hα images of the Macquarie-AAO-Strasbourg (MASH) and MASH II PNs. The implications for morphological difference in different wavelengths are discussed. The IRAC data allow us to differentiate between PNs and H II regions and be able to reject non-PNs from the optical catalog (e.g., PNG 352.1 - 00.0). Spectral energy distributions are constructed by combing the IRAC and MIPS data with existing near-, mid-, and far-IR photometry measurements. The anomalous colors of some objects allow us to infer the presence of aromatic emission bands. These multi-wavelength data provide useful insights into the nature of different nebular components contributing to the infrared emission of PNs.

  7. Spitzer IRAC mid-infrared photometry of 500-750 brown dwarf

    Energy Technology Data Exchange (ETDEWEB)

    Saumon, Didier [Los Alamos National Laboratory; Leggett, Sandy K [GEMINI OBSERVATORY; Albert, Loic [CFH TELESCOPE; Artigau, Etienne [U OF MONTREAL; Burningham, Ben [HERTFORDSHIRE U; Delfosse, Xavier [OBS. GRENOBLE; Delorme, Philippe [ST. ANDREWS U.; Forveille, Thierry [OBS. GRENOBLE; Lucas, Philip W [HERTFORDSHIRE U; Marley, Mark S [NASA AMES; Pinfield, David J [HERTFORDSHIRE U.; Reyle, Celine [OBS. BESANCON; Smart, Richard L [OSS. ASTRON, TORINO; Warren, Stephen J [IMPERIAL COLLEGE LONDON

    2010-10-26

    Mid-infrared data, including Spitzer warm-IRAC [3.6] and [4.5] photometry, is critical for understanding the cold population of brown dwarfs now being found, objects which have more in common with planets than stars. As effective temperature (T{sub eff}) drops from 800K to 400K, the fraction of flux emitted beyond 3 {mu}m increases rapidly, from about 40% to > 75%. This rapid increase makes a color like H-[4.5] a very sensitive temperature indicator, and it can be combined with a gravity- and metallicity-sensitive color like H-K to constrain all three of these fundamental properties, which in turn gives us mass and age for these slowly cooling objects. Determination of mid-infrared color trends also allows better exploitation of the WISE mission by the community. We use new Spitzer Cycle 6 IRAC photometry, together with published data, to present trends of color with type for L0 to T10 dwarfs. We also use the atmospheric and evolutionary models of Saumon and Marley to investigate the masses and ages of 13 very late-type T dwarfs, which have H-[4.5] > 3.2 and T{sub eff} {approx} 500K to 750K.

  8. SPITZER MICROLENS MEASUREMENT OF A MASSIVE REMNANT IN A WELL-SEPARATED BINARY

    Energy Technology Data Exchange (ETDEWEB)

    Shvartzvald, Y.; Bryden, G.; Henderson, C. B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Bozza, V.; Novati, S. Calchi [Dipartimento di Fisica “E. R. Caianiello,” Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy); Friedmann, M. [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Hundertmark, M. [Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K (Denmark); Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Carey, S. [Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Kerr, T.; Varricatt, W. [UKIRT, 660 N. Aohoku Place, University Park, Hilo, HI 96720 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Collaboration: and; Spitzer team; OGLE group; KMTNet group; Wise group; RoboNet; MiNDSTEp; and others

    2015-12-01

    We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M{sub 1} > 1.35 M{sub ⊙} (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r{sub ⊥} = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the “microlens parallax” effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay at 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations.

  9. Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant

    Science.gov (United States)

    Arendt, Richard G.; Dweek, Eli; Blair, William P.; Ghavamian, Parviz; Hwang, Una; Long, Knox X.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

    2010-01-01

    The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 micrometers shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

  10. DUST EVOLUTION IN PROTOPLANETARY DISKS AROUND HERBIG Ae/Be STARS-THE SPITZER VIEW

    International Nuclear Information System (INIS)

    Juhasz, A.; Bouwman, J.; Henning, Th.; Acke, B.; Waters, L. B. F. M.; Van den Ancker, M. E.; Meeus, G.; Min, M.; Dominik, C.; Tielens, A. G. G. M.

    2010-01-01

    In this paper, we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several hundreds. During the analysis of these data we tested the validity of standardized protoplanetary dust models and studied grain growth and crystal formation. On the basis of the analyzed spectra, the major constituents of protoplanetary dust around Herbig Ae/Be stars are amorphous silicates with olivine and pyroxene stoichiometry, crystalline forsterite, and enstatite and silica. No other solid-state features, indicating other abundant dust species, are present in the Spitzer spectra. Deviations of the synthetic spectra from the observations are most likely related to grain shape effects and uncertainties in the iron content of the dust grains. Our analysis revealed that larger grains are more abundant in the disk atmosphere of flatter disks than in that of flared disks, indicating that grain growth and sedimentation decrease the disk flaring. We did not find, however, correlations between the value of crystallinity and any of the investigated system parameters. Our analysis shows that enstatite is more concentrated toward the warm inner disk than forsterite, in contrast to predictions of equilibrium condensation models. None of the three crystal formation mechanisms proposed so far can alone explain all our findings. It is very likely that all three play at least some role in the formation of crystalline silicates.

  11. A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b

    Science.gov (United States)

    Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake

    2007-01-01

    We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.

  12. VizieR Online Data Catalog: Spitzer observations of Taurus members (Luhman+, 2010)

    Science.gov (United States)

    Luhman, K. L.; Allen, P. R.; Espaillat, C.; Hartmann, L.; Calvet, N.

    2016-03-01

    For our census of the disk population in Taurus, we use images at 3.6, 4.5, 5.8, and 8.0um obtained with Spitzer's Infrared Array Camera (IRAC) and images at 24um obtained with the Multiband Imaging Photometer for Spitzer (MIPS). The cameras produced images with FWHM=1.6"-1.9" from 3.6 to 8.0um and FWHM=5.9" at 24um. The available data were obtained through Guaranteed Time Observations for PID = 6, 36, 37 (G. Fazio), 53 (G. Rieke), 94 (C. Lawrence), 30540 (G. Fazio, J. Houck), and 40302 (J. Houck), Director's Discretionary Time for PID = 462 (L. Rebull), Legacy programs for PID = 139, 173 (N. Evans), and 30816 (D. Padgett), and General Observer programs for PID = 3584 (D. Padgett), 20302 (P. Andre), 20386 (P. Myers), 20762 (J. Swift), 30384 (T. Bourke), 40844 (C. McCabe), and 50584 (D. Padgett). The IRAC and MIPS observations were performed through 180 and 137 Astronomical Observation Requests (AORs), respectively. The characteristics of the resulting images are summarized in Tables 1 and 2. (6 data files).

  13. SPITZER OBSERVATIONS OF DUST DESTRUCTION IN THE PUPPIS A SUPERNOVA REMNANT

    International Nuclear Information System (INIS)

    Arendt, Richard G.; Dwek, Eli; Blair, William P.; Hwang, Una; Ghavamian, Parviz; Long, Knox S.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

    2010-01-01

    The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 μm shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

  14. Sensitive Spitzer Photometry of Supermassive Black Holes at the Final Stage of Adolescence

    Science.gov (United States)

    Shemmer, Ohad; Netzer, Hagai; Mor, Rivay; Trakhtenbrot, Benny

    2011-05-01

    We propose to obtain sensitive Spitzer snapshot observations of a unique sample of 35 Sloan Digital Sky Survey quasars at redshift 4.8 for which we obtained reliable, Mg II-based determinations of the supermassive black hole (SMBH) mass and normalized accretion rate (L/L_Edd). These quasars appear to mark the final stage of SMBH `adolescence' in the history of the Universe as their SMBHs are significantly less massive and their L/L_Edd values are significantly higher with respect to their counterparts at lower redshifts. Our observations will provide both 1) deep coverage of the fields around these quasars which will be utilized as crucial priors for our approved Herschel/SPIRE observations of these sources, and 2) coverage of the rest-frame optical SEDs of these fast accreting quasars. The results will maximize our ability to measure the star-formation rate in the host galaxies of these quasars using Herschel. We will thus be able to investigate correlations between SMBH growth and star-forming activity in the early Universe. The Spitzer photometry will also provide invaluable information about the shape of the rest-frame optical continuum in these quasars which will be used to search for extreme disk properties that may be signatures of the remarkably high accretion rates in these sources.

  15. The origin of cosmic rays

    International Nuclear Information System (INIS)

    Eichler, D.

    1986-01-01

    Enormous progress has been made in understanding the origin of cosmic rays within the past decade. The success of equation in accounting for the observed properties of cosmic rays at both the general and the detailed level is a striking illustration that nature can do marvelous things with simple equations. This paper illustrates the important role of detailed, systematic spacecraft observations in the heliosphere in testing theories of relevance to the distant mysterious phenomena that pique the curiosity of astronomers. Tracing the origin of cosmic rays back to collisionless shocks has reminded plasma astrophysicists of how much remains to be understood about the physics of such shocks, which account for much of the radiation that high energy astrophysics is based upon. The X-ray emission from shock-heated electrons, for example, cannot be fully interpreted until the physics of the shocks is understood. It is hoped that plasma simulations of shocks combined with intensive studies of the relevant microphysics will eventually lead us to such an understanding

  16. Elemental composition of cosmic ray

    International Nuclear Information System (INIS)

    Yanagida, Shohei

    1987-01-01

    The report first summarizes some data that have been obtained so far from observation of isotopes and elements in cosmic rays in the low energy region. Then, objectives of studies planned to be carried out with Astromag are outlined and the number of incident particles expected to be measured by baloon observation is estimated. Heavy elements with atomic numbers of greater than 30 are considered to be formed through neutron absorption reactions by the s- or r-process. Observations show that products of the r-process is abundant in cosmic ray sources. The escape length depends on energy. In relation to this, it has been reported that the ratios Ar-Fe and Ca-Fe increase above 200 GeV-n while such a tendency is not observed for K, Sc, Ti or V. Thus, no satisfactory models are available at present which can fully explain the changes in the escape length. The ratio 3 He- 4 He in the range of 5 - 10 GeV-n is inconsistent with the general theory that interprets the escape length of heavy elements. Some models, including the supermetallicity model and Wolf Rayet theory, have been proposed to explain unusual ratios of isotopes in cosmic rays, but more measurements are required to verify them. It is expected that Astromag can serve to make observations that can clarify these points. (Nogami, K.)

  17. Studying Cosmic Dawn with WFIRST

    Science.gov (United States)

    Rhoads, James; Malhotra, Sangeeta; Jansen, Rolf A.; Windhorst, Rogier; Tilvi, Vithal; Finkelstein, Steven; Wold, Isak; Papovich, Casey; Fan, Xiaohui; Mellema, Garrelt; Zackrisson, Erik; Jensen, Hannes; T

    2018-01-01

    Our understanding of Cosmic Dawn can be revolutionized using WFIRST's combination of wide-field, sensitive, high resolution near-infrared imaging and spectroscopy. Guest investigator studies of WFIRST's high latitude imaging survey and supernova search fields will yield orders of magnitude increases in our samples of Lyman break galaxies from z=7 to z>12. The high latitude spectrsocopic survey will enable an unprecedented search for z>7 quasars. Guest observer deep fields can extend these studies to flux levels of Hubble's deepest fields, over regions measured in square degrees. The resulting census of luminous objects in the Cosmic Dawn will provide key insights into the sources of the ultraviolet photons that powered reionization. Moreover, because WFIRST has a wide field (slitless) spectroscopic capability, it can be used to search for Lyman alpha emitting galaxies over the full history of reionization. By comparing the Lyman alpha galaxy statistics to those of continuum sources, we can directly probe the transparency of the intergalactic gas and chart reionization history.Our team is planning for both Guest Investigator and Guest Observer applications of WFIRST to studying Cosmic Dawn, and welcomes dialog with other interested members of the community.

  18. Cosmic-ray thermal neutron detection for environmental purposes

    Science.gov (United States)

    Looms, M. C.; Rosolem, R.; Klinkby, E. B.; Andreasen, M.

    2017-12-01

    Cosmic-ray neutron detection has been successfully used to produce time-series of hectometer-scale soil moisture estimates at various soil types and land covers. The method relies on measurements of epithermal neutron intensities with energies in the range of approximately 10-1000 eV (electron Volt). As the cosmic-ray neutron technology matures, additional sensing possibilities emerge, such as biomass, snow and litter layer thickness detection. The physical processes controlling neutron transport depend on the neutron energy. Because of this, many of these new applications benefit from measurements of cosmic-ray neutrons at multiple energy levels. For instance, several published studies suggest a correlation between the thermal-to-epithermal ratio and amount of biomass, where thermal neutrons refer to neutron energies below 0.5 eV. However, the vast majority of the theoretical investigations to date have focused on epithermal neutrons for environmental applications, since epithermal neutrons are more sensitive to the presence of hydrogen than at other energies. As a result, not much is known about thermal neutron transport in environmental systems. In this study, we investigate the thermal neutron behavior in environmental settings using the neutron transport model Monte Carlo N-Particle radiation transport code (MCNP6). First, we model the two common detector types: 1) The bare detector, measuring mainly thermal neutrons, and 2) the moderated detector, measuring mainly epithermal neutrons. The percentage of epithermal neutrons captured using the bare detector and the percentage of the thermal neutrons captured using the moderated detector is quantified for two separate detector systems and compared to measured values. Second, we determine whether it is relevant to correct thermal measurements for changes in vapor pressure, using a similar procedure previously proposed for epithermal neutron measurements. Finally, we investigate the area of influence of the two

  19. Cosmic ray physics goes to school

    CERN Multimedia

    2002-01-01

    With the help of a CERN physicist, German Schools bring the Largest Cosmic Ray Detector in Europe one step closer to reality   Eric Berthier and Robert Porret (CERN, ST/HM), Frej Torp and Christian Antfolk from the Polytechnics Arcada in Finland, and Karsten Eggert, physicist at CERN who initiated this project, during the installation of cosmic ray detectors in the Pays de Gex, at point 4. Niina Patrikainen and Frej Torp, Finnish students from Rovaniemi and Arcada Polytechnics, installing cosmic ray counters at the Fachhochschule in Duesseldorf. The science of cosmic ray detection is growing, literally. Cosmic rays, energetic particles from space, strike our planet all the time. They collide with the air molecules in our upper atmosphere and initiate large showers of elementary particles (mainly electrons, photons, hadrons and muons) which rain down upon the earth. The shower size and the particle density in the showers reflect the initial energy of the cosmic ray particle, a detail which makes d...

  20. Cosmic Connections:. from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields

    Science.gov (United States)

    Kusenko, Alexander

    2013-12-01

    Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed ux of ultrahigh-energy cosmicrays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

  1. Study of cosmic ray semidiurnal variations

    International Nuclear Information System (INIS)

    Krymsky, G F; Krivoshapkin, P A; Gerasimova, S K; Gololobov, P Yu

    2013-01-01

    On the basis of long-term registration of cosmic rays with the muon spectrograph at Yakutsk (62°01'N, 129°43'E) and multidirectional muon telescope at Nagoya (35°10'N, 136°58'E) the cosmic ray semidiurnal variation seasonal change and the change of cosmic ray semiduirnal variation with the solar activity level has been found. The modeling of the seasonal change has been made.

  2. ACORDE - A Cosmic Ray Detector for ALICE

    CERN Document Server

    INSPIRE-00247175; Pagliarone, C.

    2006-01-01

    ACORDE, the ALICE COsmic Ray DEtector is one of the ALICE detectors, presently under construction. It consists of an array of plastic scintillator counters placed on the three upper faces of the ALICE magnet. This array will act as Level 0 cosmic ray trigger and, together with other ALICE sub-detectors, will provide precise information on cosmic rays with primary energies around $10^{15-17}$ eV. In this paper we will describe the ACORDE detector, trigger design and electronics.

  3. Exploring Ultra-Heavy Cosmic Rays with the Trans-Iron Galactic Element Recorder (TIGER)

    Science.gov (United States)

    Link, Jason; Supertiger Collaboration

    2017-01-01

    Elements heavier than iron are primarily synthesized by neutron capture. These elements can be accelerated as cosmic-rays and measuring their abundances at Earth can yield information about galactic cosmic-rays' sources, the acceleration processes and the composition of the universe beyond the boundaries of our solar system. The Trans-Iron Galactic Element Recorder (TIGER) and its larger successor SuperTIGER was designed to measure the abundance of these ultra-heavy cosmic rays between Z=10 and Z=60. These detectors utilize scintillators with a wavelength shifter bar and PMT readout system as well as aerogel and acrylic Cherenkov detectors to identify the charge and energy of a particle and utilize a scintillating fiber hodoscope to provide trajectory information. In this talk I will review the results from this highly successful program, give the status for the next SuperTIGER flight planned for a December 2017 launch from Antarctica, and discuss the future direction of the program.

  4. Cosmic radiation exposure to airline flight passenger

    International Nuclear Information System (INIS)

    Momose, Mitsuhiro

    2000-01-01

    At the high altitudes, airline flight passengers can be exposed to some levels of cosmic radiation. The purpose of this study was to quantify this radiation exposure. Cosmic radiation was measured during 5 flights using a personal dosimeter (PDM-102, Aloka). Cosmic radiation equivalent dose rates ranged from 0.7 to 1.43 microsieverts per hour, the average rate was 1.08. For the passenger who travels only occasionally, the cosmic radiation levels are well below occupational limits, and the risks are extremely small. (author)

  5. Cosmic radiation exposure to airline flight passenger

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Mitsuhiro [Shinshu Univ., Matsumoto, Nagano (Japan). School of Medicine

    2000-08-01

    At the high altitudes, airline flight passengers can be exposed to some levels of cosmic radiation. The purpose of this study was to quantify this radiation exposure. Cosmic radiation was measured during 5 flights using a personal dosimeter (PDM-102, Aloka). Cosmic radiation equivalent dose rates ranged from 0.7 to 1.43 microsieverts per hour, the average rate was 1.08. For the passenger who travels only occasionally, the cosmic radiation levels are well below occupational limits, and the risks are extremely small. (author)

  6. High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?

    Science.gov (United States)

    Moiseev, Alexander

    2011-01-01

    This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

  7. c2d Spitzer IRS spectra of embedded low-mass young stars : gas-phase emission lines

    NARCIS (Netherlands)

    Lahuis, F.; van Dishoeck, E. F.; Jorgensen, J. K.; Blake, G. A.; Evans, N. J.

    Context. A survey of mid-infrared gas-phase emission lines of H(2), H(2)O and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the Spitzer "Cores to Disks" (c2d) legacy program. Aims. The environment of

  8. A SPITZER SURVEY OF PROTOPLANETARY DISK DUST IN THE YOUNG SERPENS CLOUD : HOW DO DUST CHARACTERISTICS EVOLVE WITH TIME?

    NARCIS (Netherlands)

    Oliveira, Isa; Pontoppidan, Klaus M.; Merin, Bruno; van Dishoeck, Ewine F.; Lahuis, Fred; Geers, Vincent C.; Jorgensen, Jes K.; Olofsson, Johan; Augereau, Jean-Charles; Brown, Joanna M.

    2010-01-01

    We present Spitzer InfraRed Spectrograph (IRS) mid-infrared (5-35 mu m) spectra of a complete flux-limited sample (>= 3 mJy at 8 mu m) of young stellar object (YSO) candidates selected on the basis of their infrared colors in the Serpens Molecular Cloud. Spectra of 147 sources are presented and

  9. Cosmic Star-Formation History

    Science.gov (United States)

    Madau, Piero; Dickinson, Mark

    2014-08-01

    Over the past two decades, an avalanche of new data from multiwavelength imaging and spectroscopic surveys has revolutionized our view of galaxy formation and evolution. Here we review the range of complementary techniques and theoretical tools that allow astronomers to map the cosmic history of star formation, heavy element production, and reionization of the Universe from the cosmic “dark ages” to the present epoch. A consistent picture is emerging, whereby the star-formation rate density peaked approximately 3.5 Gyr after the Big Bang, at z≈1.9, and declined exponentially at later times, with an e-folding timescale of 3.9 Gyr. Half of the stellar mass observed today was formed before a redshift z = 1.3. About 25% formed before the peak of the cosmic star-formation rate density, and another 25% formed after z = 0.7. Less than ˜1% of today's stars formed during the epoch of reionization. Under the assumption of a universal initial mass function, the global stellar mass density inferred at any epoch matches reasonably well the time integral of all the preceding star-formation activity. The comoving rates of star formation and central black hole accretion follow a similar rise and fall, offering evidence for coevolution of black holes and their host galaxies. The rise of the mean metallicity of the Universe to about 0.001 solar by z = 6, one Gyr after the Big Bang, appears to have been accompanied by the production of fewer than ten hydrogen Lyman-continuum photons per baryon, a rather tight budget for cosmological reionization.

  10. International Conference on Cosmic Rays

    CERN Multimedia

    W.O. LOCK

    1964-01-01

    Towards the end of last year the 8th International conference on cosmic rays, held under the auspices of the International Union of Pure and Applied Physics (I.U.P.A.P.) and the Department of Atomic Energy of the Government of India, was held at Jaipur, India. Among the participants was W.O. Lock, head of CERN's Emulsion Group, who gave an invited talk on recent work in the field of what is normally known as high-energy physics — though in the context of this conference such energies seem quite low. In this article, Dr. Lock gives a general review of the conference and of the subjects discussed.

  11. Ground level cosmic ray observations

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements); Grimani, C.; Brunetti, M.T.; Codino, A. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Papini, P.; Massimo Brancaccio, F.; Piccardi, S. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Golden, R.L. [New Mexico State Univ., Las Cruces, NM (United States). Particle Astrophysics Lab.; Hof, M. [Siegen Univ. (Germany). Fachbereich Physik

    1995-09-01

    Cosmic rays at ground level have been collected using the NMSU/Wizard - MASS2 instrument. The 17-hr observation run was made on September 9. 1991 in Fort Sumner, New Mexico, Usa. Fort Sumner is located at 1270 meters a.s.l., corresponding to an atmospheric depth of about 887 g/cm{sup 2}. The geomagnetic cutoff is 4.5 GV/c. The charge ratio of positive and negative muons and the proton to muon ratio have been determined. These observations will also be compared with data collected at a higher latitude using the same basic apparatus.

  12. Cosmic polarimetry in magnetoactive plasmas

    CERN Document Server

    Giovannini, Massimo

    2009-01-01

    Polarimetry of the Cosmic Microwave Background (CMB) represents one of the possible diagnostics aimed at testing large-scale magnetism at the epoch of the photon decoupling. The propagation of electromagnetic disturbances in a magnetized plasma leads naturally to a B-mode polarization whose angular power spectrum is hereby computed both analytically and numerically. Combined analyses of all the publicly available data on the B-mode polarization are presented, for the first time, in the light of the magnetized $\\Lambda$CDM scenario. Novel constraints on pre-equality magnetism are also derived in view of the current and expected sensitivities to the B-mode polarization.

  13. SPITZER OBSERVATIONS OF WHITE DWARFS: THE MISSING PLANETARY DEBRIS AROUND DZ STARS

    International Nuclear Information System (INIS)

    Xu, S.; Jura, M.

    2012-01-01

    We report a Spitzer/Infrared Array Camera search for infrared excesses around white dwarfs, including 14 newly observed targets and 16 unpublished archived stars. We find a substantial infrared excess around two warm white dwarfs—J220934.84+122336.5 and WD 0843+516, the latter apparently being the hottest white dwarf known to display a close-in dust disk. Extending previous studies, we find that the fraction of white dwarfs with dust disks increases as the star's temperature increases; for stars cooler than 10,000 K, even the most heavily polluted ones do not have ∼1000 K dust. There is tentative evidence that the dust disk occurrence is correlated with the volatility of the accreted material. In the Appendix, we modify a previous analysis to clarify how Poynting-Robertson drag might play an important role in transferring materials from a dust disk into a white dwarf's atmosphere.

  14. Discovery of hyperluminous infrared galaxies using Spitzer and SHARC-II

    Science.gov (United States)

    Borys, C.; Barnard, V.; Bian, C.; Blain, A. W.; Brown, M. J. I.; Dey, A.; Dowell, C. D.; Frayer, D. T.; Higdon, J.; Higdon, S.; Jannuzi, B.; Le Floch, E.; Soifer, B. T.; Phillips, T. G.

    2005-01-01

    We have used observations taken as part of the Bootes Spitzer GTO program to pre-select high redshift luminous star-forming galaxy candidates. Subsequent ground-based sub-millimeter imaging with SHARC-II at the Caltech Submillimeter Observatory detected several objects, including one particularly exotic one: An extremely bright infrared galaxy with an apparent luminosity in excess of 1013.5Lsolar. It has a spectral energy distribution similar to that of Arp 220, though appears to be at a much higher redshift. Although lensing is one possible explanation, this object has helped refine the selection method, and hints at a way to pre-select similar objects using mid-IR silicate absorption features.

  15. Observations of Hot-Jupiter occultations combining Spitzer and Kepler photometry

    Directory of Open Access Journals (Sweden)

    Knutson H.

    2011-02-01

    Full Text Available We present the status of an ongoing program which aim at measuring occultations by their parent stars of transiting hot giant exoplanets discovered recently by Kepler. The observations are obtained in the near infrared with WarmSpitzer Space Telescope and at optical wavelengths by combining more than a year of Kepler photometry. The investigation consists of measuring the mid-occultation times and the relative occultation depths in each band-passes. Our measurements of occultations depths in the Kepler bandpass is turned into the determination of the optical geometric albedo Ag in this wavelength domain. The brightness temperatures of these planets are deduced from the infrared observations. We combine the optical and near infrared planetary emergent fluxes to obtain broad band emergent spectra of individual planet. We finally compare these spectra to hot Jupiter atmospheric models in order broadly distinguishing these atmospheres between different classes of models.

  16. Spitzer ’s View of the Candidate Cluster and Protocluster Catalog (CCPC)

    Energy Technology Data Exchange (ETDEWEB)

    Franck, J. R.; McGaugh, S. S. [Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106 (United States)

    2017-02-10

    The Candidate Cluster and Protocluster Catalog contains 218 galaxy overdensities composed of more than 2000 galaxies with spectroscopic redshifts spanning the first few Gyr after the Big Bang (2.0 ≤ z < 6.6). We use Spitzer archival data to track the underlying stellar mass of these overdense regions in various temporal cross sections by building rest-frame near-infrared luminosity functions (LFs) across the span of redshifts. This exercise maps the stellar growth of protocluster galaxies, as halos in the densest environments should be the most massive from hierarchical accretion. The characteristic apparent magnitude, m *( z ), is relatively flat from 2.0 ≤ z < 6.6, consistent with a passive evolution of an old stellar population. This trend maps smoothly to lower redshift results of cluster galaxies from other works. We find no difference in the LFs of galaxies in the field versus protoclusters at a given redshift apart from their density.

  17. Spitzer/JWST Cross Calibration: IRAC Observations of Potential Calibrators for JWST

    Science.gov (United States)

    Carey, Sean J.; Gordon, Karl D.; Lowrance, Patrick; Ingalls, James G.; Glaccum, William J.; Grillmair, Carl J.; E Krick, Jessica; Laine, Seppo J.; Fazio, Giovanni G.; Hora, Joseph L.; Bohlin, Ralph

    2017-06-01

    We present observations at 3.6 and 4.5 microns using IRAC on the Spitzer Space Telescope of a set of main sequence A stars and white dwarfs that are potential calibrators across the JWST instrument suite. The stars range from brightnesses of 4.4 to 15 mag in K band. The calibration observations use a similar redundancy to the observing strategy for the IRAC primary calibrators (Reach et al. 2005) and the photometry is obtained using identical methods and instrumental photometric corrections as those applied to the IRAC primary calibrators (Carey et al. 2009). The resulting photometry is then compared to the predictions based on spectra from the CALSPEC Calibration Database (http://www.stsci.edu/hst/observatory/crds/calspec.html) and the IRAC bandpasses. These observations are part of an ongoing collaboration between IPAC and STScI investigating absolute calibration in the infrared.

  18. Spitzer spectral line mapping of the HH211 outflow

    DEFF Research Database (Denmark)

    Dionatos, Odyssefs; Nisini, Brunella; Cabrit, Sylvie

    2010-01-01

    of emission line diagnostics and an existing grid of molecular shock models. The physical properties of the warm gas are compared against other molecular jet tracers and to the results of a similar study towards the L1448-C outflow. Results: We have detected and mapped the v=0-0 S(0) - S(7) H2 lines and fine...... compared to solar abundances by a factor ~10-50. Conclusions: Spitzer spectral mapping observations reveal for the first time a cool H$_2$ component towards the CO jet of HH211 consistent with the CO material being fully molecular and warm at ~ 300 K. The maps also reveal for the first time the existence...... uncertainties on jet speed and shock conditions are too large for a definite conclusion....

  19. A Spitzer five-band analysis of the Jupiter-sized planet TrES-1

    Energy Technology Data Exchange (ETDEWEB)

    Cubillos, Patricio; Harrington, Joseph; Foster, Andrew S. D.; Lust, Nate B.; Hardy, Ryan A.; Bowman, M. Oliver [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Madhusudhan, Nikku, E-mail: pcubillos@fulbrightmail.org [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06511 (United States)

    2014-12-10

    With an equilibrium temperature of 1200 K, TrES-1 is one of the coolest hot Jupiters observed by Spitzer. It was also the first planet discovered by any transit survey and one of the first exoplanets from which thermal emission was directly observed. We analyzed all Spitzer eclipse and transit data for TrES-1 and obtained its eclipse depths and brightness temperatures in the 3.6 μm (0.083% ± 0.024%, 1270 ± 110 K), 4.5 μm (0.094% ± 0.024%, 1126 ± 90 K), 5.8 μm (0.162% ± 0.042%, 1205 ± 130 K), 8.0 μm (0.213% ± 0.042%, 1190 ± 130 K), and 16 μm (0.33% ± 0.12%, 1270 ± 310 K) bands. The eclipse depths can be explained, within 1σ errors, by a standard atmospheric model with solar abundance composition in chemical equilibrium, with or without a thermal inversion. The combined analysis of the transit, eclipse, and radial-velocity ephemerides gives an eccentricity of e=0.033{sub −0.031}{sup +0.015}, consistent with a circular orbit. Since TrES-1's eclipses have low signal-to-noise ratios, we implemented optimal photometry and differential-evolution Markov Chain Monte Carlo (MCMC) algorithms in our Photometry for Orbits, Eclipses, and Transits pipeline. Benefits include higher photometric precision and ∼10 times faster MCMC convergence, with better exploration of the phase space and no manual parameter tuning.

  20. A MID-INFRARED IMAGING SURVEY OF SUBMILLIMETER-SELECTED GALAXIES WITH THE SPITZER SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Hainline, Laura J.; Blain, A. W.; Smail, Ian; Frayer, D. T.; Chapman, S. C.; Ivison, R. J.; Alexander, D. M.

    2009-01-01

    We present Spitzer-IRAC and MIPS mid-IR observations of a sample of 73 radio-detected submillimeter-selected galaxies (SMGs) with spectroscopic redshifts, the largest such sample published to date. From our data, we find that IRAC colors of SMGs are much more uniform as compared with rest-frame UV and optical colors, and z>1.5 SMGs tend to be redder in their mid-IR colors than both field galaxies and lower-z SMGs. However, the IRAC colors of the SMGs overlap those of field galaxies sufficiently that color-magnitude and color-color selection criteria suggested in the literature to identify SMG counterparts produce ambiguous counterparts within an 8'' radius in 20%-35% of cases. We use a rest-frame J-H versus H-K color-color diagram and a S 24 /S 8.0 versus S 8.0 /S 4.5 color-color diagram to determine that 13%-19% of our sample are likely to contain active galactic nuclei which dominate their mid-IR emission. We observe in the rest-frame JHK colors of our sample that the rest-frame near-IR emission of SMGs does not resemble that of the compact nuclear starburst observed in local ultraluminous IR galaxies and is consistent with more widely distributed star formation. We take advantage of the fact that many high-z galaxy populations selected at different wavelengths are detected by Spitzer to carry out a brief comparison of mid-IR properties of SMGs to UV-selected high-z galaxies, 24 μm-selected galaxies, and high-z radio galaxies, and find that SMGs have mid-IR fluxes and colors which are consistent with being more massive and more reddened than UV-selected galaxies, while the IRAC colors of SMGs are most similar to powerful high-z radio galaxies.

