WorldWideScience

Sample records for supernova patrol scientists

  1. NASA Scientists Witness a Supernova Cosmic Rite of Passage

    Science.gov (United States)

    2005-11-01

    Scientists using NASA's Chandra X-ray Observatory have witnessed a cosmic rite of passage, the transition from a supernova to a supernova remnant, a process that has never been seen in much detail until now, leaving it poorly defined. A supernova is a massive star explosion; the remnant is the beautiful glowing shell that evolves afterwards. When does a supernova become supernova remnant? When does the shell appear and what powers its radiant glow? A science team led by Dr. Stefan Immler of NASA's Goddard Space Flight Center, Greenbelt, Md., has taken a fresh look at a supernova that exploded in 1970, called SN 1970G, just off the handle of the Big Dipper. This is the oldest supernova ever seen by X-ray telescopes. Chandra X-ray Image of SN 1970G Chandra X-ray Image of SN 1970G "Some astronomers have thought there's a moment when the supernova remnant magically turns on years after the supernova itself has faded away, when the shock wave of the explosion finally hits and lights up the interstellar medium," said Immler. "By contrast, our results show that a new supernova quickly and seamlessly evolves into a supernova remnant. The star's own debris, and not the interstellar medium gas, fuels the remnant." These results appear in The Astrophysical Journal, co-authored by Dr. Kip Kuntz, also of Goddard. They support previous Chandra observations of SN 1987A by Dr. Sangwook Park of Penn State. Using new data from Chandra and archived data from the European-led ROSAT and XMM-Newton observatories, Immler and Kuntz pieced together how SN 1970G evolved over the years. They found telltale signs of a supernova remnant - bright X-ray light - yet no evidence of interstellar gas, even across a distance around the site of the explosion 35 times larger than our solar system. Instead, the material that is heated by the supernova shock to glow in X-ray light, what we call the remnant, is from the stellar wind of the star itself and not distant gas in the interstellar medium. This

  2. Virtual patrolling

    NARCIS (Netherlands)

    Vlist, van der M.; Wismans, L.J.J.; Beek, van P.; Suijs, L.C.W.

    2016-01-01

    Approximately 25 per cent of all congestion on motorways is caused by incidents. By virtual patrolling, incidents e.g. queues, accidents and car breakdowns on a road network, can be predicted or detected in an early stage. This early detection and prediction of an incident likely to happen, offers t

  3. Supernovae

    Science.gov (United States)

    March, Marisa

    2014-03-01

    We live in a Universe that is getting bigger faster. This astonishing discovery of Universal acceleration was made in the late 1990s by two teams who made observations of a special type of exploded star known as a `Supernova Type Ia'. (SNeIa) Since the discovery of the accelerating Universe, one of the biggest questions in modern cosmology has been to determine the cause of that acceleration - the answer to this question will have far reaching implications for our theories of cosmology and fundamental physics more broadly. The two main competing explanations for this apparent late time acceleration of the Universe are modified gravity and dark energy. The Dark Energy Survey (DES) has been designed and commissioned to find to find answers to these questions about the nature of dark energy and modified gravity. The new 570 megapixel Dark Energy Camera is currently operating with the Cerro-Tololo Inter American Observatory's 4m Blanco teleccope, carrying out a systematic search for SNeIa, and mapping out the large scale structure of the Universe by making observations of galaxies. The DES science program program which saw first light in September 2013 will run for five years in total. DES SNeIa data in combination with the other DES observations of large scale structure will enable us to put increasingly accurate constraints on the expansion history of the Universe and will help us distinguish between competing theories of dark energy and modified gravity. As we draw to the close of the first observing season of DES in March 2014, we will report on the current status of the DES supernova survey, presenting first year supernovae data, preliminary results, survey strategy, discovery pipeline, spectroscopic target selection and data quality. This talk will give the first glimpse of the DES SN first year data and initial results as we begin our five year survey in search of dark energy. On behalf of the Dark Energy Survey collaboration.

  4. Green Arctic Patrol Vessel

    Science.gov (United States)

    2011-08-01

    Search Radar (2D) Non-rotating IFF system Electro- Optical security system Naval Surface Warfare Center Carderock Division Green Arctic Patrol...Speed Endurance Modular Systems and Capabilities UUV Bluefin 21 4.93 0.53 750 kg 4,500 m 25 hours Side scan sonar, multibeam ...sensors, 256 Mb flash card USV ASV 6300 6.30 Beam: 0.65 Height: 3.50 2.0 tonnes 8 kt 96 hours @ 4 kt Multibeam , sidescan sonars, CTD

  5. CERN scientists predict supernova

    CERN Multimedia

    2003-01-01

    "A team of theoretical physicists working at CERN and the Technion Institute of Technology in Israel has developed a theory to account for the mysterious gamma ray bursts that come from the depths of the Universe" (1/2 page).

  6. DNR Division of Enforcement Officer Patrol Areas

    Data.gov (United States)

    Minnesota Department of Natural Resources — This theme shows the DNR Division of Enforcement Office Patrol Areas as of January 1, 2003. Patrol areas were defined and verified by Patrol Officers during the fall...

  7. Berkeley Lab's Saul Perlmutter wins E.O. Lawrence Award; scientist's work on supernovae reveals accelerating Universe

    CERN Multimedia

    2002-01-01

    Saul Perlmutter, from Lawrence Berkeley National Laboratory Physics Division and leader of the Supernova Cosmology Project based there, has won the DOE's 2002 E.O. Lawrence Award in the physics category (2 pages).

  8. Berkeley Lab's Saul Perlmutter wins E.O. Lawrence Award scientist's work on supernovae reveals accelerating universe

    CERN Multimedia

    2002-01-01

    "Saul Perlmutter, a member of Lawrence Berkeley National Laboratory's Physics Division and leader of the international Supernova Cosmology Project based there, has won the Department of Energy's 2002 E.O. Lawrence Award in the physics category" (1/2 page).

  9. Solar Features - Solar Flares - Patrol

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  10. 32 CFR 700.922 - Shore patrol.

    Science.gov (United States)

    2010-07-01

    ... member of the shore patrol or beach guard, or is assigned in support thereof, shall partake of or indulge... 32 National Defense 5 2010-07-01 2010-07-01 false Shore patrol. 700.922 Section 700.922 National... § 700.922 Shore patrol. (a) When liberty is granted to any considerable number of persons, except in...

  11. International Ice Patrol Iceberg Drift Tracks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The International Ice Patrol (IIP) tracks, plots and predicts iceberg positions in the North Atlantic Ocean. The IIP area of responsibility is 40 to 52 degrees...

  12. International Ice Patrol (IIP) Iceberg Sightings Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The International Ice Patrol (IIP) has been collecting information on iceberg activity in the North Atlantic since 1911. This database contains the data from these...

  13. Galaxy Zoo Supernovae

    CERN Document Server

    Smith, A M; Sullivan, M; Lintott, C J; Nugent, P E; Botyanszki, J; Kasliwal, M; Quimby, R; Bamford, S P; Fortson, L F; Schawinski, K; Hook, I; Blake, S; Podsiadlowski, P; Joensson, J; Gal-Yam, A; Arcavi, I; Howell, D A; Bloom, J S; Jacobsen, J; Kulkarni, S R; Law, N M; Ofek, E O; Walters, R

    2010-01-01

    This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae. This proof of concept project uses members of the public to identify supernova candidates from the latest generation of wide-field imaging transient surveys. We describe the Galaxy Zoo Supernovae operations and scoring model, and demonstrate the effectiveness of this novel method using imaging data and transients from the Palomar Transient Factory (PTF). We examine the results collected over the period April-July 2010, during which nearly 14,000 supernova candidates from PTF were classified by more than 2,500 individuals within a few hours of data collection. We compare the transients selected by the citizen scientists to those identified by experienced PTF scanners, and find the agreement to be remarkable - Galaxy Zoo Supernovae performs comparably to the PTF scanners, and identified as transients 93% of the ~130 spectroscopically confirmed SNe that PTF located during the trial period (with no false positive iden...

  14. Optimal Patrol to Detect Attacks at Dispersed Heterogeneous Locations

    Science.gov (United States)

    2013-12-01

    path with one revisit SPR2 Shortest path with two revisits SPR3 Shortest path with three revisits TSP Traveling salesman problem UAV Unmanned aerial...path patrol pattern. Finding the shortest-path patrol pattern is an example of solving a traveling salesman problem , as described in Section 16.5 of...use of patrol paths based on the traveling salesman prob- lem (TSP), where patrollers follow the shortest Hamiltonian cycle in a graph in order to

  15. Sonneberg Sky Patrol Archive - Photometric Analysis

    CERN Document Server

    Spasovic, Milan; Lange, Christian; Jovanovic, Dragan; Schrimpf, Andreas

    2016-01-01

    The Sonneberg Sky Patrol archive so far has not yet been analyzed systematically. In this paper we present first steps towards an automated photometric analysis aiming at the search for variable stars and transient phenomena like novae. Early works on the sky patrol plates showed that photometric accuracy can be enhanced with fitting algorithms. The procedure used was a manually supported click-and-fit-routine, not suitable for automatic analysis of vast amount of photographic plates. We will present our progress on deconvolution of overlapping sources on the plates and compare photometric analysis using different methods. Our goal is to get light curves of sufficient quality from sky patrol plates, which can be classified with machine learning algorithms. The development of an automated scheme for finding transient events is in progress and the first results are very promising.

  16. Matching Supernovae to Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    One of the major challenges for modern supernova surveys is identifying the galaxy that hosted each explosion. Is there an accurate and efficient way to do this that avoids investing significant human resources?Why Identify Hosts?One problem in host galaxy identification. Here, the supernova lies between two galaxies but though the centroid of the galaxy on the right is closer in angular separation, this may be a distant background galaxy that is not actually near the supernova. [Gupta et al. 2016]Supernovae are a critical tool for making cosmological predictions that help us to understand our universe. But supernova cosmology relies on accurately identifying the properties of the supernovae including their redshifts. Since spectroscopic followup of supernova detections often isnt possible, we rely on observations of the supernova host galaxies to obtain redshifts.But how do we identify which galaxy hosted a supernova? This seems like a simple problem, but there are many complicating factors a seemingly nearby galaxy could be a distant background galaxy, for instance, or a supernovas host could be too faint to spot.The authors algorithm takes into account confusion, a measure of how likely the supernova is to be mismatched. In these illustrations of low (left) and high (right) confusion, the supernova is represented by a blue star, and the green circles represent possible host galaxies. [Gupta et al. 2016]Turning to AutomationBefore the era of large supernovae surveys, searching for host galaxies was done primarily by visual inspection. But current projects like the Dark Energy Surveys Supernova Program is finding supernovae by the thousands, and the upcoming Large Synoptic Survey Telescope will likely discover hundreds of thousands. Visual inspection will not be possible in the face of this volume of data so an accurate and efficient automated method is clearly needed!To this end, a team of scientists led by Ravi Gupta (Argonne National Laboratory) has recently

  17. Supernova detection

    Energy Technology Data Exchange (ETDEWEB)

    Nakahata, Masayuki [Kamioka Observatory, Institute for Cosmic Ray research, University of Tokyo, Higashi-Mozumi, Kamioka-cho, Hida-shi, Gifu, Japan, 506-1205 (Japan)], E-mail: nakahata@suketto.icrr.u-tokyo.ac.jp

    2008-11-01

    The detection of supernova neutrinos is reviewed, focusing on the current status of experiments to detect supernova burst neutrinos and supernova relic neutrinos. The capabilities of each detector currently operating and in development are assessed and the likely neutrino yield for a future supernova is estimated. It is expected that much more information will be obtained if a supernova burst were to occur in our Galaxy than was obtained for supernova SN1987A. The detection of supernova relic neutrinos is considered and it is concluded that a large volume detector with a neutron tagging technique is necessary.

  18. Galaxy Zoo Supernovae

    Science.gov (United States)

    Smith, A. M.; Lynn, S.; Sullivan, M.; Lintott, C. J.; Nugent, P. E.; Botyanszki, J.; Kasliwal, M.; Quimby, R.; Bamford, S. P.; Fortson, L. F.; Schawinski, K.; Hook, I.; Blake, S.; Podsiadlowski, P.; Jönsson, J.; Gal-Yam, A.; Arcavi, I.; Howell, D. A.; Bloom, J. S.; Jacobsen, J.; Kulkarni, S. R.; Law, N. M.; Ofek, E. O.; Walters, R.

    2011-04-01

    This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae. This proof-of-concept project uses members of the public to identify supernova candidates from the latest generation of wide-field imaging transient surveys. We describe the Galaxy Zoo Supernovae operations and scoring model, and demonstrate the effectiveness of this novel method using imaging data and transients from the Palomar Transient Factory (PTF). We examine the results collected over the period 2010 April-July, during which nearly 14 000 supernova candidates from the PTF were classified by more than 2500 individuals within a few hours of data collection. We compare the transients selected by the citizen scientists to those identified by experienced PTF scanners and find the agreement to be remarkable - Galaxy Zoo Supernovae performs comparably to the PTF scanners and identified as transients 93 per cent of the ˜130 spectroscopically confirmed supernovae (SNe) that the PTF located during the trial period (with no false positive identifications). Further analysis shows that only a small fraction of the lowest signal-to-noise ratio detections (r > 19.5) are given low scores: Galaxy Zoo Supernovae correctly identifies all SNe with ≥8σ detections in the PTF imaging data. The Galaxy Zoo Supernovae project has direct applicability to future transient searches, such as the Large Synoptic Survey Telescope, by both rapidly identifying candidate transient events and via the training and improvement of existing machine classifier algorithms. This publication has been made possible by the participation of more than 10 000 volunteers in the Galaxy Zoo Supernovae project ().

  19. Hanford Patrol Academy demolition sites closure plan

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-30

    The Hanford Site is owned by the U.S. Government and operated by the U.S. Department of Energy, Richland Operations Office. Westinghouse Hanford Company is a major contractor to the U.S. Department of Energy, Richland Operations Office and serves as co-operator of the Hanford Patrol Academy Demolition Sites, the unit addressed in this paper. This document consists of a Hanford Facility Dangerous Waste Part A Permit Application, Form 3 (Revision 4), and a closure plan for the site. An explanation of the Part A Form 3 submitted with this closure plan is provided at the beginning of the Part A section. This Hanford Patrol Academy Demolition Sites Closure Plan submittal contains information current as of December 15, 1994.

  20. The Optimal Dispatch of Traffic and Patrol Police Service Platforms

    Directory of Open Access Journals (Sweden)

    Ke Quan Zhao

    2012-01-01

    Full Text Available The main goal of this paper is to present a minmax programming model for the optimal dispatch of Traffic and Patrol Police Service Platforms with single traffic congestion. The objective is to minimize the longest time of the dispatch for Traffic and Patrol Police Service Platforms. Some numerical experiments are carried out, and the optimal project is given.

  1. Supernova VLBI

    Science.gov (United States)

    Bartel, N.

    2009-08-01

    We review VLBI observations of supernovae over the last quarter century and discuss the prospect of imaging future supernovae with space VLBI in the context of VSOP-2. From thousands of discovered supernovae, most of them at cosmological distances, ˜50 have been detected at radio wavelengths, most of them in relatively nearby galaxies. All of the radio supernovae are Type II or Ib/c, which originate from the explosion of massive progenitor stars. Of these, 12 were observed with VLBI and four of them, SN 1979C, SN 1986J, SN 1993J, and SN 1987A, could be imaged in detail, the former three with VLBI. In addition, supernovae or young supernova remnants were discovered at radio wavelengths in highly dust-obscured galaxies, such as M82, Arp 299, and Arp 220, and some of them could also be imaged in detail. Four of the supernovae so far observed were sufficiently bright to be detectable with VSOP-2. With VSOP-2 the expansion of supernovae can be monitored and investigated with unsurpassed angular resolution, starting as early as the time of the supernova's transition from its opaque to transparent stage. Such studies can reveal, in a movie, the aftermath of a supernova explosion shortly after shock break out.

  2. Supernova explosions

    CERN Document Server

    Branch, David

    2017-01-01

    Targeting advanced students of astronomy and physics, as well as astronomers and physicists contemplating research on supernovae or related fields, David Branch and J. Craig Wheeler offer a modern account of the nature, causes and consequences of supernovae, as well as of issues that remain to be resolved. Owing especially to (1) the appearance of supernova 1987A in the nearby Large Magellanic Cloud, (2) the spectacularly successful use of supernovae as distance indicators for cosmology, (3) the association of some supernovae with the enigmatic cosmic gamma-ray bursts, and (4) the discovery of a class of superluminous supernovae, the pace of supernova research has been increasing sharply. This monograph serves as a broad survey of modern supernova research and a guide to the current literature. The book’s emphasis is on the explosive phases of supernovae. Part 1 is devoted to a survey of the kinds of observations that inform us about supernovae, some basic interpreta tions of such data, and an overview of t...

  3. Patrolling Monocytes Control Tumor Metastasis to the Lung

    Science.gov (United States)

    Hanna, Richard N.; Cekic, Caglar; Sag, Duygu; Tacke, Robert; Thomas, Graham D.; Nowyhed, Heba; Herrley, Erica; Rasquinha, Nicole; McArdle, Sara; Wu, Runpei; Peluso, Esther; Metzger, Daniel; Ichinose, Hiroshi; Shaked, Iftach; Chodaczek, Grzegorz; Biswas, Subhra K.; Hedrick, Catherine C.

    2016-01-01

    The immune system plays an important role in regulating tumor growth and metastasis. For example, classical monocytes promote tumorigenesis and cancer metastasis; however, how nonclassical “patrolling” monocytes interact with tumors is unknown. Here we show that patrolling monocytes are enriched in the microvasculature of the lung and reduce tumor metastasis to lung in multiple mouse metastatic tumor models. Nr4a1-deficient mice, which specifically lack patrolling monocytes, showed increased lung metastasis in vivo. Transfer of Nr4a1-proficient patrolling monocytes into Nr4a1-deficient mice prevented tumor invasion in lung. Patrolling monocytes established early interactions with metastasizing tumor cells, scavenged tumor material from the lung vasculature and promoted natural killer cell recruitment and activation. Thus, patrolling monocytes contribute to cancer immunosurveillance and may be targets for cancer immunotherapy. PMID:26494174

  4. Aspherical supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kasen, Daniel Nathan [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3

  5. Aspherical supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kasen, Daniel Nathan

    2004-05-21

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3

  6. DESIGNING DAILY PATROL ROUTES FOR POLICING BASED ON ANT COLONY ALGORITHM

    Directory of Open Access Journals (Sweden)

    H. Chen

    2015-07-01

    Full Text Available In this paper, we address the problem of planning police patrol routes to regularly cover street segments of high crime density (hotspots with limited police forces. A good patrolling strategy is required to minimise the average time lag between two consecutive visits to hotspots, as well as coordinating multiple patrollers and imparting unpredictability in patrol routes. Previous studies have designed different police patrol strategies for routing police patrol, but these strategies have difficulty in generalising to real patrolling and meeting various requirements. In this research we develop a new police patrolling strategy based on Bayesian method and ant colony algorithm. In this strategy, virtual marker (pheromone is laid to mark the visiting history of each crime hotspot, and patrollers continuously decide which hotspot to patrol next based on pheromone level and other variables. Simulation results using real data testifies the effective, scalable, unpredictable and extensible nature of this strategy.

  7. Designing Daily Patrol Routes for Policing Based on ANT Colony Algorithm

    Science.gov (United States)

    Chen, H.; Cheng, T.; Wise, S.

    2015-07-01

    In this paper, we address the problem of planning police patrol routes to regularly cover street segments of high crime density (hotspots) with limited police forces. A good patrolling strategy is required to minimise the average time lag between two consecutive visits to hotspots, as well as coordinating multiple patrollers and imparting unpredictability in patrol routes. Previous studies have designed different police patrol strategies for routing police patrol, but these strategies have difficulty in generalising to real patrolling and meeting various requirements. In this research we develop a new police patrolling strategy based on Bayesian method and ant colony algorithm. In this strategy, virtual marker (pheromone) is laid to mark the visiting history of each crime hotspot, and patrollers continuously decide which hotspot to patrol next based on pheromone level and other variables. Simulation results using real data testifies the effective, scalable, unpredictable and extensible nature of this strategy.

  8. Special report of Horsefeldt-White River patrol

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers a patrol made by horseback and pack train from the headwaters of the copper River across the upper drainage to the Tanana River and terminating on...

  9. Road and Street Centerlines - MO 2010 Highway Patrol Districts (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This is a representation of current Missouri Highway Patrol Districts. Derived from TIGER/Line Files this shapefile and related database files (.dbf) that are an...

  10. 46 CFR 78.30-10 - Supervised patrol.

    Science.gov (United States)

    2010-10-01

    ..., Pilothouse Watch, Patrolmen, and Watchmen § 78.30-10 Supervised patrol. (a) The provisions of this section... approved. The stations shall be numbered as required by § 78.47-23. Sufficient watchmen shall be...

  11. SSL Demonstration: Area Lighting, Yuma Sector Border Patrol Area, AZ

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-05-28

    Along the Yuma Sector Border Patrol Area in Yuma, Arizona, the GATEWAY program conducted a trial demonstration in which the incumbent quartz metal halide area lighting was replaced with LED at three pole locations at the Yuma Sector Border Patrol Area in Yuma, Arizona. The retrofit was documented to better understand LED technology performance in high-temperature environments. This document is a summary brief of the Phase 1.0 and 1.1 reports previously published on this demonstration.

  12. Patrolling Monocytes Control Tumor Metastasis to the Lung

    OpenAIRE

    Hanna, Richard N.; Cekic, Caglar; Sag, Duygu; Tacke, Robert; Graham D. Thomas; Nowyhed, Heba; Herrley, Erica; Rasquinha, Nicole; McArdle, Sara; Wu, Runpei; Peluso, Esther; Metzger, Daniel; Ichinose, Hiroshi; Shaked, Iftach; Chodaczek, Grzegorz

    2015-01-01

    The immune system plays an important role in regulating tumor growth and metastasis. For example, classical monocytes promote tumorigenesis and cancer metastasis; however, how nonclassical “patrolling” monocytes interact with tumors is unknown. Here we show that patrolling monocytes are enriched in the microvasculature of the lung and reduce tumor metastasis to lung in multiple mouse metastatic tumor models. Nr4a1-deficient mice, which specifically lack patrolling monocytes, showed increased ...

  13. Simulation Combined Approach to Police Patrol Services Staffing

    OpenAIRE

    Zhang, Hanjing; Tako, Antuela; Lisa M. Jackson; Liu, Jiyin

    2016-01-01

    Motivated by the squeeze on public service expenditure, staffing is an important issue for service systems, which are required to maintain or even improve their service levels in order to meet general public demand. This paper considers Police Patrol Service Systems (PPSSs) where staffing issues are extremely serious and important because they have an impact on service costs, quality and public-safety. Police patrol service systems are of particularly interest because the demand for service e...

  14. Supernova Photometric Classification Challenge

    CERN Document Server

    Kessler, Richard; Jha, Saurabh; Kuhlmann, Stephen

    2010-01-01

    We have publicly released a blinded mix of simulated SNe, with types (Ia, Ib, Ic, II) selected in proportion to their expected rate. The simulation is realized in the griz filters of the Dark Energy Survey (DES) with realistic observing conditions (sky noise, point spread function and atmospheric transparency) based on years of recorded conditions at the DES site. Simulations of non-Ia type SNe are based on spectroscopically confirmed light curves that include unpublished non-Ia samples donated from the Carnegie Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan Digital Sky Survey-II (SDSS-II). We challenge scientists to run their classification algorithms and report a type for each SN. A spectroscopically confirmed subset is provided for training. The goals of this challenge are to (1) learn the relative strengths and weaknesses of the different classification algorithms, (2) use the results to improve classification algorithms, and (3) understand what spectroscopically confirmed sub-...

  15. Supernova Science Center

    Energy Technology Data Exchange (ETDEWEB)

    S. E. Woosley

    2008-05-05

    The Supernova Science Center (SNSC) was founded in 2001 to carry out theoretical and computational research leading to a better understanding of supernovae and related transients. The SNSC, a four-institutional collaboration, included scientists from LANL, LLNL, the University of Arizona (UA), and the University of California at Santa Cruz (UCSC). Intitially, the SNSC was funded for three years of operation, but in 2004 an opportunity was provided to submit a renewal proposal for two years. That proposal was funded and subsequently, at UCSC, a one year no-cost extension was granted. The total operational time of the SNSC was thus July 15, 2001 - July 15, 2007. This document summarizes the research and findings of the SNSC and provides a cummulative publication list.

  16. Medical Scientists

    Science.gov (United States)

    ... Projected Employment, 2024 Change, 2014-24 Employment by Industry Percent Numeric SOURCE: U.S. Bureau of Labor Statistics, Employment Projections program Medical scientists, except epidemiologists 19- ...

  17. Smoking Supernovae

    CERN Document Server

    Gomez, H L; Dunne, L

    2007-01-01

    The question "Are supernovae important sources of dust?" is a contentious one. Observations with the Infrared Astronomical Satellite (IRAS) and the Infrared Space Observatory (ISO) only detected very small amounts of hot dust in supernova remnants. Here, we review observations of two young Galactic remnants with the Submillimetre Common User Bolometer Array (SCUBA), which imply that large quantities of dust are produced by supernovae. The association of dust with the Cassiopeia A remnant is in question due to the contamination of foreground material. In this article, we compare the emission from cold dust with CO emission towards Kepler's supernova remnant. We detect very little CO at the location of the submillimetre peaks. A comparison of masses from the CO and the dust clouds are made, and we estimate the 3 sigma upper limit on the gas-to-dust ratios to range from 25 - 65 suggesting that we cannot yet rule out freshly-formed or swept up circumstellar dust in Kepler's supernova remnant.

  18. Robust Scientists

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    2012-01-01

    as the analytical framework for descri bing the complex relationship between academic science and its so called “external” habitat. Although relational skills and adaptability do seem to be at the heart of successful research management, the key to success does not lie with the ability to assimilate to industrial...... knowledge", Danish research policy seems to have helped develop politically and economically "robust scientists". Scientific robustness is acquired by way of three strategies: 1) tasting and discriminating between resources so as to avoid funding that erodes academic profiles and push scientists away from...... and industrial intere sts. The paper concludes by stressing the potential danger of policy habitats who have promoted the evolution of robust scientists based on a competitive system where only the fittest survive. Robust scientists, it is argued, have the potential to become a new “invasive species...

  19. Study of ground handling characteristics of a maritime patrol airship

    Science.gov (United States)

    1981-01-01

    Mooring concepts appropriate for maritime patrol airship (MPA) vehicles are investigated. The evolution of ground handling systems and procedures for all airship types is reviewed to ensure that appropriate consideration is given to past experiences. A tri-rotor maritime patrol airship is identified and described. Wind loads on a moored airship and the effects of these loads on vehicle design are analyzed. Several mooring concepts are assessed with respect to the airship design, wind loads, and mooring site considerations. Basing requirements and applicability of expeditionary mooring also are addressed.

  20. Practical results from a mathematical analysis of guard patrols

    Energy Technology Data Exchange (ETDEWEB)

    Indusi, Joseph P.

    1978-12-01

    Using guard patrols as a primary detection mechanism is not generally viewed as a highly efficient detection method when compared to electronic means. Many factors such as visibility, alertness, and the space-time coincidence of guard and adversary presence all have an effect on the probability of detection. Mathematical analysis of the guard patrol detection problem is related to that of classical search theory originally developed for naval search operations. The results of this analysis tend to support the current practice of using guard forces to assess and respond to previously detected intrusions and not as the primary detection mechanism. 6 refs.

  1. SOUSA's Swift Supernova Siblings

    CERN Document Server

    Brown, Peter J

    2015-01-01

    Swift has observed over three hundred supernovae in its first ten years. Photometry from the Ultra-Violet Optical Telescope (UVOT) is being compiled in the Swift Optical/Ultraviolet Supernovae Archive (SOUSA). The diversity of supernovae leads to a wide dynamic range of intrinsic properties. The intrinsic UV brightness of supernovae as a function of type and epoch allows one to understand the distance ranges at which Swift can reliably detect supernovae. The large Swift sample also includes supernovae from the same galaxy as other Swift supernovae. Through the first ten years, these families include 34 supernovae from 16 host galaxies (two galaxies have each hosted three Swift supernovae).

  2. Simulating Supernova Light Curves

    Energy Technology Data Exchange (ETDEWEB)

    Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  3. Robust Scientists

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    The concepts of “socially robust knowledge” and “mode 2 knowledge production” (Nowotny 2003, Gibbons et al. 1994) have migrated from STS into research policy practices. Both STS-scholars and policy makers have been known to propomote the idea that the way forward for today’s scientist is to jump...... from the ivory tower and learn how to create high-flying synergies with citizens, corporations and governments. In STS as well as in Danish research policy it has thus been argued that scientists will gain more support and enjoy greater success in their work by “externalizing” their research...... and adapting their interests to the needs of outside actors. However, when studying the concrete strategies of such successful scientists, matters seem a bit more complicated. Based on interviews with a plant biologist working in GMO the paper uses the biological concepts of field participants...

  4. 49 CFR 192.705 - Transmission lines: Patrolling.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Patrolling. 192.705 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.705 Transmission... adjacent to the transmission line right-of-way for indications of leaks, construction activity, and...

  5. The First Team of Patrol Policewomen in China

    Institute of Scientific and Technical Information of China (English)

    JANE SHAW

    1996-01-01

    IN June 1994, the Public Security Bureau of Beijing selected 66 young women from universities, colleges and some other units and founded the first team of patrol policewomen in China. At a personnel exchange meeting for university and technical secondary school graduates held at the Beijing International Exhibition Center, the Public Security Bureau looked for

  6. Cardiometabolic Health in Submariners Returning from a 3-Month Patrol

    Directory of Open Access Journals (Sweden)

    Heath G. Gasier

    2016-02-01

    Full Text Available Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF% ≥ 25% (obesity, and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR, leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5% and fat-mass (11% occurred in the obese group as a result of reduced energy intake (~2000 kJ during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population.

  7. Game Theory Models for Multi-Robot Patrolling of Infrastructures

    Directory of Open Access Journals (Sweden)

    Erik Hernández

    2013-03-01

    Full Text Available This work is focused on the problem of performing multi‐robot patrolling for infrastructure security applications in order to protect a known environment at critical facilities. Thus, given a set of robots and a set of points of interest, the patrolling task consists of constantly visiting these points at irregular time intervals for security purposes. Current existing solutions for these types of applications are predictable and inflexible. Moreover, most of the previous work has tackled the patrolling problem with centralized and deterministic solutions and only few efforts have been made to integrate dynamic methods. Therefore, one of the main contributions of this work is the development of new dynamic and decentralized collaborative approaches in order to solve the aforementioned problem by implementing learning models from Game Theory. The model selected in this work that includes belief‐based and reinforcement models as special cases is called Experience‐Weighted Attraction. The problem has been defined using concepts of Graph Theory to represent the environment in order to work with such Game Theory techniques. Finally, the proposed methods have been evaluated experimentally by using a patrolling simulator. The results obtained have been compared with previous available approaches.

  8. Ranking scientists

    CERN Document Server

    Dorogovtsev, S N

    2015-01-01

    Currently the ranking of scientists is based on the $h$-index, which is widely perceived as an imprecise and simplistic though still useful metric. We find that the $h$-index actually favours modestly performing researchers and propose a simple criterion for proper ranking.

  9. Playing Scientist

    Science.gov (United States)

    Campbell, Ashley

    2012-01-01

    Engaging students in the study of genetics is essential to building a deep understanding of heredity, a core idea in the life sciences (NRC 2012). By integrating into the curriculum the stories of famous scientists who studied genetics (e.g., Mendel, Franklin, Watson, and Crick), teachers remind their students that science is a human endeavor.…

  10. Supernova Forensics

    Science.gov (United States)

    Soderberg, Alicia M.

    2014-01-01

    For decades, the study of stellar explosions -- supernovae -- have focused almost exclusively on the strong optical emission that dominates the bolometric luminosity in the days following the ultimate demise of the star. Yet many of the leading breakthroughs in our understanding of stellar death have been enabled by obtaining data at other wavelengths. For example, I have shown that 1% of all supernovae give rise to powerful relativistic jets, representing the biggest bangs in the Universe since the Big Bang. My recent serendipitous X-ray discovery of a supernova in the act of exploding (“in flagrante delicto”) revealed a novel technique to discover new events and provide clues on the shock physics at the heart of the explosion. With the advent of sensitive new radio telescopes, my research group combines clues from across the electromagnetic spectrum (radio to gamma-ray), leading us to a holistic study of stellar death, the physics of the explosions, and their role in fertilizing the Universe with new elements, by providing the community with cosmic autopsy reports.

  11. First supernova companion star found

    Science.gov (United States)

    2004-01-01

    , 2100 seconds and 330W, 1200 seconds) shown in purple and blue, a deep blue filter (435W, 1000 seconds) shown in green and a green filter (555W, 1120 seconds) shown in red. The quarter-circle around the supernova companion is a so-called light echo originating from sheets of dust in the galaxy reflecting light from the original supernova explosion. The timing of the appearance of these echoes can be used to map out the dust structure around the supernova. The light echo was detected in late 2002 and early 2003 by two competing groups of scientists. Messier 81 spiral arm (WFPC2 image) hi-res Size hi-res: 1502 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Messier 81 spiral arm (WFPC2 image) This NASA/ESA Hubble Space Telescope image shows a small portion of one of Messier 81’s spiral arms. It extends about 0.03 x 0.03 degrees. The supernova companion is the bluish star in the upper right hand corner. Dust lanes in the spiral arms of the galaxy are seen, as well as many other stars and a few star forming nebulae. The image is composed of four separate exposures from the ESO/ST-ECF Archive through a blue filter, a green filter, a red filter and a near-infrared filter. The image was taken with Hubble’s Wide Field and Planetary Camera 2. Acknowledgement: Bob Kirshner (Harvard University, USA) Grand Spiral Messier 81 (ground-based) hi-res Size hi-res: 1502 kb Credits: ESA/INT/DSS2 Grand Spiral Messier 81 (ground-based) This ground-based image shows the spiral galaxy Messier 81 in its entirety. The image is a combination of exposures from the Isaac Newton Telescope on La Palma (courtesy of Jonathan Irwin) and Digitized Sky Survey 2 images. The dynamic duo, Messier 81 and 82 (ground-based) hi-res Size hi-res: 1502 kb Credits: Robert Gendler (http://www.robgendlerastropics.com) The dynamic duo, Messier 81 and 82 (ground-based) This wide-angle image taken by astrophotographer Robert Gendler shows the amazing duo of Messier 81 (right) and Messier 82 (left

  12. The Search for Lensed Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    Type Ia supernovae that have multiple images due to gravitational lensing can provide us with a wealth of information both about the supernovae themselves and about our surrounding universe. But how can we find these rare explosions?Clues from Multiple ImagesWhen light from a distant object passes by a massive foreground galaxy, the galaxys strong gravitational pull can bend the light, distorting our view of the backgroundobject. In severe cases, this process can cause multiple images of the distant object to appear in the foreground lensing galaxy.An illustration of gravitational lensing. Light from the distant supernova is bent as it passes through a giant elliptical galaxy in the foreground, causing multiple images of the supernova to appear to be hosted by the elliptical galaxy. [Adapted from image by NASA/ESA/A. Feild (STScI)]Observations of multiply-imaged Type Ia supernovae (explosions that occur when white dwarfs in binary systems exceed their maximum allowed mass) could answer a number of astronomical questions. Because Type Ia supernovae are standard candles, distant, lensed Type Ia supernovae can be used to extend the Hubble diagram to high redshifts. Furthermore, the lensing time delays from the multiply-imaged explosion can provide high-precision constraints on cosmological parameters.The catch? So far, weve only found one multiply-imaged Type Ia supernova: iPTF16geu, discovered late last year. Were going to need a lot more of them to develop a useful sample! So how do we identify themutiply-imaged Type Ias among the many billions of fleeting events discovered in current and future surveys of transients?Searching for AnomaliesAbsolute magnitudes for Type Ia supernovae in elliptical galaxies. None are expected to be above -20 in the B band, so if we calculate a magnitude for a Type Ia supernova thats larger than this, its probably not hosted by the galaxy we think it is! [Goldstein Nugent 2017]Two scientists from University of California, Berkeley and

  13. The Shape of Superluminous Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    What causes the tremendous explosions of superluminous supernovae? New observations reveal the geometry of one such explosion, SN 2015bn, providing clues as to its source.A New Class of ExplosionsImage of a type Ia supernova in the galaxy NGC 4526. [NASA/ESA]Supernovae are powerful explosions that can briefly outshine the galaxies that host them. There are several different classifications of supernovae, each with a different physical source such as thermonuclear instability in a white dwarf, caused by accretion of too much mass, or the exhaustion of fuel in the core of a massive star, leading to the cores collapse and expulsion of its outer layers.In recent years, however, weve detected another type of supernovae, referred to as superluminous supernovae. These particularly energetic explosions last longer months instead of weeks and are brighter at their peaks than normal supernovae by factors of tens to hundreds.The physical cause of these unusual explosions is still a topic of debate. Recently, however, a team of scientists led by Cosimo Inserra (Queens University Belfast) has obtained new observations of a superluminous supernova that might help address this question.The flux and the polarization level (black lines) along the dominant axis of SN 2015bn, 24 days before peak flux (left) and 28 days after peak flux (right). Blue lines show the authors best-fitting model. [Inserra et al. 2016]Probing GeometryInserra and collaborators obtained two sets of observations of SN 2015bn one roughly a month before and one a month after the superluminous supernovas peak brightness using a spectrograph on the Very Large Telescope in Chile. These observations mark the first spectropolarimetric data for a superluminous supernova.Spectropolarimetry is the practice of obtaining information about the polarization of radiation from an objects spectrum. Polarization carries information about broken spatial symmetries in the object: only if the object is perfectly symmetric can it

  14. Sustainable Scientists

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Evan

    2008-12-31

    Scientists are front and center in quantifying and solving environmental problems. Yet, as a spate of recent news articles in scientific journals point out, much can be done to enhance sustainability within the scientific enterprise itself, particularly by trimming the energy use associated with research facilities and the equipment therein (i,ii,iii, iv). Sponsors of research unwittingly spend on the order of $10 billion each year on energy in the U.S. alone, and the underlying inefficiencies drain funds from the research enterprise while causing 80 MT CO2-equivalent greenhouse-gas emissions (see Box). These are significant sums considering the opportunity costs in terms of the amount of additional research that could be funded and emissions that could be reduced if the underlying energy was used more efficiently. By following commercially proven best practices in facility design and operation, scientists--and the sponsors of science--can cost-effectively halve these costs, while doing their part to put society on alow-carbon diet.

  15. Detection of Supernova Neutrinos

    OpenAIRE

    Bekman, B.; Holeczek, J.; Kisiel, J4

    2004-01-01

    Matter effects on neutrino oscillations in both, a supernova and the Earth, change the observed supernova neutrino spectra. We calculate the expected number of supernova neutrino interactions for ICARUS, SK and SNO detectors as a function of the distance which they traveled in the Earth. Calculations are performed for supernova type II at 10kpc from the Earth, using standard supernova neutrino fluxes described by thermal Fermi--Dirac distributions and the PREM I Earth matter density profile.

  16. Evidence for Nearby Supernova Explosions

    CERN Document Server

    Benítez, N; Canelles, M; Benitez, Narciso; Maiz-Apellaniz, Jesus; Canelles, Matilde

    2002-01-01

    Supernova explosions are one of the most energetic--and potentially lethal--phenomena in the Universe. Scientists have speculated for decades about the possible consequences for life on Earth of a nearby supernova, but plausible candidates for such an event were lacking. Here we show that the Scorpius-Centaurus OB association, a group of young stars currently located at~130 parsecs from the Sun, has generated 20 SN explosions during the last 11 Myr, some of them probably as close as 40 pc to our planet. We find that the deposition on Earth of 60Fe atoms produced by these explosions can explain the recent measurements of an excess of this isotope in deep ocean crust samples. We propose that ~2 Myr ago, one of the SNe exploded close enough to Earth to seriously damage the ozone layer, provoking or contributing to the Pliocene-Pleistocene boundary marine extinction.

  17. Physiological stresses related to hypercapnia during patrols on submarines.

    Science.gov (United States)

    Schaeffer, K E

    1979-01-01

    Physiological studies on hypercapnic effects carried out on 13 Polaris patrols are summarized. The average CO2 concentrations ranged from 0.7-1% CO2; CO2 was identified as the only environmental contaminant of the submarine atmosphere that has a direct effect on respiration in the concentration range found in the submarine atmosphere. A comparison has been made of physiological effects produced during 42 days of exposure to 1.5% CO2 during laboratory studies (L.S.) with those observed during 50 to 60 days of exposure to 0.7-1% CO2 on patrols (P.S.). A close similarity was found in the effects on respiration and blood electrolytes under both conditions. Respiratory minute volume was elevated by 50-63% because of increased tidal volume. The physiological dead space increased 60%. Vital capacity showed a trend toward a decrease. Studies of acid-base balance carried out during patrols demonstrated cyclic changes in blood pH and bicarbonate; pH and blood bicarbonate fell during the first 17 days of exposure, rose during the subsequent 20 days, and decreased again after 40 days. These cycles cannot be explained on the basis of known renal regulations in CO2-induced acidosis and were not found during exposure to 1.5% CO2. The hypothesis is advanced that these changes in acid-base balance are caused by cycles in CO2 uptake and release in bones. The time constants of the bond CO2 stores fit the observed length of cycles in acid-base balance. Correlation with cycles of calcium metabolism provides further support for this hypothesis. Red cell electrolytes showed similar changes under 1.5% CO2 (L.S.) and 0.7-1% CO2 (P.S.). Red cell sodium increased and potassium decreased. Moreover, red cell calcium also increased under both conditions. The significance of these red cell electrolyte changes in regard to changes in permeability and active transport remains to be clarified. An increased gastric acidity was found during patrol (exposure to 0.8-0.95% CO2). The changes observed

  18. Luminous Supernovae

    CERN Document Server

    Gal-Yam, Avishay

    2012-01-01

    Supernovae (SNe), the luminous explosions of stars, were observed since antiquity, with typical peak luminosity not exceeding 1.2x10^{43} erg/s (absolute magnitude >-19.5 mag). It is only in the last dozen years that numerous examples of SNe that are substantially super-luminous (>7x10^{43} erg/s; <-21 mag absolute) were well-documented. Reviewing the accumulated evidence, we define three broad classes of super-luminous SN events (SLSNe). Hydrogen-rich events (SLSN-II) radiate photons diffusing out from thick hydrogen layers where they have been deposited by strong shocks, and often show signs of interaction with circumstellar material. SLSN-R, a rare class of hydrogen-poor events, are powered by very large amounts of radioactive 56Ni and arguably result from explosions of very massive stars due to the pair instability. A third, distinct group of hydrogen-poor events emits photons from rapidly-expanding hydrogen-poor material distributed over large radii, and are not powered by radioactivity (SLSN-I). Thes...

  19. Risk analysis of Safety Service Patrol (SSP) systems in Virginia.

    Science.gov (United States)

    Dickey, Brett D; Santos, Joost R

    2011-12-01

    The transportation infrastructure is a vital backbone of any regional economy as it supports workforce mobility, tourism, and a host of socioeconomic activities. In this article, we specifically examine the incident management function of the transportation infrastructure. In many metropolitan regions, incident management is handled primarily by safety service patrols (SSPs), which monitor and resolve roadway incidents. In Virginia, SSP allocation across highway networks is based typically on average vehicle speeds and incident volumes. This article implements a probabilistic network model that partitions "business as usual" traffic flow with extreme-event scenarios. Results of simulated network scenarios reveal that flexible SSP configurations can improve incident resolution times relative to predetermined SSP assignments.

  20. Balancing Play, Meaning and Reality: The Design Philosophy of LEVEE PATROLLER

    Science.gov (United States)

    Harteveld, Casper; Guimaraes, Rui; Mayer, Igor S.; Bidarra, Rafael

    2010-01-01

    Most serious games have been developed without a proper and comprehensive design theory. To contribute to the development of such a theory, this article presents the underlying design philosophy of LEVEE PATROLLER, a game to train levee patrollers in the Netherlands. This philosophy stipulates that the design of a digital serious game is a…

  1. 77 FR 58837 - CarePatrol, Inc.; Analysis of Proposed Consent Order To Aid Public Comment

    Science.gov (United States)

    2012-09-24

    ... violations of federal law prohibiting unfair or deceptive acts or practices or unfair methods of competition... statements CarePatrol has made in Internet advertising regarding its placement services for seniors requiring...Patrol has engaged in deceptive practices in violation of Section 5(a) of the FTC Act. The proposed order...

  2. GATEWAY Demonstrations: Trial Demonstration of Area Lighting Retrofit, Yuma Border Patrol, Yuma, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, A. M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCullough, J. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-31

    Along the Yuma Sector Border Patrol Area in Yuma, Arizona, the GATEWAY program conducted a trial demonstration in which the incumbent quartz metal halide area lighting was replaced with LED at three pole locations at the Yuma Sector Border Patrol Area in Yuma, Arizona. The retrofit was documented to better understand LED technology performance in high-temperature environments.

  3. More Supernova Surprises

    Science.gov (United States)

    2010-09-24

    SEP 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE More Supernova Surprises 5a. CONTRACT NUMBER 5b. GRANT...PERSPECTIVES More Supernova Surprises ASTRONOMY J. Martin Laming Spectroscopic observations of the supernova SN1987A are providing a new window into high...a core-collapse supernova ) have stretched and motivated research that has expanded our knowledge of astrophysics. The brightest such event in

  4. SNO and Supernovae

    CERN Document Server

    Virtue, C J

    2001-01-01

    The Sudbury Neutrino Observatory (SNO) has unique capabilities as a supernova detector. In the event of a galactic supernova there are opportunities, with the data that SNO would collect, to constrain certain intrinsic neutrino properties significantly, to test details of the various models of supernova dynamics, and to provide prompt notification to the astronomical community through the Supernova Early Warning System (SNEWS). This paper consists of a discussion of these opportunities illustrated by some preliminary Monte Carlo results.

  5. THE ENGINES BEHIND SUPERNOVAE AND GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    FRYER, CHRISTOPHER LEE [Los Alamos National Laboratory

    2007-01-23

    The authors review the different engines behind supernova (SNe) and gamma-ray bursts (GRBs), focusing on those engines driving explosions in massive stars: core-collapse SNe and long-duration GRBs. Convection and rotation play important roles in the engines of both these explosions. They outline the basic physics and discuss the wide variety of ways scientists have proposed that this physics can affect the supernova explosion mechanism, concluding with a review of the current status in these fields.

  6. Patrol Vessels «Condestable Zaragoza» Class, Patrol Boats V-class and Antisubmarine Boats LAS-class

    Directory of Open Access Journals (Sweden)

    Valentin Ruesga Herreros

    2016-09-01

    Full Text Available It’s consider information about the number of ships of the Spanish fleet, that not reflected in the available literature. It’s proved that the Spanish patrol vessels of «Condestable Zaragoza»-class and French auxiliary minesweepers «Fanfaron»-classare one the same ships. The conclusion is made based on comparisons of appearance and performance of ships. There was renovated list of patrol boats V-class, shows that their history can be divided into three main stages: the first, when the boats belonged to the Secretariat militarized protection, information about boats are extremely sketchy and incomplete, the second – their inclusion in the fleet, when the information about the service enough full, but almost previous history is not reflected, and only the third stage, when the change came a new generation of boats old boats, often with the same numbers, the story is full enough. An attempt to reconstruction of the biography of LAS-class boats, it is assumed that this former Soviet boat, put the Republicans during the Civil War.

  7. Antirationalist critique or fifth column of scientism? Challenges from Doctor Who to the mad scientist trope.

    Science.gov (United States)

    Orthia, Lindy A

    2011-07-01

    Much of the public understanding of science literature dealing with fictional scientists claims that scientist villains by their nature embody an antiscience critique. I characterize this claim and its founding assumptions as the "mad scientist" trope. I show how scientist villain characters from the science fiction television series Doctor Who undermine the trope via the programme's use of rhetorical strategies similar to Gilbert and Mulkay's empiricist and contingent repertoires, which define and patrol the boundaries between "science" and "non-science." I discuss three such strategies, including the literal framing of scientist villains as "mad." All three strategies exclude the characters from science, relieve science of responsibility for their villainy, and overtly or covertly contribute to the delivery of pro-science messages consistent with rationalist scientism. I focus on scientist villains from the most popular era of Doctor Who, the mid 1970s, when the show embraced the gothic horror genre.

  8. "Type Ia Supernovae: Tools for Studying Dark Energy" Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, Stan [Lick Observatory, San Jose, CA (United States); Kasen, Dan [Univ. of California, Berkeley, CA (United States)

    2017-05-10

    Final technical report for project "Type Ia Supernovae: Tools for the Study of Dark Energy" awarded jointly to scientists at the University of California, Santa Cruz and Berkeley, for computer modeling, theory and data analysis relevant to the use of Type Ia supernovae as standard candles for cosmology.

  9. Justice for All? Issues Faced by Linguistic Minorities and Border Patrol Agents during Interpreted Arraignment Interviews

    OpenAIRE

    2015-01-01

    The Tijuana (Mexico) - San Ysidro (San Diego County, CA) international border is the world’s busiest port of entry. The US Customs and Border Protection Agency hires over 60,000 employees, 21,000 of whom are agents in the US Border Patrol. Several steps must be taken to become a border patrol agent, but being bilingual is not a pre-requisite. In order to communicate with detainees, and interrogate them, the US Border Patrol Agency hires the services of Telephone Interpreting Companies. In thi...

  10. Remote Control of a Mobile Robot for Indoor Patrol

    Directory of Open Access Journals (Sweden)

    Shih-Yao Juang

    2016-03-01

    Full Text Available This study applies smartphone, Bluetooth, and Wi-Fi wireless network to control a wheeled mobile robot (WMR remotely. The first part of this study demonstrates that the WMR can be controlled manually by a smartphone. The smartphone can remotely control the WMR for forward, backward, left-turn, and right-turn operations. The second part of this article presents object tracking. The WMR can follow a moving object through the use of image processing for object tracking and distance detection. In the third part, infrared sensor and fuzzy system algorithms are integrated into the control scheme. Through wall-following and obstacle-avoidance control, the WMR can successfully perform indoor patrol.

  11. Data Reduction Algorithm for Optical Wide Field Patrol (OWL)

    Science.gov (United States)

    Park, S.; Park, Y.; Yim, H.; Jo, J.; Moon, H.; Bae, Y.; Lim, Y.; Choi, J.; Choi, Y.; Park, J.; Son, J.

    2014-09-01

    OWL (Optical Wide-field Patrol) has a detector system which has the chopper which consists of 4 blades in front of the CCD camera to acquire efficiently the position and time information of moving objects such as artificial satellites. Using this system, it is possible to get more position data by splitting the streaks of the moving object into many pieces with fast rotating blades during tracking. At the same time, the time data of the rotating chopper can be acquired by the time tagger connected to the photo diode. In order to derive the orbits of the targets, we need a sequential data reduction procedure including the calculation of WCS (World Coordinate System) solution to transform the positions into equatorial coordinate systems, and the combination of the time data from the time tagger and the position data. We present such a data reduction procedure and the preliminary results after applying this procedure to the observation images.