  1. Brown dwarf distances and atmospheres: Spitzer Parallaxes and the Keck/NIRSPEC upgrade

    Science.gov (United States)

    Martin, Emily C.

    2018-01-01

    Advances in infrared technology have been essential towards improving our understanding of the solar neighborhood, revealing a large population of brown dwarfs, which span the mass regime between planets and stars. My thesis combines near-infrared (NIR) spectroscopic and astrometric analysis of nearby low-mass stars and brown dwarfs with instrumentation work to upgrade the NIRSPEC instrument for the Keck II Telescope. I will present results from a program using Spitzer/IRAC data to measure precise locations and distances to 22 of the coldest and closest brown dwarfs. These distances allow us to constrain absolute physical properties, such as mass, radius, and age, of free-floating planetary-mass objects through comparison to atmospheric and evolutionary models. NIR spectroscopy combined with the Spitzer photometry reveals a detailed look into the atmospheres of brown dwarfs and gaseous extrasolar planets. Additionally, I will discuss the improvements we are making to the NIRSPEC instrument at Keck. NIRSPEC is a NIR echelle spectrograph, capable of R~2000 and R~25,000 observations in the 1-5 μm range. As part of the upgrade, I performed detector characterization, optical design of a new slit-viewing camera, mechanical testing, and electronics design. NIRSPEC’s increased efficiency will allow us to obtain moderate- and high-resolution NIR spectra of objects up to a magnitude fainter than the current NIRSPEC design. Finally, I will demonstrate the utility of a NIR laser frequency comb as a high-resolution calibrator. This new technology will revolutionize precision radial velocity measurements in the coming decade.

  2. SHARC-II Mapping of Spitzer c2d Small Clouds and Cores

    Science.gov (United States)

    Wu, Jingwen; Dunham, Michael M.; Evans, Neal J., II; Bourke, Tyler L.; Young, Chadwick H.

    2007-04-01

    We present the results of a submillimeter survey of 53 low-mass dense cores with the Submillimeter High Angular Resolution Camera II (SHARC-II). The survey is a follow-up project to the Spitzer Legacy Program "From Molecular Cores to Planet-Forming Disks," with the purpose of creating a complete data set of nearby low-mass dense cores from the infrared to the millimeter. We present maps of 52 cores at 350 μm and three cores at 450 μm, two of which were observed at both wavelengths. Of these 52 cores, 41 were detected by SHARC-II; 32 contained one submillimeter source, while 9 contained multiple sources. For each submillimeter source detected, we report various source properties including source position, fluxes in various apertures, size, aspect ratio, and position angle. For the 12 cores that were not detected we present upper limits. The sources detected by SHARC-II have, on average, smaller sizes at the 2 σ contours than those derived from longer wavelength bolometer observations. We conclude that this is not caused by a failure to integrate long enough to detect the full extent of the core; instead it arises primarily from the fact that the observations presented in this survey are insensitive to smoothly varying extended emission. We find that SHARC-II observations of low-mass cores are much better suited to distinguishing between starless and protostellar cores than observations at longer wavelengths. Very low luminosity objects, a new class of objects being discovered by the Spitzer Space Telescope in cores previously classified as starless, look very similar at 350 μm to other cores with more luminous protostars.

  3. SPATIAL VARIATIONS OF PAH PROPERTIES IN M17SW REVEALED BY SPITZER /IRS SPECTRAL MAPPING

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara 252-5210 (Japan); Kaneda, H.; Ishihara, D.; Oyabu, S.; Suzuki, T.; Nishimura, A.; Kohno, M. [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Onaka, T.; Ohashi, S. [Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nagayama, T.; Matsuo, M. [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Umemoto, T.; Minamidani, T.; Fujita, S. [Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Tsuda, Y., E-mail: yamagish@ir.isas.jaxa.jp [Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-0042 (Japan)

    2016-12-20

    We present Spitzer /IRS mid-infrared spectral maps of the Galactic star-forming region M17 as well as IRSF/SIRIUS Br γ and Nobeyama 45 m/FOREST {sup 13}CO ( J = 1–0) maps. The spectra show prominent features due to polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, 11.3, 12.0, 12.7, 13.5, and 14.2  μ m. We find that the PAH emission features are bright in the region between the H ii region traced by Br γ and the molecular cloud traced by {sup 13}CO, supporting that the PAH emission originates mostly from photo-dissociation regions. Based on the spatially resolved Spitzer /IRS maps, we examine spatial variations of the PAH properties in detail. As a result, we find that the interband ratio of PAH 7.7  μ m/PAH 11.3  μ m varies locally near M17SW, but rather independently of the distance from the OB stars in M17, suggesting that the degree of PAH ionization is mainly controlled by local conditions rather than the global UV environments determined by the OB stars in M17. We also find that the interband ratios of the PAH 12.0  μ m, 12.7  μ m, 13.5  μ m, and 14.2  μ m features to the PAH 11.3  μ m feature are high near the M17 center, which suggests structural changes of PAHs through processing due to intense UV radiation, producing abundant edgy irregular PAHs near the M17 center.

  4. Spitzer and Chandra Observations of the Deep Impact Encounter with Comet 9P/Tempel 1

    Science.gov (United States)

    Lisse, C. M.; A'Hearn, M. F.; Belton, M. J. S.; Bodewits, D.; Christian, D. J.; VanCleve, J.; Combi, M.; Dennerl, K.; Farnham, T. L.; Fernandez, Y. R.; Groussin, O.; Hoekstra, R.; Makinen, T.; McFadden, L. A.; Meech, K. J.; Schultz, P.; Weaver, H.; Wolk, S.

    2005-12-01

    On July 4, 2005 NASA's discovery mission Deep Impact (hereafter DI) sent a 375 kg impactor into the nucleus of comet 9P/Tempel 1 at 10.2 km/s relative velocity (A'Hearn et al. 2005). In the IR, Spitzer observed the comet in the unique 5-38 μm spectral range provided by the IRS instrument, allowing direct determination of silicaceous dust, PAHs, carbonates, and aluminum and iron oxides/sulfides in the subsurface material. The Spitzer observations contrasted well with the 1-5 μm spectra obtained by the DI High Resolution Instrument's IR spectrometer and ground based measurements at 1-5 um from the Keck and IRTF observatories (Meech et al. 2005), enabling us to obtain full coverage of the comet's IR spectrum from 1.0 to 38 μm. In the x-ray, the DI experiment allowed for a controlled test of the charge exchange (CXE) emission mechanism that drives cometary x-ray emission (Lisse et al. 2001, Kharchenko and Dalgarno 2001, Krasnopolsky et al. 2002) using observations with the Chandra ACIS-S CCD. The Chandra spectra show a fresh amount of neutral material was injected into a finite volume of the extended atmosphere, or coma, of the comet. In the matter of minutes, this new material directly increased the emission measure for the comet by 30 production from other measurements. Additional contemporaneous measurements by the XMM and SWIFT low energy x-ray imagers provided complimentary lightcurve data points, providing a good long term estimate of the comet's gas emission before, during, and after the Deep Impact encounter. Over the longer term, the combined lightcurves showed evidence of multiple natural outbursts of neutral gas emission from the comet.

  5. Spitzer Observations of MAMBO Galaxies: Weeding Out Active Nuclei in Starbursting Protoellipticals

    Science.gov (United States)

    Ivison, R. J.; Greve, T. R.; Serjeant, S.; Bertoldi, F.; Egami, E.; Mortier, A. M. J.; Alonso-Herrero, A.; Barmby, P.; Bei, L.; Dole, H.; Engelbracht, C. W.; Fazio, G. G.; Frayer, D. T.; Gordon, K. D.; Hines, D. C.; Huang, J.-S.; Le Floc'h, E.; Misselt, K. A.; Miyazaki, S.; Morrison, J. E.; Papovich, C.; Pérez-González, P. G.; Rieke, M. J.; Rieke, G. H.; Rigby, J.; Rigopoulou, D.; Smail, I.; Wilson, G.; Willner, S. P.

    2004-09-01

    We present 3.6-24 μm Spitzer observations of an unbiased sample of nine luminous, dusty galaxies selected at 1200 μm by MAMBO on the IRAM 30 m telescope, a population akin to the well-known submillimeter or SCUBA galaxies (hereafter SMGs). Owing to the coarse resolution of submillimeter/millimeter cameras, SMGs have traditionally been difficult to identify at other wavelengths. We compare our multiwavelength catalogs to show that the overlap between 24 and 1200 μm must be close to complete at these flux levels. We find that all (4/4) of the most secure >=4 σ SMGs have >=4 σ counterparts at 1.4 GHz, while the fraction drops to 7/9 using all >=3 σ SMGs. We show that combining mid-infrared (MIR) and marginal (>=3 σ) radio detections provides plausible identifications in the remaining cases, enabling us to identify the complete sample. Accretion onto an obscured central engine is betrayed by the shape of the MIR continuum emission for several sources, confirming Spitzer's potential to weed out active galaxies. We demonstrate the power of an S24μm/S8μm versus S8μm/S4.5μm color-color plot as a diagnostic for this purpose. However, we conclude that the majority (~75%) of SMGs have rest-frame mid/far-IR spectral energy distributions commensurate with obscured starbursts. Sensitive 24 μm observations are clearly a useful route to identify and characterize reliable counterparts to high-redshift far-IR-bright galaxies, complementing what is possible via deep radio imaging.

  6. THE SPITZER INFRARED SPECTROGRAPH DEBRIS DISK CATALOG. I. CONTINUUM ANALYSIS OF UNRESOLVED TARGETS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Christine H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Mittal, Tushar [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720-4767 (United States); Kuchner, Marc [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Forrest, William J.; Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Lisse, Carey M. [Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Manoj, P. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Sargent, Benjamin A., E-mail: cchen@stsci.edu [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2014-04-01

    During the Spitzer Space Telescope cryogenic mission, Guaranteed Time Observers, Legacy Teams, and General Observers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates. We calibrated the spectra of 571 candidates, including 64 new IRAS and Multiband Imaging Photometer for Spitzer (MIPS) debris disks candidates, modeled their stellar photospheres, and produced a catalog of excess spectra for unresolved debris disks. For 499 targets with IRS excess but without strong spectral features (and a subset of 420 targets with additional MIPS 70 μm observations), we modeled the IRS (and MIPS data) assuming that the dust thermal emission was well-described using either a one- or two-temperature blackbody model. We calculated the probability for each model and computed the average probability to select among models. We found that the spectral energy distributions for the majority of objects (∼66%) were better described using a two-temperature model with warm (T {sub gr} ∼ 100-500 K) and cold (T {sub gr} ∼ 50-150 K) dust populations analogous to zodiacal and Kuiper Belt dust, suggesting that planetary systems are common in debris disks and zodiacal dust is common around host stars with ages up to ∼1 Gyr. We found that younger stars generally have disks with larger fractional infrared luminosities and higher grain temperatures and that higher-mass stars have disks with higher grain temperatures. We show that the increasing distance of dust around debris disks is inconsistent with self-stirred disk models, expected if these systems possess planets at 30-150 AU. Finally, we illustrate how observations of debris disks may be used to constrain the radial dependence of material in the minimum mass solar nebula.

  7. THE SPITZER INFRARED SPECTROGRAPH DEBRIS DISK CATALOG. II. SILICATE FEATURE ANALYSIS OF UNRESOLVED TARGETS

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Tushar [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720-4767 (United States); Chen, Christine H. [Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 21218 (United States); Jang-Condell, Hannah [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Manoj, P. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Sargent, Benjamin A. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Lisse, Carey M., E-mail: cchen@stsci.edu [Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States)

    2015-01-10

    During the Spitzer Space Telescope cryogenic mission, astronomers obtained Infrared Spectrograph (IRS) observations of hundreds of debris disk candidates that have been compiled in the Spitzer IRS Debris Disk Catalog. We have discovered 10 and/or 20 μm silicate emission features toward 120 targets in the catalog and modeled the IRS spectra of these sources, consistent with MIPS 70 μm observations, assuming that the grains are composed of silicates (olivine, pyroxene, forsterite, and enstatite) and are located either in a continuous disk with power-law size and surface density distributions or thin rings that are well-characterized using two separate dust grain temperatures. For systems better fit by the continuous disk model, we find that (1) the dust size distribution power-law index is consistent with that expected from a collisional cascade, q = 3.5-4.0, with a large number of values outside this range, and (2) the minimum grain size, a {sub min}, increases with stellar luminosity, L {sub *}, but the dependence of a {sub min} on L {sub *} is weaker than expected from radiation pressure alone. In addition, we also find that (3) the crystalline fraction of dust in debris disks evolves as a function of time with a large dispersion in crystalline fractions for stars of any particular stellar age or mass, (4) the disk inner edge is correlated with host star mass, and (5) there exists substantial variation in the properties of coeval disks in Sco-Cen, indicating that the observed variation is probably due to stochasticity and diversity in planet formation.

  8. FINDING η CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    International Nuclear Information System (INIS)

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S.

    2013-01-01

    The late-stage evolution of the most massive stars such as η Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby (∼ 10 5 L ☉ in the IRAC bands (3.6 to 8.0 μm) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 ± 6 surviving candidates. Since we would detect true analogs of η Car for roughly 200 years post-eruption, this implies that the rate of eruptions like η Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M ☉ star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 μm, allowing identification of η Car analogs for millennia rather than centuries post-eruption.

  9. A deep Spitzer survey of circumstellar disks in the young double cluster, h and χ Persei

    Energy Technology Data Exchange (ETDEWEB)

    Cloutier, Ryan; Currie, Thayne; Jayawardhana, Ray [University of Toronto, 50 St. George Street, Toronto, ON, M5S 2J7 (Canada); Rieke, George H. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Kenyon, Scott J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02140 (United States); Balog, Zoltan, E-mail: cloutier@cita.utoronto.ca, E-mail: currie@astro.utoronto.ca, E-mail: grieke@as.arizona.edu, E-mail: skenyon@cfa.harvard.edu [Max Planck Institute for Astrophysics, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-12-01

    We analyze very deep Infrared Array Camera and Multiband Imaging Photometer for Spitzer (MIPS) photometry of ∼12, 500 members of the 14 Myr old Double Cluster, h and χ Persei, building upon our earlier, shallower Spitzer Cycle 1 studies. Numerous likely members show infrared (IR) excesses at 8 μm and 24 μm, indicative of circumstellar dust. The frequency of stars with 8 μm excess is at least 2% for our entire sample, slightly lower (higher) for B/A stars (later type, lower mass stars). Optical spectroscopy also identifies gas in about 2% of systems, but with no clear trend between the presence of dust and gas. Spectral energy distribution modeling of 18 sources with detections at optical wavelengths through MIPS 24 μm reveals a diverse set of disk evolutionary states, including a high fraction of transitional disks, though similar data for all disk-bearing members would provide constraints. Using Monte Carlo simulations, we combine our results with those for other young clusters to study the global evolution of dust/gas disks. For nominal cluster ages, the e-folding times (τ{sub 0}) for the frequency of warm dust and gas are 2.75 Myr and 1.75 Myr, respectively. Assuming a revised set of ages for some clusters, these timescales increase to 5.75 and 3.75 Myr, respectively, implying a significantly longer typical protoplanetary disk lifetime than previously thought. In both cases, the transitional disk duration, averaged over multiple evolutionary pathways, is ≈1 Myr. Finally, 24 μm excess frequencies for 4-6 M {sub ☉} stars appear lower than for 1-2.5 M {sub ☉} stars in other 10-30 Myr old clusters.

  10. US Spacesuit Knowledge Capture

    Science.gov (United States)

    Chullen, Cinda; Thomas, Ken; McMann, Joe; Dolan, Kristi; Bitterly, Rose; Lewis, Cathleen

    2011-01-01

    The ability to learn from both the mistakes and successes of the past is vital to assuring success in the future. Due to the close physical interaction between spacesuit systems and human beings as users, spacesuit technology and usage lends itself rather uniquely to the benefits realized from the skillful organization of historical information; its dissemination; the collection and identification of artifacts; and the education of those in the field. The National Aeronautics and Space Administration (NASA), other organizations and individuals have been performing United States (U.S.) Spacesuit Knowledge Capture since the beginning of space exploration. Avenues used to capture the knowledge have included publication of reports; conference presentations; specialized seminars; and classes usually given by veterans in the field. More recently the effort has been more concentrated and formalized whereby a new avenue of spacesuit knowledge capture has been added to the archives in which videotaping occurs engaging both current and retired specialists in the field presenting technical scope specifically for education and preservation of knowledge. With video archiving, all these avenues of learning can now be brought to life with the real experts presenting their wealth of knowledge on screen for future learners to enjoy. Scope and topics of U.S. spacesuit knowledge capture have included lessons learned in spacesuit technology, experience from the Gemini, Apollo, Skylab and Shuttle programs, hardware certification, design, development and other program components, spacesuit evolution and experience, failure analysis and resolution, and aspects of program management. Concurrently, U.S. spacesuit knowledge capture activities have progressed to a level where NASA, the National Air and Space Museum (NASM), Hamilton Sundstrand (HS) and the spacesuit community are now working together to provide a comprehensive closed-looped spacesuit knowledge capture system which includes

  11. Adiabatic capture and debunching

    International Nuclear Information System (INIS)

    Ng, K.Y.

    2012-01-01

    In the study of beam preparation for the g-2 experiment, adiabatic debunching and adiabatic capture are revisited. The voltage programs for these adiabbatic processes are derived and their properties discussed. Comparison is made with some other form of adiabatic capture program. The muon g-2 experiment at Fermilab calls for intense proton bunches for the creation of muons. A booster batch of 84 bunches is injected into the Recycler Ring, where it is debunched and captured into 4 intense bunches with the 2.5-MHz rf. The experiment requires short bunches with total width less than 100 ns. The transport line from the Recycler to the muon-production target has a low momentum aperture of ∼ ±22 MeV. Thus each of the 4 intense proton bunches required to have an emittance less than ∼ 3.46 eVs. The incoming booster bunches have total emittance ∼ 8.4 eVs, or each one with an emittance ∼ 0.1 eVs. However, there is always emittance increase when the 84 booster bunches are debunched. There will be even larger emittance increase during adiabatic capture into the buckets of the 2.5-MHz rf. In addition, the incoming booster bunches may have emittances larger than 0.1 eVs. In this article, we will concentrate on the analysis of the adiabatic capture process with the intention of preserving the beam emittance as much as possible. At this moment, beam preparation experiment is being performed at the Main Injector. Since the Main Injector and the Recycler Ring have roughly the same lattice properties, we are referring to adiabatic capture in the Main Injector instead in our discussions.

  12. The Pierre Auger Cosmic Ray Observatory

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albert, J. N.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Aranda, V. M.; Argiro, S.; Arisaka, K.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Awal, N.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A.; Barenthien, N.; Barkhausen, M.; Baeuml, J.; Baus, C.; Beatty, J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bergmann, T.; Bertaina, M. E.; Biermann, P. L.; Bilhaut, R.; Billoir, P.; Blaes, S. G.; Blanco, M.; Bleve, C.; Bluemer, H.; Bohacova, M.; Bolz, H.; Boncioli, D.; Bonifaz, C.; Bonino, R.; Boratav, M.; Borodai, N.; Bracci, F.; Brack, J.; Brancus, I.; Bridgeman, A.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Camin, D.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Castera, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chiosso, M.; Chudoba, J.; Cilmo, M.; Clark, P. D. J.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Colombo, E.; Colonges, S.; Coluccia, M. R.; Conceicao, R.; Contreras, F.; Cooper, M. J.; Coppens, J.; Cordier, A.; Courty, B.; Coutu, S.; Covault, C. E.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Diaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, C.; Dolron, P.; Dorofeev, A.; Hasankiadeh, Q. Dorosti; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Epele, L. N.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Ferrero, A.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipcic, A.; Fox, B. D.; Fraenkel, E. D.; Fratu, O.; Freire, M. M.; Froehlich, U.; Fuchs, B.; Fulgione, W.; Fujii, T.; Garcia, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Geenen, H.; Gemmeke, H.; Genolini, B.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Gibbs, K.; Giller, M.; Giudice, N.; Glaser, C.; Glass, H.; Gomez Berisso, M.; Gomez Vitale, P. F.; Goncalves, P.; Gonzalez, J. G.; Gonzalez, N.; Gookin, B.; Gora, D.; Gordon, J.; Gorgi, A.; Gorham, P.; Gotink, W.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Grygar, J.; Guardone, N.; Guarino, F.; Guedes, G. P.; Guglielmi, L.; Habraken, R.; Hampel, M. R.; Hansen, P.; Harari, D.; Harmsma, S.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hoerandel, J. R.; Horneffer, A.; Horvat, M.; Horvath, P.; Hrabovsky, M.; Huber, D.; Hucker, H.; Huege, T.; Iarlori, M.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kaeaepae, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kegl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Kopmann, A.; Krause, R.; Krohm, N.; Kroemer, O.; Kuempel, D.; Kunka, N.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leao, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopez, R.; Lopez Casado, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Malacari, M.; Maldera, S.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marsella, G.; Martello, D.; Martina, L.; Martinez, H.; Martinez, N.; Martinez Bravo, O.; Martraire, D.; Masias Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Melissas, M.; Mello, V. B. B.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Micanovic, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Montanet, F.; Morello, C.; Mostafa, M.; Moura, C. A.; Muller, M. A.; Mueller, G.; Mueller, S.; Muenchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Nicotra, D.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nozka, L.; Ochilo, L.; Ohnuki, T.; Oikonomou, F.; Olinto, A.; Oliveira, M.; Olmos-Gilbaja, V. M.; Pacheco, N.; PakkSelmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Patel, M.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrinca, P.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Porter, T.; Pouryamout, J.; Pouthas, J.; Prado, R. R.; Privitera, P.; Prouza, M.; Pryke, C. L.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Randriatoamanana, R.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenua, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Robbins, S.; Roberts, M.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodriguez-Frias, M. D.; Rogozin, D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovanek, P.; Schreuder, F.; Schroeder, F. G.; Schulz, A.; Schulz, J.; Schuessler, F.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Sequeiros, G.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Smialkowski, A.; Smida, R.; Smith, A. G. K.; Snow, G. R.; Sommers, P.; Sorokin, J.; Speelman, R.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanic, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijaervi, T.; Supanitsky, A. D.; Sutherland, M. S.; Sutter, M.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tcherniakhovski, D.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tome, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Trung, T. N.; Tunnicliffe, V.; Tusi, E.; Ulrich, R.; Unger, M.; Urban, M.; Valdes Galicia, J. F.; Valino, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cardenas, B.; Varnav, D. M.; Varner, G.; Vasquez, R.; Vazquez, J. R.; Vazquez, R. A.; Veberic, D.; Verkooijen, H.; Verzi, V.; Vicha, J.; Videla, M.; Villasenor, L.; Vitali, G.; Vlcek, B.; Vorenholt, H.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Walker, P.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Widom, A.; Wiebusch, C.; Wiencke, L.; Wijnen, T.; Wilczynska, B.; Wilczynski, H.; Wild, N.; Winchen, T.; Wittkowski, D.; Woerner, G.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zhou, J.; Zhu, Y.; Silva, M. Zimbres; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.

    2015-01-01

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 10(17) eV and to study the interactions of these, the most energetic

  13. From cosmic string to superconducting string

    CERN Document Server

    Kim, H C; Lee, B K

    1999-01-01

    We consider the dynamical symmetry breaking of a chirally-invariant Nambu-Jona-Lasinio model in the background gravity of a local cosmic string. By analyzing the one-loop effective action, we show how a cosmic string at a very high energy scale forms a global superconducting string to the spontaneous chiral symmetry breaking at a low energy.

  14. NEXUS: tracing the cosmic web connection

    NARCIS (Netherlands)

    Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.

    2013-01-01

    We introduce the NEXUS algorithm for the identification of cosmic web environments: clusters, filaments, walls and voids. This is a multiscale and automatic morphological analysis tool that identifies all the cosmic structures in a scale free way, without preference for a certain size or shape. We

  15. Maximum entropy analysis of cosmic ray composition

    Czech Academy of Sciences Publication Activity Database

    Nosek, D.; Ebr, Jan; Vícha, Jakub; Trávníček, Petr; Nosková, J.

    2016-01-01

    Roč. 76, Mar (2016), s. 9-18 ISSN 0927-6505 R&D Projects: GA ČR(CZ) GA14-17501S Institutional support: RVO:68378271 Keywords : ultra-high energy cosmic rays * extensive air showers * cosmic ray composition Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 3.257, year: 2016

  16. The Spine of the Cosmic Web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; Platen, Erwin; van de Weijgaert, Rien; Szalay, Alexander S.

    2010-01-01

    We present the SpineWeb framework for the topological analysis of the Cosmic Web and the identification of its walls, filaments, and cluster nodes. Based on the watershed segmentation of the cosmic density field, the SpineWeb method invokes the local adjacency properties of the boundaries between

  17. Sealed drift tube cosmic ray veto counters

    Energy Technology Data Exchange (ETDEWEB)

    Rios, R., E-mail: rrios@lanl.go [Idaho State University, Pocatello, ID 83209 (United States); Tatar, E. [Idaho State University, Pocatello, ID 83209 (United States); Bacon, J.D.; Bowles, T.J.; Hill, R.; Green, J.A.; Hogan, G.E.; Ito, T.M.; Makela, M.; Morris, C.L.; Mortenson, R.; Pasukanics, F.E.; Ramsey, J.; Saunders, A.; Seestrom, S.J.; Sondheim, W.E.; Teasdale, W. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Saltus, M. [Sloan Enterprises, NC (United States); Back, H.O.; Cottrell, C.R. [North Carolina State University, Raleigh, NC 27695 (United States)

    2011-05-01

    We describe a simple drift tube counter that has been used as a cosmic ray veto for the UCNA experiment, a first-ever measurement of the neutron beta-asymmetry using ultra-cold neutrons. These detectors provide an inexpensive alternative to more conventional scintillation detectors for large area cosmic ray anticoincidence detectors.

  18. Cosmic perspectives in space physics

    CERN Document Server

    Biswas, Sukumar

    2000-01-01

    In the early years of the twentieth century, Victor Hess of Germany flew instruments in balloons and so discovered in 1912 that an extra-~errestial radiation of unknown origin is incident on the earth with an almost constant intensity at all times. These penetrating non­ solar radiations which were called Cosmic Rays by Millikan, USA, opened the new frontier of space physics and many leading scientists were attracted to it. At the end of World War II a number of space vehicles, e.g. stratospheric balloons, rockets and satellites were developed. In 1950 and onwards, these vehicles enabled spectacular advances in space physics and space astrophysics. New horizons were opened in the explorations of cosmic rays, the earth's magnetosphere, the Sun and the heliosphere, the moon and the planets. Using space-borne instruments, exciting discoveries were made of stars, and galaxies in the infra-red, ultra violet, x-ray and gamma-ray wavelengths. In this text book these fascinating new findings are presented in depth a...

  19. Cosmic evolution, life and man

    International Nuclear Information System (INIS)

    Oro, J.

    1995-01-01

    Among the most basic problems confronting science are those regarding the origin of the universe, the origin of life and the origin of man. This general overview starts (1) with a brief introduction addressed primarily to the Cyril Ponnamperuma Memorial. Then, the thesis is presented that the appearance of life and intelligence on our planet can be understood as the result of a number of cosmic and biological evolutionary processes, including (2) the stellar thermonuclear synthesis of the biogenic elements other than hydrogen (C, N, O, P and S), their dispersal into space, and their combination into circumstellar and interstellar molecules. (3) The formation of the Solar System and the Earth-Moon System. (4) The role of comets and carbonaceous chondrites in contributing organic matter to the primitive Earth. (5) The prebiotics synthesis of amino acids, purines, pyrimidines, fatty acids, and other biochemical monomers. (6) The prebiotic condensation reactions leading to the synthesis of oligomers such as oligonucleotides and oligopeptides, with replicative and catalytic activities. (7) The synthesis of amphiphilic lipids, and their self-assembly into liposomes with bi-layered membranes. (8) The formation of protocellular structures. (9) The activation of protocells into a functioning Darwin's ancestral cell. (10) Early evolution of life. (11) The K-T boundary event and the disappearance of dinosaurs. (12) Evolution of hominids leading to Homo sapiens. (13) The rapid development of civilization. (14) The exploration of the Solar System. (15) Life beyond our planetary system. (16) Epilogue. Peace from cosmic evolution? (Abstract only)

  20. Cosmic Feast of the Elements

    Science.gov (United States)

    Morisset, C.; Delgado-Inglada, G.; García-Rojas, J.

    2017-11-01

    In the past few decades most of our understanding of the history and chemical evolution of galaxies has been guided by the study of their stars and gaseous nebulae. Nebulae, thanks to their bright emission lines, are especially useful tracers of chemical elements from the very center to the outskirts of galaxies. In order to pin down the chemical abundances in nebulae, we must rely on careful analysis of emission lines combined with detailed models of the microscopic physical processes inside nebulae and state-of-the-art atomic data. Another important piece of the puzzle is the interplay between galaxy evolution and the activity of their central engines either as optical AGNs or radio jets. Last but not least, let us not forget the huge population of lineless, retired galaxies ionized by hot low-mass evolved stars: after nuclear and star formation activity quiets down, retired galaxies are the natural consequence of galaxy evolution. Grażyna Stasińska has made important contributions to each and every one of those aspects. This conference is to honor her work. We invite you to take part and share the latest news on this cosmic feast that transmutes chemical species, the onward journey of elements inside and outside galaxies either as lonely atoms or gregarious molecules and crystals, and their recycling in stars, which starts the cosmic feast all over again.

  1. Cosmic rays and the interstellar medium

    International Nuclear Information System (INIS)

    Wolfendale, A.W.

    1986-01-01

    It is inevitable that there is a close connection between cosmic rays and the ISM insofar as the propagation of cosmic rays is conditioned by the magnetic field in the ISM and the cosmic rays interact with the gas (and photon fluxes) in this medium. This paper deals with both topics. Propagation effects manifest themselves as an anisotropy in arrival directions and a review is given of anisotropy measurements and their interpretation. The status of studies of cosmic ray interactions is examined whit particular reference to the information about the ISM itself which comes from observations of the flux of secondary γ-rays produced by cosmic ray interactions with gas, the situation regarding molecular as in the Inner Galaxy being of particular concern

  2. High energy physics in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Lawrence W. [University of Michigan, Ann Arbor, Michigan (United States)

    2013-02-07

    In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

  3. Cosmic Ray Physics with ACORDE at LHC

    CERN Document Server

    Pagliarone, C.

    2008-01-01

    The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

  4. Cosmic ray physics with ACORDE at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pagliarone, C [Universita degli Studi di Cassino and INFN Pisa, Largo B. Pontecorvo, 3 - Pisa (Italy); Fernandez-Tellez, A [Benemerita Universidad Autonoma de Puebla (BUAP), Puebla (Mexico)], E-mail: pagliarone@fnal.gov

    2008-05-15

    The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2{center_dot}10{sup 10} to 2{center_dot} 10{sup 12} eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10{sup 15} to 10{sup 17} eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

  5. Cosmic ray physics with ACORDE at LHC

    International Nuclear Information System (INIS)

    Pagliarone, C; Fernandez-Tellez, A

    2008-01-01

    The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2·10 10 to 2· 10 12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10 15 to 10 17 eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program

  6. open capture-recapture

    Indian Academy of Sciences (India)

    lyn

    ' samples in each primary sample. • Integrated approach to modeling closed and open population data. • Total of 5,725 trap-nights of effort. • 74 individual tigers (> 2 years age) photo-captured. Open Model Capture–recapture ...

  7. Neutron capture therapies

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.

    1999-11-02

    In one embodiment there is provided an application of the {sup 10}B(n,{alpha}){sup 7}Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  8. Neutron capture therapies

    Science.gov (United States)

    Yanch, Jacquelyn C.; Shefer, Ruth E.; Klinkowstein, Robert E.

    1999-01-01

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  9. Cosmic Rays and Clouds, 1. Formation of Lead Mesoatoms In Neutron Monitor By Soft Negative Muons and Expected Atmospheric Electric Field Effect In The Cosmic Ray Neutron Component

    Science.gov (United States)

    Dorman, L. I.; Dorman, I. V.

    We extend our model (Dorman and Dorman, 1995) of cosmic ray atmospheric electric field effect on the case of neutron monitor. We take into account that about 0.07 of neu- tron monitor counting rate caused by negative soft muons captured by lead nucleons and formed mesoatoms with generation of several MeV energy neutrons from lead. In this case the neutron monitor or neutron supermonitor works as analyzer which de- tects muons of only one, negative sign. It is very important because the atmospheric electric field effect have opposite signs for positive and negative muons that main part of this effect in the muon telescope or in ionization chamber is compensated and we can observe only small part of total effect of one sign muons. On the basis of our gen- eral theory of cosmic ray meteorological effects with taking into account of negative soft muon acceleration and deceleration in the Earth atmosphere (in dependence of di- rection and intensity of electric field) we discuss the possibility of existing this effect in cosmic ray neutron component and made some rough estimations. REFERENCES: Dorman L.I. and Dorman I.V., 1995. "Cosmic-ray atmospheric electric field effects". Canadian J. of Physics, Vol. 73, pp. 440-443.

  10. Discriminating between thermal and nonthermal cosmic relic neutrinos through an annual modulation at PTOLEMY

    Science.gov (United States)

    Huang, Guo-yuan; Zhou, Shun

    2016-12-01

    If massive neutrinos are Dirac particles, the proposed PTOLEMY experiment will hopefully be able to discover the cosmic neutrino background via νe+3H →3He+e- with a capture rate of ΓD≈4 yr-1 . Recently, it has been pointed out that right-handed components of Dirac neutrinos could also be copiously produced in the early Universe and become an extra thermal or nonthermal ingredient of cosmic relic neutrinos, enhancing the capture rate to ΓD≈5.1 yr-1 or ΓD≈6.1 yr-1. In this work, we investigate the possibility to distinguish between thermal and nonthermal spectra of cosmic relic neutrinos by measuring the annual modulation of the capture rate. For neutrino masses of 0.1 eV, we find that the amplitude of annual modulation in the standard case is M ≈0.05 %, which will be increased to 0.1% and 0.15% in the presence of additional thermal and nonthermal right-handed neutrinos, respectively. The future detection of such a modulation will be helpful in understanding the Majorana or Dirac nature of massive neutrinos.

  11. Space Weather Observations by GNSS Radio Occultation: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2.

    Science.gov (United States)

    Yue, Xinan; Schreiner, William S; Pedatella, Nicholas; Anthes, Richard A; Mannucci, Anthony J; Straus, Paul R; Liu, Jann-Yenq

    2014-11-01

    The joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian Global Navigation Satellite System signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4-6 times (10-15X in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters.

  12. Cosmic Ray Production in Supernovae

    Science.gov (United States)

    Bykov, A. M.; Ellison, D. C.; Marcowith, A.; Osipov, S. M.

    2018-02-01

    We give a brief review of the origin and acceleration of cosmic rays (CRs), emphasizing the production of CRs at different stages of supernova evolution by the first-order Fermi shock acceleration mechanism. We suggest that supernovae with trans-relativistic outflows, despite being rather rare, may accelerate CRs to energies above 10^{18} eV over the first year of their evolution. Supernovae in young compact clusters of massive stars, and interaction powered superluminous supernovae, may accelerate CRs well above the PeV regime. We discuss the acceleration of the bulk of the galactic CRs in isolated supernova remnants and re-acceleration of escaped CRs by the multiple shocks present in superbubbles produced by associations of OB stars. The effects of magnetic field amplification by CR driven instabilities, as well as superdiffusive CR transport, are discussed for nonthermal radiation produced by nonlinear shocks of all speeds including trans-relativistic ones.

  13. Cerenkov radiation from cosmic rays

    International Nuclear Information System (INIS)

    Turver, K.E.

    1988-01-01

    It is almost 40 years since it was suggested that Cerenkov radiations may be produced in the atmosphere by the passage of the cosmic radiation and account for a small part of the night sky brightness. The first detection of this visible Cerenkov radiation followed within a few years and by the 1960s the atmospheric Cerenkov radiation technique was established as a tool in high energy astrophysics. An exciting new field of astronomy, high energy gamma ray astronomy, has developed which relies on the atmospheric Cerenkov light. We here review the mechanism for the production of Cerenkov light in the atmosphere and summarize the contributions to high energy astrophysics made using the technique. (author)

  14. Cosmic setting for chondrule formation

    International Nuclear Information System (INIS)

    Taylor, G.J.; Scott, E.R.D.; Keil, K.

    1983-01-01

    Chondrules are igneous-textured, millimeter-sized, spherical to irregularly-shaped silicate objects which constitute the major component of most chondrites. There is agreement that chondrules were once molten. Models for chondrule origin can be divided into two categories. One involves a planetary setting, which envisages chondrules forming on the surfaces of parent bodies. Melting mechanisms include impact and volcanism. The other category is concerned with a cosmic setting in the solar nebula, prior to nebula formation. Aspects regarding the impact on planetary surfaces are considered, taking into account chondrule abundances, the abundancy of agglutinates on the moon, comminution, hypervelocity impact pits, questions of age, and chondrule compositions. Attention is also given to collisions during accretion, collisions between molten planetesimals, volcanism, and virtues of a nebular setting. 101 references

  15. Statistical Physics for Cosmic Structures

    CERN Document Server

    Gabrielli, Andrea

    2004-01-01

    The physics of scale-invariant and complex systems is a novel interdisciplinary field. Its ideas allow us to look at natural phenomena in a radically new and original way, eventually leading to unifying concepts independent of the detailed structure of the systems. The objective is the study of complex, scale-invariant, and more general stochastic structures that appear both in space and time in a vast variety of natural phenomena, which exhibit new types of collective behaviors, and the fostering of their understanding. This book has been conceived as a methodological monograph in which the main methods of modern statistical physics for cosmological structures and density fields (galaxies, Cosmic Microwave Background Radiation, etc.) are presented in detail. The main purpose is to present clearly, to a workable level, these methods, with a certain mathematical accuracy, providing also some paradigmatic examples of applications. This should result in a new and more general framework for the statistical analys...

  16. Cosmic Convergence: Art and Science

    Science.gov (United States)

    Mayo, Elizabeth A.; Zisholtz, E.; Hilton, H.

    2010-01-01

    The I.P. Stanback Museum and Planetarium is a major educational and teaching resource for South Carolina State University, K-12 schools, other universities and the community of Orangeburg and well beyond. The concept of creating a museum with a planetarium on the campus of SC State was ahead of its time. Today scholars are writing about the unity of creative disciplines. Through its integration of the arts, humanities and sciences, the Stanback, the only art museum with a planetarium at any of the Historically Black Colleges and Universities and one of the few in the nation, stands in the forefront of modern thinking. Cosmic Convergence: Art and Science, opening at the I.P. Stanback Museum and Planetarium in February 2010, will feature the works of Mildred Thompson (1936-2003), a prominent African American artist who worked in the media of painting, drawing, print making, sculpture, and photography. Thompson’s artwork shows the strong influences of her interest in physics, astronomy, and metaphysics as well as music and spiritualism. “My work in the visual arts is, and has always been, a continuous search for understanding. It is an expression of purpose and reflects a personal interpretation of the Universe.” Cosmic Convergence will explore the meeting of Art and Science through Mildred Thompson's work and the scientific basis of that work. The paintings and sculptures of the exhibit will be combined with astronomical images showing both the reality and interpretation of the surrounding Universe. Support for this work was provided by the NSF PAARE program to South Carolina State University under award AST-0750814.

  17. Symbols of a cosmic order

    Science.gov (United States)

    Madjid, F. Hadi; Myers, John M.

    2016-10-01

    The world runs on networks over which signals communicate sequences of symbols, e.g. numerals. Examining both engineered and natural communications networks reveals an unsuspected order that depends on contact with an unpredictable entity. This order has three roots. The first is a proof within quantum theory that no evidence can ever determine its explanation, so that an agent choosing an explanation must do so unpredictably. The second root is the showing that clocks that step computers do not "tell time" but serve as self-adjusting symbol-handling agents that regulate "logically synchronized" motion in response to unpredictable disturbances. Such a clock-agent has a certain independence as well as the capacity to communicate via unpredictable symbols with other clock-agents and to adjust its own tick rate in response to that communication. The third root is the noticing of unpredictable symbol exchange in natural systems, including the transmission of symbols found in molecular biology. We introduce a symbol-handling agent as a role played in some cases by a person, for example a physicist who chooses an explanation of given experimental outcomes, and in other cases by some other biological entity, and in still other cases by an inanimate device, such as a computer-based detector used in physical measurements. While we forbear to try to explain the propensity of agents at all levels from cells to civilizations to form and operate networks of logically synchronized symbol-handling agents, we point to this propensity as an overlooked cosmic order, an order structured by the unpredictability ensuing from the proof. Appreciating the cosmic order leads to a conception of agency that replaces volition by unpredictability and reconceives the notion of objectivity in a way that makes a place for agency in the world as described by physics. Some specific implications for physics are outlined.

  18. New Fitting Formula for Cosmic Nonlinear Density Distribution

    Science.gov (United States)

    Shin, Jihye; Kim, Juhan; Pichon, Christophe; Jeong, Donghui; Park, Changbom

    2017-07-01

    We have measured the probability distribution function (PDF) of a cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 ({{ N }}{{v}2}) as an alternative fitting formula to the well-known log-normal distribution. We find that {{ N }}{{v}2} provides a significantly better fit than that of the log-normal distribution for all smoothing radii (2, 5, 10, 25 [Mpc h -1]) that we studied. The improvement is substantial in the underdense regions. The development of non-Gaussianities in the cosmic matter density field is captured by continuous evolution of the skewness and shift parameters of the {{ N }}{{v}2} distribution. We present the redshift evolution of these parameters for aforementioned smoothing radii and various background cosmology models. All the PDFs measured from large and high-resolution N-body simulations that we use in this study can be obtained from the web site https://astro.kias.re.kr/jhshin.

  19. Gadolinium neutron capture therapy

    International Nuclear Information System (INIS)

    Akine, Yasuyuki; Tokita, Nobuhiko; Tokuuye, Koichi; Satoh, Michinao; Churei, Hisahiko

    1993-01-01

    Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

  20. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  1. Cosmic growth history and expansion history

    International Nuclear Information System (INIS)

    Linder, Eric V.

    2005-01-01

    The cosmic expansion history tests the dynamics of the global evolution of the universe and its energy density contents, while the cosmic growth history tests the evolution of the inhomogeneous part of the energy density. Precision comparison of the two histories can distinguish the nature of the physics responsible for the accelerating cosmic expansion: an additional smooth component--dark energy--or a modification of the gravitational field equations. With the aid of a new fitting formula for linear perturbation growth accurate to 0.05%-0.2%, we separate out the growth dependence on the expansion history and introduce a new growth index parameter γ that quantifies the gravitational modification

  2. Consistency relation for cosmic magnetic fields

    DEFF Research Database (Denmark)

    Jain, R. K.; Sloth, M. S.

    2012-01-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show...... to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields. DOI...

  3. High energy cosmic rays: sources and fluxes

    Science.gov (United States)

    Stanev, Todor; Gaisser, Thomas K.; Tilav, Serap

    2014-04-01

    We discuss the production of a unique energy spectrum of the high energy cosmic rays detected with air showers by shifting the energy estimates of different detectors. After such a spectrum is generated we fit the spectrum with three or four populations of cosmic rays that might be accelerated at different cosmic ray sources. We also present the chemical composition that the fits of the spectrum generates and discuss some new data sets presented this summer at the ICRC in Rio de Janeiro that may require new global fits.

  4. The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer

    Energy Technology Data Exchange (ETDEWEB)

    Agol, E.; /Washington U., Seattle, Astron. Dept. /Santa Barbara, KITP /UC, Santa Barbara; Cowan, Nicolas B.; /Washington U., Seattle, Astron. Dept.; Knutson, Heather A.; /UC, Berkeley, Astron. Dept.; Deming, Drake; /NASA, Goddard; Steffen, Jason H.; /Fermilab; Henry, Gregory W.; /Tennessee State U.; Charbonneau, David; /Harvard-Smithsonian Ctr. Astrophys.

    2010-07-01

    We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope IRAC camera at 8 microns, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector 'ramp' variation with a double-exponential function which performs better and is a better physical model for this detector variation. Our main scientific findings are: (1) an upper limit on the variability of the day-side planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 seconds; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the night-side variability of 17% (68% confidence); (5) a better correction for stellar variability at 8 micron causing the phase function to peak 3.5 hours before secondary eclipse, confirming that the advection and radiation timescales are comparable at the 8 micron photosphere; (6) variation in the depth of transit, which possibly implies variations in the surface brightness of the portion of the star occulted by the planet, posing a fundamental limit on non-simultaneous multi-wavelength transit absorption measurements of planet atmospheres; (7) a measurement of the infrared limb-darkening of the star, which is in good agreement with stellar atmosphere models; (8) an offset in the times of secondary eclipse of 69 seconds, which is mostly accounted for by a 31 second light travel time delay and 33 second delay due to the shift of ingress and egress by the planet hot spot; this confirms that the phase variation is due to an offset hot

  5. LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Kryukova, E.; Megeath, S. T.; Allen, T. S.; Gutermuth, R. A.; Pipher, J.; Allen, L. E.; Myers, P. C.; Muzerolle, J.

    2012-01-01

    We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1-24 μm spectral energy distributions (SEDs). Using protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1-24 μm), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L ☉ and show a tail extending toward luminosities above 100 L ☉ . The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L ☉ . Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our luminosity functions to those

  6. IPHAS A-TYPE STARS WITH MID-INFRARED EXCESSES IN SPITZER SURVEYS

    International Nuclear Information System (INIS)

    Hales, Antonio S.; Barlow, Michael J.; Drew, Janet E.; Unruh, Yvonne C.; Greimel, Robert; Irwin, Michael J.; Gonzalez-Solares, Eduardo

    2009-01-01

    We have identified 17 A-type stars in the Galactic Plane that have mid-infrared (mid-IR) excesses at 8 μm. From observed colors in the (r' - Hα) - (r' - i') plane, we first identified 23,050 early A-type main-sequence (MS) star candidates in the Isaac Newton Photometric H-Alpha Survey (IPHAS) point source database that are located in Spitzer Galactic Legacy Mid-Plane Survey Extraordinaire Galactic plane fields. Imposing the requirement that they be detected in all seven Two Micron All Sky Survey and Infrared Astronomical Satellite bands led to a sample of 2692 candidate A-type stars with fully sampled 0.6 to 8 μm spectral energy distributions (SEDs). Optical classification spectra of 18 of the IPHAS candidate A-type MS stars showed that all but one could be well fitted using MS A-type templates, with the other being an A-type supergiant. Out of the 2692 A-type candidates 17 (0.6%) were found to have 8 μm excesses above the expected photospheric values. Taking into account non-A-Type contamination estimates, the 8 μm excess fraction is adjusted to ∼0.7%. The distances to these sources range from 0.7 to 2.5 kpc. Only 10 out of the 17 excess stars had been covered by Spitzer MIPSGAL survey fields, of which five had detectable excesses at 24 μm. For sources with excesses detected in at least two mid-IR wavelength bands, blackbody fits to the excess SEDs yielded temperatures ranging from 270 to 650 K, and bolometric luminosity ratios L IR /L * from 2.2 x 10 -3 - 1.9 x 10 -2 , with a mean value of 7.9 x 10 -3 (these bolometric luminosities are lower limits as cold dust is not detectable by this survey). Both the presence of mid-IR excesses and the derived bolometric luminosity ratios are consistent with many of these systems being in the planet-building transition phase between the early protoplanetary disk phase and the later debris disk phase.

  7. LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Kryukova, E.; Megeath, S. T.; Allen, T. S. [Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Gutermuth, R. A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Pipher, J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Allen, L. E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Myers, P. C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Muzerolle, J. [Space Telescope Science Institute, Baltimore, MD (United States)

    2012-08-15

    We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1-24 {mu}m spectral energy distributions (SEDs). Using protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1-24 {mu}m), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L{sub Sun} and show a tail extending toward luminosities above 100 L{sub Sun }. The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L{sub Sun }. Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our luminosity

  8. Revisiting the Phase Curves of WASP-43b: Confronting Re-analyzed Spitzer Data with Cloudy Atmospheres

    DEFF Research Database (Denmark)

    Mendonça, João M.; Malik, Matej; Demory, Brice-Olivier

    2018-01-01

    and have a finite cloud-top pressure. The multi-wavelength phase curves are naturally consistent with our cloudy atmospheres, except for the 4.5 μm phase curve, which requires the presence of enhanced carbon dioxide in the atmosphere of WASP-43b. Multi-phase emission spectra at higher spectral resolution......Recently acquired Hubble and Spitzer phase curves of the short-period hot Jupiter WASP-43b make it an ideal target for confronting theory with data. On the observational front, we re-analyze the 3.6 and 4.5 μm Spitzer phase curves and demonstrate that our improved analysis better removes residual...

  9. CRYSTALLINE SILICATES IN EVOLVED STARS. I. SPITZER/INFRARED SPECTROGRAPH SPECTROSCOPY OF IRAS 16456-3542, 18354-0638, AND 23239+5754

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, B. W.; Zhang, Ke [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Li, Aigen [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Lisse, C. M., E-mail: bjiang@bnu.edu.cn, E-mail: kzhang@caltech.edu, E-mail: lia@missouri.edu, E-mail: carey.lisse@jhuapl.edu [Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2013-03-01

    We report the Spitzer Infrared Spectrograph (IRS) observations of three evolved stars: IRAS 16456-3542, 18354-0638, and 23239+5754. The 9.9-37.2 {mu}m Spitzer/IRS high-resolution spectra of these three sources exhibit rich sets of enstatite-dominated crystalline silicate emission features. IRAS 16456-3542 is extremely rich in crystalline silicates, with >90% of its silicate mass in crystalline form, the highest to date ever reported for crystalline silicate sources.

  10. SPITZER IRS SPECTRA OF LUMINOUS 8 μm SOURCES IN THE LARGE MAGELLANIC CLOUD: TESTING COLOR-BASED CLASSIFICATIONS

    International Nuclear Information System (INIS)

    Buchanan, Catherine L.; Kastner, Joel H.; Hrivnak, Bruce J.; Sahai, Raghvendra

    2009-01-01

    We present archival Spitzer Infrared Spectrograph (IRS) spectra of 19 luminous 8 μm selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on Two Micron All Sky Survey (2MASS)/MSX (J, H, K, and 8 μm) colors in order to test the 'JHK8' (Kastner et al.) classification scheme. The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich AGB stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission through the use of IRAC [3.6]-[4.5] and 2MASS colors.

  11. The impact of Spitzer infrared data on stellar mass estimates - and a revised galaxy stellar mass function at 0 < z < 5

    Science.gov (United States)

    Elsner, F.; Feulner, G.; Hopp, U.

    2008-01-01

    Aims:We estimate stellar masses of galaxies in the high redshift universe with the intention of determining the influence of newly available Spitzer/IRAC infrared data on the analysis. Based on the results, we probe the mass assembly history of the universe. Methods: We use the GOODS-MUSIC catalog, which provides multiband photometry from the U-filter to the 8 μm Spitzer band for almost 15 000 galaxies with either spectroscopic (for ≈7% of the sample) or photometric redshifts, and apply a standard model fitting technique to estimate stellar masses. We than repeat our calculations with fixed photometric redshifts excluding Spitzer photometry and directly compare the outcomes to look for systematic deviations. Finally we use our results to compute stellar mass functions and mass densities up to redshift z = 5. Results: We find that stellar masses tend to be overestimated on average if further constraining Spitzer data are not included into the analysis. Whilst this trend is small up to intermediate redshifts z ⪉ 2.5 and falls within the typical error in mass, the deviation increases strongly for higher redshifts and reaches a maximum of a factor of three at redshift z ≈ 3.5. Thus, up to intermediate redshifts, results for stellar mass density are in good agreement with values taken from literature calculated without additional Spitzer photometry. At higher redshifts, however, we find a systematic trend towards lower mass densities if Spitzer/IRAC data are included.

  12. Cosmic Rays in Intermittent Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S. [School of Mathematics and Statistics, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Snodin, Andrew P., E-mail: a.seta1@ncl.ac.uk, E-mail: amitseta90@gmail.com [Department of Mathematics, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok 10800 (Thailand)

    2017-04-10

    The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

  13. Lightning Discharges, Cosmic Rays and Climate

    Science.gov (United States)

    Kumar, Sanjay; Siingh, Devendraa; Singh, R. P.; Singh, A. K.; Kamra, A. K.

    2018-03-01

    The entirety of the Earth's climate system is continuously bombarded by cosmic rays and exhibits about 2000 thunderstorms active at any time of the day all over the globe. Any linkage among these vast systems should have global consequences. Numerous studies done in the past deal with partial links between some selected aspects of this grand linkage. Results of these studies vary from weakly to strongly significant and are not yet complete enough to justify the physical mechanism proposed to explain such links. This review is aimed at presenting the current understanding, based on the past studies on the link between cosmic ray, lightning and climate. The deficiencies in some proposed links are pointed out. Impacts of cosmic rays on engineering systems and the possible effects of cosmic rays on human health are also briefly discussed. Also enumerated are some problems for future work which may help in developing the grand linkage among these three vast systems.

  14. Knotlike cosmic strings in the early universe

    Science.gov (United States)

    Duan, Yi-shi; Liu, Xin

    2004-02-01

    In this paper, the knotlike cosmic strings in the Riemann-Cartan space-time of the early universe are discussed. It has been revealed that the cosmic strings can just originate from the zero points of the complex scalar quintessence field. In these strings we mainly study the knotlike configurations. Based on the integral of Chern-Simons 3-form a topological invariant for knotlike cosmic strings is constructed, and it is shown that this invariant is just the total sum of all the self-linking and linking numbers of the knots family. Furthermore, it is also pointed out that this invariant is preserved in the branch processes during the evolution of cosmic strings.

  15. Satellite observation of cosmic ray air showers

    International Nuclear Information System (INIS)

    Benson, Robert; Linsley, John

    1981-01-01

    The arrival trajectories of cosmic rays with energies greater than 10 19 eV afford the possibility of being traced backwards for distances comparable to the size of the Galaxy. They provide a means of testing models of the Galactic magnetic field as well as models of the origin of extra-Galactic cosmic rays. The large air showers produced by such cosmic rays can be observed by means of the atmospheric scintillation light they produce. It is shown here that a satellite-based system consisting of a single large mirror with an array of photon sensors at its focus would have outstanding advantages for the study of the highest energy cosmic rays

  16. Topics on Cosmic Rays. v.1

    International Nuclear Information System (INIS)

    Bellandi Filho, J.; Pemmaraju, A.

    1984-01-01

    Some theoretical and experimental results concerning with cosmic radiation works or with related ones, mainly of the Brazil-Japan Collaboration, are presented in honor of the 60th aniversary of C.M.G. Lattes. (L.C.) [pt

  17. Cosmic ray antimatter and baryon symmetric cosmology

    Science.gov (United States)

    Stecker, F. W.; Protheroe, R. J.; Kazanas, D.

    1982-01-01

    The relative merits and difficulties of the primary and secondary origin hypotheses for the observed cosmic-ray antiprotons, including the new low-energy measurement of Buffington, et al. We conclude that the cosmic-ray antiproton data may be evidence for antimatter galaxies and baryon symmetric cosmology. The present bar P data are consistent with a primary extragalactic component having /p=/equiv 1+/- 3.2/0.7x10 = to the -4 independent of energy. We propose that the primary extragalactic cosmic ray antiprotons are most likely from active galaxies and that expected disintegration of bar alpha/alpha ban alpha/alpha. We further predict a value for ban alpha/alpha =/equiv 10 to the -5, within range of future cosmic ray detectors.

  18. Comparing cosmic web classifiers using information theory

    International Nuclear Information System (INIS)

    Leclercq, Florent; Lavaux, Guilhem; Wandelt, Benjamin; Jasche, Jens

    2016-01-01

    We introduce a decision scheme for optimally choosing a classifier, which segments the cosmic web into different structure types (voids, sheets, filaments, and clusters). Our framework, based on information theory, accounts for the design aims of different classes of possible applications: (i) parameter inference, (ii) model selection, and (iii) prediction of new observations. As an illustration, we use cosmographic maps of web-types in the Sloan Digital Sky Survey to assess the relative performance of the classifiers T-WEB, DIVA and ORIGAMI for: (i) analyzing the morphology of the cosmic web, (ii) discriminating dark energy models, and (iii) predicting galaxy colors. Our study substantiates a data-supported connection between cosmic web analysis and information theory, and paves the path towards principled design of analysis procedures for the next generation of galaxy surveys. We have made the cosmic web maps, galaxy catalog, and analysis scripts used in this work publicly available.

  19. Energy estimates of cosmic ray events

    International Nuclear Information System (INIS)

    Dar, A.; Otterlund, I.; Stenlund, E.

    1978-12-01

    We propose new methods for estimating the energy of the incident particles in high energy cosmic ray collisions. We demonstrate their validity in emulsion experiments at laboratory accelerators. (author)

  20. Development of the cosmic ray techniques

    International Nuclear Information System (INIS)

    Rossi, B.

    1982-01-01

    It has been found that most advances of cosmic-ray physics have been directly related to the development of observational techniques. The history of observational techniques is discussed, taking into account ionization chambers, refinements applied to ionization chambers to make them suitable for an effective use in the study of cosmic radiation, the Wulf-type electrometer, the electrometer designed by Millikan and Neher, the Geiger-Mueller counter, the experiment of Bothe and Kolhoerster, the coincidence circuit, and a cosmic-ray telescope. Attention is given to a magnetic lens for cosmic rays, a triangular arrangement of Geiger-Mueller counters used to demonstrate the production of a secondary radiation, a stereoscopic cloud-chamber photograph of showers, the cloud-chamber picture which provided the first evidence of the positive electron, and arrangements for studying photon components, mu-mesons, and air showers. 34 references

  1. Capturing the Future: Direct and Indirect Probes of Neutron Capture

    Energy Technology Data Exchange (ETDEWEB)

    Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    This report documents aspects of direct and indirect neutron capture. The importance of neutron capture rates and methods to determine them are presented. The following conclusions are drawn: direct neutron capture measurements remain a backbone of experimental study; work is being done to take increased advantage of indirect methods for neutron capture; both instrumentation and facilities are making new measurements possible; more work is needed on the nuclear theory side to understand what is needed furthest from stability.

  2. Critical decisions on Cosmic Vision

    Science.gov (United States)

    2003-11-01

    Eddington had two aims, both remarkable and very pertinent to front-line astronomical interests. The first was to look for Earth-like planets outside our solar system - one of the key goals in the search to understand how life came to be, how it is that we live where we do in the universe and whether there are other potential life-supporting environments 'out there'. At the same time it was going to follow the path that the ESA-NASA mission SOHO had taken with the Sun of using astroseismology to look 'inside' stars. In the longer term, the loss of this one mission will not stop ESA and the scientific community pursuing the grand quests to which it would have contributed. The loss of the BepiColombo lander is also hard to take scientifically. ESA, in conjunction with the Japanese space agency, JAXA, will still put two orbiters around Mercury but the ‘ground truth’ provided by the lander is a big loss. However, to land on a planet so near the Sun is no small matter and was a bridge too far in present circumstances, and this chance for Europe to be first has probably been lost. The origins of the problems were recognised at the ESA Council meeting held in June. Several sudden demands on finance occurred in the spring, the most obvious and public being the unforeseen Ariane 5 grounding in January, delaying the launches of Rosetta and Smart-1. A temporary loan of EUR 100 million was granted, but must be paid back out of present resources by the end of 2006. ESA's SPC was therefore caught in a vice. Immediate mission starts had to be severely limited and the overall envelope of the programme contained. With this week’s decisions, the SPC has brought the scope of the Cosmic Vision programme down to a level that necessarily reflects the financial conditions rather than the ambitions of the scientific community. A long and painful discussion during the SPC meeting resulted in the conclusion that only one new mission can be started at this time, namely LISA Pathfinder

  3. MCNP6 Cosmic-Source Option

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, Gregg W [Los Alamos National Laboratory; Armstrong, Hirotatsu [Los Alamos National Laboratory; James, Michael R [Los Alamos National Laboratory; Clem, John [University of Delaware, BRI; Goldhagen, Paul [DHS, National Urban Security Technology Laboratory

    2012-06-19

    MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a new Cosmic-Source option, that has been implemented in MCNP6.

  4. Geometry and groups for cosmic topology

    International Nuclear Information System (INIS)

    Kramer, Peter

    2011-01-01

    The Cosmic Microwave Background is measured by satellite observation with great precision. It offers insight into its origin in early states of the universe. Unexpected low multipole amplitudes of the incoming CMB radiation may be due to a multiply connected topology of cosmic 3-space. We present and analyze the geometry and homotopy for the family of Platonic spherical 3-manifolds, provide their harmonic analysis, and formulate topological selection rules.

  5. ACORDE a cosmic ray detector for ALICE

    International Nuclear Information System (INIS)

    Fernandez, A.; Gamez, E.; Herrera, G.; Lopez, R.; Leon-Monzon, I.; Martinez, M.I.; Pagliarone, C.; Paic, G.; Roman, S.; Tejeda, G.; Vargas, M.A.; Vergara, S.; Villasenor, L.; Zepeda, A.

    2007-01-01

    ACORDE is one of the ALICE detectors, presently under construction at CERN. It consists of an array of plastic scintillator counters placed on the three upper faces of the ALICE magnet. It will act as a cosmic ray trigger, and, together with other ALICE sub-detectors, will provide precise information on cosmic rays with primary energies around 10 15 -10 17 eV. Here we describe the design of ACORDE along with the present status and integration into ALICE

  6. Capturing Nature's Diversity

    Science.gov (United States)

    Pascolutti, Mauro; Campitelli, Marc; Nguyen, Bao; Pham, Ngoc; Gorse, Alain-Dominique; Quinn, Ronald J.

    2015-01-01

    Natural products are universally recognized to contribute valuable chemical diversity to the design of molecular screening libraries. The analysis undertaken in this work, provides a foundation for the generation of fragment screening libraries that capture the diverse range of molecular recognition building blocks embedded within natural products. Physicochemical properties were used to select fragment-sized natural products from a database of known natural products (Dictionary of Natural Products). PCA analysis was used to illustrate the positioning of the fragment subset within the property space of the non-fragment sized natural products in the dataset. Structural diversity was analysed by three distinct methods: atom function analysis, using pharmacophore fingerprints, atom type analysis, using radial fingerprints, and scaffold analysis. Small pharmacophore triplets, representing the range of chemical features present in natural products that are capable of engaging in molecular interactions with small, contiguous areas of protein binding surfaces, were analysed. We demonstrate that fragment-sized natural products capture more than half of the small pharmacophore triplet diversity observed in non fragment-sized natural product datasets. Atom type analysis using radial fingerprints was represented by a self-organizing map. We examined the structural diversity of non-flat fragment-sized natural product scaffolds, rich in sp3 configured centres. From these results we demonstrate that 2-ring fragment-sized natural products effectively balance the opposing characteristics of minimal complexity and broad structural diversity when compared to the larger, more complex fragment-like natural products. These naturally-derived fragments could be used as the starting point for the generation of a highly diverse library with the scope for further medicinal chemistry elaboration due to their minimal structural complexity. This study highlights the possibility to capture a

  7. Properties of the Irregular Satellite System around Uranus Inferred from K2 , Herschel , and Spitzer Observations

    Energy Technology Data Exchange (ETDEWEB)

    Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Szakáts, R.; Kiss, L. L. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Mommert, M. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Müller, T., E-mail: farkas.aniko@csfk.mta.hu [Max-Plank-Institut für extraterrestrsiche Pyhsik, Garching (Germany)

    2017-09-01

    In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel /PACS and Spitzer /MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

  8. NEWLY IDENTIFIED EXTENDED GREEN OBJECTS (EGOs) FROM THE SPITZER GLIMPSE II SURVEY. I. CATALOG

    International Nuclear Information System (INIS)

    Chen, Xi; Gan, Cong-Gui; Shen, Zhi-Qiang; Ellingsen, Simon P.; Titmarsh, Anita; He, Jin-Hua

    2013-01-01

    We have produced a catalog containing 98 newly identified massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects, or EGOs). These have been identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) II data set and our new identifications increase the number of known EGOs to ∼400 in our Galaxy, adding to the ∼300 previously identified EGOs reported by Cyganowski et al. from the GLIMPSE I survey. The high detection rate (∼70%) of 95 GHz class I methanol masers achieved in a survey toward 57 of these new EGOs with the Mopra 22 m radio telescope demonstrates that the new EGOs are associated with outflows. Investigations of the mid-infrared properties and physical associations with other star formation tracers (e.g., infrared dark clouds, class I and II methanol masers, and millimeter Bolocam Galactic Plane Survey sources) reveal that the newly identified EGOs are very similar in nature to those in the sample of Cyganowski et al. All of the observational evidence supports the hypothesis that EGOs correspond to MYSOs at the earliest evolutionary stage, with ongoing outflow activity, and active rapid accretion.