  12. Supernovae neutrino pasta interaction

    Science.gov (United States)

    Lin, Zidu; Horowitz, Charles; Caplan, Matthew; Berry, Donald; Roberts, Luke

    2017-01-01

    In core-collapse supernovae, the neutron rich matter is believed to have complex structures, such as spherical, slablike, and rodlike shapes. They are collectively called ``nuclear pasta''. Supernovae neutrinos may scatter coherently on the ``nuclear pasta'' since the wavelength of the supernovae neutrinos are comparable to the nuclear pasta scale. Consequently, the neutrino pasta scattering is important to understand the neutrino opacity in the supernovae. In this work we simulated the ``nuclear pasta'' at different temperatures and densities using our semi-classical molecular dynamics and calculated the corresponding static structure factor that describes ν-pasta scattering. We found the neutrino opacities are greatly modified when the ``pasta'' exist and may have influence on the supernovae neutrino flux and average energy. Our neutrino-pasta scattering effect can finally be involved in the current supernovae simulations and we present preliminary proto neutron star cooling simulations including our pasta opacities.

  13. Supernova Neutrino Detection

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Botella, Ines, E-mail: ines.gil@ciemat.es [CIEMAT, Basic Research Department, Avenida Complutense, 22, 28040 Madrid (Spain)

    2011-07-25

    The neutrino burst from a core collapse supernova can provide information about the explosion mechanism and the mechanisms of proto neutron star cooling but also about the intrinsic properties of the neutrino such as flavor oscillations. One important question is to understand to which extend can the supernova and the neutrino physics be decoupled in the observation of a single supernova. The possibility to probe the neutrino mixing angle {theta}{sub 13} and the type of mass hierarchy from the detection of supernova neutrinos with liquid argon detectors is discussed in this paper. Moreover, a quantitatively study about the possibility to constrain the supernova parameters is presented. A very massive liquid argon detector ({approx} 100 kton) is needed to perform accurate measurements of these parameters. Finally the possible detection of the diffuse supernova neutrino background in liquid argon detectors is also described.

  14. Forensic science information needs of patrol officers: The perceptions of the patrol officers, their supervisors and administrators, detectives, and crime scene technicians

    Science.gov (United States)

    Aydogdu, Eyup

    Thanks to the rapid developments in science and technology in recent decades, especially in the past two decades, forensic sciences have been making invaluable contributions to criminal justice systems. With scientific evaluation of physical evidence, policing has become more effective in fighting crime and criminals. On the other hand, law enforcement personnel have made mistakes during the detection, protection, collection, and evaluation of physical evidence. Law enforcement personnel, especially patrol officers, have been criticized for ignoring or overlooking physical evidence at crime scenes. This study, conducted in a large American police department, was aimed to determine the perceptions of patrol officers, their supervisors and administrators, detectives, and crime scene technicians about the forensic science needs of patrol officers. The results showed no statistically significant difference among the perceptions of the said groups. More than half of the respondents perceived that 14 out of 16 areas of knowledge were important for patrol officers to have: crime scene documentation, evidence collection, interviewing techniques, firearm evidence, latent and fingerprint evidence, blood evidence, death investigation information, DNA evidence, document evidence, electronically recorded evidence, trace evidence, biological fluid evidence, arson and explosive evidence, and impression evidence. Less than half of the respondents perceived forensic entomology and plant evidence as important for patrol officers.

  15. The historical supernovae

    CERN Document Server

    Clark, David H

    1977-01-01

    The Historical Supernovae is an interdisciplinary study of the historical records of supernova. This book is composed of 12 chapters that particularly highlight the history of the Far East. The opening chapter briefly describes the features of nova and supernova, stars which spontaneously explode with a spectacular and rapid increase in brightness. The succeeding chapter deals with the search for the historical records of supernova from Medieval European monastic chronicles, Arabic chronicles, astrological works etc., post renaissance European scientific writings, and Far Eastern histories and

  16. Atomic and molecular supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  17. Design of Power Cable UAV Intelligent Patrol System Based on Adaptive Kalman Filter Fuzzy PID Control

    Directory of Open Access Journals (Sweden)

    Chen Siyu

    2017-01-01

    Full Text Available Patrol UAV has poor aerial posture stability and is largely affected by anthropic factors, which lead to some shortages such as low power cable tracking precision, captured image loss and inconvenient temperature measurement, etc. In order to solve these disadvantages, this article puts forward a power cable intelligent patrol system. The core innovation of the system is a 360° platform. This collects the position information of power cables by using far infrared sensors and carries out real-time all-direction adjustment of UAV lifting platform through the adaptive Kalman filter fuzzy PID control algorithm, so that the precise tracking of power cables is achieved. An intelligent patrol system is established to detect the faults more accurately, so that a high intelligence degree of power cable patrol system is realized.

  18. Indoor Surveillance Security Robot with a Self-Propelled Patrolling Vehicle

    Directory of Open Access Journals (Sweden)

    Hou-Tsan Lee

    2011-01-01

    Full Text Available Self-propelled patrolling vehicles can patrol periodically in the designed area to ensure the safety like men do. The proposed vehicle cannot only save manpower, but also ensure the performance without mistakes caused by man. It is different from the traditional patrolling system which is limited by the manpower and the fixed camera positions. To improve such situation, this paper proposes a self-propelled patrolling vehicle which can move automatically to a wider range and record the monitored image by IPCAM within a predefined patrolling route. Besides, the user can use the mobile device or website to connect to the vehicle at anytime and anywhere and control it to move to the position to get the indoor image user wants. The position of self-propelled vehicles can be detected by the RFID reader as a feedback and be shown on the PC screen and smart phone. The recorded images can be also transmitted back to the server via WiFi system for face tracking and discriminating analysis. On the other hand, the self-propelled vehicle patrolling routes can be modified by the Android smart-phone remote-control module. When some defined events occur, the build-in MSN module will notice users by sending messages to PC and smart phone. Experimental results are given in the paper to validate its performance.

  19. Selections from 2015: Two Kinds of Type Ia Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2015-03-01

    Editors Note:In these last two weeks of 2015, well be looking at a few selections from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume after the AAS winter meeting.The Changing Fractions of Type Ia Supernova NUVOptical Subclasses with RedshiftPublished April2015Main takeaway:A team of scientists led by Peter Milne (University of Arizona) used ultraviolet observations from the Swift spacecraft to determine that type Ia supernovae, stellar explosions previously thought to all belong in the same class, actually fall into two subgroups: those that are slightly redder in NUV wavelengths and those that are slightly bluer.Plot of the percentage of supernovae that are NUV-blue (rather than NUV-red), as a function of redshift. NUV-blue supernovae dominate at higher redshifts. [Milne et al. 2015]Why its interesting:It turns out that the fraction of supernovae in each of these two groups is redshift-dependent. At low redshifts (i.e., nearby), the population of type Ia supernovae is dominated by NUV-red supernovae. At high redshifts (i.e., far away), the population is dominated by NUV-blue supernovae. Since cosmological distances are measured using Type Ia supernovae as standard candles, the fact that weve been modeling these supernovae all the same way (rather than treating them as two separate subclasses) means we may have been systematically misinterpreting distances.What this means for the universes expansion:This seemingly simple discovery carries hefty repercussions in fact, our estimates of the expansion rate of the universe may be incorrect! The authors believe that if we correct for this error, well find that the universe is not expanding as quickly as we thought.CitationPeter A. Milne et al 2015 ApJ 803 20. doi:10.1088/0004-637X/803/1/20

  20. Neutrinos from Supernovae

    CERN Document Server

    Choubey, S; Choubey, Sandhya; Kar, Kamales

    2002-01-01

    In this review, the effect of flavor oscillations on the neutrinos released during supernova explosion after core collapse is described. In some scenarios there are large enhancement of the number of events compared to the no oscillation case. Various other features associated with supernova neutrinos are also discussed.

  1. Molecules in supernova ejecta

    CERN Document Server

    Cherchneff, Isabelle

    2011-01-01

    The first molecules detected at infrared wavelengths in the ejecta of a Type II supernova, namely SN1987A, consisted of CO and SiO. Since then, confirmation of the formation of these two species in several other supernovae a few hundred days after explosion has been obtained. However, supernova environments appear to hamper the synthesis of large, complex species due to the lack of microscopically-mixed hydrogen deep in supernova cores. Because these environments also form carbon and silicate dust, it is of importance to understand the role played by molecules in the depletion of elements and how chemical species get incorporated into dust grains. In the present paper, we review our current knowledge of the molecular component of supernova ejecta, and present new trends and results on the synthesis of molecules in these harsh, explosive events.

  2. On cooperative patrolling: optimal trajectories, complexity analysis, and approximation algorithms

    CERN Document Server

    Pasqualetti, Fabio; Bullo, Francesco

    2011-01-01

    The subject of this work is the patrolling of an environment with the aid of a team of autonomous agents. We consider both the design of open-loop trajectories with optimal properties, and of distributed control laws converging to optimal trajectories. As performance criteria, the refresh time and the latency are considered, i.e., respectively, time gap between any two visits of the same region, and the time necessary to inform every agent about an event occurred in the environment. We associate a graph with the environment, and we study separately the case of a chain, tree, and cyclic graph. For the case of chain graph, we first describe a minimum refresh time and latency team trajectory, and we propose a polynomial time algorithm for its computation. Then, we describe a distributed procedure that steers the robots toward an optimal trajectory. For the case of tree graph, a polynomial time algorithm is developed for the minimum refresh time problem, under the technical assumption of a constant number of robo...

  3. Workload demand in police officers during mountain bike patrols.

    Science.gov (United States)

    Takken, T; Ribbink, A; Heneweer, H; Moolenaar, H; Wittink, H

    2009-02-01

    To the authors' knowledge this is the first paper that has used the training impulse (TRIMP) 'methodology' to calculate workload demand. It is believed that this is a promising method to calculate workload in a range of professions in order to understand the relationship between work demands and aerobic fitness. The aim of this study was to assess workload demand in police officers from the Utrecht police department in the Netherlands, during patrol by mountain bike. Maximum oxygen intake, maximum heart rate (HRmax), ventilatory threshold (VT)1 and VT2 were determined with a maximal exercise test on a bicycle ergometer. Heart rates were registered throughout three shifts in 20 subjects using a heart rate monitor. Exercise intensity was divided into three phases: phase I (between 40% of HRmax and VT1); phase II (between VT and the respiratory compensation point (RCP)); and phase III (>RCP). The total TRIMP score was obtained by summating the results of the three phases. Average daily workload demands of 355 TRIMPs per day and 1777 TRIMPs per week were measured. Workload demand approached and in some cases exceeded the upper limit of 2000 TRIMPs per week threshold level for physiological stress demands in professional male cyclists.

  4. Seagull Syndrome: Relationships between Patrol Workers and Government Officials in NSW, Australia

    Directory of Open Access Journals (Sweden)

    Amanda Jayne Porter

    2017-03-01

    Full Text Available This paper explores the nature of relations between public officials and community workers, drawing on empirical data from a study on Indigenous patrols in New South Wales, Australia. Patrol workers interact with public officials from various state entities who are tasked with overseeing funding, carrying out evaluations and, to varying degrees, monitoring the ‘'effectiveness’' of local patrol operations. These interactions illuminate several issues regarding the ways in which knowledge about patrols is created, contested and communicated between Indigenous and non-Indigenous domains. The emergent patterns of these relations can be described as ‘'seagull syndrome’', which involves the privileging of some types of knowledge over others in decision-making regarding Indigenous affairs, often with disastrous consequences for Indigenous organisations and communities. The paper documents the core features of seagull syndrome with respect to the discrete practices, everyday decision-making and mundane communication between public officials and patrol workers in New South Wales. It considers the implications of seagull syndrome for policy-makers and academics working in the Indigenous justice space and suggests ways to resist or challenge this tendency

  5. Evidence of Historical Supernovae in Ice Cores

    Science.gov (United States)

    Young, Donna

    2011-05-01

    Within the framework of the U.S. Greenland Ice Core Science Project (GISP2), an ice core, known as the GISP H-Core, was collected in June, 1992 adjacent to the GISP2 summit drill site. The project scientists, Gisela A.M. Dreschhoff and Edward J. Zeller, were interested in dating solar proton events with volcanic eruptions. The GISP2-H 122-meter firn and ice core is a record of 415 years of liquid electrical conductivity (LEC) and nitrate concentrations, spanning the years 1992 at the surface through 1577 at the bottom. At the National Ice Core Laboratory in Denver, Colorado, the core (beneath the 12-meter firn) was sliced into 1.5 cm sections and analyzed. The resulting data set consisted of 7,776 individual analyses. The ultrahigh resolution sampling technique resulted in a time resolution of one week near the surface and one month at depth. The liquid electrical conductivity (LEC) sequence contains signals from a number of known volcanic eruptions and provides a dating system at specific locations along the core. The terrestrial and solar background nitrate records show seasonal and annual variations, respectively. However, major nitrate anomalies within the record do not correspond to any known terrestrial or solar events. There is evidence that these nitrate anomalies could be a record of supernovae events. Cosmic X-rays ionize atmospheric nitrogen, producing excess nitrate that is then deposited in the Polar Regions. The GISP2-H ice core has revealed nitrate anomalies at the times of the Tycho and Kepler supernovae. The Cassiopeia A supernova event may be documented in the core as well. We have developed a classroom activity for high school and college students, in which they examine several lines of evidence in the Greenland ice core, discriminating among nearby and mid-latitude volcanic activity, solar proton events, and supernovae. Students infer the date of the Cassiopeia A supernova.

  6. Automated search for supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  7. Supernova electron capture rates

    CERN Document Server

    Martínez-Pinedo, G

    1999-01-01

    We have calculated the Gamow-Teller strength distributions for the ground states and low lying states of several nuclei that play an important role in the precollapse evolution of supernova. The calculations reproduce the experimental GT distributions nicely. The GT distribution are used to calculate electron capture rates for typical presupernova conditions. The computed rates are noticeably smaller than the presently adopted rates. The possible implications for the supernova evolution are discussed.

  8. CLUSTERING ANALYSIS OF OFFICER'S BEHAVIOURS IN LONDON POLICE FOOT PATROL ACTIVITIES

    Directory of Open Access Journals (Sweden)

    J. Shen

    2015-07-01

    Full Text Available In this small paper we aim at presenting a framework of conceptual representation and clustering analysis of police officers’ patrol pattern obtained from mining their raw movement trajectory data. This have been achieved by a model developed to accounts for the spatio-temporal dynamics human movements by incorporating both the behaviour features of the travellers and the semantic meaning of the environment they are moving in. Hence, the similarity metric of traveller behaviours is jointly defined according to the stay time allocation in each Spatio-temporal region of interests (ST-ROI to support clustering analysis of patrol behaviours. The proposed framework enables the analysis of behaviour and preferences on higher level based on raw moment trajectories. The model is firstly applied to police patrol data provided by the Metropolitan Police and will be tested by other type of dataset afterwards.

  9. Change detection on UGV patrols with respect to a reference tour using VIS imagery

    Science.gov (United States)

    Müller, Thomas

    2015-05-01

    Autonomous driving robots (UGVs, Unmanned Ground Vehicles) equipped with visual-optical (VIS) cameras offer a high potential to automatically detect suspicious occurrences and dangerous or threatening situations on patrol. In order to explore this potential, the scene of interest is recorded first on a reference tour representing the 'everything okay' situation. On further patrols changes are detected with respect to the reference in a two step processing scheme. In the first step, an image retrieval is done to find the reference images that are closest to the current camera image on patrol. This is done efficiently based on precalculated image-to-image registrations of the reference by optimizing image overlap in a local reference search (after a global search when that is needed). In the second step, a robust spatio-temporal change detection is performed that widely compensates 3-D parallax according to variations of the camera position. Various results document the performance of the presented approach.

  10. Aligning policing and public health promotion: Insights from the world of foot patrol.

    Science.gov (United States)

    Wood, Jennifer D; Taylor, Caitlin J; Groff, Elizabeth R; Ratcliffe, Jerry H

    2015-05-01

    Foot patrol work is rarely described in relation to public health, even though police routinely encounter health risk behaviors and environments. Through a qualitative study of foot patrol policing in violent 'hotspots' of Philadelphia, we explore some prospects and challenges associated with bridging security and public health considerations in law enforcement. Noting existing efforts to help advance police officer knowledge of, and attitudes toward health vulnerabilities, we incorporate perspectives from environmental criminology to help advance this bridging agenda. Extending the notion of capable guardianship to understand foot patrol work, we suggest that the way forward for theory, policy and practice is not solely to rely on changing officer culture and behavior, but rather to advance a wider agenda for enhancing collective guardianship, and especially 'place management' for harm reduction in the city.

  11. Morbidity rates on Vanguard Class submarines during nuclear deterrent patrol: a retrospective review over 13 years.

    Science.gov (United States)

    O'Shea, M K; Scutt, M J

    2009-01-01

    The submarines responsible for the United Kingdom's nuclear deterrent have carried a junior doctor as their medical officer since the program's inception. The Vanguard Class of submarine carries approximately 150 men and deploys for about 3 months at a time. One of the central tenets of submarine operations is to remain undetected and as such the submarine will only surface in an emergency, which may include the evacuation of casualties. The prime reason for carriage of a medical officer is to mitigate against the need to evacuate personnel for medical reasons. We examined the medical section of the patrol reports submitted upon completion of each patrol over a 13 year period to determine both the rates of medical and dental attendance onboard and also the occurrence of potential medical threats to patrol integrity. The most common reasons for attendance were dermatological and musculoskeletal, consistent with previous studies of this population and working environment. There were few dental cases due to the high rates of dental fitness in the pre-sailing crews. Patrol threatening cases occurred at a rate of approximately 1 per 3 patrols, with acute appendicitis being the most common presentation. This progressed to evacuation at a rate of 1 per 15 patrols, with the successful onboard management in 79% of cases. The junior doctor onboard has limited monitoring equipment and formulary, no diagnostic equipment, basic surgical equipment and no opportunity to seek senior advice, and is therefore reliant on clinical judgement. Despite the limitations placed on the doctor on board these submarines they have proven to be effective in reducing the rate of medical evacuation.

  12. Research on Line Patrol Strategy of 110kV Transmission Line after Lightning Strike

    Directory of Open Access Journals (Sweden)

    Li Mingjun

    2016-01-01

    Full Text Available Lightning faults occupy in the majority of instantaneous fault and reclosing can usually be successful, so power supply can be restored without immediate patrol in many cases. Firstly, this paper introduces the lightning fault positioning and identifying method. Then test electrical performance of insulators after lightning strike from 110kV lines. Data shows that lightning strike has little effect on the electric performance of insulator. Finally, illustrating disposal process of the 110 kV transmission line after lightning fault, certifying that the power supply reliability be ensured without line patrol.

  13. The Border Patrol and Their Migra Corridos: Propaganda, Genre Adaptation, and Mexican Immigration

    OpenAIRE

    María Herrera-Sobek

    2012-01-01

    The U.S. Border Patrol efforts to stop illegal immigration from Mexico to the United States are manifold. In recent times, the U.S. Border Patrol has begun employing so-called corridos, or Mexican ballads, as a means of covert propaganda to slow down illegal immigration. In her article, María Herrera-Sobek discusses the appropriation of the corrido genre by the U.S. Border Control and analyzes the corridos from the point of view of extra-literary adaptations.

  14. The Border Patrol and Their Migra Corridos: Propaganda, Genre Adaptation, and Mexican Immigration

    Directory of Open Access Journals (Sweden)

    María Herrera-Sobek

    2012-05-01

    Full Text Available The U.S. Border Patrol efforts to stop illegal immigration from Mexico to the United States are manifold. In recent times, the U.S. Border Patrol has begun employing so-called corridos, or Mexican ballads, as a means of covert propaganda to slow down illegal immigration. In her article, María Herrera-Sobek discusses the appropriation of the corrido genre by the U.S. Border Control and analyzes the corridos from the point of view of extra-literary adaptations.

  15. Cosmic Supernova Rate History and Type Ia Supernova Progenitors

    OpenAIRE

    Kobayashi, Chiaki; Nomoto, Ken'ichi; Tsujimoto, Takuji

    2001-01-01

    Adopting a single degenerate scenario for Type Ia supernova progenitors with the metallicity effect, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in spiral and elliptical galaxies, and compare with the recent observational data up to z ~ 0.55.

  16. Patrol car and agent tracking/suspect tagging and tracking

    Science.gov (United States)

    Wilkins, Steven C.

    1997-01-01

    Emerging technologies in the field of law enforcement are providing today's law enforcement personnel with the advantage of an innovative and faster means of providing safety and service to the public. The use of open such technology, the Automatic Vehicle Locator (AVL) tracking device, is fast becoming a commonplace and cost-effective solution for agencies to efficiently command and control their 'officer' assets. Through the use of AVL's global positioning satellite-based system, the response time of law enforcement is greatly enhanced by permitting a dispatcher to visually identify and assign the officer closest to the location of an accident or incident. The system is effective in reducing delays due to highway blockages, improving the level of protection to the motoring public, and promoting the flow of traffic on busy freeways. Likewise, an officer or agent in distress can be assured that a dispatcher will be constantly aware of his or her location in the field. In the 1990's the demands on law enforcement agencies have grown tremendously. this is due primarily to population increases, limited funding or resources, and increases in drug, property and violent crimes. Frequently, the automobile is used for escape after the commission of these crimes. This often results in high speed pursuits involving law enforcement agencies. In California, by statute, the California Highway Patrol is the central repository for data regarding all pursuits involving state and local law enforcement agencies. Statistics show that more than 10 percent of pursuits result in injuries to the violator and/or innocent bystanders. Most pursuits last less than 10 minutes, and the AVL system provides a tremendous advantage to law enforcement's ability to immediately deploy and direct units into pursuits for rapid closure of the incident. AVL systems not only reduce the risk of personal injury by minimizing public exposure to the unsafe incident, but also enhance officer safety during the

  17. Modeling Core Collapse Supernovae

    Science.gov (United States)

    Mezzacappa, Anthony

    2017-01-01

    Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

  18. The Most Luminous Supernovae

    Science.gov (United States)

    Sukhbold, Tuguldur; Woosley, S. E.

    2016-04-01

    Recent observations have revealed a stunning diversity of extremely luminous supernovae, seemingly increasing in radiant energy without bound. We consider simple approximate limits for what existing models can provide for the peak luminosity and total radiated energy for non-relativistic, isotropic stellar explosions. The brightest possible supernova is a Type I explosion powered by a sub-millisecond magnetar with field strength B ∼ few × {10}13 G. In extreme cases, such models might reach a peak luminosity of 2× {10}46 {erg} {{{s}}}-1 and radiate a total energy of up to 4× {10}52 {erg}. Other less luminous models are also explored, including prompt hyper-energetic explosions in red supergiants, pulsational-pair instability supernovae, pair-instability supernovae, and colliding shells. Approximate analytic expressions and limits are given for each case. Excluding magnetars, the peak luminosity is near 3× {10}44 {erg} {{{s}}}-1 for the brightest models and the corresponding limit on total radiated energy is 3× {10}51 {erg}. Barring new physics, supernovae with a light output over 3× {10}51 erg must be rotationally powered, either during the explosion itself or after, the most obvious candidate being a rapidly rotating magnetar. A magnetar-based model for the recent transient event, ASASSN-15lh is presented that strains, but does not exceed the limits of what the model can provide.

  19. Results from the Supernova Photometric Classification Challenge

    CERN Document Server

    Kessler, Richard; Belov, Pavel; Bhatnagar, Vasudha; Campbell, Heather; Conley, Alex; Frieman, Joshua A; Glazov, Alexandre; Hlozek, Santiago Gonzalez-Gaitan Renee; Jha, Saurabh; Kuhlmann, Stephen; Kunz, Martin; Lampeitl, Hubert; Mahabal, Ashish; Newling, James; Nichol, Robert C; Parkinson, David; Philip, Ninan Sajeeth; Poznanski, Dovi; Richards, Joseph W; Rodney, Steven A; Sako, Masao; Schneider, Donald P; Smith, Mathew; Stritzinger, Maximilian; Varughese, Melvin

    2010-01-01

    We report results from the Supernova Photometric Classification Challenge (SNPCC), a publicly released mix of simulated SNe, with types (Ia, Ibc, II) selected in proportion to their expected rate. The simulation was realized in the griz filters of the Dark Energy Survey (DES) with realistic observing conditions (sky noise, point spread function and atmospheric transparency) based on years of recorded conditions at the DES site. Simulations of non-Ia type SNe are based on spectroscopically confirmed light curves that include unpublished non-Ia samples donated from the Carnegie Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan Digital Sky Survey-II (SDSS-II). A spectroscopically confirmed subset was provided for training. We challenged scientists to run their classification algorithms and report a type and photo-z for each SN. Participants from 10 groups contributed 13 entries for the sample that included a host galaxy photo-z for each SN, and 9 entries for the sample that had no redshi...

  20. Stories of Scientists.

    Science.gov (United States)

    Mascazine, John R.

    2001-01-01

    Presents three biographical sketches of scientists including John Wesley Powell (first to explore the geology of the Grand Canyon), Joseph von Fraunhofer (his work in optics led to the science of spectroscopy), and Gregor Mendel (of Mendelian genetics fame). Other scientists are mentioned along with sources for additional biographical information.…

  1. Making Lists, Enlisting Scientists

    DEFF Research Database (Denmark)

    Jensen, Casper Bruun

    2011-01-01

    was the indicator conceptualised? How were notions of scientific knowledge and collaboration inscribed and challenged in the process? The analysis shows a two-sided process in which scientists become engaged in making lists but which is simultaneously a way for research policy to enlist scientists. In conclusion...

  2. Read Like a Scientist

    Science.gov (United States)

    Mawyer, Kirsten K. N.; Johnson, Heather J.