  9. SPITZER OBSERVATIONS OF EXTENDED LYMAN-α CLOUDS IN THE SSA22 FIELD

    International Nuclear Information System (INIS)

    Webb, T. M. A.; Gonzalez, M.; Yamada, T.; Huang, J.-S.; Ashby, M. L. N; Matsuda, Y.; Egami, E.; Hayashimo, T.

    2009-01-01

    We present the results of a Spitzer IRAC and MIPS 24 μm study of extended Lyman-α clouds (or Lyman-α Blobs, LABs) within the SSA22 filamentary structure at z = 3.09. We detect 6/26 LABs in all IRAC filters, four of which are also detected at 24 μm, and find good correspondence with the 850 μm measurements of Geach et al. An analysis of the rest-frame ultraviolet, optical, near- and mid-infrared colors reveals that these six systems exhibit signs of nuclear activity (active galactic nucleus (AGN)) and/or extreme star formation. Notably, they have properties that bridge galaxies dominated by star formation (Lyman-break galaxies (LBGs)) and those with AGNs (LBGs classified as QSOs). The LAB systems not detected in all four IRAC bands, on the other hand, are, as a group, consistent with pure star-forming systems, similar to the majority of the LBGs within the filament. These results indicate that the galaxies within LABs do not comprise a homogeneous population, though they are also consistent with scenarios in which the gas halos are ionized through a common mechanism such as galaxy-scale winds driven by the galaxies within them, or gravitational heating of the collapsing cloud itself.

  10. SPITZER OBSERVATIONS OF LONG-TERM INFRARED VARIABILITY AMONG YOUNG STELLAR OBJECTS IN CHAMAELEON I

    Energy Technology Data Exchange (ETDEWEB)

    Flaherty, Kevin M.; Herbst, William [Van Vleck Observatory, Astronomy Department, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); DeMarchi, Lindsay [Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346 (United States); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Balog, Zoltan [Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117 Heidelberg (Germany); Megeath, S. Thomas [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Furlan, Elise [Infrared Processing and Analysis Center, California Institute of Technology, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Gutermuth, Robert [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2016-12-10

    Infrared variability is common among young stellar objects, with surveys finding daily to weekly fluctuations of a few tenths of a magnitude. Space-based observations can produce highly sampled infrared light curves, but are often limited to total baselines of about 1 month due to the orientation of the spacecraft. Here we present observations of the Chameleon I cluster, whose low declination makes it observable by the Spitzer Space Telescope over a 200-day period. We observe 30 young stellar objects with a daily cadence to better sample variability on timescales of months. We find that such variability is common, occurring in ∼80% of the detected cluster members. The change in [3.6]–[4.5] color over 200 days for many of the sources falls between that expected for extinction and fluctuations in disk emission. With our high cadence and long baseline we can derive power spectral density curves covering two orders of magnitude in frequency and find significant power at low frequencies, up to the boundaries of our 200-day survey. Such long timescales are difficult to explain with variations driven by the interaction between the disk and stellar magnetic field, which has a dynamical timescale of days to weeks. The most likely explanation is either structural or temperature fluctuations spread throughout the inner ∼0.5 au of the disk, suggesting that the intrinsic dust structure is highly dynamic.

  11. Stellar mass estimation based on IRAC photometry for Spitzer SWIRE-field galaxies

    International Nuclear Information System (INIS)

    Zhu Yinan; Wu Hong; Li Haining; Cao Chen

    2010-01-01

    We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey. We derived the formulae to calculate the stellar mass by using IRAC 3.6 μm and 4.5 μm luminosities. The mass-to-luminosity ratios of IRAC 3.6 μm and 4.5 μm luminosities are more sensitive to the star formation history of galaxies than to other factors, such as the intrinsic extinction, metallicity and star formation rate. To remove the effect of star formation history, we used g - r color to recalibrate the formulae and obtain a better result. Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae. Due to the emission from dust heated by the hottest young stars, luminous infrared galaxies present higher IRAC 4.5 μm luminosities compared to IRAC 3.6 μm luminosities. For most of type-II AGNs, the nuclear activity cannot enhance 3.6 μm and 4.5 μm luminosities compared with normal galaxies. Star formation in our AGN-hosting galaxies is also very weak, almost all of which are early-type galaxies.

  12. VizieR Online Data Catalog: Spitzer h and {chi} Persei candidate members (Cloutier+, 2014)

    Science.gov (United States)

    Cloutier, R.; Currie, T.; Rieke, G. H.; Kenyon, S. J.; Balog, Z.; Jayawardhana, R.

    2017-08-01

    The IRAC (Fazio et al. 2004ApJS..154...39F) observed h and {chi} Persei on October 30, 2008 (AOR IDs 2182740, 21828608, 21828096, 21828864, 21828352, and 2182912). Solar activity was normal to below average. Zodical emission ranged between ~0.02 and 2 MJy/sr from 3.6 um to 8 um. Image processing and photometry were performed separately for the short-exposure and long-exposure frames. The MIPS (Rieke et al. 2004ApJS..154...25R) imaged h and {chi} Persei on 2008 March 15-16, 2008 October 25-26, and 2009 March 26 and 29 as a part of General Observation Programs 40690 and 50664 (PI: Scott Kenyon). To identify and characterize disks surrounding h and {chi} Persei stars, we combine Spitzer data with optical/near-IR data for likely cluster members, updating the list from Currie et al. (2010, J/ApJS/186/191) with a more accurate one of 13956 stars (Table 1). (3 data files).

  13. Cosmic statistics on linear scales

    Science.gov (United States)

    Papai, Peter

    We use the formalism of Szapudi (2004) to derive full explicit expressions for the linear two-point correlation function, including redshift space distortions and large angle effects. We take into account a non-perturbative geometric term in the Jacobian, which is still linear in terms of the dynamics. This term had been identified previously (Kaiser, 1987; Hamilton and Culhane, 1996), but has been neglected in all subsequent explicit calculations of the linear redshift space two-point correlation function. Our results represent a significant correction to previous explicit expressions and608are in excellent agreement with our measurements in the Hubble Volume Simulation. We measure the matter probability distribution function (PDF) via counts in cells in a volume limited subsample of the Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy Catalog on scales from 30 h-1 Mpc to 150 h-1Mpc and estimate the linear integrated Sachs-Wolfe (ISW) effect produced by supervoids and superclusters in the tail of the PDF. We characterize the PDF by the variance, S3, and S4, and study in simulations the systematic effects due to finite volume, survey shape and redshift distortion. We compare our measurement to the prediction of ΛCDM with linear bias and find a good agreement. We use the moments to approximate the tail of the PDF with analytic functions. A simple Gaussian model for the superstructures appears to be consistent with the claim by Granett et al. (2008) that density fluctuations on 100 h-1Mpc scales produce hot and cold spots with DeltaT ≈ 10mu K on the cosmic microwave background. We calculate the full density and ISW profiles of spherical superstructures. We find that the Gaussian assumptions capable of describing N-body simulations and simulated ISW maps remarkably well on large scales. We construct an ISW map based on locations of superstructures identified previously in the SDSS Luminous Red Galaxy sample. A matched filter analysis of the cosmic microwave

  14. Reminiscences of cosmic ray research in Mexico

    Science.gov (United States)

    Pérez-Peraza, Jorge

    2009-11-01

    Cosmic ray research in Mexico dates from the early 1930s with the work of the pioneering physicist, Manuel Sandoval Vallarta and his students from Mexico. Several experiments of international significance were carried out during that period in Mexico: they dealt with the geomagnetic latitude effect, the north-south and west-east asymmetry of cosmic ray intensity, and the sign of the charge of cosmic rays. The international cosmic ray community has met twice in Mexico for the International Cosmic Ray Conferences (ICRC): the fourth was held in Guanajuato in 1955, and the 30th took place in Mérida, in 2007. In addition, an international meeting on the Pierre Auger Collaboration was held in Morelia in 1999, and the International Workshop on Observing UHE Cosmic Rays took place in Metepec in 2000. A wide range of research topics has been developed, from low-energy Solar Energetic Particles (SEP) to the UHE. Instrumentation has evolved since the early 1950s, from a Simpson type neutron monitor installed in Mexico City (2300 m asl) to a solar neutron telescope and an EAS Cherenkov array, (within the framework of the Auger International Collaboration), both at present operating on Mt. Sierra La Negra in the state of Puebla (4580 m asl). Research collaboration has been undertaken with many countries; in particular, the long-term collaboration with Russian scientists has been very fruitful.

  15. Dosimetry of environmental radiations (cosmic ray)

    International Nuclear Information System (INIS)

    Yamasaki, Keizo

    1978-01-01

    Cosmic ray is dominant as environmental radiation, though the experimental determination made on cosmic ray doses is few in Japan. The free air ionization intensity at sea level due to cosmic ray has been estimated in the Bay of Wakasa, Japan, at middle geomagnetic latitude (25 deg. N), in October 1977. The ionization chambers used were two air and one argon types. Where the responses to cosmic and terrestrial gamma rays were equal, the ionization intensity due to cosmic ray was obtained by subtracting the ionization intensity due to terrestrial gamma ray from the total ionization intensity. As the terrestrial gamma ray, (1) U-238 series, Th-232 series, and K-40 in seawater, (2) K-40 in the material of a wooden ship, and (3) Rn-222 and its daughter products in the atmosphere were considered. The result of free air ionization due to cosmic ray with the argon chamber was slightly smaller than those with the other two air chambers; however, both were in good agreement within standard errors. (JPN.)

  16. Spaced-based Cosmic Ray Astrophysics

    Science.gov (United States)

    Seo, Eun-Suk

    2016-03-01

    The bulk of cosmic ray data has been obtained with great success by balloon-borne instruments, particularly with NASA's long duration flights over Antarctica. More recently, PAMELA on a Russian Satellite and AMS-02 on the International Space Station (ISS) started providing exciting measurements of particles and anti-particles with unprecedented precision upto TeV energies. In order to address open questions in cosmic ray astrophysics, future missions require spaceflight exposures for rare species, such as isotopes, ultra-heavy elements, and high (the ``knee'' and above) energies. Isotopic composition measurements up to about 10 GeV/nucleon that are critical for understanding interstellar propagation and origin of the elements are still to be accomplished. The cosmic ray composition in the knee (PeV) region holds a key to understanding the origin of cosmic rays. Just last year, the JAXA-led CALET ISS mission, and the DAMPE Chinese Satellite were launched. NASA's ISS-CREAM completed its final verification at GSFC, and was delivered to KSC to await launch on SpaceX. In addition, a EUSO-like mission for ultrahigh energy cosmic rays and an HNX-like mission for ultraheavy nuclei could accomplish a vision for a cosmic ray observatory in space. Strong support of NASA's Explorer Program category of payloads would be needed for completion of these missions over the next decade.

  17. Cosmology with cosmic shear observations: a review.

    Science.gov (United States)

    Kilbinger, Martin

    2015-07-01

    Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are coherently deformed by the tidal field of matter inhomogeneities along the line of sight. By measuring galaxy shape correlations, we can study the properties and evolution of structure on large scales as well as the geometry of the Universe. Thus, cosmic shear has become a powerful probe into the nature of dark matter and the origin of the current accelerated expansion of the Universe. Over the last years, cosmic shear has evolved into a reliable and robust cosmological probe, providing measurements of the expansion history of the Universe and the growth of its structure. We review here the principles of weak gravitational lensing and show how cosmic shear is interpreted in a cosmological context. Then we give an overview of weak-lensing measurements, and present the main observational cosmic-shear results since it was discovered 15 years ago, as well as the implications for cosmology. We then conclude with an outlook on the various future surveys and missions, for which cosmic shear is one of the main science drivers, and discuss promising new weak cosmological lensing techniques for future observations.

  18. Recent developments in cosmic ray physics

    Energy Technology Data Exchange (ETDEWEB)

    Blasi, P. [INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5 50125 Firenze (Italy); Gran Sasso Science Institute (INFN), Viale F. Crispi 6, 60100 L' Aquila (Italy)

    2014-11-15

    The search for a theory of the origin of cosmic rays that may be considered as a standard, agreeable model is still ongoing. On one hand, much circumstantial evidence exists of the fact that supernovae in our Galaxy play a crucial role in producing the bulk of cosmic rays observed on Earth. On the other hand, important questions about their ability to accelerate particles up to the knee remain unanswered. The common interpretation of the knee as a feature coinciding with the maximum energy of the light component of cosmic rays and a transition to a gradually heavier mass composition is mainly based on KASCADE results. Some recent data appear to question this finding: YAC1 – Tibet Array and ARGO-YBJ find a flux reduction in the light component at ∼ 700 TeV, appreciably below the knee. Whether the maximum energy of light nuclei is as high as 3000 TeV or rather as low as a few hundred TeV has very important consequences on the supernova remnant paradigm for the origin of cosmic rays, as well on the crucial issue of the transition from Galactic to extragalactic cosmic rays. In such a complex phenomenological situation, it is important to have a clear picture of what is really known and what is not. Here I will discuss some solid and less solid aspects of the theory (or theories) for the origin of cosmic rays and the implications for future searches in this field.

  19. Relic right-handed Dirac neutrinos and implications for detection of cosmic neutrino background

    Science.gov (United States)

    Zhang, Jue; Zhou, Shun

    2016-02-01

    It remains to be determined experimentally if massive neutrinos are Majorana or Dirac particles. In this connection, it has been recently suggested that the detection of cosmic neutrino background of left-handed neutrinos νL and right-handed antineutrinos ν‾R in future experiments of neutrino capture on beta-decaying nuclei (e.g., νe +3H →3He +e- for the PTOLEMY experiment) is likely to distinguish between Majorana and Dirac neutrinos, since the capture rate is twice larger in the former case. In this paper, we investigate the possible impact of right-handed neutrinos on the capture rate, assuming that massive neutrinos are Dirac particles and both right-handed neutrinos νR and left-handed antineutrinos ν‾L can be efficiently produced in the early Universe. It turns out that the capture rate can be enhanced at most by 28% due to the presence of relic νR and ν‾L with a total number density of 95 cm-3, which should be compared to the number density 336 cm-3 of cosmic neutrino background. The enhancement has actually been limited by the latest cosmological and astrophysical bounds on the effective number of neutrino generations Neff =3.14-0.43+0.44 at the 95% confidence level. For illustration, two possible scenarios have been proposed for thermal production of right-handed neutrinos in the early Universe.

  20. Synovectomy by Neutron capture

    International Nuclear Information System (INIS)

    Vega C, H.R.; Torres M, C.

    1998-01-01

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu 239 Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  1. NASA's Chandra Reveals Origin of Key Cosmic Explosions

    Science.gov (United States)

    2010-02-01

    WASHINGTON -- New findings from NASA's Chandra X-ray Observatory have provided a major advance in understanding a type of supernova critical for studying the dark energy that astronomers think pervades the universe. The results show mergers of two dense stellar remnants are the likely cause of many of the supernovae that have been used to measure the accelerated expansion of the universe. These supernovae, called Type Ia, serve as cosmic mile markers to measure expansion of the universe because they can be seen at large distances, and they follow a reliable pattern of brightness. However, until now, scientists have been unsure what actually causes the explosions. "These are such critical objects in understanding the universe," said Marat Gilfanov of the Max Planck Institute for Astrophysics in Germany and lead author of the study that appears in the Feb. 18 edition of the journal Nature. "It was a major embarrassment that we did not know how they worked. Now we are beginning to understand what lights the fuse of these explosions." Most scientists agree a Type Ia supernova occurs when a white dwarf star -- a collapsed remnant of an elderly star -- exceeds its weight limit, becomes unstable and explodes. Scientists have identified two main possibilities for pushing the white dwarf over the edge: two white dwarfs merging or accretion, a process in which the white dwarf pulls material from a sun-like companion star until it exceeds its weight limit. "Our results suggest the supernovae in the galaxies we studied almost all come from two white dwarfs merging," said co-author Akos Bogdan, also of Max Planck. "This is probably not what many astronomers would expect." The difference between these two scenarios may have implications for how these supernovae can be used as "standard candles" -- objects of a known brightness -- to track vast cosmic distances. Because white dwarfs can come in a range of masses, the merger of two could result in explosions that vary somewhat in

  2. When did cosmic acceleration start?

    International Nuclear Information System (INIS)

    Melchiorri, Alessandro; Pagano, Luca; Pandolfi, Stefania

    2007-01-01

    A precise determination, and comparison, of the epoch of the onset of cosmic acceleration, at redshift z acc , and of dark energy domination, at z eq , provides an interesting measure with which to parametrize dark energy models. By combining several cosmological data sets, we place constraints on the redshift and age of cosmological acceleration. For a ΛCDM model, we find the constraint z acc =0.76±0.10 at 95% C.L., occurring 6.7±0.4 Gyr ago. Allowing a constant equation of state but different from -1 changes the constraint to z acc =0.81±0.12 (6.9±0.5 Gyr ago), while dynamical models markedly increase the error on the constraint z acc =0.81±0.30 (6.8±1.4 Gyr ago). Unified dark energy models such as silent quartessence yield z acc =0.8±0.16 (6.8±0.6 Gyr ago). Interestingly, we find that the best fit z acc and z eq are remarkably insensitive to both the cosmological data sets and theoretical dark energy models considered

  3. A theory of Cosmic Rays

    CERN Document Server

    Dar, Arnon; Dar, Arnon; Rújula, Alvaro De

    2008-01-01

    We present a theory of non-solar cosmic rays (CRs) based on a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the `knee(s)' and `ankle', and the CR composition and its variation with energy are all predicted in terms of very simple and completely `standard' physics. The source of CRs is extremely `economical': it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are `priors', that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a `unified view of high-energy astrophysics' --based on the `Cannonball' model of the relativistic ejecta of accreting black holes and neutron stars. If correct, this model is only lacking a satisfactory theoretical understanding of the `cannon' that emits the cannonballs in catastrophic processes of accreti...

  4. Cosmic Dark Radiation and Neutrinos

    Directory of Open Access Journals (Sweden)

    Maria Archidiacono

    2013-01-01

    Full Text Available New measurements of the cosmic microwave background (CMB by the Planck mission have greatly increased our knowledge about the universe. Dark radiation, a weakly interacting component of radiation, is one of the important ingredients in our cosmological model which is testable by Planck and other observational probes. At the moment, the possible existence of dark radiation is an unsolved question. For instance, the discrepancy between the value of the Hubble constant, H0, inferred from the Planck data and local measurements of H0 can to some extent be alleviated by enlarging the minimal ΛCDM model to include additional relativistic degrees of freedom. From a fundamental physics point of view, dark radiation is no less interesting. Indeed, it could well be one of the most accessible windows to physics beyond the standard model, for example, sterile neutrinos. Here, we review the most recent cosmological results including a complete investigation of the dark radiation sector in order to provide an overview of models that are still compatible with new cosmological observations. Furthermore, we update the cosmological constraints on neutrino physics and dark radiation properties focusing on tensions between data sets and degeneracies among parameters that can degrade our information or mimic the existence of extra species.

  5. Cosmic Visions Dark Energy. Science

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Heitmann, Katrin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Hirata, Chris [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Roodman, Aaron [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Seljak, Uroš [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Slosar, Anže [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Trodden, Mark [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-04-26

    Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena, including tight constraints on the equation of state of dark energy, the viability of modified gravity, the existence of extra light species, the masses of the neutrinos, and the potential of the field that drove inflation. Even after the Stage IV experiments, DESI and LSST, complete their surveys, there will still be much information left in the sky. This additional information will enable us to understand the physics underlying the dark universe at an even deeper level and, in case Stage IV surveys find hints for physics beyond the current Standard Model of Cosmology, to revolutionize our current view of the universe. There are many ideas for how best to supplement and aid DESI and LSST in order to access some of this remaining information and how surveys beyond Stage IV can fully exploit this regime. These ideas flow to potential projects that could start construction in the 2020's.

  6. Cosmic Visions Dark Energy: Science

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Slosar, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Heitmann, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hirata, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Honscheid, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roodman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Seljak, U. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trodden, M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-26

    Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena, including tight constraints on the equation of state of dark energy, the viability of modified gravity, the existence of extra light species, the masses of the neutrinos, and the potential of the field that drove inflation. Even after the Stage IV experiments, DESI and LSST, complete their surveys, there will still be much information left in the sky. This additional information will enable us to understand the physics underlying the dark universe at an even deeper level and, in case Stage IV surveys find hints for physics beyond the current Standard Model of Cosmology, to revolutionize our current view of the universe. There are many ideas for how best to supplement and aid DESI and LSST in order to access some of this remaining information and how surveys beyond Stage IV can fully exploit this regime. These ideas flow to potential projects that could start construction in the 2020's.

  7. Anatomy of a cosmic jet

    International Nuclear Information System (INIS)

    Kanipe, J.

    1988-01-01

    Cosmic jets are thought to arise from a supermassive, compact object at the center of a galaxy or quasar - probably a rotating black hole with a mass of several billion suns. According to current theory, gas spiraling in toward the black hole becomes compressed and superheated. Much of the gas falls into the black hole, but the rest is discharged along the poles of the hole, either squirted out by radiation pressure in the disk or caught up in magnetic field lines issuing from the black hole. These whirling magnetic field lines act like eggbeaters, churning out gas at very high velocities. Among well-observed ratio galaxies and quasars, jets are not uncommon features: hundreds have been cataloged in a variety of configurations. What distinguishes the M87 jet from all other jets, however, is its proximity to our Galaxy. Lying only 55 million light-years away, the M87 jet is the nearest known jet observable from the Northern Hemisphere. This makes it the most accessible for detailed study. One of the most important results learned from the VLA observations is that the interior of the jet may be hollow. Instead of being filled with hot, rapidly flowing material, the jet may be a nonradiating conduit for high-energy electrons rushing out of the galaxy's nucleus. Optical and radio emission would be produced when the electrons encountered the boundary between the jet and the denser interstellar medium

  8. Capturing the Daylight Dividend

    Energy Technology Data Exchange (ETDEWEB)

    Peter Boyce; Claudia Hunter; Owen Howlett

    2006-04-30

    Capturing the Daylight Dividend conducted activities to build market demand for daylight as a means of improving indoor environmental quality, overcoming technological barriers to effective daylighting, and informing and assisting state and regional market transformation and resource acquisition program implementation efforts. The program clarified the benefits of daylight by examining whole building systems energy interactions between windows, lighting, heating, and air conditioning in daylit buildings, and daylighting's effect on the human circadian system and productivity. The project undertook work to advance photosensors, dimming systems, and ballasts, and provided technical training in specifying and operating daylighting controls in buildings. Future daylighting work is recommended in metric development, technology development, testing, training, education, and outreach.

  9. Robust automated knowledge capture.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  10. Radiative electron capture [REC

    International Nuclear Information System (INIS)

    Vane, C.R.; Datz, S.; Dittner, P.; Giese, J.; Gomez del Campo, J.; Jones, N.; Krause, H.; Miller, P.D.; Schoere, H.; Schulz, M.

    1989-01-01

    This paper contains experimental data on ion channeling in solids. The x-ray spectrum for 160 MeV sulfur ions passing through a silicon target is given. Peaks are due to target and projectile K x-rays and from L- and L-radiative electron capture (REC) processes in which a target electron is transfered to the L- or K-shell, respectively, of a bare- or one-electron sulfur projectile ion moving in the solid and a photon is emitted which carries away the excess energy.lso given is (1) the x-ray spectrum for 160 MeV bare sulfur ions axially channeled through silicon, (2) charge state distributions of sulfur ions exiting a silicon crystal in channeling and random orientations, (3) schematic representations of the REC process, (4) cross sections for radiative recombination and REC, (5) REC portions of x-ray spectra for bare sulfur ions channeled axially through a silicon crystal, (6) measured and calculated K-REC peak positions for bare- and one-electron sulfur ions channeled through silicon crystals, (7) measured and calculated widths of the K-REC peaks for bare sulfur ions channeled in silicon crystals, (8) K-REC peak centroid position results for 120 to 130 MeV sulfur 16+, (9) yield of K-REC x-rays from bare sulfur ions channeled through silicon crystals, (10) x-ray spectra generated by bare oxygen ions traversing a hydrogen gas, and (11) comparison between x-ray data and a computer generated simulation based on radiative electron capture from an atomic hydrogen target

  11. One century of cosmic rays – A particle physicist's view

    Directory of Open Access Journals (Sweden)

    Sutton Christine

    2015-01-01

    Full Text Available Experiments on cosmic rays and the elementary particles share a common history that dates back to the 19th century. Following the discovery of radioactivity in the 1890s, the paths of the two fields intertwined, especially during the decades after the discovery of cosmic rays. Experiments demonstrated that the primary cosmic rays are positively charged particles, while other studies of cosmic rays revealed various new sub-atomic particles, including the first antiparticle. Techniques developed in common led to the birth of neutrino astronomy in 1987 and the first observation of a cosmic γ-ray source by a ground-based cosmic-ray telescope in 1989.

  12. Cosmographic Constraints and Cosmic Fluids

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2013-12-01

    Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.

  13. Cosmology Quantized in Cosmic Time

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, M

    2004-06-03

    This paper discusses the problem of inflation in the context of Friedmann-Robertson-Walker Cosmology. We show how, after a simple change of variables, to quantize the problem in a way which parallels the classical discussion. The result is that two of the Einstein equations arise as exact equations of motion and one of the usual Einstein equations (suitably quantized) survives as a constraint equation to be imposed on the space of physical states. However, the Friedmann equation, which is also a constraint equation and which is the basis of the Wheeler-deWitt equation, acquires a welcome quantum correction that becomes significant for small scale factors. We discuss the extension of this result to a full quantum mechanical derivation of the anisotropy ({delta} {rho}/{rho}) in the cosmic microwave background radiation, and the possibility that the extra term in the Friedmann equation could have observable consequences. To clarify the general formalism and explicitly show why we choose to weaken the statement of the Wheeler-deWitt equation, we apply the general formalism to de Sitter space. After exactly solving the relevant Heisenberg equations of motion we give a detailed discussion of the subtleties associated with defining physical states and the emergence of the classical theory. This computation provides the striking result that quantum corrections to this long wavelength limit of gravity eliminate the problem of the big crunch. We also show that the same corrections lead to possibly measurable effects on the CMB radiation. For the sake of completeness, we discuss the special case, {lambda} = 0, and its relation to Minkowski space. Finally, we suggest interesting ways in which these techniques can be generalized to cast light on the question of chaotic or eternal inflation. In particular, we suggest one can put an experimental lower bound on the distance to a universe with a scale factor very different from our own, by looking at its effects on our CMB

  14. SPITZER SAGE-SMC INFRARED PHOTOMETRY OF MASSIVE STARS IN THE SMALL MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    Bonanos, A. Z.; Lennon, D. J.; Massa, D. L.

    2010-01-01

    We present a catalog of 5324 massive stars in the Small Magellanic Cloud (SMC), with accurate spectral types compiled from the literature, and a photometric catalog for a subset of 3654 of these stars, with the goal of exploring their infrared properties. The photometric catalog consists of stars with infrared counterparts in the Spitzer SAGE-SMC survey database, for which we present uniform photometry from 0.3to24 μm in the UBVIJHK s +IRAC+MIPS24 bands. We compare the color-magnitude diagrams and color-color diagrams to those of stars in the Large Magellanic Cloud (LMC), finding that the brightest infrared sources in the SMC are also the red supergiants, supergiant B[e] (sgB[e]) stars, luminous blue variables, and Wolf-Rayet stars, with the latter exhibiting less infrared excess, the red supergiants being less dusty and the sgB[e] stars being on average less luminous. Among the objects detected at 24 μm in the SMC are a few very luminous hypergiants, four B-type stars with peculiar, flat spectral energy distributions, and all three known luminous blue variables. We detect a distinct Be star sequence, displaced to the red, and suggest a novel method of confirming Be star candidates photometrically. We find a higher fraction of Oe and Be stars among O and early-B stars in our SMC catalog, respectively, when compared to the LMC catalog, and that the SMC Be stars occur at higher luminosities. We estimate mass-loss rates for the red supergiants, confirming the correlation with luminosity even at the metallicity of the SMC. Finally, we confirm the new class of stars displaying composite A and F type spectra, the sgB[e] nature of 2dFS1804 and find the F0 supergiant 2dFS3528 to be a candidate luminous blue variable with cold dust.

  15. THE SPITZER INFRARED SPECTROGRAPH SURVEY OF PROTOPLANETARY DISKS IN ORION A. I. DISK PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. H. [Korea Astronomy and Space Science Institute (KASI), 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Watson, Dan M.; Manoj, P.; Forrest, W. J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Furlan, Elise [Infrared Processing and Analysis Center, Caltech, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Najita, Joan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Sargent, Benjamin [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623 (United States); Hernández, Jesús [Centro de Investigaciones de Astronomía, Apdo. Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Calvet, Nuria [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Adame, Lucía [Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, San Nicolás de los Garza, Nuevo León, C.P. 66451, México (Mexico); Espaillat, Catherine [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Megeath, S. T. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States); Muzerolle, James, E-mail: quarkosmos@kasi.re.kr [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2016-09-01

    We present our investigation of 319 Class II objects in Orion A observed by Spitzer /IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with those of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μ m silicate feature ( F {sub 11.3}/ F {sub 9.8}). (4) The 20–31 μ m continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ {sup 1} Ori C. A possible explanation is UV ablation of the outer parts of disks.

  16. THE SPITZER INFRARED SPECTROGRAPH SURVEY OF T TAURI STARS IN TAURUS

    International Nuclear Information System (INIS)

    Furlan, E.; Luhman, K. L.; Espaillat, C.

    2011-01-01

    We present 161 Spitzer Infrared Spectrograph (IRS) spectra of T Tauri stars and young brown dwarfs in the Taurus star-forming region. All of the targets were selected based on their infrared excess and are therefore surrounded by protoplanetary disks; they form the complete sample of all available IRS spectra of T Tauri stars with infrared excesses in Taurus. We also present the IRS spectra of seven Class 0/I objects in Taurus to complete the sample of available IRS spectra of protostars in Taurus. We use spectral indices that are not significantly affected by extinction to distinguish between envelope- and disk-dominated objects. Together with data from the literature, we construct spectral energy distributions for all objects in our sample. With spectral indices derived from the IRS spectra we infer disk properties such as dust settling and the presence of inner disk holes and gaps. We find a transitional disk frequency, which is based on objects with unusually large 13-31 μm spectral indices indicative of a wall surrounding an inner disk hole, of about 3%, and a frequency of about 20% for objects with unusually large 10 μm features, which could indicate disk gaps. The shape and strength of the 10 μm silicate emission feature suggests weaker 10 μm emission and more processed dust for very low mass objects and brown dwarfs (spectral types M6-M9). These objects also display weaker infrared excess emission from their disks, but do not appear to have more settled disks than their higher-mass counterparts. We find no difference for the spectral indices and properties of the dust between single and multiple systems.