    2017-01-01

    Scientists read, and so should students. Unfortunately, many high school teachers overlook science texts as a way to engage students in the work of scientists. This article addresses how to help students develop literacy skills by strategically reading a variety of science texts. Unfortunately, most science teachers aren't trained to teach…

  3. Nearby supernova factory announces 34 supernovae in one year'; best Rookie year ever for supernova search

    CERN Multimedia

    2003-01-01

    The Nearby Supernova Factory (SNfactory), an international collaboration based at Lawrence Berkeley National Laboratory, announced that it had discovered 34 supernovae during the first year of the prototype system's operation (2 pages).

  4. Cosmology with Superluminous Supernovae

    CERN Document Server

    Scovacricchi, Dario; Bacon, David; Sullivan, Mark; Prajs, Szymon

    2015-01-01

    We predict cosmological constraints for forthcoming surveys using Superluminous Supernovae (SLSNe) as standardisable candles. Due to their high peak luminosity, these events can be observed to high redshift (z~3), opening up new possibilities to probe the Universe in the deceleration epoch. We describe our methodology for creating mock Hubble diagrams for the Dark Energy Survey (DES), the "Search Using DECam for Superluminous Supernovae" (SUDSS) and a sample of SLSNe possible from the Large Synoptic Survey Telescope (LSST), exploring a range of standardisation values for SLSNe. We include uncertainties due to gravitational lensing and marginalise over possible uncertainties in the magnitude scale of the observations (e.g. uncertain absolute peak magnitude, calibration errors). We find that the addition of only ~100 SLSNe from SUDSS to 3800 Type Ia Supernovae (SNe Ia) from DES can improve the constraints on w and Omega_m by at least 20% (assuming a flat wCDM universe). Moreover, the combination of DES SNe Ia a...

  5. The Effects of Fleet Ballistic Missile Submarine Patrols on Oral Health

    Science.gov (United States)

    Maintenance of optimum oral health for Fleet Ballistic Missile submarine personnel is a continuing effort. Information is required concerning oral ... health status and patrol effects on this status. Ninety-one crew members of the USS JOHN MARSHALL (SSBN 611 (Gold)) were evaluated predeployment, during

  6. Metabolic Heal and Energy Expenditure Estimates of Border Patrol Personnel Obtained using the Factorial Method

    Science.gov (United States)

    2010-08-01

    training these individuals reported averaging 6.4 + 1.7 miles of running per workout , min = 3 miles, max = 8 miles. EXPERIMENTAL PROCEDURE...maintain cardiac output as the blood pools in the skin and subcutaneous vascular beds (10). Heat dissipation of Border Patrol personnel is

  7. Configuration, Deployment, and Scheduling Models for Management and Optimization of Patrol Services

    Directory of Open Access Journals (Sweden)

    Bin Yang

    2015-01-01

    Full Text Available This paper presents a decision support system (DSS and its models for patrol service center (PSC. PSC plays an important role in public security and emergency management. The configuration, deployment, and scheduling of resources of PSC are important for improving the efficiency of patrol-related resources, service quantity, and emergency response capability. A series of decision-making models of the DSS are studied. First, the criteria and models are proposed for configuring and deploying PSCs; second, three types of models for incremental, direct, and redeployment optimization are built in views for decisions aiming at PSC configuration, deployment, and scheduling problems; third, considering three typical patrol-related service scenarios (alarm assignment, main road blockade, and besiege program, three scheduling models are built, respectively, for PSC-related service and coordination of multiple PSCs. This work contributes to the literature on patrol services and network optimization problems in the following aspects: based on a series of models, a DSS framework is designed for PSCs; the models are formulated for resource management and scheduling upon geography information system; coordination strategies among close PSCs are incorporated into decision models. These features are examined in integration manners. The assessment criteria and optimization models studied in the paper are beneficial for building DSSs for PSC.

  8. Ship Response Capability Models for Counter-Piracy Patrols in the Gulf of Aden

    Science.gov (United States)

    2011-09-01

    9 2.1.2 Ripple Propagation Algorithm . . . . . . . . . . . . . . . . . . . 9 2.1.3 Marsaglia et al. Algorithm...of Marsaglia et al. (1990) . . . . . . . . . . . . . . . . . . . . . 47 Annex D: Error Calculations for 1D model...effectively patrolled by a particular asset. One 2D approach uses the an- alytical work of Marsaglia et al. [10] to generate the probability distribution of

  9. A design of toxic gas detecting security robot car based on wireless path-patrol

    Directory of Open Access Journals (Sweden)

    Cheng Ho-Chih

    2017-01-01

    Full Text Available Because a toxic gas detecting/monitoring system in a chemical plant is not movable, a gas detecting/monitoring system will be passive and the detecting range will also be constrained. This invention is an active multi-functional wireless patrol car that can substitute for humans that inspect a plant's security. In addition, to widen the monitoring vision within the environment, two motors used to rotate a wireless IPCAM with two axes are presented. Also, to control the robot car's movement, two axis motors used to drive the wheel of the robot car are also installed. Additionally, a toxic gas detector is linked to the microcontroller of the patrol car. The detected concentration of the gas will be fed back to the server pc. To enhance the robot car's patrolling duration, a movable electrical power unit in conjunction with a wireless module is also used. Consequently, this paper introduces a wireless path-patrol and toxic gas detecting security robot car that can assure a plant's security and protect workers when toxic gases are emitted.

  10. Physics of supernovae

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-12-13

    Presupernova models of massive stars are presented and their explosion by ''delayed neutrino transport'' examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 Msub solar. Carbon deflagration in white dwarfs is discussed as the probable explanation of Type I supernovae and special attention is paid to the physical processes whereby a nuclear flame propagates through degenerate carbon. 89 refs., 12 figs.

  11. Demonstrating Supernova Remnant Evolution

    Science.gov (United States)

    Leahy, Denis A.; Williams, Jacqueline

    2017-01-01

    We have created a software tool to calculate at display supernova remnant evolution which includes all stages from early ejecta dominated phase to late-time merging with the interstellar medium. The software was created using Python, and can be distributed as Python code, or as an executable file. The purpose of the software is to demonstrate the different phases and transitions that a supernova remnant undergoes, and will be used in upper level undergraduate astrophysics courses as a teaching tool. The usage of the software and its graphical user interface will be demonstrated.

  12. BVRI Photometry of Supernovae

    OpenAIRE

    Ho, Wynn C. G.; Van Dyk, Schuyler D.; Peng, Chien Y.; Filippenko, Alexei V.; Leonard, Douglas C.; Matheson, Thomas; Treffers, Richard R.; Richmond, Michael W.

    2001-01-01

    We present optical photometry of one Type IIn supernova (1994Y) and nine Type Ia supernovae (1993Y, 1993Z, 1993ae, 1994B, 1994C, 1994M, 1994Q, 1994ae, and 1995D). SN 1993Y and SN 1993Z appear to be normal SN Ia events with similar rates of decline, but we do not have data near maximum brightness. The colors of SN 1994C suggest that it suffers from significant reddening or is intrinsically red. The light curves of SN 1994Y are complicated; they show a slow rise and gradual decline near maximum...

  13. Development of clinical scientists.

    Science.gov (United States)

    Smith, R V

    1987-01-01

    The education and training of clinical scientists has served society in several ways. For academic pharmacy, the emergence of clinical science has provided research and scholarship opportunities for clinical faculty development. Clinical scientists have also begun to play important roles in industrial drug research and development. For all faculty and students, clinical science research reinforces a "research mindset" that will become increasingly important as our society moves from a production/extraction to an information-based economy. Pharmacy will best evolve by increasing its commitment to clinical science research. In the process, academic pharmacy must continue to improve and support excellent education and training programs for clinical scientists.

  14. Tracking Object Existence From an Autonomous Patrol Vehicle

    Science.gov (United States)

    Wolf, Michael; Scharenbroich, Lucas

    2011-01-01

    An autonomous vehicle patrols a large region, during which an algorithm receives measurements of detected potential objects within its sensor range. The goal of the algorithm is to track all objects in the region over time. This problem differs from traditional multi-target tracking scenarios because the region of interest is much larger than the sensor range and relies on the movement of the sensor through this region for coverage. The goal is to know whether anything has changed between visits to the same location. In particular, two kinds of alert conditions must be detected: (1) a previously detected object has disappeared and (2) a new object has appeared in a location already checked. For the time an object is within sensor range, the object can be assumed to remain stationary, changing position only between visits. The problem is difficult because the upstream object detection processing is likely to make many errors, resulting in heavy clutter (false positives) and missed detections (false negatives), and because only noisy, bearings-only measurements are available. This work has three main goals: (1) Associate incoming measurements with known objects or mark them as new objects or false positives, as appropriate. For this, a multiple hypothesis tracker was adapted to this scenario. (2) Localize the objects using multiple bearings-only measurements to provide estimates of global position (e.g., latitude and longitude). A nonlinear Kalman filter extension provides these 2D position estimates using the 1D measurements. (3) Calculate the probability that a suspected object truly exists (in the estimated position), and determine whether alert conditions have been triggered (for new objects or disappeared objects). The concept of a probability of existence was created, and a new Bayesian method for updating this probability at each time step was developed. A probabilistic multiple hypothesis approach is chosen because of its superiority in handling the

  15. Scientists vs. the administration

    CERN Multimedia

    2004-01-01

    Article denouncing the supposed impartiality of signatories of a report released by the Union of Concerned Scientists (UCS), which accused the Bush administration of systemically suborning objective science to a political agenda (1 page).

  16. Scientists and Human Rights

    Science.gov (United States)

    Makdisi, Yousef

    2012-02-01

    The American Physical Society has a long history of involvement in defense of human rights. The Committee on International Freedom of Scientists was formed in the mid seventies as a subcommittee within the Panel On Public Affairs ``to deal with matters of an international nature that endangers the abilities of scientists to function as scientists'' and by 1980 it was established as an independent committee. In this presentation I will describe some aspects of the early history and the impetus that led to such an advocacy, the methods employed then and how they evolved to the present CIFS responsibility ``for monitoring concerns regarding human rights for scientists throughout the world''. I will also describe the current approach and some sample cases the committee has pursued recently, the interaction with other human rights organizations, and touch upon some venues through which the community can engage to help in this noble cause.

  17. Scientists planning new internet

    CERN Multimedia

    Cookson, C

    2000-01-01

    British scientists are preparing to build the next generation internet - 'The Grid'. The government is expected to announce about 100 million pounds of funding for the project, to be done in collaboration with CERN (1/2 p).

  18. Theoretical models for supernovae

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-09-21

    The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to (i) the nucleosynthesis expected from intermediate mass (10sub solar less than or equal to M less than or equal to 100 Msub solar) Type II supernovae and detonating white dwarf models for Type I supernovae, (ii) a realistic estimate of the ..gamma..-line fluxes expected from this nucleosynthesis, (iii) the continued evolution, in one and two dimensions, of intermediate mass stars wherein iron core collapse does not lead to a strong, mass-ejecting shock wave, and (iv) the evolution and explosion of vary massive stars (M greater than or equal to 100 Msub solar of both Population I and III. In one dimension, nuclear burning following a failed core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by hypernovae, the explosions of stars in the mass range 100 M/sub solar/ to 300 M/sub solar/. Above approx. 300 M/sub solar/ a black hole is created by stellar collapse following carbon ignition. Still more massive stars may be copious producers of /sup 4/He and /sup 14/N prior to their collapse on the pair instability.

  19. Supernova 2013by

    DEFF Research Database (Denmark)

    Valenti, S.; Sand, D.; Stritzinger, M.

    2015-01-01

    We present multiband ultraviolet and optical light curves, as well as visual-wavelength and near-infrared spectroscopy of the Type II linear (IIL) supernova (SN) 2013by. We show that SN 2013by and other SNe IIL in the literature, after their linear decline phase that start after maximum, have...

  20. QCD and Supernovas

    Science.gov (United States)

    Barnes, T.

    2005-12-01

    In this contribution we briefly summarize aspects of the physics of QCD which are relevant to the supernova problem. The topic of greatest importance is the equation of state (EOS) of nuclear and strongly-interacting matter, which is required to describe the physics of the proto-neutron star (PNS) and the neutron star remnant (NSR) formed during a supernova event. Evaluation of the EOS in the regime of relevance for these systems, especially the NSR, requires detailed knowledge of the spectrum and strong interactions of hadrons of the accessible hadronic species, as well as other possible phases of strongly interacting matter, such as the quark-gluon plasma (QGP). The forces between pairs of baryons (both nonstrange and strange) are especially important in determining the EOS at NSR densities. Predictions for these forces are unfortunately rather model dependent where not constrained by data, and there are several suggestions for the QCD mechanism underlying these short-range hadronic interactions. The models most often employed for determining these strong interactions are broadly of two types, 1) meson exchange models (usually assumed in the existing neutron star and supernova literature), and 2) quark-gluon models (mainly encountered in the hadron, nuclear and heavy-ion literature). Here we will discuss the assumptions made in these models, and discuss how they are applied to the determination of hadronic forces that are relevant to the supernova problem.

  1. The Most Luminous Supernovae

    CERN Document Server

    Sukhbold, Tuguldur

    2016-01-01

    Recent observations have revealed an amazing diversity of extremely luminous supernovae, seemingly increasing in radiant energy without bound. We consider here the physical limits of what existing models can provide for the peak luminosity and total radiated energy for non-relativistic, isotropic stellar explosions. The brightest possible supernova is a Type I explosion powered by a sub-millisecond magnetar. Such models can reach a peak luminosity of $\\rm 2\\times10^{46}\\ erg\\ s^{-1}$ and radiate a total energy of $\\rm 4 \\times10^{52}\\ erg$. Other less luminous models are also explored, including prompt hyper-energetic explosions in red supergiants, pulsational-pair instability supernovae, and pair-instability supernovae. Approximate analytic expressions and limits are given for each case. Excluding magnetars, the peak luminosity is near $\\rm 1\\times10^{44}\\ erg\\ s^{-1}$ for the brightest models. The corresponding limits on total radiated power are $\\rm3 \\times 10^{51}\\ erg$ (Type I) and $\\rm1 \\times 10^{51}\\ ...

  2. Supernovae and Dark Energy

    Science.gov (United States)

    Domínguez, I.; Bravo, E.; Piersanti, L.; Straniero, O.; Tornambé, A.

    2009-08-01

    A decade ago the observations of thermonuclear supernovae at high-redhifts showed that the expansion rate of the Universe is accelerating and since then, the evidence for cosmic acceleration has gotten stronger. This acceleration requires that the Universe is dominated by dark energy, an exotic component characterized by its negative pressure. Nowadays all the available astronomical data (i.e. thermonuclear supernovae, cosmic microwave background, barionic acoustic oscillations, large scale structure, etc.) agree that our Universe is made of about 70% of dark energy, 25% of cold dark matter and only 5% of known, familiar matter. This Universe is geometrically flat, older than previously thought, its destiny is no longer linked to its geometry but to dark energy, and we ignore about 95% of its components. To understand the nature of dark energy is probably the most fundamental problem in physics today. Current astronomical observations are compatible with dark energy being the vacuum energy. Supernovae have played a fundamental role in modern Cosmology and it is expected that they will contribute to unveil the dark energy. In order to do that it is mandatory to understand the limits of supernovae as cosmological distance indicators, improving their precision by a factor 10.

  3. Scientists as writers

    Science.gov (United States)

    Yore, Larry D.; Hand, Brian M.; Prain, Vaughan

    2002-09-01

    This study attempted to establish an image of a science writer based on a synthesis of writing theory, models, and research literature on academic writing in science and other disciplines and to contrast this image with an actual prototypical image of scientists as writers of science. The synthesis was used to develop a questionnaire to assess scientists' writing habits, beliefs, strategies, and perceptions about print-based language. The questionnaire was administered to 17 scientists from science and applied science departments of a large Midwestern land grant university. Each respondent was interviewed following the completion of the questionnaire with a custom-designed semistructured protocol to elaborate, probe, and extend their written responses. These data were analyzed in a stepwise fashion using the questionnaire responses to establish tentative assertions about the three major foci (type of writing done, criteria of good science writing, writing strategies used) and the interview responses to verify these assertions. Two illustrative cases (a very experienced, male physical scientist and a less experienced, female applied biological scientist) were used to highlight diversity in the sample. Generally, these 17 scientists are driven by the academy's priority of publishing their research results in refereed, peer-reviewed journals. They write their research reports in isolation or as a member of a large research team, target their writing to a few journals that they also read regularly, use writing in their teaching and scholarship to inform and persuade science students and other scientists, but do little border crossing into other discourse communities. The prototypical science writer found in this study did not match the image based on a synthesis of the writing literature in that these scientists perceived writing as knowledge telling not knowledge building, their metacognition of written discourse was tacit, and they used a narrow array of genre

  4. A patrol and reconnaissance of the Arctic National Wildlife Range, 6/9/65 to 6/25/65

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Patrol and reconnaissance of ANWR from June 9 to June 25, 1965, including notes on active mineral exploration, condition of previous year's camps, other human...

  5. Reconciling Scientists and Journalists

    Science.gov (United States)

    Rosner, H.

    2006-12-01

    The very nature of scientists' and journalists' jobs can put them at cross-purposes. Scientists work for years on one research project, slowly accumulating data, and are hesitant to draw sweeping conclusions without multiple rounds of hypothesis-testing. Journalists, meanwhile, are often looking for "news"—a discovery that was just made ("scientists have just discovered that...") or that defies conventional wisdom and is therefore about to turn society's thinking on its head. The very criteria that the mediamakers often use to determine newsworthiness can automatically preclude some scientific progress from making the news. There are other built-in problems in the relationship between journalists and scientists, some of which we can try to change and others of which we can learn to work around. Drawing on my personal experience as a journalist who has written for a wide variety of magazines, newspapers, and web sites, this talk will illustrate some of the inherent difficulties and offer some suggestions for how to move beyond them. It will provide a background on the way news decisions are made and how the journalist does her job, with an eye toward finding common ground and demonstrating how scientists can enjoy better relationships with journalists—relationships that can help educate the public on important scientific topics and avoid misrepresentation of scientific knowledge in the media.

  6. U.S. Coast Guard Cutter Procurement Lessons Impacts on the Offshore Patrol Cutter (OPC) Program Affordability

    Science.gov (United States)

    2015-12-01

    Sponsored Report Series U.S. Coast Guard Cutter Procurement Lessons’ Impacts on the Offshore Patrol Cutter (OPC) Program Affordability December 2015...School of Business & Public Policy - i - Naval Postgraduate School ABSTRACT The U.S. Coast Guard’s upcoming acquisition of the Offshore Patrol...School NPS-AM-16-012 Acquisition Research Program Sponsored Report Series U.S. Coast Guard Cutter Procurement Lessons’ Impacts on the Offshore

  7. GATEWAY Demonstrations: LED System Performance in a Trial Installation--Two Years Later, Yuma Border Patrol, Yuma, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Andrea M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sullivan, Gregory P. [Efficiency Solutions, Inc., Richland, WA (United States); Davis, Robert G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    Along the Yuma Sector Border Patrol Area in Yuma, Arizona, the GATEWAY program conducted a trial demonstration in which the incumbent quartz metal halide area lighting was replaced with LED at three pole locations at the Yuma Sector Border Patrol Area in Yuma, Arizona. The retrofit was documented to better understand LED technology performance in high-temperature environments. This report follows the GATEWAY Yuma Phase 1.1 Report and reflects LED system results documented two years after the demonstration began.

  8. U.S. Border Patrol OCONUS: Possible Contributions to the Whole of Government Approach to Stability Operations

    Science.gov (United States)

    2010-06-11

    Agents (ACPA) Randall Baldwin, Gerald S. Bryan, and Anthony Porvaznik; Patrol Agents in Charge Gregory Bovino , Desi D. DeLeon, Vincent J. Hampel, and...leaders to improve relations with the DBE. 94 In 2001, Gregory Bovino was a Supervisory Border Patrol Agent (SBPA) with the BORTAC operating in...Honduras. Gregory Bovino is now a PAIC. PAIC Bovino helped organize and train host-nation border security forces in Honduras from the ground up through

  9. GATEWAY Demonstrations: LED System Performance in a Trial Installation--One Year Later, Yuma Border Patrol, Yuma, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, A. M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Davis, R. G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-01

    Along the Yuma Sector Border Patrol Area in Yuma, Arizona, the GATEWAY program conducted a trial demonstration in which the incumbent quartz metal halide area lighting was replaced with LED at three pole locations at the Yuma Sector Border Patrol Area in Yuma, Arizona. The retrofit was documented to better understand LED technology performance in high-temperature environments. This report follows the GATEWAY Yuma Phase 1.0 Report and reflects LED system results documented one year after the demonstration began.

  10. Marketing for scientists

    CERN Document Server

    Kuchner, Marc J

    2012-01-01

    It's a tough time to be a scientist: universities are shutting science departments, funding organisations are facing flat budgets, and many newspapers have dropped their science sections altogether. But according to Marc Kuchner, this anti-science climate doesn't have to equal a career death knell - it just means scientists have to be savvier about promoting their work and themselves. In "Marketing for Scientists", he provides clear, detailed advice about how to land a good job, win funding, and shape the public debate. As an astrophysicist at NASA, Kuchner knows that "marketing" can seem like a superficial distraction, whether your daily work is searching for new planets or seeking a cure for cancer. In fact, he argues, it's a critical component of the modern scientific endeavour, not only advancing personal careers but also society's knowledge. Kuchner approaches marketing as a science in itself. He translates theories about human interaction and sense of self into methods for building relationships - one o...

  11. Collective supernova neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [Max Planck Institute for Physics, Munich (Germany)

    2009-07-01

    Neutrinos emitted by core-collapse supernovae (SNe) represent an important laboratory for both particle physics and astrophysics. While propagating in the dense SN environment, they can feel not only the presence of background matter (via ordinary Mikheev-Smirnov-Wolfenstein effects) but also of the gas of neutrinos and antineutrinos (via neutrino-neutrino interaction effects). The neutrino-neutrino interactions appear to modify the flavor evolution of SN neutrinos in a collective way, completely different from the ordinary matter effects. In these conditions, the flavor evolution equations become highly nonlinear, sometimes resulting in surprising phenomena when the entire neutrino system oscillates coherently as a single collective mode. In this talk, I present the recent results on collective supernova neutrino flavor conversions and I discuss about the sensitivity of these effects to the ordering of the neutrino mass spectrum.

  12. ADIDAS SUPERNOVA CTR10

    Institute of Scientific and Technical Information of China (English)

    刘楠

    2008-01-01

    ADIDAS SUPERNOVA CTR10作为ADIDAS控制型跑鞋中的佼佼者,鞋款结合了如立体FORMOTION,大面积的PRO-MODERATOR特殊材质,以及强化型的07款鞋模(EL-07),前脚掌大块ADIPRENE+等诸多ADIDAS的当家技术,但在实际的跑步过程中,这些技术点能否真正为跑步者带来明显的感受?请随我们进入到ADIDAS SUPERNOVA CONTROL10评测环节。

  13. Galaxy Outflows Without Supernovae

    CERN Document Server

    Sur, Sharanya; Ostriker, Eve C

    2016-01-01

    High surface density, rapidly star-forming galaxies are observed to have $\\approx 50-100\\,{\\rm km\\,s^{-1}}$ line-of-sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly-compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds $\\approx 35\\,{\\rm km\\...

  14. Nurseries of Supernovae

    DEFF Research Database (Denmark)

    Frederiksen, Teddy

    Type Ia supernovae (SNe) have long been the gold standard for precision cosmology and after several decades of intense research the supernova (SN) community was in 2011 honored by giving the Nobel Prize in physics for the discovery of Dark Energy to the leaders of the two big SN collaborations...... the gasphase metallicity, stellar mass and stellar age for this z = 1.55 host galaxy. I am also able to rule out the presence of any AGN though emission-line ratios. The host is classified as a highly star forming, low mass, low metallicity galaxy. It is a clear outlier in star formation and stellar mass...... compared to most low redshift (z 1) redshift SNe. This is mainly due to the change in specific star-formation rate as a function of redshift. This can potentially impact the use of high redshift SN Ia as standard candels...

  15. Achievements in creation of the space patrol apparatus of ionizing radiation of the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, S.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Afanas' ev, I.M. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation)]. E-mail: afanasy@pochta.ru; Kuvaldin, E.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Leonov, N.B. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Savushkin, A.V. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Serova, A.E. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation); Voronin, N.A. [S.I. Vavilov State Optical Institute, Birgevaya linia, 12, Saint-Petersburg 199034 (Russian Federation)

    2005-05-01

    The paper describes the results and achievements of our work in the creation of optical-electronic instruments for space patrol apparatus of ionizing radiation of the Sun. At present, such monitoring of the most important solar irradiance in the spectral range of 0.8-119 nm does not exist anywhere in the world because of the methodological and technical difficulties. The main difficulty was overcome only after the creation of a 'solar-blind' detector-open secondary electron multiplier (SEM), which was produced by the S.I. Vavilov State Optical Institute (SOI). Now all the space patrol instrumentation has been created and laboratory tested. The basic points of the work are presented here.

  16. For a Greater Horn of Africa Sea Patrol

    DEFF Research Database (Denmark)

    Struwe, Lars Bangert

    Patrol. The capacity and resources devoted by the individual states, alliances and organisations to combating piracy could be used more efficiently by establishing a regional unit: a Greater Horn of Africa Sea Patrol (GHASP). GHASP could be built up on a regional basis founded on the states in and around...... the Horn of Africa. The international community must provide help with this as the pirates chiefly attack ships without considering their nationality. GHASP could be entrusted with such tasks as: • Carrying out surveillance and securing free navigation • Establishing security by combating illegal acts...... for providing radar installations and aerial surveillance, training personnel and equipping maritime vessels. It would also be necessary to attach courts and punitive measures to GHASP. The establishment and operation of GHASP could be funded to advantage by the states that are presently providing capacity...

  17. Trial Demonstration of Area Lighting Retrofit: Yuma Border Patrol, Yuma Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Andrea M.; McCullough, Jeffrey J.