  17. MODELS OF THE η CORVI DEBRIS DISK FROM THE KECK INTERFEROMETER, SPITZER, AND HERSCHEL

    Energy Technology Data Exchange (ETDEWEB)

    Lebreton, J.; Beichman, C.; Millan-Gabet, R. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Bryden, G.; Mennesson, B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91107 (United States); Defrère, D. [Department of Astronomy, University of Arizona, 993 N. Cherry Avenue, Tucson, AZ, 85721 (United States); Boccaletti, A., E-mail: lebretoj@gmail.com [LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France)

    2016-02-01

    Debris disks are signposts of analogs to small-body populations of the solar system, often, however, with much higher masses and dust production rates. The disk associated with the nearby star η Crv is especially striking, as it shows strong mid- and far-infrared excesses despite an age of ∼1.4 Gyr. We undertake constructing a consistent model of the system that can explain a diverse collection of spatial and spectral data. We analyze Keck Interferometer Nuller measurements and revisit Spitzer and additional spectrophotometric data, as well as resolved Herschel images, to determine the dust spatial distribution in the inner exozodi and in the outer belt. We model in detail the two-component disk and the dust properties from the sub-AU scale to the outermost regions by fitting simultaneously all measurements against a large parameter space. The properties of the cold belt are consistent with a collisional cascade in a reservoir of ice-free planetesimals at 133 AU. It shows marginal evidence for asymmetries along the major axis. KIN enables us to establish that the warm dust consists of a ring that peaks between 0.2 and 0.8 AU. To reconcile this location with the ∼400 K dust temperature, very high albedo dust must be invoked, and a distribution of forsterite grains starting from micron sizes satisfies this criterion, while providing an excellent fit to the spectrum. We discuss additional constraints from the LBTI and near-infrared spectra, and we present predictions of what James Webb Space Telescope can unveil about this unusual object and whether it can detect unseen planets.

  18. DEEP JHKs AND SPITZER IMAGING OF FOUR ISOLATED MOLECULAR CLOUD CORES

    International Nuclear Information System (INIS)

    Chapman, Nicholas L.; Mundy, Lee G.

    2009-01-01

    We present observations in eight wavebands from 1.25 to 24 μm of four dense cores: L204C-2, L1152, L1155C-2, and L1228. Our goals are to study the young stellar object (YSO) population of these cores and to measure the mid-infrared extinction law. With our combined near-infrared and Spitzer photometry, we classify each source in the cores as, among other things, background stars, galaxies, or embedded YSOs. L1152 contains three YSOs and L1228 has seven, but neither L204C-2 nor L1155C-2 appear to contain any YSOs. We estimate an upper limit of 7 x 10 -5 to 5 x 10 -4 L sun for any undiscovered YSOs in our cores. We also compute the line-of-sight extinction law toward each background star. These measurements are averaged spatially, to create χ 2 maps of the changes in the mid-infrared extinction law throughout our cores, and also in different ranges of extinction. From the χ 2 maps, we identify two small regions in L1152 and L1228 where the outflows in those cores appear to be destroying the larger dust grains, thus altering the extinction law in those regions. On average, however, our extinction law is relatively flat from 3.6 to 24 μm for all ranges of extinction and in all four cores. From 3.6 to 8 μm, this law is consistent with a dust model that includes larger dust grains than the diffuse interstellar medium, which suggests grain growth has occurred in our cores. At 24 μm, our extinction law is two to four times higher than predicted by dust models. However, it is similar to other empirical measurements.

  19. THE LUMINOSITIES OF PROTOSTARS IN THE SPITZER c2d AND GOULD BELT LEGACY CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, Michael M.; Arce, Hector G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Allen, Lori E. [National Optical Astronomy Observatories, Tucson, AZ (United States); Evans II, Neal J.; Harvey, Paul M. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Broekhoven-Fiene, Hannah; Matthews, Brenda C. [Herzberg Institute, National Research Council of Canada, 5071 W. Saanich Road, Victoria, BC V9E 2E7 (Canada); Chapman, Nicholas L. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, 2145 Sheridan Road, Evanston, IL 60208 (United States); Cieza, Lucas A. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Hatchell, Jennifer [Astrophysics Group, Physics, University of Exeter, Exeter EX4 4QL (United Kingdom); Huard, Tracy L.; Miller, Jennifer F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Kirk, Jason M. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Merin, Bruno [Herschel Science Centre, ESAC-ESA, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Peterson, Dawn E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Spezzi, Loredana, E-mail: michael.dunham@yale.edu [European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen (Germany)

    2013-04-15

    Motivated by the long-standing 'luminosity problem' in low-mass star formation whereby protostars are underluminous compared to theoretical expectations, we identify 230 protostars in 18 molecular clouds observed by two Spitzer Space Telescope Legacy surveys of nearby star-forming regions. We compile complete spectral energy distributions, calculate L{sub bol} for each source, and study the protostellar luminosity distribution. This distribution extends over three orders of magnitude, from 0.01 L{sub Sun} to 69 L{sub Sun }, and has a mean and median of 4.3 L{sub Sun} and 1.3 L{sub Sun }, respectively. The distributions are very similar for Class 0 and Class I sources except for an excess of low luminosity (L{sub bol} {approx}< 0.5 L{sub Sun }) Class I sources compared to Class 0. 100 out of the 230 protostars (43%) lack any available data in the far-infrared and submillimeter (70 {mu}m <{lambda} < 850 {mu}m) and have L{sub bol} underestimated by factors of 2.5 on average, and up to factors of 8-10 in extreme cases. Correcting these underestimates for each source individually once additional data becomes available will likely increase both the mean and median of the sample by 35%-40%. We discuss and compare our results to several recent theoretical studies of protostellar luminosities and show that our new results do not invalidate the conclusions of any of these studies. As these studies demonstrate that there is more than one plausible accretion scenario that can match observations, future attention is clearly needed. The better statistics provided by our increased data set should aid such future work.

  20. Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant

    Science.gov (United States)

    Williams, Brian J.; Borkowski, Kazimierz; Reynolds, Stephen P.; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sankrit, Ravi

    2012-01-01

    Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally-heated dust emission from fast shocks (> 1000 km/s) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

  1. A new look at Spitzer primary transit observations of the exoplanet HD 189733b

    Energy Technology Data Exchange (ETDEWEB)

    Morello, G.; Waldmann, I. P.; Tinetti, G.; Howarth, I. D. [Department of Physics and Astronomy, University College London, Gower Street, WC1E6BT (United Kingdom); Peres, G. [Dipartimento di Fisica, Università degli Studi di Palermo, via Archirafi I-90123, Italy. (Italy); Micela, G., E-mail: giuseppe.morello.11@ucl.ac.uk [Dipartimento di Fisica e Chimica (previously Dipartimento di Fisica), Specola Universitaria, Università degli Studi di Palermo, Piazza del Parlamento 1 I-90123 (Italy)

    2014-05-01

    Blind source separation techniques are used to reanalyze two exoplanetary transit light curves of the exoplanet HD 189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6 μm during the 'cold' era. These observations, together with observations at other IR wavelengths, are crucial to characterize the atmosphere of the planet HD 189733b. Previous analyses of the same data sets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent way is novel in the literature. The advantage of our reanalyses over previous work is that we do not have to make any assumptions on the structure of the unknown instrumental systematics. Such 'admission of ignorance' may result in larger error bars than reported in the literature, up to a factor 1.6. This is a worthwhile tradeoff for much higher objectivity, necessary for trustworthy claims. Our main results are (1) improved and robust values of orbital and stellar parameters, (2) new measurements of the transit depths at 3.6 μm, (3) consistency between the parameters estimated from the two observations, (4) repeatability of the measurement within the photometric level of ∼2 × 10{sup –4} in the IR, and (5) no evidence of stellar variability at the same photometric level within one year.

  2. A Spitzer search for transits of radial velocity detected super-Earths

    International Nuclear Information System (INIS)

    Kammer, J. A.; Knutson, H. A.; Desert, J.-M.; Howard, A. W.; Laughlin, G. P.; Fortney, J. J.; Deming, D.; Todorov, K. O.; Agol, E.; Burrows, A.; Showman, A. P.; Lewis, N. K.

    2014-01-01

    Unlike hot Jupiters or other gas giants, super-Earths are expected to have a wide variety of compositions, ranging from terrestrial bodies like our own to more gaseous planets like Neptune. Observations of transiting systems, which allow us to directly measure planet masses and radii and constrain atmospheric properties, are key to understanding the compositional diversity of the planets in this mass range. Although Kepler has discovered hundreds of transiting super-Earth candidates over the past 4 yr, the majority of these planets orbit stars that are too far away and too faint to allow for detailed atmospheric characterization and reliable mass estimates. Ground-based transit surveys focus on much brighter stars, but most lack the sensitivity to detect planets in this size range. One way to get around the difficulty of finding these smaller planets in transit is to start by choosing targets that are already known to host super-Earth sized bodies detected using the radial velocity (RV) technique. Here we present results from a Spitzer program to observe six of the most favorable RV-detected super-Earth systems, including HD 1461, HD 7924, HD 156668, HIP 57274, and GJ 876. We find no evidence for transits in any of their 4.5 μm flux light curves, and place limits on the allowed transit depths and corresponding planet radii that rule out even the most dense and iron-rich compositions for these objects. We also observed HD 97658, but the observation window was based on a possible ground-based transit detection that was later ruled out; thus the window did not include the predicted time for the transit detection recently made by the Microvariability and Oscillations of Stars space telescope.

  3. Dust Processing in Supernova Remnants: Spitzer MIPS SED and IRS Observations

    Science.gov (United States)

    Hewitt, John W.; Petre, Robert; Katsuda Satoru; Andersen, M.; Rho, J.; Reach, W. T.; Bernard, J. P.

    2011-01-01

    We present Spitzer MIPS SED and IRS observations of 14 Galactic Supernova Remnants previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [OI] emission, ionic lines, and emission from molecular hydrogen. Through black-body fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three component dust model composed of populations of big grains, very small grains, and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of very small grains to big grains is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2--3. We suggest that dust shattering is responsible for the relative over-abundance of small grains, in agreement with prediction from dust destruction models. However, two of the SNRs are best fit with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 $\\mu$m in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs.

  4. Detection of Planetary Emission from the Exoplanet TrES-2 Using Spitzer/IRAC

    Science.gov (United States)

    Donovan, Francis T.; Charbonneau, David; Harrington, Joseph; Madhusudhan, N.; Seager, Sara; Deming, Drake; Knutson, Heather A.

    2010-01-01

    We present here the results of our observations of TrES-2 using the Infrared Array Camera on Spitzer. We monitored this transiting system during two secondary eclipses, when the planetary emission is blocked by the star. The resulting decrease in flux is 0.127% +/- 0.021%, 0.230% +/- 0.024%, 0.199% +/- 0.054%, and 0.359% +/- 0.060% at 3.6 microns, 4.5 microns, 5.8 microns, and 8.0 microns, respectively. We show that three of these flux contrasts are well fit by a blackbody spectrum with T(sub eff) = 1500 K, as well as by a more detailed model spectrum of a planetary atmosphere. The observed planet-to-star flux ratios in all four lRAC channels can be explained by models with and without a thermal inversion in the atmosphere of TrES-2, although with different atmospheric chemistry. Based on the assumption of thermochemical equilibrium, the chemical composition of the inversion model seems more plausible, making it a more favorable scenario. TrES-2 also falls in the category of highly irradiated planets which have been theoretically predicted to exhibit thermal inversions. However, more observations at infrared and visible wavelengths would be needed to confirm a thermal inversion in this system. Furthermore, we find that the times of the secondary eclipses are consistent with previously published times of transit and the expectation from a circular orbit. This implies that TrES-2 most likely has a circular orbit, and thus does not obtain additional thermal energy from tidal dissipation of a non-zero orbital eccentricity, a proposed explanation for the large radius of this planet. Key words: eclipses - infrared: stars - planetary systems - stars: individual (OSC 03549-02811) - techniques: photometric

  5. PHOTOMETRIC MONITORING OF THE COLDEST KNOWN BROWN DWARF WITH THE SPITZER SPACE TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Esplin, T. L.; Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Cushing, M. C.; Hardegree-Ullman, K. K.; Trucks, J. L.; Schneider, A. C. [Department of Physics and Astronomy, The University of Toledo, OH 43606 (United States); Burgasser, A. J., E-mail: taran.esplin@psu.edu [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)

    2016-11-20

    Because WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (∼250 K) and one of the Sun’s closest neighbors (2.2 pc), it offers a unique opportunity to study a planet-like atmosphere in an unexplored regime of temperature. To detect and characterize inhomogeneities in its atmosphere (e.g., patchy clouds, hot spots), we have performed time-series photometric monitoring of WISE 0855-0714 at 3.6 and 4.5 μ m with the Spitzer Space Telescope during two 23 hr periods that were separated by several months. For both bands, we have detected variability with peak-to-peak amplitudes of 4%–5% and 3%–4% in the first and second epochs, respectively. The light curves are semiperiodic in the first epoch for both bands, but they are more irregular in the second epoch. Models of patchy clouds have predicted a large increase in mid-infrared (mid-IR) variability amplitudes (for a given cloud covering fraction) with the appearance of water ice clouds at T {sub eff} < 375 K, so if such clouds are responsible for the variability of WISE 0855-0714, then its small amplitudes of variability indicate a very small deviation in cloud coverage between hemispheres. Alternatively, the similarity in mid-IR variability amplitudes between WISE 0855-0714 and somewhat warmer T and Y dwarfs may suggest that they share a common origin for their variability (i.e., not water clouds). In addition to our variability data, we have examined other constraints on the presence of water ice clouds in the atmosphere of WISE 0855-0714, including the recent mid-IR spectrum from Skemer et al. (2016). We find that robust evidence of such clouds is not yet available.

  6. Asteroid (16) Psyche: Evidence for a silicate regolith from spitzer space telescope spectroscopy

    Science.gov (United States)

    Landsman, Zoe A.; Emery, Joshua P.; Campins, Humberto; Hanuš, Josef; Lim, Lucy F.; Cruikshank, Dale P.

    2018-04-01

    Asteroid (16) Psyche is a unique, metal-rich object belonging to the "M" taxonomic class. It may be a remnant protoplanet that has been stripped of most silicates by a hit-and-run collision. Because Psyche offers insight into the planetary formation process, it is the target of NASA's Psyche mission, set to launch in 2023. In order to constrain Psyche's surface properties, we have carried out a mid-infrared (5-14 μm) spectroscopic study using data collected with the Spitzer Space Telescope's Infrared Spectrograph. Our study includes two observations covering different rotational phases. Using thermophysical modeling, we find that Psyche's surface is smooth and likely has a thermal inertia Γ = 5-25 J/m2/K/s1/2 and bolometric emissivity ɛ = 0.9, although a scenario with ɛ = 0.7 and thermal inertia up to 95 J/m2/K/s1/2 is possible if Psyche is somewhat larger than previously determined. The smooth surface is consistent with the presence of a metallic bedrock, which would be more ductile than silicate bedrock, and thus may not readily form boulders upon impact events. From comparisons with laboratory spectra of silicate and meteorite powders, Psyche's 7-14 μm emissivity spectrum is consistent with the presence of fine-grained (< 75 μm) silicates on Psyche's surface. We conclude that Psyche is likely covered in a fine silicate regolith, which may also contain iron grains, overlying an iron-rich bedrock.

  7. BOOK REVIEW: The Cosmic Microwave Background The Cosmic Microwave Background

    Science.gov (United States)

    Coles, Peter

    2009-08-01

    With the successful launch of the European Space Agency's Planck satellite earlier this year the cosmic microwave background (CMB) is once again the centre of attention for cosmologists around the globe. Since its accidental discovery in 1964 by Arno Penzias and Robert Wilson, this relic of the Big Bang has been subjected to intense scrutiny by generation after generation of experiments and has gradually yielded up answers to the deepest questions about the origin of our Universe. Most recently, the Wilkinson Microwave Anisotropy Probe (WMAP) has made a full-sky analysis of the pattern of temperature and polarization variations that helped establish a new standard cosmological model, confirmed the existence of dark matter and dark energy, and provided strong evidence that there was an epoch of primordial inflation. Ruth Durrer's book reflects the importance of the CMB for future developments in this field. Aimed at graduate students and established researchers, it consists of a basic introduction to cosmology and the theory of primordial perturbations followed by a detailed explanation of how these manifest themselves as measurable variations in the present-day radiation field. It then focuses on the statistical methods needed to obtain accurate estimates of the parameters of the standard cosmological model, and finishes with a discussion of the effect of gravitational lensing on the CMB and on the evolution of its spectrum. The book apparently grew out of various lecture notes on CMB anisotropies for graduate courses given by the author. Its level and scope are well matched to the needs of such an audience and the presentation is clear and well-organized. I am sure that this book will be a useful reference for more senior scientists too. If I have a criticism, it is not about what is in the book but what is omitted. In my view, one of the most exciting possibilities for future CMB missions, including Planck, is the possibility that they might discover physics

  8. LHCf sheds new light on cosmic rays

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    The energy spectrum of the single photon obtained using data from the LHCf experiment has turned out to be very different from that predicted by the theoretical models used until now to describe the interactions between very high-energy cosmic rays and the earth's atmosphere. The consequences of this discrepancy for cosmic ray studies could be significant.   Artistic impression of cosmic rays entering Earth's atmosphere. (Credit: Asimmetrie/Infn). It took physicists by surprise when analysis of the data collected by the two LHCf calorimeters in 2010 showed that high-energy cosmic rays don't interact with the atmosphere in the manner predicted by theory. The LHCf detectors, set up 140 metres either side of the ATLAS interaction point, are dedicated to the study of the secondary particles emitted at very small angles during proton-proton collisions in the LHC, with energies comparable to cosmic rays entering the earth's atmosphere at 2.5x1016 eV. The aim of the experiment is to r...

  9. A demonstration device for cosmic rays telescopes

    Science.gov (United States)

    Esposito, Salvatore

    2018-01-01

    We describe a hands-on accurate demonstrator for cosmic rays realized by six high school students. The main aim is to show the relevance and the functioning of the principal parts of a cosmic ray telescope (muon detector), with the help of two large sized wooden artefacts. The first one points out how cosmic rays can be tracked in a muon telescope, while the other one shows the key avalanche process of electronic ionization that effectively allows muon detection through a photomultiplier. Incoming cosmic rays are visualized in terms of laser beams, whose 3D trajectory is highlighted by turning on LEDs on two orthogonal matrices. Instead the avalanche ionization process is demonstrated through the avalanche falling off glass marbles on an inclined plane, finally turning on a LED. A pictured poster accompanying the demonstrator is as effective in assisting cosmic ray demonstration and its detection. The success of the demonstrator has been fully proven by the general public during a science festival, in which the corresponding project won the Honorable Mention in a dedicated competition.

  10. Current constraints on the cosmic growth history

    International Nuclear Information System (INIS)

    Bean, Rachel; Tangmatitham, Matipon

    2010-01-01

    We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from ΛCDM as might arise if cosmic acceleration is due to modifications to general relativity or inhomogeneous dark energy. We combine measures of the cosmic expansion history, from Type 1a supernovae, baryon acoustic oscillations, and the cosmic microwave background (CMB), with constraints on the growth of structure from recent galaxy, CMB, and weak lensing surveys along with integated Sachs Wolfe-galaxy cross correlations. Deviations from ΛCDM are parameterized by phenomenological modifications to the Poisson equation and the relationship between the two Newtonian potentials. We find modifications that are present at the time the CMB is formed are tightly constrained through their impact on the well-measured CMB acoustic peaks. By contrast, constraints on late-time modifications to the growth history, as might arise if modifications are related to the onset of cosmic acceleration, are far weaker, but remain consistent with ΛCDM at the 95% confidence level. For these late-time modifications we find that differences in the evolution on large and small scales could provide an interesting signature by which to search for modified growth histories with future wide angular coverage, large scale structure surveys.

  11. Xenia: A Probe of Cosmic Chemical Evolution

    Science.gov (United States)

    Kouveliotou, Chryssa; Piro, L.; Xenia Collaboration

    2008-03-01

    Xenia is a concept study for a medium-size astrophysical cosmology mission addressing the Cosmic Origins key objective of NASA's Science Plan. The fundamental goal of this objective is to understand the formation and evolution of structures on various scales from the early Universe to the present time (stars, galaxies and the cosmic web). Xenia will use X-and γ-ray monitoring and wide field X-ray imaging and high-resolution spectroscopy to collect essential information from three major tracers of these cosmic structures: the Warm Hot Intergalactic Medium (WHIM), Galaxy Clusters and Gamma Ray Bursts (GRBs). Our goal is to trace the chemo-dynamical history of the ubiquitous warm hot diffuse baryon component in the Universe residing in cosmic filaments and clusters of galaxies up to its formation epoch (at z =0-2) and to map star formation and galaxy metal enrichment into the re-ionization era beyond z 6. The concept of Xenia (Greek for "hospitality") evolved in parallel with the Explorer of Diffuse Emission and GRB Explosions (EDGE), a mission proposed by a multinational collaboration to the ESA Cosmic Vision 2015. Xenia incorporates the European and Japanese collaborators into a U.S. led mission that builds on the scientific objectives and technological readiness of EDGE.

  12. Xenia: A Probe of Cosmic Chemical Evolution

    Science.gov (United States)

    Kouveliotou, Chryssa; Piro, L.

    2008-01-01

    Xenia is a concept study for a medium-size astrophysical cosmology mission addressing the Cosmic Origins key objective of NASA's Science Plan. The fundamental goal of this objective is to understand the formation and evolution of structures on various scales from the early Universe to the present time (stars, galaxies and the cosmic web). Xenia will use X-and y-ray monitoring and wide field X-ray imaging and high-resolution spectroscopy to collect essential information from three major tracers of these cosmic structures: the Warm Hot Intergalactic Medium (WHIM), Galaxy Clusters and Gamma Ray Bursts (GRBs). Our goal is to trace the chemo-dynamical history of the ubiquitous warm hot diffuse baryon component in the Universe residing in cosmic filaments and clusters of galaxies up to its formation epoch (at z =0-2) and to map star formation and galaxy metal enrichment into the re-ionization era beyond z 6. The concept of Xenia (Greek for "hospitality") evolved in parallel with the Explorer of Diffuse Emission and GRB Explosions (EDGE), a mission proposed by a multinational collaboration to the ESA Cosmic Vision 2015. Xenia incorporates the European and Japanese collaborators into a U.S. led mission that builds on the scientific objectives and technological readiness of EDGE.

  13. Cosmic rays and tests of fundamental principles

    Science.gov (United States)

    Gonzalez-Mestres, Luis

    2011-03-01

    It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles…Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both "conventional" and new Physics. Status, prospects, new ideas, and open questions in the field are discussed.

  14. Cosmic rays and tests of fundamental principles

    International Nuclear Information System (INIS)

    Gonzalez-Mestres, Luis

    2011-01-01

    It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles... Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both 'conventional' and new Physics. Status, prospects, new ideas, and open questions in the field are discussed.

  15. Cosmic Ray Interactions in Shielding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

    2011-09-08

    This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

  16. a Cosmic Ray Detector Array for Schools in the Cambridge Region

    Science.gov (United States)

    Wotton, S. A.; Goodrick, M. J.; Hommels, B.; Parker, M. A.

    2011-06-01

    Particle physics, astrophysics and cosmology are areas of research that have captured the imagination of the general public in recent years. By giving school students first-hand experience of building and operating a particle detector and the analysis of the data in a collaborative environment we anticipate that they will gain a deeper insight into the many and diverse facets of experimental particle physics. Cosmic rays provide a readily available source of high energy particles and other projects have already exploited this in building arrays of cosmic ray detectors located in schools and linked together via the internet. We aim to extend this concept by creating our own network of detectors in our region with a particular emphasis on hands-on involvement by school students in the partner schools. This talk outlines our plans towards the implementation of this project and our wider goals of integrating our local network with other projects both nationally and internationally.

  17. Cosmic ray measurements with the AMS experiment

    CERN Document Server

    Bertucci, B

    2001-01-01

    The Alpha Magnetic Spectrometer (AMS) was flown in June 1998 on board of the shuttle DISCOVERY during its STS91 mission. During 10 days, AMS recorded about 100 Million triggers along a 51.7 inclined orbit at altitudes ranging from 320 to 390 Km. We report on the AMS measurement of the cosmic proton spectrum in the kinetic energy range 0.2 to 200 GeV and of the cosmic helium spectrum in the kinetic energy range 0.1 to 100 GeV/nucleon. The good accuracy of these measurements provides better constraints in the modelling of the primary cosmic ray fluxes, first ingredient for a correct calculation of the atmospheric nu fluxes.

  18. The propagation of galactic cosmic rays

    International Nuclear Information System (INIS)

    Hall, A.N.

    1981-01-01

    Large scale (approximately 15 pc) turbulence in the interstellar medium (ISM) causes the firehose and mirror instabilities to occur. These produce small scale (approximately 10 -7 pc) magnetic irregularities, which scatter cosmic rays. We use pulsar scintillation data, and a model of the origin of these scintillations, to construct a slab model of the turbulent ISM. Then we find the amplitudes and wavelengths of the magnetic irregularities that arise, and we calculate the coefficients for the diffusion of cosmic rays along the interstellar magnetic fields. We incorporate this diffusion into our model of the turbulent ISM, and show that it can account naturally for both the lifetime of low energy cosmic rays, and the variation of their mean pathlength with energy. Our model has no galactic halo, and contains no scattering by Alfven waves. (author)

  19. Cosmic-Ray Observations with HAWC30

    Science.gov (United States)

    Fiorino, Daniel

    2013-04-01

    The High-Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 meters on the slope of Volc'an Sierra Negra near Puebla, Mexico. HAWC is an extensive air-shower array comprising 300 optically-isolated water Cherenkov detectors. Each detector contains 200,000 liters of filtered water and four upward-facing photomultiplier tubes. Since September 2012, 30 water Cherenkov detectors have been instrumented and operated in data acquisition. With 10 percent of the detector complete and six months of operation, the event statistics are already sufficient to perform detailed studies of cosmic rays observed at the site. We will report on cosmic-ray observations with HAWC30, in particular the detection and study of the shadow of the moon. From these observations, we infer the pointing accuracy of the detector and our angular resolution of the detector reconstruction.

  20. Weak cosmic censorship: as strong as ever.

    Science.gov (United States)

    Hod, Shahar

    2008-03-28

    Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments.

  1. The Probe of Inflation and Cosmic Origins

    Science.gov (United States)

    Hanany, Shaul; Inflation Probe Mission Study Team

    2018-01-01

    The Probe of Inflation and Cosmic Origins will map the polarization of the cosmic microwave background over the entire sky with unprecedented sensitivity. It will search for gravity wave signals from the inflationary epoch, thus probing quantum gravity and constraining the energy scale of inflation; it will test the standard model of particle physics by measuring the number of light particles in the Universe and the mass of the neutrino; it will elucidate the nature of dark matter and search for new forms of matter in the early Universe; it will constrain star formation history over cosmic time; and it will determine the mechanisms of structure formation from galaxy cluster to stellar scales. I will review the status of design of this probe-scale mission.

  2. Cosmic evolution in a cyclic universe

    International Nuclear Information System (INIS)

    Steinhardt, Paul J.; Turok, Neil

    2002-01-01

    Based on concepts drawn from the ekpyrotic scenario and M theory, we elaborate our recent proposal of a cyclic model of the universe. In this model, the universe undergoes an endless sequence of cosmic epochs which begin with the universe expanding from a 'big bang' and end with the universe contracting to a 'big crunch'. Matching from 'big crunch' to 'big bang' is performed according to the prescription recently proposed with Khoury, Ovrut and Seiberg. The expansion part of the cycle includes a period of radiation and matter domination followed by an extended period of cosmic acceleration at low energies. The cosmic acceleration is crucial in establishing the flat and vacuous initial conditions required for ekpyrosis and for removing the entropy, black holes, and other debris produced in the preceding cycle. By restoring the universe to the same vacuum state before each big crunch, the acceleration ensures that the cycle can repeat and that the cyclic solution is an attractor

  3. Consistency relation for cosmic magnetic fields

    Science.gov (United States)

    Jain, Rajeev Kumar; Sloth, Martin S.

    2012-12-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show that there exists a new simple consistency relation for the non-Gaussian cross correlation function of the scalar metric perturbation with two powers of the magnetic field in the squeezed limit where the momentum of the metric perturbation vanishes. We emphasize that such a consistency relation turns out to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields.

  4. Handbook of cosmic hazards and planetary defense

    CERN Document Server

    Allahdadi, Firooz

    2015-01-01

    Covers in a comprehensive fashion all aspects of cosmic hazards and possible strategies for contending with these threats through a comprehensive planetary defense strategy. This handbook brings together in a single reference work a rich blend of information about the various types of cosmic threats that are posed to human civilization by asteroids, comets, bolides, meteors, solar flares and coronal mass ejections, cosmic radiation and other types of threats that are only recently beginning to be understood and studied, such as investigation of the “cracks” in the protective shield provided by the Van Allen belts and the geomagnetosphere, of matter-antimatter collisions, orbital debris and radiological or biological contamination. Some areas that are addressed involve areas about which there is a good deal of information that has been collected for many decades by multiple space missions run by many different space agencies, observatories and scientific researchers. Other areas involving research and ...

  5. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

  6. Cosmic rays and radiations from the cosmos

    International Nuclear Information System (INIS)

    Parizot, E.

    2005-12-01

    This document gathers a lot of recent information concerning cosmic radiations, it is divided into 4 parts. Part I: energy, mass and angular spectra of cosmic rays. Part II: general phenomenology of cosmic rays, this part deals with the standard model, the maximal energy of protons inside supernova remnants, nucleosynthesis of light elements, and super-bubbles. Part III: radiations from the cosmos, this part deals with high energy gamma rays, non-thermal radiation of super-bubbles, positron transport, and the Compton trail of gamma-ray bursts. Part IV: the Pierre Auger observatory (OPA), this part deals with the detection of gamma ray bursts at OPA, the measurement of anisotropy, and top-down models. (A.C.)

  7. Anomalous isotopic composition of cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, S.E.; Weaver, T.A.

    1980-06-20

    Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

  8. PRECISE COSMIC RAYS MEASUREMENTS WITH PAMELA

    Directory of Open Access Journals (Sweden)

    A. Bruno

    2013-12-01

    Full Text Available The PAMELA experiment was launched on board the Resurs-DK1 satellite on June 15th 2006. The apparatus was designed to conduct precision studies of charged cosmic radiation over a wide energy range, from tens of MeV up to several hundred GeV, with unprecedented statistics. In five years of continuous data taking in space, PAMELA accurately measured the energy spectra of cosmic ray antiprotons and positrons, as well as protons, electrons and light nuclei, sometimes providing data in unexplored energetic regions. These important results have shed new light in several astrophysical fields like: an indirect search for Dark Matter, a search for cosmological antimatter (anti-Helium, and the validation of acceleration, transport and secondary production models of cosmic rays in the Galaxy. Some of the most important items of Solar and Magnetospheric physics were also investigated. Here we present the most recent results obtained by the PAMELA experiment.

  9. Inland capture fisheries

    Science.gov (United States)

    Welcomme, Robin L.; Cowx, Ian G.; Coates, David; Béné, Christophe; Funge-Smith, Simon; Halls, Ashley; Lorenzen, Kai

    2010-01-01

    The reported annual yield from inland capture fisheries in 2008 was over 10 million tonnes, although real catches are probably considerably higher than this. Inland fisheries are extremely complex, and in many cases poorly understood. The numerous water bodies and small rivers are inhabited by a wide range of species and several types of fisher community with diversified livelihood strategies for whom inland fisheries are extremely important. Many drivers affect the fisheries, including internal fisheries management practices. There are also many drivers from outside the fishery that influence the state and functioning of the environment as well as the social and economic framework within which the fishery is pursued. The drivers affecting the various types of inland water, rivers, lakes, reservoirs and wetlands may differ, particularly with regard to ecosystem function. Many of these depend on land-use practices and demand for water which conflict with the sustainability of the fishery. Climate change is also exacerbating many of these factors. The future of inland fisheries varies between continents. In Asia and Africa the resources are very intensely exploited and there is probably little room for expansion; it is here that resources are most at risk. Inland fisheries are less heavily exploited in South and Central America, and in the North and South temperate zones inland fisheries are mostly oriented to recreation rather than food production. PMID:20713391

  10. Vehicle capture system

    Science.gov (United States)

    Tacke, Kenneth L.

    1998-12-01

    Primex Aerospace Company, under contract with the U.S. Army Armament Research Development & Engineering Center (ARDEC), has developed a portable vehicle capture system for use at vehicle checkpoints. Currently when a vehicle does not stop at a checkpoint, there are three possible reactions: let the vehicle go unchallenged, pursue the vehicle or stop the vehicle with lethal force. This system provides a non-lethal alternative that will stop and contain the vehicle. The system is completely portable with the heaviest component weighing less than 120 pounds. It can be installed with no external electrical power or permanent anchors required. In its standby mode, the system does not impede normal traffic, but on command erects a barrier in less than 1.5 seconds. System tests have been conducted using 5,100 and 8.400 pound vehicles, traveling at speeds up to 45 mph. The system is designed to minimize vehicle damage and occupant injury, typically resulting in deceleration forces of less than 2.5 gs on the vehicle. According to the drivers involved in tests at 45 mph, the stopping forces feel similar to a panic stop with the vehicle brakes locked. The system is completely reusable and be rapidly reset.

  11. Captured by Aliens

    Science.gov (United States)

    Achenbach, Joel

    2000-03-01

    Captured by Aliens is a long and twisted voyage from science to the supernatural and back again. I hung out in Roswell, N.M., spent time with the Mars Society, met a guy who was figuring out the best way to build a spaceship to go to Alpha Centauri. I visited the set of the X-Files and talked to Mulder and Scully. One day over breakfast I was told by NASA administrator Dan Goldin, We live in a fog, man! He wants the big answers to the big questions. I spent a night in the base of a huge radio telescope in the boondocks of West Virginia, awaiting the signal from the aliens. I was hypnotized in a hotel room by someone who suspected that I'd been abducted by aliens and that this had triggered my interest in the topic. In the last months of his life, I talked to Carl Sagan, who believed that the galaxy riots with intelligent civilizations. He's my hero, for his steadfast adherence to the scientific method. What I found in all this is that the big question that needs immediate attention is not what's out THERE, but what's going on HERE, on Earth, and why we think the way we do, and how we came to be here in the first place.

  12. Preliminary Results of High-Energy Cosmic Ray Muons as ...

    Indian Academy of Sciences (India)

    quasi-periodicity. 1. Introduction. Cosmic ray studies are linked to many branches of physics and astrophysics. Cosmic ray experiments allow high-energy physics researchers to extend their interaction models to super-accelerator energies, lead-.

  13. How to restore the fiduciary relationship. An interview with Eliot Spitzer. Interview by Louise O'Brien.

    Science.gov (United States)

    Spitzer, Eliot

    2004-05-01

    Eliot Spitzer's investigations into the mutual fund and investment-banking industries have made the New York State attorney general the de facto flag bearer of corporate reform. His exposure of conflicts of interest between investment bankers and research analyst in Wall Street firms led to the $1.4 billion global settlement between regulators and banking houses in 2003. In this interview, Spitzer describes the challenge of protecting public markets from conflicts of interest, paying particular attention to how such conflicts get institutionalized in an industry. "The cases that have gotten me and my fellow regulators most upset are the ones where we've seen senior management being tolerant of rank abuses," he says. "Because then you know that the entire structure is rotten." He also points the finger squarely at boards, maintaining that board members are drawn from pools of company and industry insiders. He cites "a void in values in a lot of boardrooms," holding up executive compensation as a powerful example. "Board compensation committees ... are self-selected and interwoven--it's a rigged marketplace." He continues, "It would be interesting to see what the world would look like if CEO pay packages had to be submitted to shareholder votes." Spitzer suggests that what's really needed is for all business leaders to reinstill throughout their organizations the critical notion of a fiduciary duty--whether it is to the shareholder or to the customer. Using the mutual fund industry as an example, he also contrasts the value of enforcement with that of regulation and articulates an important--and surprisingly limited--role for government in protecting free markets.

  14. The Demographics and Properties of Wide-Orbit, Planetary-Mass Companions from PSF Fitting of Spitzer/IRAC Images

    Science.gov (United States)

    Martinez, Raquel; Kraus, Adam L.

    2017-06-01

    Over the past decade, a growing population of planetary-mass companions ( 100 AU) from their host stars, challenging existing models of both star and planet formation. It is unclear whether these systems represent the low-mass extreme of stellar binary formation or the high-mass and wide-orbit extreme of planet formation theories, as various proposed formation pathways inadequately explain the physical and orbital aspects of these systems. Even so, determining which scenario best reproduces the observed characteristics of the PMCs will come once a statistically robust sample of directly-imaged PMCs are found and studied.We are developing an automated pipeline to search for wide-orbit PMCs to young stars in Spitzer/IRAC images. A Markov Chain Monte Carlo (MCMC) algorithm is the backbone of our novel point spread function (PSF) subtraction routine that efficiently creates and subtracts χ2-minimizing instrumental PSFs, simultaneously measuring astrometry and infrared photometry of these systems across the four IRAC channels (3.6 μm, 4.5 μm, 5.8 μm, and 8 μm). In this work, we present the results of a Spitzer/IRAC archival imaging study of 11 young, low-mass (0.044-0.88 M⊙ K3.5-M7.5) stars known to have faint, low-mass companions in 3 nearby star-forming regions (Chameleon, Taurus, and Upper Scorpius). We characterize the systems found to have low-mass companions with non-zero [I1] - [I4] colors, potentially signifying the presence of a circum(sub?)stellar disk. Plans for future pipeline improvements and paths forward will also be discussed. Once this computational foundation is optimized, the stage is set to quickly scour the nearby star-forming regions already imaged by Spitzer, identify potential candidates for further characterization with ground- or space-based telescopes, and increase the number of widely-separated PMCs known.

  15. Spitzer Observations of Comet 9P/Tempel 1 During Deep Impact : Water and Dust Production and Spatial Distribution

    Science.gov (United States)

    Gicquel, Adeline; Bockelée-Morvan, D.; Kelley, M. S.; Woodward, C. E.

    2009-09-01

    The Deep Impact (DI) spacecraft encountered comet 9P/Tempel 1 on July 4th, 2005 (rh = 1.506 AU). Spectral maps covering 20'' x 67'' (1.85''/pixel) were acquired with the IRS instrument on the Spitzer Space Telescope (ΔSpitzer = 0.72 AU) at different times around the Deep Impact event: twice before impact (TI-41.3hrs and TI-22.9hrs) and twelve times after impact (between TI+0.67hrs and TI+1027hrs). These IRS observations (Lisse et al 2006, Sciences 313, 635) were taken from the Spitzer data archive. We present the interpretation of 5.2-7.6 µm spectra obtained in the second order of the short-wavelength module (SL2). To reduce the contribution of artifacts in the spectra, 5x5 pixel extraction apertures (9.25''x9.25'') were used. On the first stage we studied the water ν2 vibrational band emission at 6.4µm, which is present in most spectra. The water production rate before impact is deduced ( 4.25e27 molecules/sec). In order to study both the amount and origin of the water molecules released after impact, we used extractions centered on the nucleus and along the length of the slit. We analyzed the spatial distribution of water and its time evolution with a time-dependent model which describes the evolution of the water cloud after impact. The underlying continuum in the spectra provides information on the evolution and color temperature of the dust ejecta. The dust mass and dust/gas ratio in the ejecta cloud are derived and compared with other values published in the literature.

  16. On horizons and the Cosmic Landscape

    Science.gov (United States)

    Ellis, George F. R.

    2006-07-01

    Susskind claims in his recent book The Cosmic Landscape that evidence for the existence and nature of ‘pocket universes’ in a multiverse would be available in the detailed nature of the Cosmic Blackbody Background Radiation that constantly bathes all parts of our observable universe. I point out that acceptance of the complex chain of argument involved does not imply possible experimental verification of multiverses at the present time. Rather this claim relates only to theoretically possible observations in the very far future of the universe.

  17. Gravitational Lensing Signatures of Long Cosmic Strings

    CERN Document Server

    De Laix, A A; Vachaspati, T; Laix, Andrew A. de; Krauss, Lawrence M.; Vachaspati, Tanmay

    1997-01-01

    The gravitational lensing by long, wiggly cosmic strings is shown to produce a large number of lensed images of a background source. In addition to pairs of images on either side of the string, a number of small images outline the string due to small-scale structure on the string. This image pattern could provide a highly distinctive signature of cosmic strings. Since the optical depth for multiple imaging of distant quasar sources by long strings may be comparable to that by galaxies, these image patterns should be clearly observable in the next generation of redshift surveys such as the Sloan Digital Sky Survey.

  18. Cosmic Origins Program Annual Technology Report

    Science.gov (United States)

    Pham, Bruce Thai; Neff, Susan Gale

    2016-01-01

    What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time.

  19. Structure formation cosmic rays: Identifying observational constraints

    Directory of Open Access Journals (Sweden)

    Prodanović T.

    2005-01-01

    Full Text Available Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs would essentially be primordial in composition, namely, mostly made of protons and alpha particles. However, very little is known about this population of cosmic rays. One way to test the level of its presence is to look at the products of hadronic reactions between SFCRs and the ISM. A perfect probe of these reactions would be Li. The rare isotope Li is produced only by cosmic rays, dominantly in αα → 6Li fusion reactions with the ISM helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays. Exactly because of this unique property is Li affected most by the presence of an additional cosmic ray population. In turn, this could have profound consequences for the Big-Bang nucleosynthesis: cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a "contaminant" to the primordial 7Li content of metalpoor halo stars. Given the already existing problem of establishing the concordance between Li observed in halo stars and primordial 7Li as predicted by the WMAP, it is crucial to set limits to the level of this "contamination". However, the history of SFCRs is not very well known. Thus we propose a few model-independent ways of testing the SFCR species and their history, as well as the existing lithium problem: 1 we establish the connection between gamma-ray and Li production, which enables us to place constraints on the SFCR-made lithium by using the observed Extragalactic Gamma-Ray Background (EGRB; 2 we propose a new site for testing the primordial and SFCR-made lithium, namely, low-metalicity High-Velocity Clouds (HVCs, which retain the pre-Galactic composition without any significant depletion. Although using one method alone may not give us strong constraints, using them in

  20. Thin shells joining local cosmic string geometries

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F. [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Rubin de Celis, Emilio; Simeone, Claudio [Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Ciudad Universitaria Pabellon I, IFIBA-CONICET, Buenos Aires (Argentina)

    2016-10-15

    In this article we present a theoretical construction of spacetimes with a thin shell that joins two different local cosmic string geometries. We study two types of global manifolds, one representing spacetimes with a thin shell surrounding a cosmic string or an empty region with Minkowski metric, and the other corresponding to wormholes which are not symmetric across the throat located at the shell. We analyze the stability of the static configurations under perturbations preserving the cylindrical symmetry. For both types of geometries we find that the static configurations can be stable for suitable values of the parameters. (orig.)

  1. Cosmic strings: A problem or a solution?

    International Nuclear Information System (INIS)

    Bennett, D.P.; Bouchet, F.R.

    1987-10-01

    The most fundamental issue in the theory of cosmic strings is addressed by means of Numerical Simulations: the existence of a scaling solution. The resolution of this question will determine whether cosmic strings can form the basis of an attractive theory of galaxy formation or prove to be a cosmological disaster like magnetic monopoles or domain walls. After a brief discussion of our numerical technique, results are presented which, though still preliminary, offer the best support to date of this scaling hypothesis. 6 refs., 2 figs

  2. Search for Antihelium in the Cosmic Radiation

    DEFF Research Database (Denmark)

    Streitmatter, R.E.; Barbier, L.M.; Christian, E.R.

    1996-01-01

    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba Canada on July 16-17, 1992. Sixteen hours of data were taken. Measurements of multiple dE/dX, rigidity, and time of flight were used to search for antihelium in the cosmic radiation. A report on the r......The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba Canada on July 16-17, 1992. Sixteen hours of data were taken. Measurements of multiple dE/dX, rigidity, and time of flight were used to search for antihelium in the cosmic radiation. A report...

  3. COSMIC RAYS: From knee to ankle

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Despite the advent of TeV machines providing energies of 10 12 electronvolts, the highest particle energies by far are still provided by cosmic rays, where a sprinkling of particles from outer space go beyond 10 17 electronvolts, a hundred thousand times up on the highest laboratory levels. New results from the 'Fly's Eye' cosmic ray detector in Utah provide new hints on the energy spectrum of these particles. Included in the sample is an event at 3 x 10 20 eV, the highest energy interaction ever recorded

  4. The Spitzer search for the transits of HARPS low-mass planets. II. Null results for 19 planets

    Science.gov (United States)

    Gillon, M.; Demory, B.-O.; Lovis, C.; Deming, D.; Ehrenreich, D.; Lo Curto, G.; Mayor, M.; Pepe, F.; Queloz, D.; Seager, S.; Ségransan, D.; Udry, S.

    2017-05-01

    Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization. Searching for the transits of the low-mass planets detected by Doppler surveys is a straightforward way to achieve this goal. Indeed, Doppler surveys target the most nearby main-sequence stars, they regularly detect close-in low-mass planets with significant transit probability, and their radial velocity data constrain strongly the ephemeris of possible transits. In this context, we initiated in 2010 an ambitious Spitzer multi-Cycle transit search project that targeted 25 low-mass planets detected by radial velocity, focusing mainly on the shortest-period planets detected by the HARPS spectrograph. We report here null results for 19 targets of the project. For 16 planets out of 19, a transiting configuration is strongly disfavored or firmly rejected by our data for most planetary compositions. We derive a posterior probability of 83% that none of the probed 19 planets transits (for a prior probability of 22%), which still leaves a significant probability of 17% that at least one of them does transit. Globally, our Spitzer project revealed or confirmed transits for three of its 25 targeted planets, and discarded or disfavored the transiting nature of 20 of them. Our light curves demonstrate for Warm Spitzer excellent photometric precisions: for 14 targets out of 19, we were able to reach standard deviations that were better than 50 ppm per 30 min intervals. Combined with its Earth-trailing orbit, which makes it capable of pointing any star in the sky and to monitor it continuously for days, this work confirms Spitzer as an optimal instrument to detect sub-mmag-deep transits on the bright nearby stars targeted by Doppler surveys. The photometric and radial velocity time series used in this work are only available at the

  5. The Spitzer survey of interstellar clouds in the Gould Belt. III. A multi-wavelength view of Corona Australis

    DEFF Research Database (Denmark)

    Peterson, Dawn E.; Caratti o Garatti, Alessio; Bourke, Tyler L.

    2011-01-01

    retrieved from the literature are also added to the list, and a total of 116 candidate YSOs in CrA are compiled. Based on these YSO candidates, the star formation rate is computed to be 12 M sun Myr-1, similar to that of the Lupus clouds. A clustering analysis was also performed, finding that the main....... Using the Spitzer data, we identify 51 young stellar objects (YSOs) in CrA which include sources in the well-studied Coronet cluster as well as sources distributed throughout the molecular cloud. Twelve of the YSOs discussed are new candidates, one of which is located in the Coronet. Known YSOs...

  6. LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Désert, Jean-Michel; Brown, Timothy M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Charbonneau, David; Torres, Guillermo; Fressin, François; Ballard, Sarah; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bryson, Stephen T.; Borucki, William J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Batalha, Natalie M. [San Jose State University, San Jose, CA 95192 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Ford, Eric B. [University of Florida, Gainesville, FL 32611 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Seager, Sara, E-mail: desert@colorado.edu [Massachusetts Institute of Technology, Cambridge, MA 02159 (United States)

    2015-05-01

    NASA’s Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate’s transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated

  7. THE LAST GASP OF GAS GIANT PLANET FORMATION: A SPITZER STUDY OF THE 5 Myr OLD CLUSTER NGC 2362

    International Nuclear Information System (INIS)

    Currie, Thayne; Lada, Charles J.; Robitaille, Thomas P.; Irwin, Jonathan; Kenyon, Scott J.; Plavchan, Peter

    2009-01-01

    Expanding upon the Infrared Array Camera (IRAC) survey from Dahm and Hillenbrand, we describe Spitzer IRAC and Multiband Imaging Photometer for Spitzer observations of the populous, 5 Myr old open cluster NGC 2362. We analyze the mid-IR colors of cluster members and compared their spectral energy distributions (SEDs) to star+circumstellar disk models to constrain the disk morphologies and evolutionary states. Early/intermediate-type confirmed/candidate cluster members either have photospheric mid-IR emission or weak, optically thin IR excess emission at λ ≥ 24 μm consistent with debris disks. Few late-type, solar/subsolar-mass stars have primordial disks. The disk population around late-type stars is dominated by disks with inner holes (canonical 'transition disks') and 'homologously depleted' disks. Both types of disks represent an intermediate stage between primordial disks and debris disks. Thus, in agreement with previous results, we find that multiple paths for the primordial-to-debris disk transition exist. Because these 'evolved primordial disks' greatly outnumber primordial disks, our results undermine standard arguments in favor of a ∼ 5 yr timescale for the transition based on data from Taurus-Auriga. Because the typical transition timescale is far longer than 10 5 yr, these data also appear to rule out standard ultraviolet photoevaporation scenarios as the primary mechanism to explain the transition. Combining our data with other Spitzer surveys, we investigate the evolution of debris disks around high/intermediate-mass stars and investigate timescales for giant planet formation. Consistent with Currie et al., the luminosity of 24 μm emission in debris disks due to planet formation peaks at ∼10-20 Myr. If the gas and dust in disks evolve on similar timescales, the formation timescale for gas giant planets surrounding early-type, high/intermediate-mass (∼>1.4 M sun ) stars is likely 1-5 Myr. Most solar/subsolar-mass stars detected by Spitzer

  8. The Generic Data Capture Facility

    Science.gov (United States)

    Connell, Edward B.; Barnes, William P.; Stallings, William H.

    1987-01-01

    The Generic Data Capture Facility, which can provide data capture support for a variety of different types of spacecraft while enabling operations costs to be carefully controlled, is discussed. The data capture functions, data protection, isolation of users from data acquisition problems, data reconstruction, and quality and accounting are addressed. The TDM and packet data formats utilized by the system are described, and the development of generic facilities is considered.

  9. Cosmic Ballet or Devil's Mask?

    Science.gov (United States)

    2004-04-01

    Stars like our Sun are members of galaxies, and most galaxies are themselves members of clusters of galaxies. In these, they move around among each other in a mostly slow and graceful ballet. But every now and then, two or more of the members may get too close for comfort - the movements become hectic, sometimes indeed dramatic, as when galaxies end up colliding. ESO PR Photo 12/04 shows an example of such a cosmic tango. This is the superb triple system NGC 6769-71, located in the southern Pavo constellation (the Peacock) at a distance of 190 million light-years. This composite image was obtained on April 1, 2004, the day of the Fifth Anniversary of ESO's Very Large Telescope (VLT). It was taken in the imaging mode of the VIsible Multi-Object Spectrograph (VIMOS) on Melipal, one of the four 8.2-m Unit Telescopes of the VLT at the Paranal Observatory (Chile). The two upper galaxies, NGC 6769 (upper right) and NGC 6770 (upper left), are of equal brightness and size, while NGC 6771 (below) is about half as bright and slightly smaller. All three galaxies possess a central bulge of similar brightness. They consist of elderly, reddish stars and that of NGC 6771 is remarkable for its "boxy" shape, a rare occurrence among galaxies. Gravitational interaction in a small galaxy group NGC 6769 is a spiral galaxy with very tightly wound spiral arms, while NGC 6770 has two major spiral arms, one of which is rather straight and points towards the outer disc of NGC 6769. NGC 6770 is also peculiar in that it presents two comparatively straight dark lanes and a fainter arc that curves towards the third galaxy, NGC 6771 (below). It is also obvious from this new VLT photo that stars and gas have been stripped off NGC 6769 and NGC 6770, starting to form a common envelope around them, in the shape of a Devil's Mask. There is also a weak hint of a tenuous bridge between NGC 6769 and NGC 6771. All of these features testify to strong gravitational interaction between the three galaxies

  10. Resource capture by single leaves

    Energy Technology Data Exchange (ETDEWEB)

    Long, S.P.

    1992-05-01

    Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.

  11. Low-energy cosmic rays in the Orion region

    DEFF Research Database (Denmark)

    Pohl, M.

    1998-01-01

    The recently observed nuclear gamma-ray line emission from the Orion complex implies a high flux of low-energy cosmic rays (LECR) with unusual abundance. This cosmic ray component would dominate the energy density, pressure, and ionising power of cosmic rays, and thus would have a strong impact...

  12. Cosmic Rays Astrophysics: The Discipline, Its Scope, and Its Applications

    Science.gov (United States)

    Barghouty, A. F.

    2009-01-01

    This slide presentation gives an overview of the discipline surrounding cosmic ray astrophysics. It includes information on recent assertions surrounding cosmic rays, exposure levels, and a short history with specific information on the origin, acceleration, transport, and modulation of cosmic rays.

  13. SPARC: MASS MODELS FOR 175 DISK GALAXIES WITH SPITZER PHOTOMETRY AND ACCURATE ROTATION CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Lelli, Federico; McGaugh, Stacy S. [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Schombert, James M., E-mail: federico.lelli@case.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2016-12-01

    We introduce SPARC ( Spitzer Photometry and Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6  μ m and high-quality rotation curves from previous H i/H α studies. SPARC spans a broad range of morphologies (S0 to Irr), luminosities (∼5 dex), and surface brightnesses (∼4 dex). We derive [3.6] surface photometry and study structural relations of stellar and gas disks. We find that both the stellar mass–H i mass relation and the stellar radius–H i radius relation have significant intrinsic scatter, while the H i   mass–radius relation is extremely tight. We build detailed mass models and quantify the ratio of baryonic to observed velocity ( V {sub bar}/ V {sub obs}) for different characteristic radii and values of the stellar mass-to-light ratio (ϒ{sub ⋆}) at [3.6]. Assuming ϒ{sub ⋆} ≃ 0.5 M {sub ⊙}/ L {sub ⊙} (as suggested by stellar population models), we find that (i) the gas fraction linearly correlates with total luminosity; (ii) the transition from star-dominated to gas-dominated galaxies roughly corresponds to the transition from spiral galaxies to dwarf irregulars, in line with density wave theory; and (iii)  V {sub bar}/ V {sub obs} varies with luminosity and surface brightness: high-mass, high-surface-brightness galaxies are nearly maximal, while low-mass, low-surface-brightness galaxies are submaximal. These basic properties are lost for low values of ϒ{sub ⋆} ≃ 0.2 M {sub ⊙}/ L {sub ⊙} as suggested by the DiskMass survey. The mean maximum-disk limit in bright galaxies is ϒ{sub ⋆} ≃ 0.7 M {sub ⊙}/ L {sub ⊙} at [3.6]. The SPARC data are publicly available and represent an ideal test bed for models of galaxy formation.

  14. INFRARED SPECTROSCOPY OF COMET 73P/SCHWASSMANN-WACHMANN 3 USING THE SPITZER SPACE TELESCOPE

    International Nuclear Information System (INIS)

    Sitko, Michael L.; Whitney, Barbara A.; Wolff, Michael J.; Lisse, Carey M.; Kelley, Michael S.; Polomski, Elisha F.; Lynch, David K.; Russell, Ray W.; Kimes, Robin L.; Harker, David E.

    2011-01-01

    We have used the Spitzer Space Telescope Infrared Spectrograph (IRS) to observe the 5-37 μm thermal emission of comet 73P/Schwassmann-Wachmann 3 (SW3), components B and C. We obtained low spectral resolution (R ∼ 100) data over the entire wavelength interval, along with images at 16 and 22 μm. These observations provided an unprecedented opportunity to study nearly pristine material from the surface and what was until recently the interior of an ecliptic comet-the cometary surface having experienced only two prior perihelion passages, and including material that was totally fresh. The spectra were modeled using a variety of mineral types including both amorphous and crystalline components. We find that the degree of silicate crystallinity, ∼35%, is somewhat lower than most other comets with strong emission features, while its abundance of amorphous carbon is higher. Both suggest that SW3 is among the most chemically primitive solar system objects yet studied in detail, and that it formed earlier or farther from the Sun than the bulk of the comets studied so far. The similar dust compositions of the two fragments suggest that these are not mineralogically heterogeneous, but rather uniform throughout their volumes. The best-fit particle size distribution for SW3B has a form dn/da ∼ a -3.5 , close to that expected for dust in collisional equilibrium, while that for SW3C has dn/da ∼ a -4.0 , as seen mostly in active comets with strong directed jets, such as C/1995 O1 Hale-Bopp. The total mass of dust in the comae plus nearby tail, extrapolated from the field of view of the IRS peak-up image arrays, is (3-5) x 10 8 kg for B and (7-9) x 10 8 kg for C. Atomic abundances derived from the spectral models indicate a depletion of O compared to solar photospheric values, despite the inclusion of water ice and gas in the models. Atomic C may be solar or slightly sub-solar, but its abundance is complicated by the potential contribution of spectrally featureless mineral

  15. SPITZER SPECTROSCOPY OF CIRCUMSTELLAR DISKS IN THE 5 Myr OLD UPPER SCORPIUS OB ASSOCIATION

    International Nuclear Information System (INIS)

    Dahm, S. E.; Carpenter, John M.

    2009-01-01

    We present mid-infrared spectra between 5.2 and 38 μm for 26 disk-bearing members of the ∼5 Myr old Upper Scorpius OB association obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. We find clear evidence for changes in the spectral characteristics of dust emission between the early-type (B+A) and late-type (K+M) infrared excess stars. The early-type members exhibit featureless continuum excesses that become apparent redward of ∼8 μm. In contrast, 10 and 20 μm silicate features or polycyclic aromatic hydrocarbon emission are present in all but one of the late-type excess members of Upper Scorpius. The strength of silicate emission among late-type Upper Scorpius members is spectral-type dependent, with the most prominent features being associated with K5-M2-type stars. By fitting the spectral energy distributions (SED) of a representative sample of low-mass stars with accretion disk models, we find that the SEDs are consistent with models having inner disk radii ranging from ∼0.2 to 1.2 AU. Complementary high-resolution (R ∼ 33, 000) optical (λλ4800-9200) spectra for the Upper Scorpius excess stars were examined for signatures of gaseous accretion. Of the 35 infrared excess stars identified in Upper Scorpius, only seven (all late-type) exhibit definitive signatures of accretion. Mass-accretion rates for these stars were estimated to range from 10 -11 to 10 -8.9 M sun yr -1 . Compared to Class II sources in Taurus-Auriga, the disk population in Upper Scorpius exhibits reduced levels of near- and mid-infrared excess emission and an order of magnitude lower mass-accretion rates. These results suggest that the disk structure has changed significantly over the 2-4 Myr in age separating these two stellar populations. The ubiquity of depleted inner disks in the Upper Scorpius excess sample implies that such disks are a common evolutionary pathway that persists for some time.

  16. Electron Energy Distribution in Hotspots of Cygnus A:Filling the Gap with Spitzer Space Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Stawarz, L.; Cheung, C.C.; Harris, D.E.; Ostrowski, M.

    2007-03-06

    Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 {micro}m and 8.0 {micro}m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B {approx} 170 {micro}G in spot A, and B {approx} 270 {micro}G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to {approx} 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of {approx} 1GeV. We argue that the shape of the electron continuum most likely reflects two different regimes of the electron acceleration process taking place at mildly relativistic shocks, rather than resulting from radiative cooling and/or absorption e.ects. In this picture the protons inertia defines the critical energy for the hotspot electrons above which Fermi-type acceleration processes may play a major role, but below which the operating acceleration mechanism has to be of a different type. At energies {approx}> 100 GeV, the electron spectra cut-off/steepen again, most likely as a result of spectral aging due to radiative loss effects. We discuss several implications of the presented analysis for the physics of extragalactic jets.

  17. Electron Energy Distribution in Hotspots of Cygnus A:Filling the Gap with Spitzer Space Telescope

    International Nuclear Information System (INIS)

    Stawarz, L.; Cheung, C.C.; Harris, D.E.; Ostrowski, M.

    2007-01-01

    Here we present Spitzer Space Telescope imaging of Cyg A with the Infrared Array Camera at 4.5 (micro)m and 8.0 (micro)m, resulting in the detection of the high-energy tails or cut-offs in the synchrotron spectra for all four hotspots of this archetype radio galaxy. When combined with the other data collected (and re-analyzed) from the literature, our observations allow for detailed modeling of the broad-band (radio-to-X-ray) emission for the brightest spots A and D. We confirm that the X-ray flux detected previously from these features is consistent with the synchrotron self-Compton radiation for the magnetic field intensity B ∼ 170 (micro)G in spot A, and B ∼ 270 (micro)G in spot D. We also find that the energy density of the emitting electrons is most likely larger by a factor of a few than the energy density of the hotspots magnetic field. We construct energy spectra of the radiating ultrarelativistic electrons. We find that for both hotspots A and D these spectra are consistent with a broken power-law extending from at least 100MeV up to ∼ 100GeV, and that the spectral break corresponds almost exactly to the proton rest energy of ∼ 1GeV. We argue that the shape of the electron continuum most likely reflects two different regimes of the electron acceleration process taking place at mildly relativistic shocks, rather than resulting from radiative cooling and/or absorption e.ects. In this picture the protons inertia defines the critical energy for the hotspot electrons above which Fermi-type acceleration processes may play a major role, but below which the operating acceleration mechanism has to be of a different type. At energies ∼> 100 GeV, the electron spectra cut-off/steepen again, most likely as a result of spectral aging due to radiative loss effects. We discuss several implications of the presented analysis for the physics of extragalactic jets

  18. Physical Characterization of Warm Spitzer-observed Near-Earth Objects

    Science.gov (United States)

    Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbo, Marco; Hora, Joseph L.; Mueller, Michael

    2014-01-01

    Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datasets. For instance, some taxonomic classes can be separated into distinct compositional groupings with albedo and different mineralogies with similar albedos can be distinguished with spectroscopy. To that end, we have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program that obtained albedos and diameters of nearly 600 NEOs (Trilling et al., 2010). The spectroscopy campaign included visible and near-infrared observations of ExploreNEOs targets from various observatories. Here we present the results of observations using the low-resolution prism mode (approx. 0.7-2.5 microns) of the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We also include near-infrared observations of Explore-NEOs targets from the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our dataset includes near-infrared spectra of 187 ExploreNEOs targets (125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey). We identify a taxonomic class for each spectrum and use band parameter analysis to investigate the mineralogies for the S-, Q-, and V-complex objects. Our analysis suggests that for spectra that contain near-infrared data but lack the visible wavelength region, the Bus-DeMeo system misidentifies some S-types as Q-types. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We investigate the correlations of phase angle with band area ratio and near-infrared spectral slope. We find slightly negative Band Area Ratio (BAR) correlations with phase angle for Eros and Ivar, but a positive BAR correlation with phase angle for Ganymed.The results of our

  19. Empirical model for the Earth's cosmic ray shadow at 400 KM: prohibited cosmic ray access

    International Nuclear Information System (INIS)

    Humble, J.E.; Smart, D.F.; Shea, M.A.