    2014-12-30

    The Yuma Sector Border Patrol Area is a high flux lighting application in a high temperature environment, presenting a formidable challenge for light-emitting diodes (LEDs). This retrofit is an Energy Savings Performance Contract ENABLE project under the U.S. Department of Energy (DOE) Federal Energy Management Program. If high flux LED technology performs well in a region with high ambient temperature and solar radiation, it can perform well in most outdoor environments. The design process for the Yuma retrofit has already provided valuable knowledge to CBP and DOE. The LED lighting system selected for the retrofit is expected to reduce energy consumption 69% compared to the incumbent quartz metal halide (QMH) lighting system. If the LED lighting system is installed, GATEWAY will continue to document and disseminate information regarding the installation and long-term performance so that others may also gain valuable knowledge from the Yuma Sector Border Patrol Area lighting retrofit.

  18. Trial Demonstration of Area Lighting Retrofit: Yuma Border Patrol, Yuma Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Andrea M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCullough, Jeffrey J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    The Yuma Sector Border Patrol Area is a high flux lighting application in a high temperature environment, presenting a formidable challenge for light-emitting diodes (LEDs). This retrofit is an Energy Savings Performance Contract ENABLE project under the U.S. Department of Energy (DOE) Federal Energy Management Program. If high flux LED technology performs well in a region with high ambient temperature and solar radiation, it can perform well in most outdoor environments. The design process for the Yuma retrofit has already provided valuable knowledge to CBP and DOE. The LED lighting system selected for the retrofit is expected to reduce energy consumption 69% compared to the incumbent quartz metal halide (QMH) lighting system. If the LED lighting system is installed, GATEWAY will continue to document and disseminate information regarding the installation and long-term performance so that others may also gain valuable knowledge from the Yuma Sector Border Patrol Area lighting retrofit.

  19. Design of a System for Auto-patrolling Power Supplies and Displaying Beam Status In HIRFL

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A practical application for patrolling the device’s status and displalying beam status of HIRFL has been described.With regard to the kinds of the controlled devices,the system consists of two parts:First,the alarm system is applied to monitor all power supplies,which are decomposed into six groups in accordance with their positions for the convenience of user’s operation.The amount of magnet lens and power supplies of pre-beam

  20. The U.S. Navy, the Neutrality Patrol, and Atlantic Fleet Escort Operations, 1939-1941

    Science.gov (United States)

    1991-05-13

    command counted forty-five destroyers, fifty-one patrol planes, one destroyer tender, three aircraft tenders, and ten minecraft . Training the Support...File "Are We Ready?", Box 47, Strategic Plans Division Records, Series III, OA, NHC. 9. Frederick Marks, Wind Over Sand (Athens: University of Georgia...Roosevelt’s Navy, p. 70. 37. Patrick J. Hearden, Roosevelt Confronts Hitler (Dekalk, Illinois: Northern Illinois University Press, 1987), p. 139. 38

  1. METHODOLOGY OF THE HYBRID PROPULSION SYSTEM (DMP & DEP FOR TRIMARAN TYPE FAST PATROL BOAT

    Directory of Open Access Journals (Sweden)

    Aulia Widyandari

    2012-04-01

    Full Text Available There are lot of research done to develop a patrol boat, from the modification of hull model until propulsion system equipment. For example the model ship type AMV (Advanced Marine Vehicle was developed starting from the Catamaran, Trimaran and  Pentamaran model. Everything is aimed at obtaining the ship design that has the speed and stability. In addition to achieving high-speed vessel must be equipped with propulsion (Main Power is great, that means the main engine dimensions, auxiliary equipments and fuel tanks is too large. Many Limitations of space on the ship's engine room trimaran vessel is the main obstacle in designing propulsion system. Beside that Patrol boat should have many missions speed, so propulsion system should be designed at that conditions.   Hybrid propulsion is a combination of Diesel Mechanical Propulsion (DMP with Diesel Electric Propulsion (DEP. DMP system is connected directly to the propeller shaft (or through a reduction-gear. DMP has provide more efficiency rate of 95%. While DEP is only able to provide efficiency by 85% - 89% is slightly lower than DMP, but the DEP offers many advantages such as simplicity and suitability in the rotational speed settings, control systems, engine power production Redundancy, Flexibility in the design of equipments layout in engine rooms, noise, vibration and fuel consumption efficiency which affects the lower pollution.   Design of Hybrid Propulsion system can be satisfied and achieved the Power requirements and optimally at all speed condition of patrol boat. Therefore the author made using modeling Maxsurf-11.12 software and carried out various optimization of the choice of main engine, propeller and system conditions for fast patrol boat cruise. 

  2. MULTI-VEHICLE COVERING TOUR PROBLEM: BUILDING ROUTES FOR URBAN PATROLLING

    OpenAIRE

    Washington Alves Oliveira; Antonio Carlos Moretti; Ednei Felix Reis

    2015-01-01

    ABSTRACT In this paper we study a particular aspect of the urban community policing: routine patrol route planning. We seek routes that guarantee visibility, as this has a sizable impact on the community perceived safety, allowing quick emergency responses and providing surveillance of selected sites (e.g., hospitals, schools). The planning is restricted to the availability of vehicles and strives to achieve balanced routes. We study an adaptation of the model for the multi-vehicle covering t...

  3. From Atmospheric Scientist to Data Scientist

    Science.gov (United States)

    Knuth, S. L.

    2015-12-01

    Most of my career has been spent analyzing data from research projects in the atmospheric sciences. I spent twelve years researching boundary layer interactions in the polar regions, which included five field seasons in the Antarctic. During this time, I got both a M.S. and Ph.D. in atmospheric science. I learned most of my data science and programming skills throughout this time as part of my research projects. When I graduated with my Ph.D., I was looking for a new and fresh opportunity to enhance the skills I already had while learning more advanced technical skills. I found a position at the University of Colorado Boulder as a Data Research Specialist with Research Computing, a group that provides cyber infrastructure services, including high-speed networking, large-scale data storage, and supercomputing, to university students and researchers. My position is the perfect merriment between advanced technical skills and "softer" skills, while at the same time understanding exactly what the busy scientist needs to understand about their data. I have had the opportunity to help shape our university's data education system, a development that is still evolving. This presentation will detail my career story, the lessons I have learned, my daily work in my new position, and some of the exciting opportunities that opened up in my new career.

  4. A romantic scientist

    Science.gov (United States)

    Skaar Jacobsen, Anja

    2013-12-01

    While giving a lecture on electricity, electrochemistry and magnetism in the spring of 1820, the Danish scientist Hans Christian Ørsted noticed something remarkable: the magnetic needle he was using for one of his demonstrations was deflected by an electric current in a nearby wire.

  5. Early Primary Invasion Scientists

    Science.gov (United States)

    Spellman, Katie V.; Villano, Christine P.

    2011-01-01

    "We really need to get the government involved," said one student, holding his graph up to USDA scientist Steve Seefeldt. Dr. Steve studies methods to control "invasive" plants, plants that have been introduced to an area by humans and have potential to spread rapidly and negatively affect ecosystems. The first grader and his classmates had become…

  6. Ethics for life scientists

    NARCIS (Netherlands)

    Korthals, M.J.J.A.A.; Bogers, R.J.

    2004-01-01

    In this book we begin with two contributions on the ethical issues of working in organizations. A fruitful side effect of this start is that it gives a good insight into business ethics, a branch of applied ethics that until now is far ahead of ethics for life scientists. In the second part, ethics

  7. Ethics for life scientists

    NARCIS (Netherlands)

    Korthals, M.J.J.A.A.; Bogers, R.J.

    2004-01-01

    In this book we begin with two contributions on the ethical issues of working in organizations. A fruitful side effect of this start is that it gives a good insight into business ethics, a branch of applied ethics that until now is far ahead of ethics for life scientists. In the second part, ethics

  8. Becoming a Spider Scientist

    Science.gov (United States)

    Patrick, Patricia; Getz, Angela

    2008-01-01

    In this integrated unit, third grade students become spider scientists as they observe spiders in their classroom to debunk some common misconceptions about these intimidating creatures. "Charlotte's Web" is used to capture students' interest. In addition to addressing philosophical topics such as growing-up, death, and friendship; E.B. White's…

  9. Crime Modeling with Truncated Levy Flights and Effects of Police Patrol

    CERN Document Server

    Pan, Chaohao; Zhang, Yuqi; Geldner, Nathan; Wang, Chuntian; Wang, Li; Bertozzi, Andrea

    2016-01-01

    In this paper, we developed a truncated Levy flight model to study the crime dynamics. In the discrete case, our model allows criminals to perform long jumps in between committing crimes with a speed light. This is a more realistic extension of a pioneering random walk model by Short et. al and a Levy flight model thereafter in Chaturapruek, et al. We also derive a continuum limit and perform a stability analysis to study the formation of crime hotspots. Our model is more realistic than the Levy Flight Model, and provides an alternative to the Random Walk Model when the criminals can perform long jumps in between committing crimes. In the next step, we introduce patrolling police officers to our new model following that in. We examine the effects of police patrol when the police choose to adopt different strategies, including unbiased random walk, biased random walk, and truncated Levy flight. We evaluate the effectiveness of the police patrol with the number of crime events in a given time frame. With spatia...

  10. Predictors of patrol officer interest in cybercrime training and investigation in selected United States police departments.

    Science.gov (United States)

    Holt, Thomas J; Bossler, Adam M

    2012-09-01

    Cybercrime has created substantial challenges for law enforcement, particularly at the local level. Most scholars and police administrators believe that patrol officers need to become more effective first responders to cybercrime calls. The evidence illustrates, however, that many patrol officers are neither adequately prepared nor strongly interested in taking an active role in addressing cybercrime at the local level. This study, therefore, examined the factors that predicted patrol officer interest in cybercrime training and investigations in two southeastern U.S. cities. The study specifically examined the relationship between demographics, cybercrime exposure, computer training, computer proficiency, Internet and cybercrime perceptions, and views on policing cybercrime with officer interest in cybercrime investigation training and conducting cybercrime investigations in the future. Officer views on policing cybercrime, particularly whether they valued cybercrime investigations and believed that cybercrime would dramatically change policing, along with their computer skills, were the strongest predictors of interest in cybercrime efforts. Officers who had received previous computer training were less interested in additional training and conducting investigations. These findings support the argument that more command and departmental meetings focusing on the value of investigating these types of crime need to be held in order to increase officer interest.

  11. ECNS '99 - Young scientists forum

    DEFF Research Database (Denmark)

    Ceretti, M.; Janssen, S.; McMorrow, D.F.

    2000-01-01

    The Young Scientists Forum is a new venture for ECNS and follows the established tradition of an active participation by young scientists in these conferences. At ECNS '99 the Young Scientists Forum brought together 30 young scientists from 13 European countries. In four working groups...

  12. Supernova Remnant in 3-D

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for the movie For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays. Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images. To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer wavelengths. Since the amount

  13. Comparing the characteristics of snowboarders injured in a terrain park who present to the ski patrol, the emergency department or both.

    Science.gov (United States)

    Russell, Kelly; Meeuwisse, Willem; Nettel-Aguirre, Alberto; Emery, Carolyn A; Wishart, Jillian; Romanow, Nicole T R; Rowe, Brian H; Goulet, Claude; Hagel, Brent E

    2014-01-01

    Ski patrol report forms are a common data source in ski/snowboard research, but it is unclear if those who only present to the emergency department (ED) are systematically different from those who see the ski patrol. To determine the proportion and characteristics of injured snowboarders who bypass the ski patrol before presenting to the ED, three groups of injured snowboarders were compared: presented to the ED only, ski patrol only and ski patrol and ED. Data were collected from ski patrol Accident Report Forms (ARFs), ED medical records and telephone interviews. There were 333 injured snowboarders (ED only: 34, ski patrol only: 107, both: 192). Ability, time of day, snow conditions or drugs/alcohol predicted ED only presentation. Concussions (RRR: 4.66; 95% CI: 1.83, 11.90), sprains/strains (RRR: 4.22; 95% CI: 1.87, 9.49), head/neck (RRR: 2.90; 95% CI: 1.48, 5.78), trunk (RRR: 4.17; 95% CI: 1.92, 9.09) or lower extremity (RRR: 3.65; 95% CI: 1.32, 10.07) injuries were significantly more likely to present to ski patrol only versus ski patrol and ED. In conclusion, snowboarders who presented to the ED only had similar injuries as those who presented to both.

  14. Observations and Theory of Supernovae

    CERN Document Server

    Wheeler, J C

    2003-01-01

    This Resource Letter provides a guide to the literature on the observations of supernovae and the theory of their explosion mechanisms. Journal articles and books are cited for the following topics: observations of the spectra, spectropolarimetry, and light curves of supernovae of various types, theory of thermonuclear explosions, core collapse, and radioactive decay, applications to cosmology, and possible connections to gamma-ray bursts.

  15. Collective neutrino oscillations in supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Huaiyu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  16. Mass Varying Neutrinos in Supernovae

    CERN Document Server

    Rossi-Torres, F; de Holanda, P C; Peres, O L G

    2010-01-01

    We study limits for the mass varying neutrino model, using constrains from supernova neutrinos placed by the r-process condition, $Y_e<0.5$. Also, we use this model in a supernova environment to study the regions of survival probability in the oscillation space parameter ($\\tan^2\\theta$ and $\\Delta m^2_0$), considering the channel $\

  17. The Great Scientists

    Science.gov (United States)

    Meadows, Jack

    1989-11-01

    This lively history of the development of science and its relationship to society combines vivid biographies of twelve pivotal scientists, commentary on the social and historical events of their time, and over four hundred illustrations, including many in color. The biographies span from classical times to the Atomic Age, covering Aristotle, Galileo, Harvey, Newton, Lavoisier, Humboldt, Faraday, Darwin, Pasteur, Curie, Freud, and Einstein. Through the biographies and a wealth of other material, the volume reveals how social forces have influenced the course of science. Along with the highly informative color illustrations, it contains much archival material never before published, ranging from medieval woodcuts, etchings from Renaissance anatomy texts, and pages from Harvey's journal, to modern false-color x-rays and infrared photographs of solar flares. A beautifully-designed, fact-filled, stimulating work, The Great Scientists will fascinate anyone with an interest in science and how history can influence scientific discovery.

  18. Electronic Portfolios for Scientists

    OpenAIRE

    Dahn, I.; Christmann, A.

    2007-01-01

    Electronic portfolios (ePortfolios) are electronic versions of paper based portfolios. They are increasingly applied in education. Software for building and maintaining ePortfolios is emerging; open specifications for the exchange of ePortfolios exist. They show the potential to serve as a standard tool for documenting achievements in lifelong learning. In this paper we explore the potential of ePortfolios for scientists.

  19. Scientists want more children.

    Directory of Open Access Journals (Sweden)

    Elaine Howard Ecklund

    Full Text Available Scholars partly attribute the low number of women in academic science to the impact of the science career on family life. Yet, the picture of how men and women in science--at different points in the career trajectory--compare in their perceptions of this impact is incomplete. In particular, we know little about the perceptions and experiences of junior and senior scientists at top universities, institutions that have a disproportionate influence on science, science policy, and the next generation of scientists. Here we show that having fewer children than wished as a result of the science career affects the life satisfaction of science faculty and indirectly affects career satisfaction, and that young scientists (graduate students and postdoctoral fellows who have had fewer children than wished are more likely to plan to exit science entirely. We also show that the impact of science on family life is not just a woman's problem; the effect on life satisfaction of having fewer children than desired is more pronounced for male than female faculty, with life satisfaction strongly related to career satisfaction. And, in contrast to other research, gender differences among graduate students and postdoctoral fellows disappear. Family factors impede talented young scientists of both sexes from persisting to research positions in academic science. In an era when the global competitiveness of US science is at risk, it is concerning that a significant proportion of men and women trained in the select few spots available at top US research universities are considering leaving science and that such desires to leave are related to the impact of the science career on family life. Results from our study may inform university family leave policies for science departments as well as mentoring programs in the sciences.

  20. Scientists want more children.

    Science.gov (United States)

    Ecklund, Elaine Howard; Lincoln, Anne E

    2011-01-01

    Scholars partly attribute the low number of women in academic science to the impact of the science career on family life. Yet, the picture of how men and women in science--at different points in the career trajectory--compare in their perceptions of this impact is incomplete. In particular, we know little about the perceptions and experiences of junior and senior scientists at top universities, institutions that have a disproportionate influence on science, science policy, and the next generation of scientists. Here we show that having fewer children than wished as a result of the science career affects the life satisfaction of science faculty and indirectly affects career satisfaction, and that young scientists (graduate students and postdoctoral fellows) who have had fewer children than wished are more likely to plan to exit science entirely. We also show that the impact of science on family life is not just a woman's problem; the effect on life satisfaction of having fewer children than desired is more pronounced for male than female faculty, with life satisfaction strongly related to career satisfaction. And, in contrast to other research, gender differences among graduate students and postdoctoral fellows disappear. Family factors impede talented young scientists of both sexes from persisting to research positions in academic science. In an era when the global competitiveness of US science is at risk, it is concerning that a significant proportion of men and women trained in the select few spots available at top US research universities are considering leaving science and that such desires to leave are related to the impact of the science career on family life. Results from our study may inform university family leave policies for science departments as well as mentoring programs in the sciences.

  1. Cosmological and supernova neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Balantekin, A. B. [Department of Physics, University of Wisconsin - Madison, Wisconsin 53706 (United States); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Mathews, G. J. [Department of Physics, University of Notre Dame, IN 46556 (United States); Nakamura, K. [Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Pehlivan, Y. [Mimar Sinan GSÜ, Department of Physics, Şişli, İstanbul 34380 (Turkey); Suzuki, T. [Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  2. Cosmology with superluminous supernovae

    Science.gov (United States)

    Scovacricchi, D.; Nichol, R. C.; Bacon, D.; Sullivan, M.; Prajs, S.

    2016-02-01

    We predict cosmological constraints for forthcoming surveys using superluminous supernovae (SLSNe) as standardizable candles. Due to their high peak luminosity, these events can be observed to high redshift (z ˜ 3), opening up new possibilities to probe the Universe in the deceleration epoch. We describe our methodology for creating mock Hubble diagrams for the Dark Energy Survey (DES), the `Search Using DECam for Superluminous Supernovae' (SUDSS) and a sample of SLSNe possible from the Large Synoptic Survey Telescope (LSST), exploring a range of standardization values for SLSNe. We include uncertainties due to gravitational lensing and marginalize over possible uncertainties in the magnitude scale of the observations (e.g. uncertain absolute peak magnitude, calibration errors). We find that the addition of only ≃100 SLSNe from SUDSS to 3800 Type Ia Supernovae (SNe Ia) from DES can improve the constraints on w and Ωm by at least 20 per cent (assuming a flat wCDM universe). Moreover, the combination of DES SNe Ia and 10 000 LSST-like SLSNe can measure Ωm and w to 2 and 4 per cent, respectively. The real power of SLSNe becomes evident when we consider possible temporal variations in w(a), giving possible uncertainties of only 2, 5 and 14 per cent on Ωm, w0 and wa, respectively, from the combination of DES SNe Ia, LSST-like SLSNe and Planck. These errors are competitive with predicted Euclid constraints, indicating a future role for SLSNe for probing the high-redshift Universe.

  3. GALAXY OUTFLOWS WITHOUT SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Sur, Sharanya [Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore 560034 (India); Scannapieco, Evan [School of Earth and Space Exploration, Arizona State University, P.O. Box 876004, Tempe-85287 (United States); Ostriker, Eve C., E-mail: sharanya.sur@iiap.res.in, E-mail: sharanya.sur@asu.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-02-10

    High surface density, rapidly star-forming galaxies are observed to have ≈50–100 km s{sup −1} line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s{sup −1}, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M{sub ⊙} yr{sup −1} kpc{sup −2}. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

  4. Supernovae anisotropy power spectrum

    CERN Document Server

    Ghodsi, Hoda; Habibi, Farhang

    2016-01-01

    We contribute another anisotropy study to this field of research using Supernovae Type Ia (SNe Ia). In this work, we utilise the power spectrum calculation method and apply it to both the current SNe Ia data and simulation. Our simulations are constructed with the characteristics of the upcoming survey of the Large Synoptic Survey Telescope (LSST), which shall bring us the largest SNe Ia collection to date. We make predictions for the amplitude of a possible dipole anisotropy or anisotropy in higher multipole moments that would be detectable by the LSST.

  5. X-Ray Supernovae

    CERN Document Server

    Immler, S; Immler, Stefan; Lewin, Walter H.G.

    2002-01-01

    We present a review of X-ray observations of supernovae (SNe). By observing the (~0.1--100 keV) X-ray emission from young SNe, physical key parameters such as the circumstellar matter (CSM) density, mass-loss rate of the progenitor and temperature of the outgoing and reverse shock can be derived as a function of time. Despite intensive search over the last ~25 years, only 15 SNe have been detected in X-rays. We review the individual X-ray observations of these SNe and discuss their implications as to our understanding of the physical processes giving rise to the X-ray emission.

  6. Automated Supernova Discovery (Abstract)

    Science.gov (United States)

    Post, R. S.

    2015-12-01

    (Abstract only) We are developing a system of robotic telescopes for automatic recognition of Supernovas as well as other transient events in collaboration with the Puckett Supernova Search Team. At the SAS2014 meeting, the discovery program, SNARE, was first described. Since then, it has been continuously improved to handle searches under a wide variety of atmospheric conditions. Currently, two telescopes are used to build a reference library while searching for PSN with a partial library. Since data is taken every night without clouds, we must deal with varying atmospheric and high background illumination from the moon. Software is configured to identify a PSN, reshoot for verification with options to change the run plan to acquire photometric or spectrographic data. The telescopes are 24-inch CDK24, with Alta U230 cameras, one in CA and one in NM. Images and run plans are sent between sites so the CA telescope can search while photometry is done in NM. Our goal is to find bright PSNs with magnitude 17.5 or less which is the limit of our planned spectroscopy. We present results from our first automated PSN discoveries and plans for PSN data acquisition.

  7. The Nearby Supernova Factory

    CERN Document Server

    Wood-Vasey, W M; Lee Byung Cheol; Loken, S; Nugent, P; Perlmutter, S; Siegrist, J L; Wang, L; Antilogus, P; Astier, Pierre; Hardin, D; Pain, R; Copin, Y; Smadja, G; Gangler, E; Castera, A; Adam, G; Bacon, R; Lemonnier, J P; Pecontal, A; Pécontal, E; Kessler, R

    2004-01-01

    The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe~Ia) at redshifts 0.03

  8. Ernest Rutherford: scientist supreme

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. [Physics Department, University of Canterbury, Christchurch (New Zealand)

    1998-09-01

    One hundred years ago this month, Ernest Rutherford a talented young New Zealander who had just spent three years as a postgraduate student in Britain left for Canada, where he was to do the work that won him a Nobel prize. All three countries can justifiably claim this great scientist as their own. Ernest Rutherford is one of the most illustrious scientists that the world has ever seen. He achieved enduring international fame because of an incredibly productive life, during which he altered our view of nature on three separate occasions. Combining brilliantly conceived experiments with much hard work and special insight, he explained the perplexing problem of naturally occurring radioactivity, determined the structure of the atom, and was the world's first successful alchemist, changing nitrogen into oxygen. Rutherford received a Nobel prize for the first discovery, but the other two would have been equally worthy candidates, had they been discovered by someone else. Indeed, any one of his other secondary achievements many of which are now almost forgotten would have been enough to bring fame to a lesser scientist. For example, he invented an electrical method for detecting individual ionizing radiations, he dated the age of the Earth, and briefly held the world record for the distance over which wireless waves could be detected. He predicted the existence of neutrons, he oversaw the development of large-scale particle accelerators, and, during the First World War, he led the allied research into the detection of submarines. In this article the author describes the life and times of Ernest Rutherford. (UK)

  9. Supernova olivine from cometary dust

    Science.gov (United States)

    Messenger, Scott; Keller, Lindsay P.; Lauretta, Dante S.

    2005-01-01

    An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (olivine (forsterite 83) grains olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

  10. Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae

    CERN Document Server

    Albert, J; Allam, S; Althouse, W E; Amanullah, R; Annis, J; Astier, Pierre; Aumeunier, M; Bailey, S; Baltay, C; Barrelet, E; Basa, S; Bebek, C; Bergström, L; Bernstein, G; Bester, M; Besuner, B; Bigelow, B; Blandford, R; Bohlin, R; Bonissent, A; Bower, C; Brown, M; Campbell, M; Carithers, W; Cole, D; Commins, Eugene D; Craig, W; Davis, T; Dawson, K; Day, C; De Harveng, M; De Jongh, F; Deustua, S; Diehl, H; Dobson, T; Dodelson, S; Ealet, A; Ellis, R; Emmet, W; Figer, D; Fouchez, D; Frerking, M; Frieman, J A; Fruchter, A; Gerdes, D; Gladney, L; Goldhaber, G; Goobar, A; Groom, D; Heetderks, H; Hoff, M; Holland, S; Huffer, M; Hui, L; Huterer, D; Jain, B; Jelinsky, P; Juramy, C; Karcher, A; Kent, S; Kahn, S; Kim, A; Kolbe, W; Krieger, B; Kushner, G; Kuznetsova, N; Lafever, R; Lamoureux, J; Lampton, M; Lefèvre, O; Lebrun, V; Levi, M; Limon, P; Lin, H; Linder, E; Loken, S; Lorenzon, W; Malina, R; Marian, L; Marriner, J P; Marshall, P; Massey, R; Mazure, A; McGinnis, B; McKay, T; McKee, S; Miquel, R; Mobasher, B; Morgan, N; Mortsell, E; Mostek, N; Mufson, S; Musser, J; Nakajima, R; Nugent, P; Olus, H; Pain, R; Palaio, N; Pankow, D; Peoples, John; Perlmutter, S; Peterson, D; Prieto, E; Rabinowitz, D; Réfrégier, A; Rhodes, J; Roe, N; Rusin, D; Scarpine, V; Schubnell, M; Seiffert, M; Sholl, M; Shukla, H; Smadja, G; Smith, R M; Smoot, George F; Snyder, J; Spadafora, A; Stabenau, F; Stebbins, A; Stoughton, C; Szymkowiak, A; Tarle, G; Taylor, K; Tilquin, A; Tomasch, A; Tucker, D; Vincent, D; Von der Lippe, H; Walder, J P; Wang, G; Weinstein, A; Wester, W; White, M

    2005-01-01

    The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a companion White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties lead to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. SNAP has achieved technological readiness and the collaboration is poised to begin construction.