    1985-01-01

    The possibility of constructing a unit sphere of access that describes the cosmic radiation allowed to an Earth-orbiting spacecraft is discussed. It is found that it is possible to model the occluded portion of the cosmic ray sphere of access as a circular projection with a diameter bounded by the satellite-Earth horizon. Maintaining tangency at the eastern edge of the spacecraft-Earth horizon, this optically occluded area is projected downward by an angle beta which is a function of the magnetic field inclination and cosmic ray arrival direction. This projected plane, corresponding to the forbidden area of cosmic ray access, is bounded by the spacecraft-Earth horizon in easterly directions, and is rotated around the vertical axis by an angle alpha from the eastern direction, where the angle alpha is a function of the offset dipole latitude of the spacecraft

  20. Inflation Fossils in Cosmic Structure

    Science.gov (United States)

    Kamionkowski, Marc

    The agreement of the predictions of inflation with increasingly precise cosmic microwave background (CMB) and large-scale-structure (LSS) data is remarkable. The notion that such a simple early-Universe scenario, based on still-mysterious ultra-high-energy physics, can explain such a wealth of precise data is simply amazing. An active ongoing program of research is afoot to seek the CMB polarization signatures of inflationary gravitational waves and measure the primordial bispectrum in order to learn about inflation. Still, there is far more that can be done to probe inflationary physics, and no stone should be left unturned in this quest. Here we propose a multi-component program of theoretical research that includes model building, new CMB/LSS tests, a potentially powerful new survey strategy, and the investigation of a new observational avenue for large-scale structure. We propose to broaden the circle of ideas to empirically probe inflation. To begin, the hemispherical power asymmetry seen in WMAP and Planck is truly striking. While it may simply be an unusual statistical fluke, a more tantalizing possibility is that it is a remnant of the pre-inflationary Universe. We propose to develop and study several physical models for this asymmetry and work out other testable predictions of these models. Only by pursuing other signatures of whatever new physics may be responsible for this asymmetry will we be able to infer if it is truly a window to new physics. We also plan to develop departures from statistical isotropy (SI) as a test of inflationary models. We have recently shown that single-field slow-roll inflation generically predicts a quadrupolar departure from SI in primordial perturbations, albeit a very small one. The power quadrupole is expected, however, to be significantly larger in more general inflationary models. We propose to calculate these power quadrupoles so that new constraints to the power quadrupole from CMB and LSS data can be applied to test

  1. Iodine neutron capture therapy

    Science.gov (United States)

    Ahmed, Kazi Fariduddin

    A new technique, Iodine Neutron Capture Therapy (INCT) is proposed to treat hyperthyroidism in people. Present thyroid therapies, surgical removal and 131I treatment, result in hypothyroidism and, for 131I, involve protracted treatment times and excessive whole-body radiation doses. The new technique involves using a low energy neutron beam to convert a fraction of the natural iodine stored in the thyroid to radioactive 128I, which has a 24-minute half-life and decays by emitting 2.12-MeV beta particles. The beta particles are absorbed in and damage some thyroid tissue cells and consequently reduce the production and release of thyroid hormones to the blood stream. Treatment times and whole-body radiation doses are thus reduced substantially. This dissertation addresses the first of the several steps needed to obtain medical profession acceptance and regulatory approval to implement this therapy. As with other such programs, initial feasibility is established by performing experiments on suitable small mammals. Laboratory rats were used and their thyroids were exposed to the beta particles coming from small encapsulated amounts of 128I. Masses of 89.0 mg reagent-grade elemental iodine crystals have been activated in the ISU AGN-201 reactor to provide 0.033 mBq of 128I. This activity delivers 0.2 Gy to the thyroid gland of 300-g male rats having fresh thyroid tissue masses of ˜20 mg. Larger iodine masses are used to provide greater doses. The activated iodine is encapsulated to form a thin (0.16 cm 2/mg) patch that is then applied directly to the surgically exposed thyroid of an anesthetized rat. Direct neutron irradiation of a rat's thyroid was not possible due to its small size. Direct in-vivo exposure of the thyroid of the rat to the emitted radiation from 128I is allowed to continue for 2.5 hours (6 half-lives). Pre- and post-exposure blood samples are taken to quantify thyroid hormone levels. The serum T4 concentration is measured by radioimmunoassay at

  2. Carbon Capture and Storage

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, S

    2007-10-03

    Carbon capture and sequestration (CCS) is the long-term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. This includes a range of approaches including soil carbon sequestration (e.g., through no-till farming), terrestrial biomass sequestration (e.g., through planting forests), direct ocean injection of CO{sub 2} either onto the deep seafloor or into the intermediate depths, injection into deep geological formations, or even direct conversion of CO{sub 2} to carbonate minerals. Some of these approaches are considered geoengineering (see the appropriate chapter herein). All are considered in the 2005 special report by the Intergovernmental Panel on Climate Change (IPCC 2005). Of the range of options available, geological carbon sequestration (GCS) appears to be the most actionable and economic option for major greenhouse gas reduction in the next 10-30 years. The basis for this interest includes several factors: (1) The potential capacities are large based on initial estimates. Formal estimates for global storage potential vary substantially, but are likely to be between 800 and 3300 Gt of C (3000 and 10,000 Gt of CO{sub 2}), with significant capacity located reasonably near large point sources of the CO{sub 2}. (2) GCS can begin operations with demonstrated technology. Carbon dioxide has been separated from large point sources for nearly 100 years, and has been injected underground for over 30 years (below). (3) Testing of GCS at intermediate scale is feasible. In the US, Canada, and many industrial countries, large CO{sub 2} sources like power plants and refineries lie near prospective storage sites. These plants could be retrofit today and injection begun (while bearing in mind scientific uncertainties and unknowns). Indeed, some have, and three projects described here provide a great deal of information on the operational needs and field implementation of CCS. Part of this interest comes from several

  3. Smooth halos in the cosmic web

    International Nuclear Information System (INIS)

    Gaite, José

    2015-01-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ''smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness

  4. Actinides and the sources of cosmic rays

    Science.gov (United States)

    Pfeiffer, B.; Kratz, K.-L.; Lingenfelter, R. E.; Higdon, J. C.

    2004-02-01

    The abundances of the actinide elements in the cosmic rays can provide critical constraints on the major sites of their acceleration. Using recent calculations of the r-process yields in core-collapse supernovae (SNe), we have determined the actinide abundances averaged over various assumed time intervals for their supernovae generation and their cosmic-ray acceleration. Using standard Galactic chemical evolution models, we have also determined the expected actinide abundances in the present interstellar medium. From these two components, we have calculated the U/Th and other actinide abundances expected in the SN-active cores of superbubbles, as a function of their ages and mean metallicity. We calculate the expected actinide abundances in cosmic-rays accelerated by Galactic SNe. We find that the current measurements of actinide/Pt-group and preliminary estimates of the UPuCM/Th ratio in cosmic rays are all consistent with the expected values if superbubble cores have mean metallicities of around three times solar. Future measurements of the abundance ratios will help to solve these questions. First results of experiments performed on the MIR space station (ECCO) and with balloon flights (TIGER) are promising.

  5. Cosmic Rays Accelerated at Cosmological Shock Waves

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Based on hydrodynamic numerical simulations and diffusive shock acceleration model, we calculated the ratio of cosmic ray (CR) to thermal energy. We found that the CR fraction can be less than ∼ 0.1 in the intracluster medium, while it would be of order unity in the warm-hot intergalactic medium.

  6. The hunt for cosmic accelerators. Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Resconi, Elisa [TUM, Munich (Germany)

    2016-07-01

    The recent discovery of high energy cosmic neutrinos from the IceCube Neutrino Observatory opens new opportunities for particle and astrophysics. We report here the IceCube observation of a diffuse neutrino background and the on-going searches for counterparts.

  7. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    Phase transitions of quantum fields in the early universe produced very thin tubes of false vacuum, known as cosmic strings [1]. These are topological defects which can form when either a local or a global symmetry is spontaneously broken in a phase transition. The first one is called gauge string and the latter is called ...

  8. Cosmic Shear With ACS Pure Parallels

    Science.gov (United States)

    Rhodes, Jason

    2002-07-01

    Small distortions in the shapes of background galaxies by foreground mass provide a powerful method of directly measuring the amount and distribution of dark matter. Several groups have recently detected this weak lensing by large-scale structure, also called cosmic shear. The high resolution and sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear accurately on small scales. Using 260 parallel orbits in Sloan textiti {F775W} we will measure for the first time: beginlistosetlength sep0cm setlengthemsep0cm setlengthopsep0cm em the cosmic shear variance on scales Omega_m^0.5, with signal-to-noise {s/n} 20, and the mass density Omega_m with s/n=4. They will be done at small angular scales where non-linear effects dominate the power spectrum, providing a test of the gravitational instability paradigm for structure formation. Measurements on these scales are not possible from the ground, because of the systematic effects induced by PSF smearing from seeing. Having many independent lines of sight reduces the uncertainty due to cosmic variance, making parallel observations ideal.

  9. Could the cosmic acceleration be transient?

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Antonio C.C.; Lima, J.A.S. [Universidade de Sao Paulo (IAG/USP), SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas

    2011-07-01

    Full text: The possibility of a transient cosmic acceleration appears in several theoretical scenarios and is theoretically interesting because it solves some difficulties inherent to eternally accelerating universes (like {Lambda}CDM). On the observational side, some authors, using a dynamical Ansatz for the dark energy equation of state, have suggested that the cosmic acceleration have already peaked and that we are currently witnessing its slowing down. Here, a possible slowing down of the cosmic expansion is investigated through a cosmographic approach. By expanding the luminous distance to fourth order and fitting the SNe Ia data from the most recent compilations (Union, Constitution and Union 2), the marginal likelihood distribution for the deceleration parameter today indicates that there is a considerable probability for q{sub 0} > 0. Also in contrast to the prediction of the {Lambda}CDM model, the cosmographic q(z) reconstruction suggests that the cosmic acceleration could already have peaked and be presently slowing down, what would imply that the recent accelerated expansion of the Universe is a transient phenomenon. It is also shown that to describe a transient acceleration the luminous distance needs to be expanded at least to fourth order. The present cosmographic results depend neither on the validity of general relativity nor on the matter-energy contents of the Universe. (author)

  10. Compact source origin of cosmic ray antiprotons

    International Nuclear Information System (INIS)

    Dermer, C.D.

    1989-02-01

    The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV γ-rays produced by neutron-decay protons in the reaction p + p → π 0 → 2γ could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point sources, and future high-resolution observations of galactic point sources by Gamma-1 and the Egret telescope onboard the Gamma Ray Observatory may provide supporting evidence for this model. 12 refs., 2 figs

  11. Constraints on Cosmological Models from Cosmic Flows

    Science.gov (United States)

    Hudson, M. J.; Smith, R. J.; Lucey, J. R.; Schlegel, D. J.; Davies, R. L.

    Cosmic flows are the only probe of the large-scale mass power spectrum available at low redshift. An important statistic is the bulk flow of a peculiar velocity sample with respect to the Cosmic Microwave background. We compare the bulk flow of the SMAC cluster sample to the predictions of popular cosmological models and to other recent large-scale peculiar velocity surveys. Both analyses account for aliasing of small-scale power due to the sparse and non-uniform sampling of the surveys. We conclude that the SMAC bulk flow is in marginal conflict with flat COBE-normalized ΛCDM models which fit the cluster abundance constraint. However, power spectra which are steeper shortward of the peak are consistent with all of the above constraints. When recent large-scale peculiar velocity surveys are compared, we conclude that all measured bulk flows (with the possible exception of that of Lauer & Postman) are consistent with each other given the errors, provided the latter allow for ``cosmic covariance''. A rough estimate of the mean bulk flow of all surveys (except Lauer & Postman) is ˜400 km/s with respect to the Cosmic Microwave Background.

  12. Height dependence of secondary cosmic ray variations

    International Nuclear Information System (INIS)

    Belov, A.V.; Dorman, L.I.; Sirotina, I.V.

    1986-01-01

    Altitude dependences of coupling coefficients and secondary cosmic ray variations are investigated. The partial and variational barometric coefficients are calculated according to data on coupling coefficients of a neutron component. Application of data on altitude dependence of variations for calculation of barometric coefficient changes and for determination of a rigidity primary variation spectrum is discussed

  13. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

    Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

  14. Low cloud properties influenced by cosmic rays

    DEFF Research Database (Denmark)

    Marsh, Nigel; Svensmark, Henrik

    2000-01-01

    The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (less than or equal to3 km...

  15. Bogomol'nyi bounds for cosmic strings

    International Nuclear Information System (INIS)

    Comtet, A.; Gibbons, G.W.; Cambridge Univ.

    1987-09-01

    We establish Bogomol'nyi inequalities for the deficit angle of some cylindrically symmetric asymptotically local flat (CALF) spacetimes containing cosmic strings. These results prove the stability against arbitrary cylindrical deformations of those configurations which saturate the bound. Such configurations satisfy first order equations which can, in some cases, be solved exactly

  16. Goldstone bosons as fractional cosmic neutrinos.

    Science.gov (United States)

    Weinberg, Steven

    2013-06-14

    It is suggested that Goldstone bosons may be masquerading as fractional cosmic neutrinos, contributing about 0.39 to what is reported as the effective number of neutrino types in the era before recombination. The broken symmetry associated with these Goldstone bosons is further speculated to be the conservation of the particles of dark matter.

  17. Alpha Shape Topology of the Cosmic Web

    NARCIS (Netherlands)

    Weygaert, Rien van de; Platen, Erwin; Vegter, Gert; Eldering, Bob; Kruithof, Nico

    2010-01-01

    We study the topology of the Megaparsec Cosmic Web on the basis of the Alpha Shapes of the galaxy distribution. The simplicial complexes of the alpha shapes are used to determine the set of Betti numbers (βk, k = 1, . . . , D), which represent a complete characterization of the topology of a

  18. Multiscale phenomenology of the cosmic web

    NARCIS (Netherlands)

    Aragón-Calvo, Miguel A.; van de Weygaert, Rien; Jones, Bernard J. T.

    2010-01-01

    We analyse the structure and connectivity of the distinct morphologies that define the cosmic web. With the help of our multiscale morphology filter (MMF), we dissect the matter distribution of a cosmological Lambda cold dark matter N-body computer simulation into cluster, filaments and walls. The

  19. Radiation Exposure of Passengers to Cosmic Radiation

    International Nuclear Information System (INIS)

    Salah El-Din, T.; Gomaa, M.A.; Sallah, N.

    2010-01-01

    The main aim of the present study is to review exposure of Egyptian passengers and occupational workers to cosmic radiation during their work. Computed effective dose of passengers by computer code CARI-6 using during either short route, medium route or long route as well as recommended allowed number of flights per year

  20. Cosmic ray propagation with CRPropa 3

    International Nuclear Information System (INIS)

    Batista, R Alves; Evoli, C; Sigl, G; Van Vliet, A; Erdmann, M; Kuempel, D; Mueller, G; Walz, D; Kampert, K-H; Winchen, T

    2015-01-01

    Solving the question of the origin of ultra-high energy cosmic rays (UHECRs) requires the development of detailed simulation tools in order to interpret the experimental data and draw conclusions on the UHECR universe. CRPropa is a public Monte Carlo code for the galactic and extragalactic propagation of cosmic ray nuclei above ∼ 10 17 eV, as well as their photon and neutrino secondaries. In this contribution the new algorithms and features of CRPropa 3, the next major release, are presented. CRPropa 3 introduces time-dependent scenarios to include cosmic evolution in the presence of cosmic ray deflections in magnetic fields. The usage of high resolution magnetic fields is facilitated by shared memory parallelism, modulated fields and fields with heterogeneous resolution. Galactic propagation is enabled through the implementation of galactic magnetic field models, as well as an efficient forward propagation technique through transformation matrices. To make use of the large Python ecosystem in astrophysics CRPropa 3 can be steered and extended in Python. (paper)

  1. ACCESS - Another Step in NASA's Cosmic Journey

    Science.gov (United States)

    Wilson, Thomas; Wefel, John

    2000-10-01

    ACCESS (Advanced Cosmic-ray Composition Experiment for Space Station) is a new mission payload concept planned for the International Space Station (ISS) as part of NASA's Cosmic Journeys initiative [1,2]. Currently manifested for launch in 2007, ACCESS will address several basic questions regarding cosmic rays - their origin, composition, and acceleration mechanisms. These science goals take advantage of the ISS as an observational platform capable of handling large massive payloads for long-duration measurements in orbit above the Earth's atmosphere at the threshold of space. ACCESS combines well-established techniques of charged-particle identification in a 5.5-metric-ton instrument with approximately 6-m^2 aperature and a three- or four-year stay on-orbit. This will allow ACCESS to go far beyond the results of balloon-borne detectors. The ACCESS instrument, consisting primarily of a transition radiation detector and a calorimeter, should make valuable measurements of nuclei throughout the periodic table at spectral energies up to the "knee" in the neighborhood of 10^15 eV. [1] ACCESS, A Cosmic Journey, NASA Goddard Space Flight Center (2000). [2] Wilson, T., & Wefel, J., eds., ACCESS Accommodation Study Report, NASA TP-1999-209202 (1999).

  2. Catching Cosmic Rays with a DSLR

    Science.gov (United States)

    Sibbernsen, Kendra

    2010-01-01

    Cosmic rays are high-energy particles from outer space that continually strike the Earth's atmosphere and produce cascades of secondary particles, which reach the surface of the Earth, mainly in the form of muons. These particles can be detected with scintillator detectors, Geiger counters, cloud chambers, and also can be recorded with commonly…

  3. Current Status of Astrophysics of Cosmic Rays

    Science.gov (United States)

    Moskalenko, Igor

    2016-03-01

    I will review the current instrumentation and recent results. I will discuss which measurements have to be done in the near future to significantly advance our knowledge about the phenomenon of cosmic rays, their sources, and their interactions with the interstellar medium. A support from NASA APRA Grant No. NNX13AC47G is greatly acknowledged.

  4. Cosmic ray propagation with CRPropa 3

    Science.gov (United States)

    Alves Batista, R.; Erdmann, M.; Evoli, C.; Kampert, K.-H.; Kuempel, D.; Mueller, G.; Sigl, G.; Van Vliet, A.; Walz, D.; Winchen, T.

    2015-05-01

    Solving the question of the origin of ultra-high energy cosmic rays (UHECRs) requires the development of detailed simulation tools in order to interpret the experimental data and draw conclusions on the UHECR universe. CRPropa is a public Monte Carlo code for the galactic and extragalactic propagation of cosmic ray nuclei above ∼ 1017 eV, as well as their photon and neutrino secondaries. In this contribution the new algorithms and features of CRPropa 3, the next major release, are presented. CRPropa 3 introduces time-dependent scenarios to include cosmic evolution in the presence of cosmic ray deflections in magnetic fields. The usage of high resolution magnetic fields is facilitated by shared memory parallelism, modulated fields and fields with heterogeneous resolution. Galactic propagation is enabled through the implementation of galactic magnetic field models, as well as an efficient forward propagation technique through transformation matrices. To make use of the large Python ecosystem in astrophysics CRPropa 3 can be steered and extended in Python.

  5. Cosmic R-string in thermal history

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ohashi, Keisuke [Osaka City Univ. (Japan). Dept. of Mathematics and Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research

    2013-03-15

    We study stabilization of an unstable cosmic string associated with spontaneously broken U(1){sub R} symmetry, which otherwise causes a dangerous roll-over process. We demonstrate that in a gauge mediation model, messengers can receive enough corrections from the thermal plasma of the supersymmetric standard model particles to stabilize the unstable modes of the string.

  6. A database of charged cosmic rays

    Science.gov (United States)

    Maurin, D.; Melot, F.; Taillet, R.

    2014-09-01

    Aims: This paper gives a description of a new online database and associated online tools (data selection, data export, plots, etc.) for charged cosmic-ray measurements. The experimental setups (type, flight dates, techniques) from which the data originate are included in the database, along with the references to all relevant publications. Methods: The database relies on the MySQL5 engine. The web pages and queries are based on PHP, AJAX and the jquery, jquery.cluetip, jquery-ui, and table-sorter third-party libraries. Results: In this first release, we restrict ourselves to Galactic cosmic rays with Z ≤ 30 and a kinetic energy per nucleon up to a few tens of TeV/n. This corresponds to more than 200 different sub-experiments (i.e., different experiments, or data from the same experiment flying at different times) in as many publications. Conclusions: We set up a cosmic-ray database (CRDB) and provide tools to sort and visualise the data. New data can be submitted, providing the community with a collaborative tool to archive past and future cosmic-ray measurements. http://lpsc.in2p3.fr/crdb; Contact: crdatabase@lpsc.in2p3.fr

  7. BIBLICAL METAPHOR: THE COSMIC GARDEN HERITAGE

    African Journals Online (AJOL)

    garden estate, found throughout biblical texts – and trust learning can be transferred. Pentateuchal .... agents are appointed to wreak devastation, and the dwelling place becomes bereft of fruitfulness and joy. .... ourselves living – on commodity real estate or in the cosmic garden – and it will affect our behavior. The role of ...

  8. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...

  9. Tracking performance with cosmic rays in CMS

    CERN Document Server

    Cerati, G B

    2008-01-01

    The CMS Tracker is the biggest all-silicon detector in the world and is designed to be extremely efficient and accurate even in a very hostile environment such as that close to the CMS collision point. It consists of an inner pixel detector, made of three barrel layers (48M pixels) and four forward disks (16M pixels), and an outer micro-strip detector, divided in two barrel sub-detectors, TIB and TOB, and two endcap sub-detectors, TID and TEC, for a total of 9.6M strips. The commissioning of the CMS Tracker detector has been initially carried out at the Tracker Integration Facility at CERN (TIF), where cosmic ray data were collected for the strip detector only, and is still ongoing at the CMS site (LHC Point 5). Here the Strip and Pixel detectors have been installed in the experiment and are taking part to the cosmic global-runs. After an overview of the tracking algorithms for cosmic-ray data reconstruction, the resulting tracking performance on cosmic data both at TIF and at P5 are presented. The excellent ...

  10. Quasar Mass Functions Across Cosmic Time

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2010-01-01

    I present mass functions of actively accreting black holes detected in different quasar surveys which in concert cover a wide range of cosmic history. I briefly address what we learn from these mass functions. I summarize the motivation for such a study and the methods by which we determine black...... hole masses....

  11. The Sticky Geometry of the Cosmic Web

    NARCIS (Netherlands)

    Hidding, Johan; Weygaert, Rien van de; Vegter, Gert; Jones, Bernard J.T.; Teillaud, Monique

    2012-01-01

    In this video we highlight the application of Computational Geometry to our understanding of the formation and dynamics of the Cosmic Web. The emergence of this intricate and pervasive weblike structure of the Universe on Megaparsec scales can be approximated by a well-known equation from fluid

  12. Probing Cosmic Accelerators Using VHE Gamma Rays and UHE Cosmic Rays

    International Nuclear Information System (INIS)

    Levinson, Amir

    2009-01-01

    The γ-ray emission observed in several classes of Galactic and extragalactic astrophysical sources appears to be linked to accreting black holes and rotational powered neutron stars. These systems are prodigious cosmic accelerators, and are also potential sources of the UHE cosmic rays detected by several experiments and VHE neutrinos. We review a recent progress in our understanding of these objects, and demonstrate how recent and future observations can be employed to probe the conditions in the sources.

  13. Measuring Behavior using Motion Capture

    NARCIS (Netherlands)

    Fikkert, F.W.; van der Kooij, Herman; Ruttkay, Z.M.; van Welbergen, H.; Spink, A.J.; Ballintijn, M.R.; Bogers, N.D.; Grieco, F; Loijens, L.W.S.; Noldus, L.P.J.J.; Smit, G; Zimmerman, P.H.

    2008-01-01

    Motion capture systems, using optical, magnetic or mechanical sensors are now widely used to record human motion. Motion capture provides us with precise measurements of human motion at a very high recording frequency and accuracy, resulting in a massive amount of movement data on several joints of

  14. Nuclear muon capture - theoretical aspects

    International Nuclear Information System (INIS)

    Mukhopadhyay, N.C.

    1978-01-01

    Nuclear muon capture processes are considered with especial reference to particle physics interests and the possibility of probing aspects of nuclear structure such as nuclear symmetries, cluster correlations and giant resonance excitations. The question of the adequacy of the free muon-nucleon weak interaction inputs in an impulse approximation treatment of the muon capture by complex nuclei is examined. (U.K.)

  15. Fish welfare in capture fisheries

    NARCIS (Netherlands)

    Veldhuizen, L.J.L.; Berentsen, P.B.M.; Boer, de I.J.M.; Vis, van de J.W.; Bokkers, E.A.M.

    2018-01-01

    Concerns about the welfare of production animals have extended from farm animals to fish, but an overview of the impact of especially capture fisheries on fish welfare is lacking. This review provides a synthesis of 85 articles, which demonstrates that research interest in fish welfare in capture

  16. OBSERVATIONAL 5-20 μm INTERSTELLAR EXTINCTION CURVES TOWARD STAR-FORMING REGIONS DERIVED FROM SPITZER IRS SPECTRA

    International Nuclear Information System (INIS)

    McClure, M.

    2009-01-01

    Using Spitzer Infrared Spectrograph observations of G0-M4 III stars behind dark clouds, I construct 5-20 μm empirical extinction curves for 0.3 ≤ A K V between ∼3 and 50. For A K K > 1, the curve exhibits lower contrast between the silicate and absorption continuum, develops ice absorption, and lies closer to the Weingartner and Draine R V = 5.5 Case B curve, a result which is consistent with that of Flaherty et al. and Chiar et al. Recently, work using Spitzer Infrared Array Camera data by Chapman et al. independently reaches a similar conclusion that the shape of the extinction curve changes as a function of increasing A K . By calculating the optical depths of the 9.7 μm silicate and 6.0, 6.8, and 15.2 μm ice features, I determine that a process involving ice is responsible for the changing shape of the extinction curve and speculate that this process is a coagulation of ice-mantled grains rather than ice-mantled grains alone.

  17. Revisiting the Phase Curves of WASP-43b: Confronting Re-analyzed Spitzer Data with Cloudy Atmospheres

    Science.gov (United States)

    Mendonça, João M.; Malik, Matej; Demory, Brice-Olivier; Heng, Kevin

    2018-04-01

    Recently acquired Hubble and Spitzer phase curves of the short-period hot Jupiter WASP-43b make it an ideal target for confronting theory with data. On the observational front, we re-analyze the 3.6 and 4.5 μm Spitzer phase curves and demonstrate that our improved analysis better removes residual red noise due to intra-pixel sensitivity, which leads to greater fluxes emanating from the nightside of WASP-43b, thus reducing the tension between theory and data. On the theoretical front, we construct cloud-free and cloudy atmospheres of WASP-43b using our Global Circulation Model (GCM), THOR, which solves the non-hydrostatic Euler equations (compared to GCMs that typically solve the hydrostatic primitive equations). The cloud-free atmosphere produces a reasonable fit to the dayside emission spectrum. The multi-phase emission spectra constrain the cloud deck to be confined to the nightside and have a finite cloud-top pressure. The multi-wavelength phase curves are naturally consistent with our cloudy atmospheres, except for the 4.5 μm phase curve, which requires the presence of enhanced carbon dioxide in the atmosphere of WASP-43b. Multi-phase emission spectra at higher spectral resolution, as may be obtained using the James Webb Space Telescope, and a reflected-light phase curve at visible wavelengths would further constrain the properties of clouds in WASP-43b.

  18. SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR

    Energy Technology Data Exchange (ETDEWEB)

    Udalski, A.; Skowron, J.; Kozłowski, S.; Poleski, R.; Pietrukowicz, P.; Pietrzyński, G.; Szymański, M. K.; Mróz, P.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Gould, A.; Zhu, W.; Pogge, R. W. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Carey, S. [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Calchi Novati, S. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-02-01

    We combine Spitzer and ground-based observations to measure the microlens parallax vector π{sub E}, and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m ∼ 0.5 M {sub jup} and M ∼ 0.7 M {sub ☉} and are separated by a ∼ 3.1 AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius θ{sub E}, rather than uncertainty in π{sub E}, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the π{sub E} measurement, but also the first independent test of a ground-based π{sub E} measurement.

  19. Spitzer IRS (8-30 micron) Spectra of Basaltic Asteroids 1459 Magnya and 956 Elisa: Mineralogy and Thermal Properties

    Science.gov (United States)

    Lim, Lucy F.; Emery, J. P.; Moskovitz, N. A.

    2009-01-01

    We report preliminary results from Spitzer IRS (Infrared Spectrograph) spectroscopy of 956 Elisa, 1459 Magnya, and other small basaltic asteroids with the Spitzer IRS. Program targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), several outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid 4055 Magellan. The preliminary thermal model (STM) fit to the 5--35 micron spectrum of 956 Elisa gives a radius of 5.4 +/- 0.3 km and a subsolar- point temperature of 282.2 +/- 0.5 K. This temperature corresponds to eta approximately equals 1.06 +/- 0.02, which is substantially higher than the eta approximately equals 0.756 characteristic of large main-belt asteroids. Unlike 4 Vesta and other large asteroids, therefore, 956 Elisa has significant thermal inertia in its surface layer. The wavelength of the Christiansen feature (emissivity maximum near 9 micron), the positions and shapes of the narrow maxima (10 micron, 11 micron) within the broad 9--14 micron silicate band, and the 19--20 micron minimum are consistent with features found in the laboratory spectra of diogenites and of low-Ca pyroxenes of similar composition (Wo<5, En50-En75).

  20. A Search to Uncover the Infrared Excess (IRXS) Sources in the Spitzer Enhanced Imaging Products (SEIP) Catalog

    Science.gov (United States)

    Rowe, Jamie Lynn; Duranko, Gary; Gorjian, Varoujan; Lineberger, Howard; Orr, Laura; Adewole, Ayomikun; Bradford, Eric; Douglas, Alea; Kohl, Steven; Larson, Lillia; Lascola, Gus; Orr, Quinton; Scott, Mekai; Walston, Joseph; Wang, Xian

    2018-01-01

    The Spitzer Enhanced Imaging Products catalog (SEIP) is a collection of nearly 42 million point sources obtained by the Spitzer Space Telescope during its 5+ year cryogenic mission. Strasburger et al (2014) isolated sources with a signal-to-noise ratio (SNR) >10 in five infrared (IR) wavelength channels (3.6, 4.5, 5.8, 8 and 24 microns) to begin a search for sources with infrared excess (IRXS). They found 76 objects that were never catalogued before. Based on this success, we intend to dig deeper into the catalog in an attempt to find more IRXS sources, specifically by lowering the SNR on the 3.6, 4.5, and 24 micron channels. The ultimate goal is to use this large sample to seek rare astrophysical sources that are transitional in nature and evolutionarily very important.Our filtering of the database at SNR > 5 yielded 461,000 sources. This was further evaluated and reduced to only the most interesting based on source location on a [3.6]-[4.5] vs [4.5]-[24] color-color diagram. We chose a sample of 985 extreme IRXS sources for further inspection. All of these candidate sources were visually inspected and cross-referenced against known sources in existing databases, resulting in a list of highly reliable IRXS sources.These sources will prove important in the study of galaxy and stellar evolution, and will serve as a starting point for further investigation.

  1. The intergalactic propagation of ultrahigh energy cosmic ray nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

    2006-08-01

    We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

  2. Proceedings of the 21. European Cosmic Ray Symposium

    International Nuclear Information System (INIS)

    Kiraly, P.; Kudela, K.; Wolfendale, A. W.

    2008-09-01

    Scientific symposium deals with problems of cosmic ray. The Symposium included the following sessions: (1): Relationship of cosmic rays to the environment; (2) Energetic particles and the magnetosphere of the Earth; (3) Energetic particles in the heliosphere; (4) Solar-terrestrial effects on different time scales; (5) Cosmic rays below the knee; (6) Cosmic rays above the knee (7) High energy interactions; (8) GeV and TeV gamma ray astronomy; (9) European projects related to cosmic rays; Future perspectives. Proceedings contains 122 papers dealing with the scope of INIS.

  3. Stardust Interstellar Preliminary Examination IX: High-Speed Interstellar Dust Analog Capture in Stardust Flight-Spare Aerogel

    Science.gov (United States)

    Postberg, F.; Sterken, V.; Achilles, C.; Allen, C.; Bastien, R. K.; Frank, D.; Sandford, S. A.; Zolensky, M. E.; Butterworth, A.; Gainesforth, Z.

    2014-01-01

    The NASA Stardust mission used silica aerogel slabs to slowly decelerate and capture impinging cosmic dust particles for return to Earth. During this process, impact tracks are generated along the trajectory of the particle into the aerogel. It is believed that the morphology and dimensions of these tracks, together with the state of captured grains at track termini, may be linked to the size, velocity, and density of the impacting cosmic dust grain. Here, we present the results of laboratory hypervelocity impact experiments, during which cosmic dust analog particles (diameters of between 0.2 and 0.4 lm), composed of olivine, orthopyroxene, or an organic polymer, were accelerated onto Stardust flight spare low-density (approximately 0.01 g/cu cm) silica aerogel. The impact velocities (3-21 km/s) were chosen to simulate the range of velocities expected during Stardust's interstellar dust (ISD) collection phases. Track lengths and widths, together with the success of particle capture, are analyzed as functions of impact velocity and particle composition, density, and size. Captured terminal particles from low-density organic projectiles become undetectable at lower velocities than those from similarly sized, denser mineral particles, which are still detectable (although substantially altered by the impact process) at 15 km/s. The survival of these terminal particles, together with the track dimensions obtained during low impact speed capture of small grains in the laboratory, indicates that two of the three best Stardust candidate extraterrestrial grains were actually captured at speeds much lower than predicted. Track length and diameters are, in general, more sensitive to impact velocities than previously expected, which makes tracks of particles with diameters of 0.4 lm and below hard to identify at low capture speeds (<10 km/s). Therefore, although captured intact, the majority of the interstellar dust grains returned to Earth by Stardust remain to be found.