  11. Photometric redshifts for supernovae Ia in the Supernova Legacy Survey

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Pascal, S; Rich, J; Guy, J; Bazin, G; Astier, P; Balland, C; Basa, S; Carlberg, R G; Conley, A; Fouchez, D; Hardin, D; Hook, I M; Howell, D A; Pain, R; Perrett, K; Pritchet, C J; Regnault, N; Sullivan, M

    2009-01-01

    We present a method using the SALT2 light curve fitter to determine the redshift of Type Ia supernovae in the Supernova Legacy Survey (SNLS) based on their photometry in g', r', i' and z'. On 289 supernovae of the first three years of SNLS data, we obtain a precision $\\sigma_{\\Delta z/(1+z)} = 0.022$ on average up to a redshift of 1.0, with a higher precision of 0.016 for z0.45. The rate of events with $|\\Delta z|/(1+z)>0.15$ (catastrophic errors) is 1.4%. Both the precision and the rate of catastrophic errors are better than what can be currently obtained using host galaxy photometric redshifts. Photometric redshifts of this precision may be useful for future experiments which aim to discover up to millions of supernovae Ia but without spectroscopy for most of them.

  12. CCN1/CYR61-mediated meticulous patrolling by Ly6Clow monocytes fuels vascular inflammation.

    Science.gov (United States)

    Imhof, Beat A; Jemelin, Stephane; Ballet, Romain; Vesin, Christian; Schapira, Marco; Karaca, Melis; Emre, Yalin

    2016-08-16

    Inflammation is characterized by the recruitment of leukocytes from the bloodstream. The rapid arrival of neutrophils is followed by a wave of inflammatory lymphocyte antigen 6 complex (Ly6C)-positive monocytes. In contrast Ly6C(low) monocytes survey the endothelium in the steady state, but their role in inflammation is still unclear. Here, using confocal intravital microscopy, we show that upon Toll-like receptor 7/8 (TLR7/8)-mediated inflammation of mesenteric veins, platelet activation drives the rapid mobilization of Ly6C(low) monocytes to the luminal side of the endothelium. After repeatedly interacting with platelets, Ly6C(low) monocytes commit to a meticulous patrolling of the endothelial wall and orchestrate the subsequent arrival and extravasation of neutrophils through the production of proinflammatory cytokines and chemokines. At a molecular level, we show that cysteine-rich protein 61 (CYR61)/CYR61 connective tissue growth factor nephroblastoma overexpressed 1 (CCN1) protein is released by activated platelets and enables the recruitment of Ly6C(low) monocytes upon vascular inflammation. In addition endothelium-bound CCN1 sustains the adequate patrolling of Ly6C(low) monocytes both in the steady state and under inflammatory conditions. Blocking CCN1 or platelets with specific antibodies impaired the early arrival of Ly6C(low) monocytes and abolished the recruitment of neutrophils. These results refine the leukocyte recruitment cascade model by introducing endothelium-bound CCN1 as an inflammation mediator and by demonstrating a role for platelets and patrolling Ly6C(low) monocytes in acute vascular inflammation.

  13. Scientists need political literacy

    Science.gov (United States)

    Simarski, Lynn Teo

    Scientists need to sharpen their political literacy to promote public and congressional awareness of science policy issues. This was the message of a panel of politically savvy scientists at a recent workshop at the American Association for the Advancement of Science's annual meeting in Washington, D.C. Researchers can maximize their lobbying efforts by targeting critical points of the legislative and federal funding cycles, the panel said, and by understanding the differences between the science and policy processes.Drastic modifications to the federal budget process this year will influence how much funding flows to research and development. A new feature for FY 1991-1993 is caps on federal expenditure in three areas: defense, foreign aid, and domestic “discretionary” spending. (Most of the agencies that fund geophysics fall into the domestic category.) Money cannot now be transferred from one of these areas to another, said Michael L. Telson, analyst for the House Budget Committee, and loopholes will be “very tough to find.” What is more, non-defense discretionary spending has dropped over a decade from 24% of the budget to the present 15%. Another new requirement is the “pay-as-you-go” system. Under this, a bill that calls for an increase in “entitlement” or other mandatory spending must offset this by higher taxes or by a cut in other spending.

  14. CONFERENCE OF YOUNG SCIENTISTS

    Directory of Open Access Journals (Sweden)

    article editorial

    2008-01-01

    Full Text Available A conference of young scientists dedicated to the 245th anniversary of the Scientific Center of Children's Health was held on September 12, 2008.Speakers at the conference were young professionals working at SCCH of RAMS, Sechenov Moscow Medical Academy, Institute of Pediatric Hematology, Oncology, and Immunology. During the conference the poster session was held in which young scientists of the Centre took part. Presentations of participants were evaluated by the members of the Academic Council of SCCH, leading specialists of the Center. Gifts to the winners of the conference were provided by "Procter & Gamble".Winners and awardees:I place: Chistyakova V.P. - Clinical intern at SCCH of RAMS;II place: Gudkova E.Yu. - Researcher at the Department of Rheumatology of SCCH of RAMS;III place: Darmanyan A.S. - Researcher at the Department of diagnostics and rehabilitation treatment of SCCH of RAMS.Best poster paper: Plyakin V.A. - Researcher at Surgical Department NTSZD RAMS.Audience Award: Tikhomirova E.A. - Researcher at the Department of functional diagnostics of SCCH of RAMS.

  15. Another Kind of Scientist Activism

    Science.gov (United States)

    Marino, Lori

    2009-01-01

    In a well-cited 1996 editorial in "Science," "The Activist Scientist," Jaleh Daie calls for scientists to take an assertive role in educating politicians and the public about the importance of government support for research. She writes that most scientists are reluctant to become involved in political lobbying for a variety of reasons--time…

  16. Supernova 1987A: The Supernova of a Lifetime

    Science.gov (United States)

    Kirshner, Robert

    2017-01-01

    Supernova 1987A, the brightest supernova since Kepler's in 1604, was detected 30 years ago at a distance of 160 000 light years in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. Visible with the naked eye and detected with the full range of technology constructed since Kepler's time, SN 1987A has continued to be a rich source of empirical information to help understand supernova explosions and their evolution into supernova remnants. While the light output has faded by a factor of 10 000 000 over those 30 years, instrumentation, like the Hubble Space Telescope, the Chandra X-ray Observatory, and the Atacama Large Millimeter Array has continued to improve so that this supernova continues to be visible in X-rays, ultraviolet light, visible light, infrared light and in radio emission. In this review, I will sketch what has been learned from these observations about the pre-supernova star and its final stages of evolution, the explosion physics, the energy sources for emission, and the shock physics as the expanding debris encounters the circumstellar ring that was created about 20 000 years before the explosion. Today, SN 1987A is making the transition to a supernova remnant- the energetics are no longer dominated by the radioactive elements produced in the explosion, but by the interaction of the expanding debris with the surrounding gas. While we are confident that the supernova explosion had its origin in gravitational collapse, careful searches for a compact object at the center of the remnant place upper limits of a few solar luminosities on that relic. Support for HST GO programs 13401 and 13405 was provided by NASA through grants from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  17. Magnetar-Powered Supernovae in Two Dimensions. I. Superluminous Supernovae

    OpenAIRE

    Chen, Ke-Jung; Woosley, S. E.; Sukhbold, Tuguldur

    2016-01-01

    Previous studies have shown that the radiation emitted by a rapidly rotating magnetar embedded in a young supernova can greatly amplify its luminosity. These one-dimensional studies have also revealed the existence of an instability arising from the piling up of radiatively accelerated matter in a thin dense shell deep inside the supernova. Here we examine the problem in two dimensions and find that, while instabilities cause mixing and fracture this shell into filamentary structures that red...

  18. WFIRST CGI Adjutant Scientist

    Science.gov (United States)

    Kasdin, N.

    One of the most exciting developments in exoplanet science is the inclusion of a coronagraph instrument on WFIRST. After more than 20 years of research and development on coronagraphy and wavefront control, the technology is ready for a demonstration in space and to be used for revolutionary science. Good progress has already been made at JPL and partner institutions on the coronagraph technology and instrument design and test. The next five years as we enter Phase A will be critical for raising the TRL of the coronagraph to the needed level for flight and for converging on a design that is robust, low risk, and meets the science requirements. In addition, there is growing excitement over the possibility of rendezvousing an occulter with WFIRST/AFTA as a separate mission; this would both demonstrate that important technology and potentially dramatically enhance the science reach, introducing the possibility of imaging Earth-like planets in the habitable zone of nearby stars. In this proposal I will be applying for the Coronagraph Adjutant Scientist (CAS) position. I bring to the position the background and skills needed to be an effective liaison between the project office, the instrument team, and the Science Investigation Team (SIT). My background in systems engineering before coming to Princeton (I was Chief Systems Engineer for the Gravity Probe-B mission) and my 15 years of working closely with NASA on both coronagraph and occulter technology make me well-suited to the role. I have been a lead coronagraph scientist for the WFIRST mission from the beginning, including as a member of the SDT. Together with JPL and NASA HQ, I helped organize the process for selecting the coronagraphs for the CGI, one of which, the shaped pupil, has been developed in my lab. All of the key algorithms for wavefront control (including EFC and Stroke Minimization) were originally developed by students or post-docs in my lab at Princeton. I am thus in a unique position to work with

  19. Ship manoeuvrability: full scale trials of colombian navy riverine support patrol vessel

    OpenAIRE

    Carreño Moreno, Jorge; Sierra Vanegas, Etty; Jimenez Gonzalez, Victor

    2011-01-01

    Methodology and results of full scale maneuvering trials for Riverine Support Patrol Vessel “RSPV”, built by COTECMAR for the Colombian Navy are presented. !is ship is equipped with a “Pump – Jet” propulsion system and the hull corresponds to a wide-hull with a high Beam – Draft ratio (B/T=9.5). Tests were based on the results of simulation of turning diameters obtained from TRIBON M3© design software, applying techniques of Design of Experiments “DOE”, to rationalize the number of runs...

  20. A structural analysis of an ocean going patrol boat subjected to planning loads

    Science.gov (United States)

    Clark, James H.; Lafreniere, Robert; Stoodt, Robert; Wiedenheft, John

    1987-01-01

    A static structural analysis of an ocean going patrol vessel subjected to hydrodynamic planning loads is discussed. The analysis required the development of a detailed model that included hull plating, five structural bulkheads, longitudinal and transverse stiffners, and a coarse representation of the superstructure. The finite element model was developed from fabrication drawings using the Navy computer aided design system. Various stress and displacement contours are shown for the entire hull. Because several critical areas appeared to be overstressed, these areas were remeshed for detail and are presented for completeness.

  1. Moving Object Tracking and Its Application to an Indoor Dual-Robot Patrol

    Directory of Open Access Journals (Sweden)

    Cheng-Han Shih

    2016-11-01

    Full Text Available This paper presents an application of image tracking using an omnidirectional wheeled mobile robot (WMR. The objective of this study is to integrate image processing of hue, saturation, and lightness (HSL for fuzzy color space, and use mean shift tracking for object detection and a Radio Frequency Identification (RFID reader for confirming destination. Fuzzy control is applied to omnidirectional WMR for indoor patrol and intruder detection. Experimental results show that the proposed control scheme can make the WMRs perform indoor security service.

  2. The Vela Supernova Remnant

    Science.gov (United States)

    Raymond, John C.

    We wish to obtain both emission and absorption line observations of the Vela Supernova remnant. The filament we wish to study in emission is the brightest filament in the SNR, so it will provide a spectrum twice the quality of any in existence. It is also located at the edge of an unusual bulge in the SNR, and it can be used to test the level of departure from pressure equilibrium in the remnant, which is useful as a test of evaporative models of SNR evolution. The absorption line studies will look for evidence of the drastically unstable behavior of shocks above 150 km/s predicted by Innes and Giddings. Four of the stars studied by Jenkins, Silk and Wallerstein showed marginal evidence for two positive or two negative high velocity components. If these multiple velocity components are confirmed, they support the secondary shock predictions of Innes and Giddings.

  3. Neutrinos and nucleosynthesis in supernova

    Energy Technology Data Exchange (ETDEWEB)

    Solis, U [Instituto de Ciencias Nucleares, Departamento de Fisica de Altas EnergIas, Universidad Nacional Autonoma de Mexico (ICN-UNAM). Apartado Postal 70-543, 04510 Mexico, D.F. (Mexico); D' Olivo, J C [Instituto de Ciencias Nucleares, Departamento de Fisica de Altas EnergIas, Universidad Nacional Autonoma de Mexico (ICN-UNAM). Apartado Postal 70-543, 04510 Mexico, D.F. (Mexico); Cabral-Rosetti, L G [Departamento de Posgrado, Centro Interdisciplinario de Investigacion y Docencia en Educacion Tecnica (CIIDET), Av. Universidad 282 Pte., Col. Centro, A. Postal 752, C.P. 76000, Santiago de Queretaro, Qro. (Mexico)

    2006-05-15

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.

  4. The Diffuse Supernova Neutrino Background

    CERN Document Server

    Beacom, John F

    2010-01-01

    The Diffuse Supernova Neutrino Background (DSNB) is the weak glow of MeV neutrinos and antineutrinos from distant core-collapse supernovae. The DSNB has not been detected yet, but the Super-Kamiokande (SK) 2003 upper limit on the electron antineutrino flux is close to predictions, now quite precise, based on astrophysical data. If SK is modified with dissolved gadolinium to reduce detector backgrounds and increase the energy range for analysis, then it should detect the DSNB at a rate of a few events per year, providing a new probe of supernova neutrino emission and the cosmic core-collapse rate. If the DSNB is not detected, then new physics will be required. Neutrino astronomy, while uniquely powerful, has proven extremely difficult -- only the Sun and the nearby Supernova 1987A have been detected to date -- so the promise of detecting new sources soon is exciting indeed.

  5. Chandra Associates Pulsar and Historic Supernova

    Science.gov (United States)

    2001-01-01

    SAN DIEGO -- Scientists using NASA’s Chandra X-ray Observatory have found new evidence that a pulsar in the constellation of Sagittarius was created when a massive star exploded, witnessed by Chinese astronomers in the year 386 AD. If confirmed, this will be only the second pulsar to be clearly associated with a historic event. These results were presented today by Victoria Kaspi and Mallory Roberts of McGill University at the American Astronomical Society meeting. Also participating in the research were Gautum Vasisht from the Jet Propulsion Laboratory, Eric Gotthelf from Columbia University, Michael Pivovaroff from Therma-Wave, Inc., and Nobuyuki Kawai from the Institute of Physical and Chemical Research, Japan. The scientists used Chandra to locate the pulsar exactly at the geometric center of the supernova remnant known as G11.2-0.3. This location provides very strong evidence that the pulsar, a neutron star that is rotating 14 times a second, was formed in the supernova of 386 AD, and therefore has an age of 1615 years. "Determining the true ages of astronomical objects is notoriously difficult, and for this reason, historical records of supernovas are of great importance,"said Kaspi."In roughly the past 2,000 years, fewer than 10 reports of probable supernovae have been archived mostly by Asian astronomers. Of those handful, the remnant of 1054 AD, the Crab Nebula, was until now the only pulsar whose birth could be associated with a historic event - and, hence, the only neutron star that has a firm age." Between mid-April and mid-May in the year 386 AD, a young "guest star", presumably a supernova, was recorded by Chinese observers in the direction of the sky now known as the constellation of Sagittarius. In the 1970s, radio astronomers discovered an expanding nebula of gas and high-energy particles, called G11.2-0.3, that is believed to be the remnant of that explosion. In 1997, a team of X-ray astronomers used Japan’s ASCA satellite to discover a pulsar

  6. Toward a Standard Model of Core Collapse Supernovae

    OpenAIRE

    Mezzacappa, A.

    2000-01-01

    In this paper, we discuss the current status of core collapse supernova models and the future developments needed to achieve significant advances in understanding the supernova mechanism and supernova phenomenology, i.e., in developing a supernova standard model.

  7. Supernovae and Gamma Ray Bursts

    Directory of Open Access Journals (Sweden)

    M. Della Valle

    2007-01-01

    Full Text Available Se revisa el estatus observacional de la conexi on Supernova (SN/Estallido de Rayos-Gamma (GRB. Recientes (y no tan recientes observaciones de GRBs largos sugieren que una fracci on signi cativa de ellos (pero no todos est an asociados con supernovas brillantes del tipo Ib/c. Estimaciones actuales de las tasas de producci on de GRBs y SNs dan una raz on para GRB/SNe-Ibc en el rango 0:4%

  8. Habituating field scientists.

    Science.gov (United States)

    Alcayna-Stevens, Lys

    2016-12-01

    This article explores the sensory dimensions of scientific field research in the only region in the world where free-ranging bonobos ( Pan paniscus) can be studied in their natural environment; the equatorial rainforest of the Democratic Republic of Congo. If, as sensory anthropologists have argued, the senses are developed, grown and honed in a given cultural and environmental milieu, how is it that field scientists come to dwell among familiarity in a world which is, at first, unfamiliar? This article builds upon previous anthropological and philosophical engagements with habituation that have critically examined primatologists' attempts to become 'neutral objects in the environment' in order to habituate wild apes to their presence. It does so by tracing the somatic modes of attention developed by European and North American researchers as they follow bonobos in these forests. The argument is that as environments, beings and their elements become familiar, they do not become 'neutral', but rather, suffused with meaning.

  9. Python for scientists

    CERN Document Server

    Stewart, John M

    2017-01-01

    Scientific Python is a significant public domain alternative to expensive proprietary software packages. This book teaches from scratch everything the working scientist needs to know using copious, downloadable, useful and adaptable code snippets. Readers will discover how easy it is to implement and test non-trivial mathematical algorithms and will be guided through the many freely available add-on modules. A range of examples, relevant to many different fields, illustrate the language's capabilities. The author also shows how to use pre-existing legacy code (usually in Fortran77) within the Python environment, thus avoiding the need to master the original code. In this new edition, several chapters have been re-written to reflect the IPython notebook style. With an extended index, an entirely new chapter discussing SymPy and a substantial increase in the number of code snippets, researchers and research students will be able to quickly acquire all the skills needed for using Python effectively.

  10. Voices of Romanian scientists

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    As Romania has now become a Member State of CERN, Romanian scientists share their thoughts about this new era of partnership for their community.   Members of ATLAS from Romanian institutes at CERN (from left to right): Dan Ciubotaru, Michele Renda, Bogdan Blidaru, Alexandra Tudorache, Marina Rotaru, Ana Dumitriu, Valentina Tudorache, Adam Jinaru, Calin Alexa. On 17 July 2016, Romania became the twenty-second Member State of CERN, 25 years after the first cooperation agreement with the country was signed. “CERN and Romania already have a long history of strong collaboration”, says Emmanuel Tsesmelis, head of Relations with Associate Members and Non-Member States. “We very much look forward to strengthening this collaboration as Romania becomes CERN’s twenty-second Member State, which promises the development of mutual interests in scientific research, related technologies and education,” he affirms. Romania&...

  11. Ozone Depletion from Nearby Supernovae

    CERN Document Server

    Gehrels, N; Jackman, C H; Cannizzo, J K; Mattson, B J; Chen, W; Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan

    2003-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time, improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made in theoretical modeling of supernovae and of the resultant gamma-ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma-rays and cosmic rays. We find that for the combined ozone depletion roughly to double the ``biologically active'' UV flux received at the surface of the Earth, the supernova mu...

  12. Ozone Depletion from Nearby Supernovae

    Science.gov (United States)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  13. Intravascular Immune Surveillance by CXCR6+ NKT Cells Patrolling Liver Sinusoids

    Directory of Open Access Journals (Sweden)

    Geissmann Frederic

    2005-01-01

    Full Text Available We examined the in vivo behavior of liver natural killer T cells (NKT cells by intravital fluorescence microscopic imaging of mice in which a green fluorescent protein cDNA was used to replace the gene encoding the chemokine receptor CXCR6. NKT cells, which account for most CXCR6+ cells in liver, were found to crawl within hepatic sinusoids at 10-20 µm/min and to stop upon T cell antigen receptor activation. CXCR6-deficient mice exhibited a selective and severe reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. CXCL16, the cell surface ligand for CXCR6, is expressed on sinusoidal endothelial cells, and CXCR6 deficiency resulted in reduced survival, but not in altered speed or pattern of patrolling of NKT cells. Thus, NKT cells patrol liver sinusoids to provide intravascular immune surveillance, and CXCR6 contributes to liver-based immune responses by regulating their abundance.

  14. Intravascular immune surveillance by CXCR6+ NKT cells patrolling liver sinusoids.

    Directory of Open Access Journals (Sweden)

    Frederic Geissmann

    2005-04-01

    Full Text Available We examined the in vivo behavior of liver natural killer T cells (NKT cells by intravital fluorescence microscopic imaging of mice in which a green fluorescent protein cDNA was used to replace the gene encoding the chemokine receptor CXCR6. NKT cells, which account for most CXCR6(+ cells in liver, were found to crawl within hepatic sinusoids at 10-20 microm/min and to stop upon T cell antigen receptor activation. CXCR6-deficient mice exhibited a selective and severe reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. CXCL16, the cell surface ligand for CXCR6, is expressed on sinusoidal endothelial cells, and CXCR6 deficiency resulted in reduced survival, but not in altered speed or pattern of patrolling of NKT cells. Thus, NKT cells patrol liver sinusoids to provide intravascular immune surveillance, and CXCR6 contributes to liver-based immune responses by regulating their abundance.

  15. How Bright Can Supernovae Get?

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Supernovae enormous explosions associated with the end of a stars life come in a variety of types with different origins. A new study has examined how the brightest supernovae in the Universe are produced, and what limits might be set on their brightness.Ultra-Luminous ObservationsRecent observations have revealed many ultra-luminous supernovae, which haveenergies that challenge our abilities to explain them usingcurrent supernova models. An especially extreme example is the 2015 discovery of the supernova ASASSN-15lh, which shone with a peak luminosity of ~2*1045 erg/s, nearly a trillion times brighter than the Sun. ASASSN-15lh radiated a whopping ~2*1052 erg in the first four months after its detection.How could a supernova that bright be produced? To explore the answer to that question, Tuguldur Sukhbold and Stan Woosley at University of California, Santa Cruz, have examined the different sources that could produce supernovae and calculated upper limits on the potential luminosities ofeach of these supernova varieties.Explosive ModelsSukhbold and Woosley explore multiple different models for core-collapse supernova explosions, including:Prompt explosionA stars core collapses and immediately explodes.Pair instabilityElectron/positron pair production at a massive stars center leads to core collapse. For high masses, radioactivity can contribute to delayed energy output.Colliding shellsPreviously expelled shells of material around a star collide after the initial explosion, providing additional energy release.MagnetarThe collapsing star forms a magnetar a rapidly rotating neutron star with an incredibly strong magnetic field at its core, which then dumps energy into the supernova ejecta, further brightening the explosion.They then apply these models to different types of stars.Setting the LimitThe authors show that the light curve of ASASSN-15lh (plotted in orange) can be described by a model (black curve) in which a magnetar with an initial spin period of 0.7 ms

  16. Scientists present their design for Einstein Telescope

    CERN Multimedia

    ASPERA Press Release

    2011-01-01

    Plans shape up for a revolutionary new observatory that will explore black holes and the Big Bang. This detector will ‘see’ the Universe in gravitational waves.   A new era in astronomy will come a step closer when scientists from across Europe present their design study today for an advanced observatory capable of making precision measurements of gravitational waves – minute ripples in the fabric of spacetime – predicted to emanate from cosmic catastrophes such as merging black holes and collapsing stars and supernovae. It also offers the potential to probe the earliest moments of the Universe just after the Big Bang, which are currently inaccessible. The Einstein Observatory (ET) is a so-called third-generation gravitational-wave (GW) detector, which will be 100 times more sensitive than current instruments. Like the first two generations of GW detectors, it is based on the measurement of tiny changes (far less than the size of an atomic nucleus) in the le...

  17. The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

    Energy Technology Data Exchange (ETDEWEB)

    Miknaitis, Gajus; Pignata, G.; Rest, A.; Wood-Vasey, W.M.; Blondin, S.; Challis, P.; Smith, R.C.; Stubbs, C.W.; Suntzeff, N.B.; Foley, R.J.; Matheson, T.; Tonry, J.L.; Aguilera, C.; Blackman, J.W.; Becker, A.C.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Filippenko, A.V.; Garg, A.; Garnavich, P.M.; /Fermilab /Chile U., Catolica /Cerro-Tololo

    2007-01-08

    We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w = P/{rho}c{sup 2} for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z {approx} 0.5 {+-} 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al. (2007).