  4. An Eagle of Cosmic Proportions

    Science.gov (United States)

    2009-07-01

    Today ESO has released a new and stunning image of the sky around the Eagle Nebula, a stellar nursery where infant star clusters carve out monster columns of dust and gas. Located 7000 light-years away, towards the constellation of Serpens (the Snake), the Eagle Nebula is a dazzling stellar nursery, a region of gas and dust where young stars are currently being formed and where a cluster of massive, hot stars, NGC 6611, has just been born. The powerful light and strong winds from these massive new arrivals are shaping light-year long pillars, seen in the image partly silhouetted against the bright background of the nebula. The nebula itself has a shape vaguely reminiscent of an eagle, with the central pillars being the "talons". The star cluster was discovered by the Swiss astronomer, Jean Philippe Loys de Chéseaux, in 1745-46. It was independently rediscovered about twenty years later by the French comet hunter, Charles Messier, who included it as number 16 in his famous catalogue, and remarked that the stars were surrounded by a faint glow. The Eagle Nebula achieved iconic status in 1995, when its central pillars were depicted in a famous image obtained with the NASA/ESA Hubble Space Telescope. In 2001, ESO's Very Large Telescope (VLT) captured another breathtaking image of the nebula in the near-infrared, giving astronomers a penetrating view through the obscuring dust, and clearly showing stars being formed in the pillars. The newly released image, obtained with the Wide-Field Imager camera attached to the MPG/ESO 2.2-metre telescope at La Silla, Chile, covers an area on the sky as large as the full Moon, and is about 15 times more extensive than the previous VLT image, and more than 200 times more extensive than the iconic Hubble visible-light image. The whole region around the pillars can now be seen in exquisite detail. The "Pillars of Creation" are in the middle of the image, with the cluster of young stars, NGC 6611, lying above and to the right. The

  5. Muon reconstruction performance using cosmic rays in CMS

    CERN Document Server

    Calderon, Alicia

    2009-01-01

    After the incident with the Large Hadron Collider (LHC) in September 2008, the Compact Muon Solenoid (CMS) collaboration invested a considerable effort in further refining the understanding of the detector using cosmic muon data. About 300 million cosmic events were recorded with the CMS detector fully operational and the central solenoid switched on at the nominal value of 3.8 Tesla. The resulting data set provides ample statistics to study in great detail the detector performance and allows to analyze properties of cosmic rays. We present recent results on detector performance from the cosmic muon analysis activities and compare cosmic data to dedicated cosmic Monte Carlo samples. These results demonstrate the readiness of the CMS detector to do physics analysis with muons, and the study of cosmic muon properties provides interesting links to astrophysics.

  6. Materials For Gas Capture, Methods Of Making Materials For Gas Capture, And Methods Of Capturing Gas

    KAUST Repository

    Polshettiwar, Vivek

    2013-06-20

    In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure, in one aspect, relate to materials that can be used for gas (e.g., CO.sub.2) capture, methods of making materials, methods of capturing gas (e.g., CO.sub.2), and the like, and the like.

  7. Electron capture and stellar collapse

    International Nuclear Information System (INIS)

    Chung, K.C.

    1979-01-01

    In order, to investigate the function of electron capture in the phenomenon of pre-supernovae gravitacional collapse, an hydrodynamic caculation was carried out, coupling capture, decay and nuclear reaction equation system. A star simplified model (homogeneous model) was adopted using fermi ideal gas approximation for tthe sea of free electrons and neutrons. The non simplified treatment from quasi-static evolution to collapse is presented. The capture and beta decay rates, as wellas neutron delayed emission, were calculated by beta decay crude theory, while the other reaction rates were determined by usual theories. The preliminary results are presented. (M.C.K.) [pt

  8. The X-ray properties of five galactic supernova remnants detected by the Spitzer glimpse survey

    International Nuclear Information System (INIS)

    Pannuti, Thomas G.; Moffitt, William P.; Rho, Jeonghee; Heinke, Craig O.

    2014-01-01

    We present a study of the X-ray properties of five Galactic supernova remnants (SNRs)—Kes 17 (G304.6+0.1), G311.5–0.3, G346.6–0.2, CTB 37A (G348.5+0.1), and G348.5–0.0—that were detected in the infrared by Reach et al. in an analysis of data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) that was conducted by the Spitzer Space Telescope. We present and analyze archival ASCA observations of Kes 17, G311.5–0.3, and G346.6–0.2, archival XMM-Newton observations of Kes 17, CTB 37A, and G348.5–0.0, and an archival Chandra observation of CTB 37A. All of the SNRs are clearly detected in the X-ray except possibly G348.5–0.0. Our study reveals that the four detected SNRs all feature center-filled X-ray morphologies and that the observed emission from these sources is thermal in all cases. We argue that these SNRs should be classified as mixed-morphology SNRs (MM SNRs); our study strengthens the correlation between MM SNRs and SNRs interacting with molecular clouds and suggests that the origin of MM SNRs may be due to the interactions between these SNRs and adjacent clouds. Our ASCA analysis of G311.5–0.3 reveals for the first time X-ray emission from this SNR: the X-ray emission is center-filled within the radio and infrared shells and thermal in nature (kT ∼ 0.98 keV), thus motivating its classification as an MM SNR. We find considerable spectral variations in the properties associated with the plasmas of the other X-ray-detected SNRs, such as a possible overabundance of magnesium in the plasma of Kes 17. Our new results also include the first detailed spatially resolved spectroscopic study of CTB 37A using Chandra as well as a spectroscopic study of the discrete X-ray source CXOU J171428.5–383601, which may be a neutron star associated with CTB 37A. Finally, we also estimate such properties as electron density n e , radiative age t rad and swept-up mass M X for each of the four X-ray-detected SNRs. Each of these values

  9. Carbon capture and sequestration (CCS)

    Science.gov (United States)

    2009-06-19

    Carbon capture and sequestration (or storage)known as CCShas attracted interest as a : measure for mitigating global climate change because large amounts of carbon dioxide (CO2) : emitted from fossil fuel use in the United States are potentiall...

  10. MOTOR PROTEINS Kinesin's gait captured

    NARCIS (Netherlands)

    Peterman, E.J.G.

    2016-01-01

    Kinesin is a motor protein that drives intracellular transport by stepping along microtubules in a hand-over-hand manner. Advanced dark-field microscopy has made it possible to capture the gait of this motor with unprecedented resolution.

  11. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  12. A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b

    Science.gov (United States)

    Lanotte, A. A.; Gillon, M.; Demory, B.-O.; Fortney, J. J.; Astudillo, N.; Bonfils, X.; Magain, P.; Delfosse, X.; Forveille, T.; Lovis, C.; Mayor, M.; Neves, V.; Pepe, F.; Queloz, D.; Santos, N.; Udry, S.

    2014-12-01

    Context. GJ 436b is one of the few transiting warm Neptunes for which a detailed characterisation of the atmosphere is possible, whereas its non-negligible orbital eccentricity calls for further investigation. Independent analyses of several individual datasets obtained with Spitzer have led to contradicting results attributed to the different techniques used to treat the instrumental effects. Aims: We aim at investigating these previous controversial results and developing our knowledge of the system based on the full Spitzer photometry dataset combined with new Doppler measurements obtained with the HARPS spectrograph. We also want to search for additional planets. Methods: We optimise aperture photometry techniques and the photometric deconvolution algorithm DECPHOT to improve the data reduction of the Spitzer photometry spanning wavelengths from 3-24 μm. Adding the high-precision HARPS radial velocity data, we undertake a Bayesian global analysis of the system considering both instrumental and stellar effects on the flux variation. Results: We present a refined radius estimate of RP = 4.10 ± 0.16 R⊕ , mass MP = 25.4 ± 2.1 M⊕, and eccentricity e = 0.162 ± 0.004 for GJ 436b. Our measured transit depths remain constant in time and wavelength, in disagreement with the results of previous studies. In addition, we find that the post-occultation flare-like structure at 3.6 μm that led to divergent results on the occultation depth measurement is spurious. We obtain occultation depths at 3.6, 5.8, and 8.0 μm that are shallower than in previous works, in particular at 3.6 μm. However, these depths still appear consistent with a metal-rich atmosphere depleted in methane and enhanced in CO/CO2, although perhaps less than previously thought. We could not detect a significant orbital modulation in the 8 μm phase curve. We find no evidence of a potential planetary companion, stellar activity, or a stellar spin-orbit misalignment. Conclusions: Recent theoretical

  13. Toward transformational carbon capture systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Litynski, John T. [Office of Fossil Energy, U.S. Dept. of Energy, Washington DC (United States); Brickett, Lynn A. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Morreale, Bryan D. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States)

    2015-10-28

    This paper will briefly review the history and current state of Carbon Capture and Storage (CCS) research and development and describe the technical barriers to carbon capture. it will argue forcefully for a new approach to R&D, which leverages both simulation and physical systems at the laboratory and pilot scales to more rapidly move the best technoogies forward, prune less advantageous approaches, and simultaneously develop materials and processes.

  14. CO2 capture-sequestration

    International Nuclear Information System (INIS)

    Huffer, Elisabeth

    2008-01-01

    CO 2 capture-sequestration could be an acceptable temporary solution for the abatement of greenhouse gas releases to the atmosphere, before the implementation of new carbon-free power generation means. This paper briefly summarizes the principles of this technology: capture (post-combustion, oxi-combustion, pre-combustion); CO 2 transport and sequestration (deep saline aquifers, injection in depleted hydrocarbon reservoirs, injection in abandoned coal seams); examples of operations in progress

  15. Radiative muon capture on hydrogen

    International Nuclear Information System (INIS)

    Bertl, W.; Ahmad, S.; Chen, C.Q.; Gumplinger, P.; Hasinoff, M.D.; Larabee, A.J.; Sample, D.G.; Schott, W.; Wright, D.H.; Armstrong, D.S.; Blecher, M.; Azuelos, G.; Depommier, P.; Jonkmans, G.; Gorringe, T.P.; Henderson, R.; Macdonald, J.A.; Poutissou, J.M.; Poutissou, R.; Von Egidy, T.; Zhang, N.S.; Robertson, B.D.

    1992-01-01

    The radiative capture of negative muons by protons can be used to measure the weak induced pseudoscalar form factor. Brief arguments why this method is preferable to ordinary muon capture are given followed by a discussion of the experimental difficulties. The solution to these problems as attempted by experiment no. 452 at TRIUMF is presented together with preliminary results from the first run in August 1990. An outlook on the expected final precision and the experimental schedule is also given. (orig.)

  16. Alignment in double capture processes

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A. (IRSAMC, URA CNRS 770, Univ. Paul Sabatier, 118 rte de Narbonne, 31062 Toulouse Cedex (France))

    1993-06-05

    The electron spectra emitted when a double capture occurs in N[sup 7+]+He and Ne[sup 8+]+He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3[ell]3[ell] [prime] lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned.

  17. The SAURON project - XX. The Spitzer [3.6] - [4.5] colour in early-type galaxies : colours, colour gradients and inverted scaling relations

    NARCIS (Netherlands)

    Peletier, Reynier F.; Kutdemir, Elif; van der Wolk, Guido; Falcon-Barroso, Jesus; Bacon, Roland; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; de Zeeuw, P. Tim; Emsellem, Eric; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M.; Sarzi, Marc; Scott, Nicholas; Shapiro, Kristen L.; van den Bosch, Remco C. E.; van de Ven, Glenn

    We investigate the [3.6]-[4.5] Spitzer-IRAC colour behaviour of the early-type galaxies of the SAURON survey, a representative sample of 48 nearby ellipticals and lenticulars. We investigate how this colour, which is unaffected by dust extinction, can be used to constrain the stellar populations in

  18. THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

    NARCIS (Netherlands)

    Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Delgado, R. Gonzalez; Groves, B.

    2009-01-01

    We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05

  19. "TNOs are Cool" : A survey of the trans-Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations

    NARCIS (Netherlands)

    Lellouch, E.; Santos-Sanz, P.; Lacerda, P.; Mommert, M.; Duffard, R.; Ortiz, J. L.; Müller, T. G.; Fornasier, S.; Stansberry, J.; Kiss, Cs.; Vilenius, E.; Mueller, M.; Peixinho, N.; Moreno, R.; Groussin, O.; Delsanti, A.; Harris, A. W.

    2013-01-01

    Aims: The goal of this work is to characterize the ensemble thermal properties of the Centaurs / trans-Neptunian population. Methods: Thermal flux measurements obtained with Herschel/PACS and Spitzer/MIPS provide size, albedo, and beaming factors for 85 objects (13 of which are presented here for

  20. Cosmic-Ray Extremely Distributed Observatory: a global cosmic ray detection framework

    Science.gov (United States)

    Sushchov, O.; Homola, P.; Dhital, N.; Bratek, Ł.; Poznański, P.; Wibig, T.; Zamora-Saa, J.; Almeida Cheminant, K.; Alvarez Castillo, D.; Góra, D.; Jagoda, P.; Jałocha, J.; Jarvis, J. F.; Kasztelan, M.; Kopański, K.; Krupiński, M.; Michałek, M.; Nazari, V.; Smelcerz, K.; Smolek, K.; Stasielak, J.; Sułek, M.

    2017-12-01

    The main objective of the Cosmic-Ray Extremely Distributed Observatory (CREDO) is the detection and analysis of extended cosmic ray phenomena, so-called super-preshowers (SPS), using existing as well as new infrastructure (cosmic-ray observatories, educational detectors, single detectors etc.). The search for ensembles of cosmic ray events initiated by SPS is yet an untouched ground, in contrast to the current state-of-the-art analysis, which is focused on the detection of single cosmic ray events. Theoretical explanation of SPS could be given either within classical (e.g., photon-photon interaction) or exotic (e.g., Super Heavy Dark Matter decay or annihilation) scenarios, thus detection of SPS would provide a better understanding of particle physics, high energy astrophysics and cosmology. The ensembles of cosmic rays can be classified based on the spatial and temporal extent of particles constituting the ensemble. Some classes of SPS are predicted to have huge spatial distribution, a unique signature detectable only with a facility of the global size. Since development and commissioning of a completely new facility with such requirements is economically unwarranted and time-consuming, the global analysis goals are achievable when all types of existing detectors are merged into a worldwide network. The idea to use the instruments in operation is based on a novel trigger algorithm: in parallel to looking for neighbour surface detectors receiving the signal simultaneously, one should also look for spatially isolated stations clustered in a small time window. On the other hand, CREDO strategy is also aimed at an active engagement of a large number of participants, who will contribute to the project by using common electronic devices (e.g., smartphones), capable of detecting cosmic rays. It will help not only in expanding the geographical spread of CREDO, but also in managing a large manpower necessary for a more efficient crowd-sourced pattern recognition scheme to

  1. The COsmic-ray Soil Moisture Interaction Code (COSMIC for use in data assimilation

    Directory of Open Access Journals (Sweden)

    J. Shuttleworth

    2013-08-01

    Full Text Available Soil moisture status in land surface models (LSMs can be updated by assimilating cosmic-ray neutron intensity measured in air above the surface. This requires a fast and accurate model to calculate the neutron intensity from the profiles of soil moisture modeled by the LSM. The existing Monte Carlo N-Particle eXtended (MCNPX model is sufficiently accurate but too slow to be practical in the context of data assimilation. Consequently an alternative and efficient model is needed which can be calibrated accurately to reproduce the calculations made by MCNPX and used to substitute for MCNPX during data assimilation. This paper describes the construction and calibration of such a model, COsmic-ray Soil Moisture Interaction Code (COSMIC, which is simple, physically based and analytic, and which, because it runs at least 50 000 times faster than MCNPX, is appropriate in data assimilation applications. The model includes simple descriptions of (a degradation of the incoming high-energy neutron flux with soil depth, (b creation of fast neutrons at each depth in the soil, and (c scattering of the resulting fast neutrons before they reach the soil surface, all of which processes may have parameterized dependency on the chemistry and moisture content of the soil. The site-to-site variability in the parameters used in COSMIC is explored for 42 sample sites in the COsmic-ray Soil Moisture Observing System (COSMOS, and the comparative performance of COSMIC relative to MCNPX when applied to represent interactions between cosmic-ray neutrons and moist soil is explored. At an example site in Arizona, fast-neutron counts calculated by COSMIC from the average soil moisture profile given by an independent network of point measurements in the COSMOS probe footprint are similar to the fast-neutron intensity measured by the COSMOS probe. It was demonstrated that, when used within a data assimilation framework to assimilate COSMOS probe counts into the Noah land surface

  2. Cosmic Ray Signatures of Decaying Dark Matter

    International Nuclear Information System (INIS)

    Ibarra, Alejandro

    2011-01-01

    Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into Standard Model particles might occur at a sufficiently large rate to allow the indirect detection of dark matter through an anomalous contribution to the high energy cosmic ray fluxes. We analyze the implications of the excess in the total electron plus positron flux and the positron fraction reported by the Fermi and PAMELA collaborations, respectively, for the scenario of decaying dark matter. We also discuss the constraints on this scenario from measurements of other cosmic ray species and the predictions for the diffuse gamma ray flux and the neutrino flux. In particular, we expect a sizable dipole-like anisotropy which may be observed in the near future by the Fermi-LAT.

  3. Astroparticle Physics: Detectors for Cosmic Rays

    International Nuclear Information System (INIS)

    Salazar, Humberto; Villasenor, Luis

    2006-01-01

    We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the measurement of the muon lifetime and the ratio of positive to negative muons in the natural background of cosmic ray muons at 2000 m.a.s.l. Next we describe the detection of decaying and crossing muons in a water Cherenkov detector as well as a technique to separate isolated particles. We also describe the detection of isolated muons and electrons in a liquid scintillator detector and their separation. Next we describe the detection of extensive air showers (EAS) with a hybrid detector array consisting of water Cherenkov and liquid scintillator detectors, located at the campus of the University of Puebla. Finally we describe work in progress to detect EAS at 4600 m.a.s.l. with a water Cherenkov detector array and a fluorescence telescope at the Sierra Negra mountain

  4. Astroparticle Physics: Detectors for Cosmic Rays

    Science.gov (United States)

    Salazar, Humberto; Villaseñor, Luis

    2006-09-01

    We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the measurement of the muon lifetime and the ratio of positive to negative muons in the natural background of cosmic ray muons at 2000 m.a.s.l. Next we describe the detection of decaying and crossing muons in a water Cherenkov detector as well as a technique to separate isolated particles. We also describe the detection of isolated muons and electrons in a liquid scintillator detector and their separation. Next we describe the detection of extensive air showers (EAS) with a hybrid detector array consisting of water Cherenkov and liquid scintillator detectors, located at the campus of the University of Puebla. Finally we describe work in progress to detect EAS at 4600 m.a.s.l. with a water Cherenkov detector array and a fluorescence telescope at the Sierra Negra mountain.

  5. The glacial cycles and cosmic rays

    CERN Document Server

    Kirkby, Jasper; Müller, R A

    2004-01-01

    The cause of the glacial cycles remains a mystery. The origin is widely accepted to be astronomical since paleoclimatic archives contain strong spectral components that match the frequencies of Earth's orbital modulation. Milankovitch insolation theory contains similar frequencies and has become established as the standard model of the glacial cycles. However, high precision paleoclimatic data have revealed serious discrepancies with the Milankovitch model that fundamentally challenge its validity and re-open the question of what causes the glacial cycles. We propose here that the ice ages are initially driven not by insolation cycles but by cosmic ray changes, probably through their effect on clouds. This conclusion is based on a wide range of evidence, including results presented here on speleothem growth in caves in Austria and Oman, and on a record of cosmic ray flux over the past 220 kyr obtained from the 10Be composition of deep-ocean sediments.

  6. Cosmic rays, solar activity and the climate

    International Nuclear Information System (INIS)

    Sloan, T; Wolfendale, A W

    2013-01-01

    Although it is generally believed that the increase in the mean global surface temperature since industrialization is caused by the increase in green house gases in the atmosphere, some people cite solar activity, either directly or through its effect on cosmic rays, as an underestimated contributor to such global warming. In this letter a simplified version of the standard picture of the role of greenhouse gases in causing the global warming since industrialization is described. The conditions necessary for this picture to be wholly or partially wrong are then introduced. Evidence is presented from which the contributions of either cosmic rays or solar activity to this warming is deduced. The contribution is shown to be less than 10% of the warming seen in the twentieth century. (letter)

  7. Cosmic Muon Detection for Geophysical Applications

    Directory of Open Access Journals (Sweden)

    László Oláh

    2013-01-01

    Full Text Available A portable cosmic muon detector has been developed for environmental, geophysical, or industrial applications. The device is a tracking detector based on the Close Cathode Chamber, an MWPC-like technology, allowing operation in natural underground caves or artificial tunnels, far from laboratory conditions. The compact, low power consumption system with sensitive surface of 0.1 m2 measures the angular distribution of cosmic muons with a resolution of 10 mrad, allowing for a detailed mapping of the rock thickness above the muon detector. Demonstration of applicability of the muon telescope (REGARD Muontomograph for civil engineering and measurements in artificial underground tunnels or caverns are presented.

  8. Multi-messenger aspects of cosmic neutrinos*

    Directory of Open Access Journals (Sweden)

    Ahlers Markus

    2016-01-01

    Full Text Available The recent observation of TeV-PeV neutrinos by IceCube has opened a new window to the high-energy Universe. I will discuss this signal in the context of multi-messenger astronomy. For extragalactic source scenarios the corresponding gamma-rays are not directly observable due to interactions with the cosmic radiation backgrounds. Nevertheless, the isotropic sub-TeV gamma ray background observed by Fermi-LAT contains indirect information from secondary emission produced in electromagnetic cascades. On the other hand, observation of PeV gamma rays would provide a smoking-gun signal for Galactic emission. Interestingly, the overall energy density of the observed neutrino flux is close to a theoretical limit for neutrino production in ultra-high energy cosmic ray sources and might indicate a common origin of these phenomena. I will highlight various multi-messenger relations and their implications for neutrino source scenarios.

  9. Cosmic Ray Mass Measurements with LOFAR

    Directory of Open Access Journals (Sweden)

    Buitink Stijn

    2017-01-01

    Full Text Available In the dense core of LOFAR individual air showers are detected by hundreds of dipole antennas simultaneously. We reconstruct Xmax by using a hybrid technique that combines a two-dimensional fit of the radio profile to CoREAS simulations and a one-dimensional fit of the particle density distribution. For high-quality detections, the statistical uncertainty on Xmax is smaller than 20 g/cm2. We present results of cosmic-ray mass analysis in the energy regime of 1017 - 1017.5 eV. This range is of particular interest as it may harbor the transition from a Galactic to an extragalactic origin of cosmic rays.

  10. Can quantum mechanics fool the cosmic censor?

    International Nuclear Information System (INIS)

    Matsas, G. E. A.; Silva, A. R. R. da; Richartz, M.; Saa, A.; Vanzella, D. A. T.

    2009-01-01

    We revisit the mechanism for violating the weak cosmic-censorship conjecture (WCCC) by overspinning a nearly-extreme charged black hole. The mechanism consists of an incoming massless neutral scalar particle, with low energy and large angular momentum, tunneling into the hole. We investigate the effect of the large angular momentum of the incoming particle on the background geometry and address recent claims that such a backreaction would invalidate the mechanism. We show that the large angular momentum of the incident particle does not constitute an obvious impediment to the success of the overspinning quantum mechanism, although the induced backreaction turns out to be essential to restoring the validity of the WCCC in the classical regime. These results seem to endorse the view that the 'cosmic censor' may be oblivious to processes involving quantum effects.

  11. Cosmic strings and galaxy formation: Current status

    International Nuclear Information System (INIS)

    Stebbins, A.

    1987-04-01

    Successes and remaining problems with cosmic string theories of galaxy formation are outlined. Successes of the theory include predictions for the correct amplitude of initial inhomogeneities leading to galaxy formation, the distribution of observed inhomogeneities, the observed correlation function of clusters, and the density profiles of dark matter halos. Potentially serious problems which have been raised are the biased galaxy production (why do galaxies occur in clusters?), the core radius problem (density profiles of galactic halos do not match predictions), the maximal rotation velocity problem (why is there a sharp cutoff in observed rotational velocity of galaxies?), the small galaxy problem (why are all the galaxies relatively small structures?), the angular momentum problem (where do baryons acquire their angular momentum in order to form spirals), and the large-scale structure problem (why do most galaxies appear to lie on surfaces surrounding voids?). Possible approaches to each of these problems are suggested and the future of cosmic string theory is discussed. 25 refs

  12. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...... accuracy. The information which the CMB provides has helped in creating the current standard cosmological model - the CDM model - and the theory of cosmic inflation as well as constrain a vast amount of cosmological parameters. The accuracy of observations of the CMB radiation is thus of extreme importance...... the observed CMB signal. We assume that emission from the Kuiper belt around the solar system in combination with a dipole modulation of the signal due to an unknown systematic effect may explain both the observed parity asymmetry, as well as the peculiar alignment of the quadrupole and octupole. We find...

  13. Small scale structure on cosmic strings

    International Nuclear Information System (INIS)

    Albrecht, A.

    1989-01-01

    I discuss our current understanding of cosmic string evolution, and focus on the question of small scale structure on strings, where most of the disagreements lie. I present a physical picture designed to put the role of the small scale structure into more intuitive terms. In this picture one can see how the small scale structure can feed back in a major way on the overall scaling solution. I also argue that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small structure, which I argue in any case would be extremely valuable in filling the gaps in our resent understanding of cosmic string evolution. 24 refs., 8 figs

  14. Cosmic muons, as messengers from the Universe

    International Nuclear Information System (INIS)

    Brancus, I. M.; Rebel, H.

    2015-01-01

    Penetrating from the outer space into the Earth atmosphere, primary cosmic rays are producing secondary radiation by the collisions with the air target subsequently decaying in hadrons, pions, muons, electrons and photons, phenomenon called Extensive air Shower (EAS). The muons, considered as the “penetrating” component, survive the propagation to the Earth and even they are no direct messenger of the Universe, they reflect the features of the primary particles. The talk gives a description of the development of the extensive air showers generating the secondary particles, especially the muon component. Results of the muon flux and of the muon charge ratio, (the ratio between the positive and the negative muons), obtained in different laboratories and in WILLI experiment, are shown. At the end, the contribution of the muons measured in EAS to the investigation of the nature of the primary cosmic rays is emphasized in KASCADE and WILLI-EAS experiments

  15. Solar cosmic rays fundamentals and applications

    CERN Document Server

    Miroshnichenko, Leonty

    2015-01-01

    The book summarizes the results of solar cosmic ray (SCR) investigations since 1942. The present monograph, unlike the reviews published earlier, treats the problem in self-contained form, in all its associations—from fundamental astrophysical aspects to geophysical, aeronautical and cosmonautical applications. It includes a large amount of new data, accumulated during the last several decades of space research. As a result of the "information burst" in space physics, there are a lot of new interesting theoretical concepts, models and ideas that deserve attention. The author gives an extensive bibliography, which covers non-partially the main achievements and failures in this field. The book will be helpful for a wide audience of space physicists and it will be relevant to graduate and postgraduate courses. The book will serve as a reference work for researchers and students in solar physics and astrophysical plasma physics, as well as in cosmic rays physics, astroparticle physics, space science, solar-terr...

  16. Cosmic Ray physics with ARGO-YBJ

    Energy Technology Data Exchange (ETDEWEB)

    Iacovacci, M. [Dipartimento di Fisica dell' Università di Napoli ”Federico II” and INFN Napoli, Complesso Universitario MSA, Via Cintia, 80126 Napoli (Italy)

    2013-06-15

    The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the Yang-BaJing Cosmic Ray Laboratory (Tibet, P.R.China, 4300 m a.s.l.). It exploits the full coverage and the high altitude to detect air showers with an energy threshold as low as a few hundred GeV. The detector is made of a single layer of RPCs operated in streamer mode, fully instrumenting a central carpet of about 5800 m{sup 2}. A guard ring extends the partially instrumented area to about 11,000 m{sup 2}. The main results so far achieved on Cosmic Ray physics are reported.

  17. Cosmic Origins Program Annual Technology Report

    Science.gov (United States)

    Pham, Bruce Thai; Neff, Susan Gale

    2015-01-01

    What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time. COR also seeks to understand how stars and planets form from clouds in these galaxies to create the heavy elements that are essential to life starting with the first generation of stars to seed the universe, and continuing through the birth and eventual death of all subsequent generations of stars. The COR Programs purview includes the majority of the field known as astronomy, from antiquity to the present.

  18. Cosmic time dilation: The clock paradox revisited

    International Nuclear Information System (INIS)

    Tomaschitz, Roman

    2004-01-01

    The relativistic time dilation is reviewed in a cosmological context. We show that a clock or twin paradox does not arise if cosmic time is properly taken into account. The receding galaxy background provides a unique frame of reference, and the proper times of geodesic as well as accelerated observers can be linked to the universal cosmic time parameter. This suggests to compare the proper time differentials of the respective observers by determining their state of motion in the galaxy grid. In this way, each observer can figure out whether his proper time is dilated or contracted relative to any other. In particular one can come to unambiguous conclusions on the aging of uniformly moving observers, without reference to asymmetries in measurement procedures or accelerations they may have undergone

  19. Planck 2013 results. XXX. Cosmic infrared background measurements and implications for star formation

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bethermin, M.; Bielewicz, P.; Blagrave, K.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chen, X.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Kalberla, P.; Keihänen, E.; Kerp, J.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lacasa, F.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Langer, M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Serra, P.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Türler, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Welikala, N.; White, M.; White, S. D. M.; Winkel, B.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    We present new measurements of cosmic infrared background (CIB) anisotropies using Planck. Combining HFI data with IRAS, the angular auto- and cross-frequency power spectrum is measured from 143 to 3000 GHz, and the auto-bispectrum from 217 to 545 GHz. The total areas used to compute the CIB power spectrum and bispectrum are about 2240 and 4400 deg2, respectively. After careful removal of the contaminants (cosmic microwave background anisotropies, Galactic dust, and Sunyaev-Zeldovich emission), and a complete study of systematics, the CIB power spectrum is measured with unprecedented signal to noise ratio from angular multipoles ℓ ~ 150 to 2500. The bispectrum due to the clustering of dusty, star-forming galaxies is measured from ℓ ~ 130 to 1100, with a total signal to noise ratio of around 6, 19, and 29 at 217, 353, and 545 GHz, respectively. Two approaches are developed for modelling CIB power spectrum anisotropies. The first approach takes advantage of the unique measurements by Planck at large angular scales, and models only the linear part of the power spectrum, with a mean bias of dark matter haloes hosting dusty galaxies at a given redshift weighted by their contribution to the emissivities. The second approach is based on a model that associates star-forming galaxies with dark matter haloes and their subhaloes, using a parametrized relation between the dust-processed infrared luminosity and (sub-)halo mass. The two approaches simultaneously fit all auto- and cross-power spectra very well. We find that the star formation history is well constrained up to redshifts around 2, and agrees with recent estimates of the obscured star-formation density using Spitzer and Herschel. However, at higher redshift, the accuracy of the star formation history measurement is strongly degraded by the uncertainty in the spectral energy distribution of CIB galaxies. We also find that the mean halo mass which is most efficient at hosting star formation is log (Meff/M⊙) = 12

  20. Relic right-handed Dirac neutrinos and implications for detection of cosmic neutrino background

    Directory of Open Access Journals (Sweden)

    Jue Zhang

    2016-02-01

    Full Text Available It remains to be determined experimentally if massive neutrinos are Majorana or Dirac particles. In this connection, it has been recently suggested that the detection of cosmic neutrino background of left-handed neutrinos νL and right-handed antineutrinos ν‾R in future experiments of neutrino capture on beta-decaying nuclei (e.g., νe+H3→He3+e− for the PTOLEMY experiment is likely to distinguish between Majorana and Dirac neutrinos, since the capture rate is twice larger in the former case. In this paper, we investigate the possible impact of right-handed neutrinos on the capture rate, assuming that massive neutrinos are Dirac particles and both right-handed neutrinos νR and left-handed antineutrinos ν‾L can be efficiently produced in the early Universe. It turns out that the capture rate can be enhanced at most by 28% due to the presence of relic νR and ν‾L with a total number density of 95 cm−3, which should be compared to the number density 336 cm−3 of cosmic neutrino background. The enhancement has actually been limited by the latest cosmological and astrophysical bounds on the effective number of neutrino generations Neff=3.14−0.43+0.44 at the 95% confidence level. For illustration, two possible scenarios have been proposed for thermal production of right-handed neutrinos in the early Universe.