  18. Distant Supernovae Indicate Ever-Expanding Universe

    Science.gov (United States)

    1998-12-01

    ESO Astronomers Contribute towards Resolution of Cosmic Puzzle Since the discovery of the expansion of the Universe by American astronomer Edwin Hubble in the 1920's, by measurement of galaxy velocities, astronomers have tried to learn how this expansion changes with time. Until now, most scientists have been considering two possibilities: the expansion rate is slowing down and will ultimately either come to a halt - whereafter the Universe would start to contract, or it will continue to expand forever. However, new studies by two independent research teams, based on observations of exploding stars ( supernovae ) by ESO astronomers [1] with astronomical telescopes at the La Silla Observatory as well as those of their colleagues at other institutions, appear to show that the expansion of the Universe is accelerating . The results take the discovery of the cosmological expansion one step further and challenge recent models of the Universe. If the new measurements are indeed correct, they show that the elusive "cosmological constant" , as proposed by Albert Einstein , contributes significantly to the evolution of the Universe. The existence of a non-zero cosmological constant implies that a repulsive force, counter-acting gravity, currently dominates the universal expansion , and consequently leads to an ever-expanding Universe. This new research is being named as the "Breakthrough of the Year" by the renowned US science journal Science in the December 18, 1998, issue. A Press Release is published by the journal on this occasion. "Fundamental Parameters" of the Universe Three fundamental parameters govern all cosmological models based on the theory of General Relativity. They are 1. the current expansion rate as described by Hubble's constant , i.e. the proportionality factor between expansion velocity and distance 2. the average matter density in the Universe, and 3. the amount of "other energy" present in space. From the measured values of these fundamental

  19. A Serendipitous Scientist.

    Science.gov (United States)

    Lefkowitz, Robert J

    2017-07-17

    Growing up in a middle-class Jewish home in the Bronx, I had only one professional goal: to become a physician. However, as with most of my Vietnam-era MD colleagues, I found my residency training interrupted by the Doctor Draft in 1968. Some of us who were academically inclined fulfilled this obligation by serving in the US Public Health Service as commissioned officers stationed at the National Institutes of Health. This experience would eventually change the entire trajectory of my career. Here I describe how, over a period of years, I transitioned from the life of a physician to that of a physician scientist; my 50 years of work on cellular receptors; and some miscellaneous thoughts on subjects as varied as Nobel prizes, scientific lineages, mentoring, publishing, and funding. Expected final online publication date for the Annual Review of Pharmacology and Toxicology Volume 58 is January 6, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  20. Data Processing for Scientists.

    Science.gov (United States)

    Heumann, K F

    1956-10-26

    This brief survey of integrated and electronic data processing has touched on such matters as the origin of the concepts, their use in business, machines that are available, indexing problems, and, finally, some scientific uses that surely foreshadow further development. The purpose of this has been to present for the consideration of scientists a point of view and some techniques which have had a phenomenal growth in the business world and to suggest that these are worth consideration in scientific data-handling problems (30). To close, let me quote from William Bamert on the experience of the C. and O. Railroad once more (8, p. 121): "Frankly, we have been asked whether we weren't planning for Utopia-the implication being that everyone except starry-eyed visionaries knows that Utopia is unattainable. Our answer is that of course we are! Has anyone yet discovered a better way to begin program planning of this nature? Our feeling is that compromise comes early enough in the normal order of things."

  1. Light-echo spectroscopy of historic Supernovae

    Science.gov (United States)

    Krause, Oliver

    Young Galactic supernova remnants are unique laboratories for supernova physics. Due to their proximity they provide us with the most detailed view of the outcome of a supernova. However, the exact spectroscopic types of their original explosions have been undetermined so far -hindering to link the wealth of multi-wavelength knowledge about their remnants with the diverse population of supernovae. Light echoes, reflektions of the brilliant supernova burst of light by interstellar dust, provide a unique opportunity to reobserve today -with powerful scientific instruments of the 21st century -historic supernova exlosions even after hundreds of years and to conclude on their nature. We report on optical light-echo spectroscopy of two famous Galactic supernovae: Tycho Brahe's SN 1572 and the supernova that created the Cassiopeia A remnant around the year 1680. These observations finally recovered the missing spectroscopic classifications and provide new constraints on explosion models for future studies.

  2. Supernova Physics at DUNE

    CERN Document Server

    Ankowski, Artur; Benhar, Omar; Chen, Sun; Cherry, John; Cui, Yanou; Friedland, Alexander; Gil-Botella, Ines; Haghighat, Alireza; Horiuchi, Shunsaku; Huber, Patrick; Kneller, James; Laha, Ranjan; Li, Shirley; Link, Jonathan; Lovato, Alessandro; Macias, Oscar; Mariani, Camillo; Mezzacappa, Anthony; O'Connor, Evan; O'Sullivan, Erin; Rubbia, Andre; Scholberg, Kate; Takeuchi, Tatsu

    2016-01-01

    The DUNE/LBNF program aims to address key questions in neutrino physics and astroparticle physics. Realizing DUNE's potential to reconstruct low-energy particles in the 10-100 MeV energy range will bring significant benefits for all DUNE's science goals. In neutrino physics, low-energy sensitivity will improve neutrino energy reconstruction in the GeV range relevant for the kinematics of DUNE's long-baseline oscillation program. In astroparticle physics, low-energy capabilities will make DUNE's far detectors the world's best apparatus for studying the electron-neutrino flux from a supernova. This will open a new window to unrivaled studies of the dynamics and neutronization of a star's central core in real time, the potential discovery of the neutrino mass hierarchy, provide new sensitivity to physics beyond the Standard Model, and evidence of neutrino quantum-coherence effects. The same capabilities will also provide new sensitivity to `boosted dark matter' models that are not observable in traditional direc...

  3. A Supernova's Shockwaves

    Science.gov (United States)

    2007-01-01

    Supernovae are the explosive deaths of the universe's most massive stars. In death, these volatile creatures blast tons of energetic waves into the cosmos, destroying much of the dust surrounding them. This false-color composite from NASA's Spitzer Space Telescope and NASA's Chandra X-ray Observatory shows the remnant of one such explosion. The remnant, called N132D, is the wispy pink shell of gas at the center of this image. The pinkish color reveals a clash between the explosion's high-energy shockwaves and surrounding dust grains. In the background, small organic molecules called polycyclic aromatic hydrocarbons are shown as tints of green. The blue spots represent stars in our galaxy along this line of sight. N132D is located 163,000 light-years away in a neighboring galaxy called, the Large Magellanic Cloud. In this image, infrared light at 4.5 microns is mapped to blue, 8.0 microns to green and 24 microns to red. Broadband X-ray light is mapped purple. The infrared data were taken by Spitzer's infrared array camera and multiband imaging photometer, while the X-ray data were captured by Chandra.

  4. Astronomers Make "Movie" of Radio Images Showing Supernova Explosion

    Science.gov (United States)

    1995-11-01

    Astronomers using an international network of radio telescopes have produced a "movie" showing details of the expansion of debris from an exploding star. Their sequence of images constitutes the best determination yet made of the details of a new supernova remnant, and already has raised new questions about such events. The scientists used radio telescopes in Europe and the United States, including the National Science Foundation's Very Large Array (VLA) and Very Long Baseline Array (VLBA), to make very high- resolution images of Supernova 1993J, which was discovered by a Spanish amateur astronomer on March 28, 1993 in the galaxy M81, some 11 million light-years distant in the constellation Ursa Major. Their results are reported in the December 1 issue of the journal Science. The "movie" is based on five images of the supernova, made during 1993 and 1994. The work was done by: Jon Marcaide and Eduardo Ros of the University of Valencia, Spain; Antxon Alberdi of the Special Laboratory for Astrophysics and Fundamental Physics of Madrid, Spain and the Institute of Astrophysics at Andalucia, Spain; Philip Diamond of the National Radio Astronomy Observatory in Socorro, NM; Irwin Shapiro of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; Jose-Carlos Guirado, Dayton Jones and Robert Preston of the Jet Propulsion Laboratory in Pasadena, CA; Thomas Krichbaum and Arno Witzel of the Max-Planck Institute for Radioastronomy in Bonn, Germany; Franco Mantovani of the Institute of Radioastronomy in Bologna, Italy; Antonio Rius of the Special Laboratory for Astrophysics and Fundamental Physics of Madrid, Spain and the Center for Advanced Studies at Blanes, Spain; Richard Schilizzi of the Joint Institute for VLBI in Europe and Leiden Observatory in the Netherlands; Corrado Trigilio of the Institute of Radioastronomy in Noto, Italy; and Alan Whitney of the MIT- Haystack Observatory in Massachusetts. The capability to make such high-quality images with widely

  5. Characterising Dark Energy through supernovae

    CERN Document Server

    Davis, Tamara M

    2016-01-01

    Type Ia supernovae are a powerful cosmological probe, that gave the first strong evidence that the expansion of the universe is accelerating. Here we provide an overview of how supernovae can go further to reveal information about what is causing the acceleration, be it dark energy or some modification to our laws of gravity. We first summarise the many different approaches used to explain or test the acceleration, including parametric models (like the standard model, LambdaCDM), non-parametric models, dark fluid models such as quintessence, and extensions to standard gravity. We also show how supernova data can be used beyond the Hubble diagram, to give information on gravitational lensing and peculiar velocities that can be used to distinguish between models that predict the same expansion history. Finally, we review the methods of statistical inference that are commonly used, making a point of separating parameter estimation from model selection.

  6. Featured Image: Modeling Supernova Remnants

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!CitationPaul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76

  7. Standardization of type Ia supernovae

    CERN Document Server

    Coelho, Rodrigo C V; Reis, Ribamar R R; Siffert, Beatriz B

    2014-01-01

    Type Ia supernovae (SNe Ia) have been intensively investigated due to its great homogeneity and high luminosity, which make it possible to use them as standardizable candles for the determination of cosmological parameters. In 2011, the physics Nobel prize was awarded for the discovery of the accelerating expansion of the Universe through observations of distant supernovae. This is a pedagogical article, aimed at those starting their study of that subject, in which we dwell on some topics related to the analysis of SNe Ia and their use in luminosity distance estimators. Here we investigate their spectral properties and light curve standardization, paying careful attention to the fundamental quantities directly related to the SNe Ia observables. Finally, we describe our own step-by-step implementation of a classical light curve fi?tter, the stretch, applying it to real data from the Carnegie Supernova Project.

  8. Dynamics of Kepler's supernova remnant

    Science.gov (United States)

    Borkowski, Kazimierz J.; Blondin, John M.; Sarazin, Craig L.

    1992-01-01

    Observations of Kepler's SNR have revealed a strong interaction with the ambient medium, far in excess of that expected at a distance of about 600 pc away from the Galactic plane where Kepler's SNR is located. This has been interpreted as a result of the interaction of supernova ejecta with the dense circumstellar medium (CSM). Based on the bow-shock model of Bandiera (1985), we study the dynamics of this interaction. The CSM distribution consists of an undisturbed stellar wind of a moving supernova progenitor and a dense shell formed in its interaction with a tenuous interstellar medium. Supernova ejecta drive a blast wave through the stellar wind which splits into the transmitted and reflected shocks upon hitting this bow-shock shell. We identify the transmitted shock with the nonradiative, Balmer-dominated shocks found recently in Kepler's SNR. The transmitted shock most probably penetrated the shell in the vicinity of the stagnation point.

  9. Frontier Scientists use Modern Media

    Science.gov (United States)

    O'connell, E. A.

    2013-12-01

    Engaging Americans and the international community in the excitement and value of Alaskan Arctic discovery is the goal of Frontier Scientists. With a changing climate, resources of polar regions are being eyed by many nations. Frontier Scientists brings the stories of field scientists in the Far North to the public. With a website, an app, short videos, and social media channels; FS is a model for making connections between the public and field scientists. FS will demonstrate how academia, web content, online communities, evaluation and marketing are brought together in a 21st century multi-media platform, how scientists can maintain their integrity while engaging in outreach, and how new forms of media such as short videos can entertain as well as inspire.

  10. High Cadence Digital Full Disk Hα Patrol Device at Kanzelhöhe

    Science.gov (United States)

    Otruba, W.

    1999-09-01

    The need for monitoring the sun in the prominent Hα-line is evident. For a long time this recording was done on photographic film at Kanzelhöhe Solar Observatory. Now with the evolution of CCDs and digital mass storage devices it is possible and even more economical to do this job digitally. A 1kx1k CCD camera and a standard frame grabbing system on a conventional PC are attached to the established Kanzelhöhe Patrol Instrument with a narrow band Hα filter. At the present state a very simple frame selection mechanism is installed to improve the image quality. The data are archived on CDs. The development of a standard image processing and evaluation system is in progress. Low cadence synoptic images are currently fed into the SOHO synoptic database. Instant data access from the Kanzelhöhe database via WWW is planned.

  11. Imparting protean behavior to mobile robots accomplishing patrolling tasks in the presence of adversaries.

    Science.gov (United States)

    Curiac, Daniel-Ioan; Volosencu, Constantin

    2015-10-08

    Providing unpredictable trajectories for patrol robots is essential when coping with adversaries. In order to solve this problem we developed an effective approach based on the known protean behavior of individual prey animals-random zig-zag movement. The proposed bio-inspired method modifies the normal robot's path by incorporating sudden and irregular direction changes without jeopardizing the robot's mission. Such a tactic is aimed to confuse the enemy (e.g. a sniper), offering less time to acquire and retain sight alignment and sight picture. This idea is implemented by simulating a series of fictive-temporary obstacles that will randomly appear in the robot's field of view, deceiving the obstacle avoiding mechanism to react. The new general methodology is particularized by using the Arnold's cat map to obtain the timely random appearance and disappearance of the fictive obstacles. The viability of the proposed method is confirmed through an extensive simulation case study.

  12. MULTI-VEHICLE COVERING TOUR PROBLEM: BUILDING ROUTES FOR URBAN PATROLLING

    Directory of Open Access Journals (Sweden)

    Washington Alves de Oliveira

    2015-12-01

    Full Text Available ABSTRACT In this paper we study a particular aspect of the urban community policing: routine patrol route planning. We seek routes that guarantee visibility, as this has a sizable impact on the community perceived safety, allowing quick emergency responses and providing surveillance of selected sites (e.g., hospitals, schools. The planning is restricted to the availability of vehicles and strives to achieve balanced routes. We study an adaptation of the model for the multi-vehicle covering tour problem, in which a set of locations must be visited, whereas another subset must be close enough to the planned routes. It constitutes an NP-complete integer programming problem. Suboptimal solutions are obtained with several heuristics, some adapted from the literature and others developed by us. We solve some adapted instances from TSPLIB and an instance with real data, the former being compared with results from literature, and latter being compared with empirical data.

  13. LED system performance in a trial installation - one year later: Yuma border patrol, Yuma, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Andrea M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Davis, Robert G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-01

    The Yuma Sector Border Patrol Area is a high temperature and high solar radiation environment, providing an opportunity for the U.S. Department of Energy (DOE) to study thermal effects on outdoor light-emitting diode (LED) luminaires outside of the testing laboratory. Six LED luminaires were installed on three poles on the U.S.- Mexico border in February 2014 as part of a trial installation, which was detailed in a prior GATEWAY report.1 The initial trial installation was intended as a short - term test of six luminaires installed on three poles before proceeding with the complete installation of over 400 luminaires. Unexpected delays in the full installation have prevented the detailed evaluations initially planned, but the six installed LED luminaires continue to be monitored, and over the past year illuminance measurements were recorded initially in February 2014 and again in September 2014 at about 2500 hours of operation and in March 2015 at about 5000 hours of operation.

  14. Software Based Supernova Recognition

    Science.gov (United States)

    Walters, Stephen M.

    2014-05-01

    This paper describes software for detecting Supernova (SN) in images. The software can operate in real-time to discover SN while data is being collected so the instrumentation can immediately be re-tasked to perform spectroscopy or photometry of a discovery. Because the instrumentation captures two images per minute, the realtime budget is constrained to 30 seconds per target, a challenging goal. Using a set of two to four images, the program creates a "Reference" (REF) image and a "New" (NEW) image where all images are used in both NEW and REF but any SN survives the combination process only in the NEW image. This process produces good quality images having similar noise characteristics but without artifacts that might be interpreted as SN. The images are then adjusted for seeing and brightness differences using a variant of Tomaney and Crotts method of Point Spread Function (PSF) matching after which REF is subtracted from NEW to produce a Difference (DIF) image. A Classifier is then trained on a grid of artificial SN to estimate the statistical properties of four attributes and used in a process to mask false positives that can be clearly identified as such. Further training to avoid any remaining false positives sets the range, in standard deviations for each attribute, that the Classifier will accept as a valid SN. This training enables the Classifier to discriminate between SN and most subtraction residue. Lastly, the DIF image is scanned and measured by the Classifier to find locations where all four properties fall within their acceptance ranges. If multiple locations are found, the one best conforming to the training estimates is chosen. This location is then declared as a Candidate SN, the instrumentation re-tasked and the operator notified.

  15. Dust around Type Ia supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lifan

    2005-10-20

    An explanation is given of the low value of R lambda triple bond A lambda/E(B - V), the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the circumstellar environment, or at the highest velocity shells of the supernova ejecta. The scattered light tends to reduce the effective R lambda in the optical, but has an opposite effect in the ultraviolet. The presence of circumstellar dust can be tested by ultraviolet to near infrared observations and by multi-epoch spectropolarimetry of SNe Ia.

  16. Hot Dust! Late-Time Infrared Emission From Supernovae

    Science.gov (United States)

    Fox, Ori; Skrutskie, M. F.; Chevalier, R. A.

    2010-01-01

    Supernovae light curves typically peak and fade in the course of several months. Some supernovae , however, exhibit late-time infrared emission that in some cases can last for several years. These supernovae tend to be of the Type IIn subclass, which is defined by narrow hydrogen and helium emission lines arising from a dense, pre-existing circumstellar medium excited by the supernova radiation. Such a late-time ``IR excess'' with respect to the optical blackbody counterpart typically indicates the presence of warm dust. The origin and heating mechanism of the dust is not, however, always well constrained. In this talk, I will explore several scenarios that explain the observed late-time emission. In particular, I will discuss the case of the Type IIn SN 2005ip, which has displayed an ``IR excess'' for over 3 years. The results allow us to interpret the progenitor system and better understand the late stages of stellar evolution. Much of the data used for this analysis were obtained with TripleSpec, a medium-resolution near-infrared spectrograph located at Apache Point Observatory, NM, and FanCam, a JHK imager located at Fan Mountain Observatory, just outside of Charlottesville, VA. These two instruments were designed, fabricated, built, and commissioned by our instrumentation group at the University of Virginia. I will also spend some time discussing these instruments. I would like to thank the following for financial support of this work throughout my graduate career: NASA GSRP, NSF AAG-0607737, Spitzer PID 50256, Achievement Reward for College Scientists (ARCS), and the Virginia Space Grant Consortium.

  17. Magnetar-Powered Supernovae in Two Dimensions. I. Superluminous Supernovae

    CERN Document Server

    Chen, Ke-Jung; Sukhbold, Tuguldur

    2016-01-01

    Previous studies have shown that the radiation emitted by a rapidly rotating magnetar embedded in a young supernova can greatly amplify its luminosity. These one-dimensional studies have also revealed the existence of an instability arising from the piling up of radiatively accelerated matter in a thin dense shell deep inside the supernova. Here we examine the problem in two dimensions and find that, while instabilities cause mixing and fracture this shell into filamentary structures that reduce the density contrast, the concentration of matter in a hollow shell persists. The extent of the mixing depends upon the relative energy input by the magnetar and the kinetic energy of the inner ejecta. The light curve and spectrum of the resulting supernova will be appreciably altered, as will the appearance of the supernova remnant, which will be shellular and filamentary. A similar pile up and mixing might characterize other events where energy is input over an extended period by a centrally concentrated source, e.g...

  18. Are Supernovae Recorded in Indigenous Astronomical Traditions?

    CERN Document Server

    Hamacher, Duane W

    2014-01-01

    Novae and supernovae are rare astronomical events that would have had an influence on the sky-watching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral and material culture, and claims from around the world are discussed to determine if they meet these criteria. Australian Aboriginal traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Indigenous traditions, and an account of a nova in Aboriginal traditions has been confirmed, there are currently no confirmed accounts of supernovae in Indigenous oral or material traditions.

  19. Supernova neutrinos and explosive nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  20. The Supernova - A Stellar Spectacle.

    Science.gov (United States)

    Straka, W. C.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics concerning supernovae are included: the outburst as observed and according to theory, the stellar remnant, the nebular remnant, and a summary…

  1. Strange matter, detonations and supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, O.G.; Horvath, J.E.; Vucetich, H.

    1989-01-01

    The authors present a possible scenario driven by QCD deconfinement in a high density nuclear matter medium. Some expected consequences for type II supernovae explosions are also given, particularly, the output energy that might be enough to account for the observed events.

  2. Women Scientists Dedicated to Medicine

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    This old-style courtyard building in Beijing is located at the Chinese Academy of Medical Sciences, where a large number of Chinese medical scientists work, and worldwide medical research achievements are accomplished every year.

  3. SCIENCE, SCIENTISTS, AND POLICY ADVOCACY

    Science.gov (United States)

    Effectively resolving the typical ecological policy issue requires providing an array of scientific information to decision-makers. In my experience, the ability of scientists (and scientific information) to inform constructively ecological policy deliberations has been diminishe...

  4. [Scientists in cartoons: humanizing science].

    Science.gov (United States)

    Fioravanti, Carlos Henrique; Andrade, Rodrigo de Oliveira; Marques, Ivan da Costa

    2016-01-01

    Published daily from 1994 to 2002 in Correio Popular, a Campinas-based newspaper, Os cientistas (The scientists) comic strips produced by Brazilian researchers and journalists presented science critically and irreverently, exposing the insecurities and frustrations of scientists, as well as the conflicts between them and their communication difficulties with other groups, like journalists. This article shows the diversity of personalities, subjects, graphic styles, and potential meanings in a sample of comic strips published in the first four years.

  5. An Earth System Scientist Network for Student and Scientist Partnerships

    Science.gov (United States)

    Ledley, T. S.

    2001-05-01

    Successful student and scientist partnerships require that there is a mutual benefit from the partnership. This means that the scientist needs to be able to see the advantage of having students work on his/her project, and the students and teachers need to see that the students contribute to the project and develop the skills in inquiry and the content knowledge in the geosciences that are desired. Through the Earth System Scientist Network (ESSN) for Student and Scientist Partnerships project we are working toward developing scientific research projects for the participation of high school students. When these research projects are developed they will be posted on the ESSN web site that will appear in the Digital Library for Earth System Education (DLESE). In DLESE teachers and students who are interested in participating in a research program will be able to examine the criteria for each project and select the one that matches their needs and situation. In this paper we will report on how the various ESSN research projects are currently being developed to assure that both the scientist and the students benefit from the partnership. The ESSN scientists are working with a team of scientists and educators to 1) completely define the research question that the students will be addressing, 2) determine what role the students will have in the project, 3) identify the data that the students and teachers will work with, 4) map out the scientific protocols that the students will follow, and 5) determine the background and support materials needed to facilitate students successfully participating in the project. Other issues that the team is addressing include 1) identifying the selection criteria for the schools, 2) identifying rewards and recognition for the students and teacher by the scientist, and 3) identifying issues in Earth system science, relevant to the scientists data, that the students and teachers could use as a guide help develop students investigative

  6. X-Ray Studies of Supernova Remnants: A Different View of Supernova Explosions

    CERN Document Server

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent data sets accumulated on young, ejecta dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I will review the most relevant results on supernova remnants obtained during the first...

  7. Professional Ethics for Climate Scientists

    Science.gov (United States)

    Peacock, K.; Mann, M. E.

    2014-12-01

    Several authors have warned that climate scientists sometimes exhibit a tendency to "err on the side of least drama" in reporting the risks associated with fossil fuel emissions. Scientists are often reluctant to comment on the implications of their work for public policy, despite the fact that because of their expertise they may be among those best placed to make recommendations about such matters as mitigation and preparedness. Scientists often have little or no training in ethics or philosophy, and consequently they may feel that they lack clear guidelines for balancing the imperative to avoid error against the need to speak out when it may be ethically required to do so. This dilemma becomes acute in cases such as abrupt ice sheet collapse where it is easier to identify a risk than to assess its probability. We will argue that long-established codes of ethics in the learned professions such as medicine and engineering offer a model that can guide research scientists in cases like this, and we suggest that ethical training could be regularly incorporated into graduate curricula in fields such as climate science and geology. We recognize that there are disanalogies between professional and scientific ethics, the most important of which is that codes of ethics are typically written into the laws that govern licensed professions such as engineering. Presently, no one can legally compel a research scientist to be ethical, although legal precedent may evolve such that scientists are increasingly expected to communicate their knowledge of risks. We will show that the principles of professional ethics can be readily adapted to define an ethical code that could be voluntarily adopted by scientists who seek clearer guidelines in an era of rapid climate change.

  8. Tissue-resident memory CD8+ T cells continuously patrol skin epithelia to quickly recognize local antigen.

    Science.gov (United States)

    Ariotti, Silvia; Beltman, Joost B; Chodaczek, Grzegorz; Hoekstra, Mirjam E; van Beek, Anna E; Gomez-Eerland, Raquel; Ritsma, Laila; van Rheenen, Jacco; Marée, Athanasius F M; Zal, Tomasz; de Boer, Rob J; Haanen, John B A G; Schumacher, Ton N

    2012-11-27

    Recent work has demonstrated that following the clearance of infection a stable population of memory T cells remains present in peripheral organs and contributes to the control of secondary infections. However, little is known about how tissue-resident memory T cells behave in situ and how they encounter newly infected target cells. Here we demonstrate that antigen-specific CD8(+) T cells that remain in skin following herpes simplex virus infection show a steady-state crawling behavior in between keratinocytes. Spatially explicit simulations of the migration of these tissue-resident memory T cells indicate that the migratory dendritic behavior of these cells allows the detection of antigen-expressing target cells in physiologically relevant time frames of minutes to hours. Furthermore, we provide direct evidence for the identification of rare antigen-expressing epithelial cells by skin-patrolling memory T cells in vivo. These data demonstrate the existence of skin patrol by memory T cells and reveal the value of this patrol in the rapid detection of renewed infections at a previously infected site.

  9. Patrol of the short wavelength activity and flares of Sun as star

    Science.gov (United States)

    Afanasiev, I.; Avakyan, S.; Leonov, N.; Serova, A.; Voronin, N.

    Monitoring of the spectral range which most affects solar-terrestrial relationship - soft X-ray and extreme UV-radiations allows to solve ? problem of solar activity influence on all aspects of the Sun - Earth ties and to select the most important precursors of solar flares and the solar events related with a flare (such as proton events, high-velocity plasma streams in the solar wind, shock waves, coronal mass ejection and, the most important, the beginning of principal magnetic storms). Solar activity is constantly monitored at present (in the USA) only in two sections of the spectrum of ionizing radiation: 115 (119) nm. However, so far there has been no monitoring of the flux in the most geoeffective region of the spectrum (0.8-115 nm) from the entire disk of the sun; this region completely monitors the main part of the ionosphere of the earth and the ionosphere of the other planets of the solar system, including the formation and status of the main ionospheric maxima. This occurs solely because of technical and methodological difficulties in performing the measurements and calibration in this spectral range on spacecraft, because it is necessity to use only windowless optics. At the present the solar the optical - electronic equipment (OEE) is testing and there are plans to launch OEE of Space Solar Patrol (SSP) consisting of solar radiometers and spectrometers at the Russian Module of the International Space Station. So the solving the problem of the permanent monitoring-patrol of ionizing radiation from the full disk of the Sun appears in the main tasks of fundamental scientific studies in space. The results of this monitoring can be contribution in development of simultaneous studies in several sciences, such as: - solar astrophysics (state of all solar atmospheric regions), - meteorology, physics of atmosphere (the influence of solar activity on global changes, climate and weather including the effects of atmo s pheric electricity), - aeronomy, astronautics

  10. Structures of twilight patrol in the "Churyumov's Unified network" to ensure continuous monitoring

    Science.gov (United States)

    Churyumov, K. I.; Steklov, A. F.; Vidmachenko, A. P.; Dashkiev, G. N.; Steklov, E. A.; Slipchenko, A. S.; Romaniuk, Ya. O.; Nevodovskyi, P. V.

    2016-10-01

    calibrating control of facts and traces of all kinds of dangerous invasions. 3. Twilight patrol of "Churyumov Unified Network" and the study of invasions of fragments of cometary nuclei in the Earth's atmosphere. The costs of the study of the comet Churyumov-Gerasimenko 67P and its nuclei, on all mission of Rosetta-Philae, amounted to about EUR 2 billion [6]. Its results have significantly improved our understanding of the physics of cometary phenomena have further exacerbated problems of asteroid and comet hazard. In 2016, astronomers a lot of effort and time allocated for study of the disintegration of cometary nucleus of Ikeya - Murakami (P / 2010 V1) at least 17 of fragments. The authors have created a twilight patrol of "United Network Churyumov" to implement of daytime and twilight observations

  11. Supernova neutrino detection in LAr TPCs

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Botella, Ines, E-mail: ines.gil@ciemat.es [CIEMAT, Basic Research Department, Avenida Complutense, 22, 28040 Madrid (Spain)

    2011-08-10

    The neutrino burst from a core collapse supernova can provide information about the explosion mechanism and the mechanisms of proto neutron star cooling but also about the intrinsic properties of the neutrino such as flavor oscillations. One important question is to understand to which extent can the supernova and the neutrino physics be decoupled in the observation of a single supernova. The possibility to probe the neutrino mixing angle {theta}{sub 13} and the type of mass hierarchy from the detection of supernova neutrinos with liquid argon detectors is summarized in this paper. Moreover, a quantitative study about the possibility to constrain the supernova parameters is presented. A very massive liquid argon detector ({approx} 100 kton) is needed to perform accurate measurements of these parameters. In addition, these detectors could also provide information on the {nu}{sub e} component of the diffuse supernova neutrino background.

  12. Finding Distances to Type Ia Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    Type Ia supernovae are known as standard candles due to their consistency, allowing us to measure distances based on their brightness. But what if these explosions arent quite as consistent as we thought? Due scientific diligence requires careful checks, so a recent study investigates whether the metallicity of a supernovas environment affects the peak luminosity of the explosion.Metallicity Dependence?Type Ia supernovae are incredibly powerful tools for determining distances in our universe. Because these supernovae are formed by white dwarfs that explode when they reach a uniform accreted mass, the supernova peak luminosity is thought to be very consistent. This consistency allows these supernovae to be used as standard candles to measure distances to their host galaxies.But what if that peak luminosity is affected by a factor that we havent taken into account? Theorists have proposed that the luminosities of Type Ia supernovae might depend on the metallicity of their environments with high-metallicity environments suppressing supernova luminosities. If this is true, then we could be systematically mis-measuring cosmological distances using these supernovae.Testing AbundancesSupernova brightnesses vs. the metallicity of their environments. Low-metallicity supernovae (blue shading) and high-metallicity supernovae (red shading) have an average magnitude difference of ~0.14. [Adapted from Moreno-Raya et al. 2016]A team led by Manuel Moreno-Raya, of the Center for Energy, Environment and Technology (CIEMAT) in Spain, has observed 28 Type Ia supernovae in an effort to test for such a metallicity dependence. These supernovae each have independent distance measurements (e.g., from Cepheids or the Tully-Fisher relation).Moreno-Raya and collaborators used spectra from the 4.2-m William Herschel Telescope to estimate oxygen abundances in the region where each of these supernovae exploded. They then used these measurements to determine if metallicity of the local region

  13. VLBI observations of young Type II supernovae

    CERN Document Server

    Pérez-Torres, M A; Marcaide, J M

    2005-01-01

    We give an overview of circumstellar interaction in young Type II supernovae, as seen through the eyes of very-long-baseline interferometry (VLBI) observations. The resolution attained by such observations (best than 1 mas) is a powerful tool to probe the interaction that takes place after a supernova goes off. The direct imaging of a supernova permits, in principle, to estimate the deceleration of its expansion, and to obtain information on the eject and circumstellar density profiles, as well as estimates of the magnetic field intensity and relativistic particle energy density in the supernova. Unfortunately, only a handful of radio supernovae are close and bright enough as to permit their study with VLBI. We present results from our high-resolution observations of the nearby Type II radio supernovae SN1986J and SN2001gd.

  14. Improvements to type Ia supernova models

    Science.gov (United States)

    Saunders, Clare M.

    Type Ia Supernovae provided the first strong evidence of dark energy and are still an important tool for measuring the accelerated expansion of the universe. However, future improvements will be limited by systematic uncertainties in our use of Type Ia supernovae as standard candles. Using Type Ia supernovae for cosmology relies on our ability to standardize their absolute magnitudes, but this relies on imperfect models of supernova spectra time series. This thesis is focused on using data from the Nearby Supernova Factory both to understand current sources of uncertainty in standardizing Type Ia supernovae and to develop techniques that can be used to limit uncertainty in future analyses. (Abstract shortened by ProQuest.).

  15. Radio Supernovae in the Local Universe

    CERN Document Server

    Kamble, Atish; Berger, Edo; Zauderer, Ashley; Chakraborti, Sayan; Williams, Peter

    2014-01-01

    In the last three decades, about 50 radio supernovae have been detected as a result of targeted searches of optically discovered supernovae in the local universe. Despite this relatively small number some diversity among them has already been identified which is an indication of the underlying richness of radio supernovae waiting to be discovered. For example, comparison of star formation and supernova discovery rate imply that as many as half of the supernovae remain undetected in the traditional optical searches, either because of intrinsic dimness or due to dust obscuration. This has far reaching consequences to the models of stellar and galaxy evolution. A radio sky survey would be ideal to uncover larger supernova population. Transient radio sky would benefit significantly from such a survey. With the advent of advanced gravitational wave detectors a new window is set to open on the local Universe. Localization of these gravitational detectors is poor to identify electromagnetic counterparts of the gravi...

  16. The Scientific Potential of Supernova Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Pagliaroli, G.; Vissani, F.

    2013-04-15

    Thanks to recent theoretical progresses and to the test bench of SN1987A, it has been possible to improve our ability to extract information from the future observations. In this paper we discuss a parameterized model of the neutrino emission. Two applications of this model are considered: 1) the investigation of the scientific potential of a future supernova for the study of the astrophysical parameters; 2) the expectations regarding the diffuse supernova neutrino background, namely, the relic supernova neutrinos.

  17. Magnetares como fuentes para potenciar supernovas superluminosas

    Science.gov (United States)

    Bersten, M. C.; Benvenuto, O. G.

    2016-08-01

    Magnetars have been proposed as one of the possible sources to power the light curve of super-luminous supernovae. We have included the energy deposited by a hypothetical magnetar in our one-dimensional hydrodynamical code, and analyzed the dynamical effect on the supernova ejecta. In particular, we present a model for SN 2011kl, the first object associated with a ultra-long-duration gamma-ray burst. Finally, we show its effect on the light curves of hydrogen rich supernovae.

  18. Magnetar Powered Ordinary Type IIP Supernovae

    OpenAIRE

    Sukhbold, Tuguldur; Thompson, Todd A.

    2017-01-01

    We investigate the properties of Type IIP supernovae that are dominantly powered by the rotational kinetic energy of the newly born neutron star. While the spin-down of a magnetar has previously been proposed as a viable energy source in the context of super-luminous supernovae, we show that a similar mechanism could produce both normal and peculiar Type IIP supernova light curves from red supergiant progenitors for a range of initial spin periods and equivalent dipole magnetic field strength...

  19. Interface dynamos in supernova progenitors

    CERN Document Server

    Blackman, E G; Thomas, J H; Blackman, Eric G.; Nordhaus, Jason T.; Thomas, John H.

    2004-01-01

    Observational evidence for anisotropy in supernovae (SN) and their phenomenological connection to jetted sources such as gamma-ray bursts^Mhave revived considerations of the role magnetohydrodynamic outflows might play therein. Understanding the types of dynamos that might operate in supernova progenitors is therefore relevant. In contrast to previous work, here we study an ``interface dynamo'' for the conditions of a rapidly rotating neutron star surrounded by a convective envelope. Such dynamos have been studied for the Sun, naked white dwarfs,and post-AGB stars, where analogous configurations of strong shear layers surrounded by convective envelopes are present. The interface dynamo provides estimates of large-scale poloidal and toroidal fields, whose product enters the Poynting flux. Because the poloidal field is much weaker than the toroidal magnetic field, the actual average Poynting flux is lower than rough estimates which invoke the only the magnitude of the total magnetic energy. The lower value is s...

  20. Cosmology from Type Ia Supernovae

    CERN Document Server

    Perlmutter, S; Deustua, S; Fabbro, S; Goldhaber, Gerson; Groom, D E; Kim, A G; Kim, M Y; Knop, R A; Nugent, P; Pennypacker, C R; Goobar, A; Pain, R; Hook, I M; Lidman, C E; Ellis, Richard S; Irwin, M J; McMahon, R G; Ruiz-Lapuente, P; Walton, N A; Schaefer, B; Boyle, B J; Filippenko, A V; Matheson, T; Fruchter, A S; Panagia, N; Newberg, H J M; Couch, W J

    1997-01-01

    This presentation reports on first evidence for a low-mass-density/positive-cosmological-constant universe that will expand forever, based on observations of a set of 40 high-redshift supernovae. The experimental strategy, data sets, and analysis techniques are described. More extensive analyses of these results with some additional methods and data are presented in the more recent LBNL report #41801 (Perlmutter et al., 1998; accepted for publication in Ap.J.), astro-ph/9812133 . This Lawrence Berkeley National Laboratory reprint is a reduction of a poster presentation from the Cosmology Display Session #85 on 9 January 1998 at the American Astronomical Society meeting in Washington D.C. It is also available on the World Wide Web at http://supernova.LBL.gov/ This work has also been referenced in the literature by the pre-meeting abstract citation: Perlmutter et al., B.A.A.S., volume 29, page 1351 (1997).

  1. Environmental impact of Supernova Remnants

    CERN Document Server

    Dubner, Gloria

    2015-01-01

    The explosion of a supernovae (SN) represents the sudden injection of about 10^51 ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

  2. Connecting supernovae with their environments

    Science.gov (United States)

    Galbany, L.

    2017-03-01

    We present MUSE observations of galaxy NGC 7469 from its Science Verification to show how powerful is the combination of high-resolution wide-field integral field spectroscopy with both photometric and spectroscopic observations of supernova (SN) explosions. Using STARLIGHT and H II explorer, we selected all H II regions of the galaxy and produced 2-dimensional maps of the Hα equivalent width, average luminosity-weighted stellar age, and oxygen abundance. We measured deprojected galactocentric distances for all H II regions, and radial gradients for all above-mentioned parameters. We positioned the type Ia SN2008ec in the Branch et al. diagram, and finally discussed the characteristics of the SN parent H II region compared to all other H II regions in the galaxy. In a near future, the AMUSING survey will be able to reproduce this analysis and construct statistical samples to enable the characterization of the progenitors of different supernova types.

  3. An Update on Radio Supernovae

    Science.gov (United States)

    van Dyk, Schuyler D.; Sramek, Richard A.; Weiler, Kurt W.; Montes, Marcos J.; Panagia, Nino

    The radio emission from supernovae (SNe) is nonthermal synchrotron radiation of high brightness temperature, with a ``turn-on'' delay at longer wavelengths, power-law decline after maximum with index beta, and spectral index alpha asymptotically decreasing with time to a final, optically thin value. Radio supernovae (RSNe) are best described by the Chevalier (1982) ``mini-shell'' model, with modifications by Weiler \\etal\\ (1990). RSNe observations provide a valuable probe of the SN circumstellar environment and constraints on progenitor masses. We present a progress report on a number of recent RSNe, as well as on new behavior from RSNe 1979C and 1980K, and on RSNe as potential distance indicators. In particular, we present updated radio light curves for SN 1993J in M81.

  4. Convection in Type 2 supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.S.

    1993-10-15

    Results are presented here from several two dimensional numerical calculations of events in Type II supernovae. A new 2-D hydrodynamics and neutrino transport code has been used to compute the effect on the supernova explosion mechanism of convection between the neutrinosphere and the shock. This convection is referred to as exterior convection to distinguish it from convection beneath the neutrinosphere. The model equations and initial and boundary conditions are presented along with the simulation results. The 2-D code was used to compute an exterior convective velocity to compare with the convective model of the Mayle and Wilson 1-D code. Results are presented from several runs with varying sizes of initial perturbation, as well as a case with no initial perturbation but including the effects of rotation. The M&W code does not produce an explosion using the 2-D convective velocity. Exterior convection enhances the outward propagation of the shock, but not enough to ensure a successful explosion. Analytic estimates of the growth rate of the neutron finger instability axe presented. It is shown that this instability can occur beneath the neutrinosphere of the proto-neutron star in a supernova explosion with a growth time of {approximately} 3 microseconds. The behavior of the high entropy bubble that forms between the shock and the neutrinosphere in one dimensional calculations of supernova is investigated. It has been speculated that this bubble is a site for {gamma}-process generation of heavy elements. Two dimensional calculations are presented of the time evolution of the hot bubble and the surrounding stellar material. Unlike one dimensional calculations, the 2D code fails to achieve high entropies in the bubble. When run in a spherically symmetric mode the 2-D code reaches entropies of {approximately} 200. When convection is allowed, the bubble reaches {approximately} 60 then the bubble begins to move upward into the cooler, denser material above it.

  5. Understanding Core-Collapse Supernovae

    CERN Document Server

    Burrows, A

    2004-01-01

    I summarize, in the form of an extended abstract, the ongoing efforts at the University of Arizona (and in collaboration) to understand core-collapse supernovae theoretically. Included are short discussions of 1D (SESAME) and 2D (VULCAN/2D) codes and results, as well as discussions of the possible role of rotation. Highlighted are recent developments in multi-dimensional radiation hydrodynamics and the essential physics of the neutrino-driven mechanism.

  6. Convection in Type 2 supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Douglas Scott [Univ. of California, Davis, CA (United States)

    1993-10-15

    Results are presented here from several two dimensional numerical calculations of events in Type II supernovae. A new 2-D hydrodynamics and neutrino transport code has been used to compute the effect on the supernova explosion mechanism of convection between the neutrinosphere and the shock. This convection is referred to as exterior convection to distinguish it from convection beneath the neutrinosphere. The model equations and initial and boundary conditions are presented along with the simulation results. The 2-D code was used to compute an exterior convective velocity to compare with the convective model of the Mayle and Wilson 1-D code. Results are presented from several runs with varying sizes of initial perturbation, as well as a case with no initial perturbation but including the effects of rotation. The M&W code does not produce an explosion using the 2-D convective velocity. Exterior convection enhances the outward propagation of the shock, but not enough to ensure a successful explosion. Analytic estimates of the growth rate of the neutron finger instability axe presented. It is shown that this instability can occur beneath the neutrinosphere of the proto-neutron star in a supernova explosion with a growth time of ~ 3 microseconds. The behavior of the high entropy bubble that forms between the shock and the neutrinosphere in one dimensional calculations of supernova is investigated. It has been speculated that this bubble is a site for γ-process generation of heavy elements. Two dimensional calculations are presented of the time evolution of the hot bubble and the surrounding stellar material. Unlike one dimensional calculations, the 2D code fails to achieve high entropies in the bubble. When run in a spherically symmetric mode the 2-D code reaches entropies of ~ 200. When convection is allowed, the bubble reaches ~60 then the bubble begins to move upward into the cooler, denser material above it.

  7. Cosmic Ray Acceleration in Supernova Remnants

    CERN Document Server

    Blasi, Pasquale

    2010-01-01

    We review the main observational and theoretical facts about acceleration of Galactic cosmic rays in supernova remnants, discussing the arguments in favor and against a connection between cosmic rays and supernova remnants, the so-called supernova remnant paradigm for the origin of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of 1) magnetic field amplification, 2) acceleration of nuclei heavier than hydrogen, 3) presence of neutrals in the circumstellar environment. The status of the supernova-cosmic ray connection in the time of Fermi-LAT and Cherenkov telescopes is also discussed.

  8. Do scientists trace hot topics?

    Science.gov (United States)

    Wei, Tian; Li, Menghui; Wu, Chensheng; Yan, Xiao-Yong; Fan, Ying; Di, Zengru; Wu, Jinshan

    2013-01-01

    Do scientists follow hot topics in their scientific investigations? In this paper, by performing analysis to papers published in the American Physical Society (APS) Physical Review journals, it is found that papers are more likely to be attracted by hot fields, where the hotness of a field is measured by the number of papers belonging to the field. This indicates that scientists generally do follow hot topics. However, there are qualitative differences among scientists from various countries, among research works regarding different number of authors, different number of affiliations and different number of references. These observations could be valuable for policy makers when deciding research funding and also for individual researchers when searching for scientific projects.

  9. Pulsational-Pair Instability Supernovae

    CERN Document Server

    Woosley, S E

    2016-01-01

    The final evolution of stars in the mass range 60 - 150 solar masses is explored. Depending upon their mass loss and rotation rates, many of these stars will end their lives as pulsational pair-instability supernovae. Even a non-rotating 70 solar mass star is pulsationally unstable during oxygen shell burning and can power a sub-luminous supernova. Rotation decreases the limit further. For more massive stars, the pulsations are less frequent, span a longer time, and are more powerful. Violent pulsations eject not only any residual low density envelope, but also that fraction of the helium core mass outside about 35 - 50 solar masses. The remaining core of helium and heavy elements continues to evolve, ultimately forming an iron core of about 2.5 solar masses that probably collapses to a black hole. A variety of observational transients result with total durations ranging from days to 10,000 years, and luminosities from 10$^{41}$ to 10$^{44}$ erg s$^{-1}$. Many transients resemble ordinary Type IIp supernovae,...

  10. Dark Energy and Termonuclear Supernovae

    Science.gov (United States)

    Domíngez, I.; Bravo, E.; Piersanti, L.; Tornambé, A.; Straniero, O.; Höflich, P.

    2008-12-01

    Nowadays it is widely accepted that the current Universe is dominated by dark energy and exotic matter, the so called StandardModel of Cosmoloy or CDM model. All the available data (Thermonuclear Supernovae, Cosmic Microwave Background, Baryon Acoustic Oscillations, Large Scale Structure, etc.) are compatible with a flat Universe made by ~70% of dark energy. Up to now observations agree that dark energy may be the vacuum energy (or cosmological constant) although improvements are needed to constrain further its equation of state. In this context, the cosmic destiny of the Universe is no longer linked to its geometry but to the nature of dark energy; it may be flat and expand forever or collapse. To understand the nature of dark energy is probably the most fundamental problem in physics today; it may open new roads of knowledge and led to unify gravity with the other fundamental interactions in nature. It is expected that astronomical data will continue to provide directions to theorists and experimental physicists. Type Ia supernovae (SNe Ia) have played a fundamental role, showing the acceleration of the expansion rate of the Universe a decade ago, and up to now they are the only astronomical observations that provide a direct evidence of the acceleration. However, in order to determine the source of the dark energy term it is mandatory to improve the precision of supernovae as distance indicators on cosmological scale.

  11. OH Masers and Supernova Remnants

    CERN Document Server

    Wardle, Mark

    2012-01-01

    OH(1720 MHz) masers are created by the interaction of supernova remnants with molecular clouds. These masers are pumped by collisions in warm, shocked molecular gas with OH column densities in the range 10^{16}--10^{17} cm^{-2}. Excitation calculations suggest that inversion of the 6049 MHz OH line may occur at the higher column densities that have been inferred from main-line absorption studies of supernova remnants with the Green Bank Telescope. OH(6049 MHz) masers have therefore been proposed as a complementary indicator of remnant-cloud interaction. This motivated searches for 6049 MHz maser emission from supernova remnants using the Parkes 63 m and Effelsberg 100 m telescopes, and the Australia Telescope Compact Array. A total of forty-one remnants have been examined by one or more of these surveys, but without success. To check the accuracy of the OH column densities inferred from the single-dish observations we modelled OH absorption at 1667 MHz observed with the Very Large Array towards three supernov...

  12. A spitzer space telescope study of SN 2002hh: An infrared echo from a type llP supernova

    DEFF Research Database (Denmark)

    Meikle, W. P. S.; Mattila, S.; Gerardy, C. L.;

    2006-01-01

    Stars: Supernovae: General, supernovae: individual (NGC 6946), Stars: Supernovae: Individual: Alphanumeric: SN 2002hh Udgivelsesdato: May 22......Stars: Supernovae: General, supernovae: individual (NGC 6946), Stars: Supernovae: Individual: Alphanumeric: SN 2002hh Udgivelsesdato: May 22...

  13. Intravital live cell triggered imaging system reveals monocyte patrolling and macrophage migration in atherosclerotic arteries

    Science.gov (United States)

    McArdle, Sara; Chodaczek, Grzegorz; Ray, Nilanjan; Ley, Klaus

    2015-02-01

    Intravital multiphoton imaging of arteries is technically challenging because the artery expands with every heartbeat, causing severe motion artifacts. To study leukocyte activity in atherosclerosis, we developed the intravital live cell triggered imaging system (ILTIS). This system implements cardiac triggered acquisition as well as frame selection and image registration algorithms to produce stable movies of myeloid cell movement in atherosclerotic arteries in live mice. To minimize tissue damage, no mechanical stabilization is used and the artery is allowed to expand freely. ILTIS performs multicolor high frame-rate two-dimensional imaging and full-thickness three-dimensional imaging of beating arteries in live mice. The external carotid artery and its branches (superior thyroid and ascending pharyngeal arteries) were developed as a surgically accessible and reliable model of atherosclerosis. We use ILTIS to demonstrate Cx3cr1GFP monocytes patrolling the lumen of atherosclerotic arteries. Additionally, we developed a new reporter mouse (Apoe-/-Cx3cr1GFP/+Cd11cYFP) to image GFP+ and GFP+YFP+ macrophages "dancing on the spot" and YFP+ macrophages migrating within intimal plaque. ILTIS will be helpful to answer pertinent open questions in the field, including monocyte recruitment and transmigration, macrophage and dendritic cell activity, and motion of other immune cells.

  14. Feeding the wavefront sensors of LINC-NIRVANA: the dedicated Patrol Camera

    Science.gov (United States)

    Lorenzetti, Dario; D'Alessio, Francesco; Li Causi, Gianluca; Vitali, Fabrizio; Centrone, Mauro; Speziali, Roberto; Diolaiti, Emiliano; Farinato, Jacopo; Ragazzoni, Roberto; Bertram, Thomas; Briegel, Florian; De Bonis, Fulvio; Gässler, Wolfgang; Herbst, Tom; Kürster, Martin; Rohloff, Ralf-Rainer

    2010-07-01

    LINC-NIRVANA is the IR Fizeau interferometric imager that will be installed within a couple of years on the Large Binocular Telescope (LBT) in Arizona. Here we present a particular sub-system, the so-called Patrol Camera (PC), which has been now completed, along with the results of the laboratory tests. It images (in the range 600-900 nm) the same 2 arcmin FoV seen by the Medium-High Wavefront Sensor (MHWS), adequately sampled to provide the MHWS star enlargers with the positions of the FoV stars with an accuracy of 0.1 arcsec. To this aim a diffraction-limited performance is not required, while a distortion free focal plane is needed to provide a suitable astrometric output. Two identical systems have been realized, one for each single arm, which corresponds to each single telescope. We give here the details concerning the optical and mechanical layout, as well as the CCD and the control system. The interfaces (mainly software procedures) with LINC-NIRVANA (L-N) are also presented.

  15. Portable Gas Analyzer Based on Fourier Transform Infrared Spectrometer for Patrolling and Examining Gas Exhaust

    Directory of Open Access Journals (Sweden)

    Yuntao Liang

    2015-01-01

    Full Text Available Aimed at monitoring emission of organic gases such as CH4, C2H6, C3H8, iso-C4H10, n-C4H10, C2H4, C3H6, C2H2, CO, and CO2, from coal mines, petroleum refineries, and other plants, a Fourier Transform Infrared (FT-IR spectrometer was used to develop a portable gas analyzer for patrolling and examining gas exhaust. Firstly, structure of the instrument was introduced. Then, a spectral analysis approach was presented. Finally, instrument was tested with standard gases and with actual gases emitted from a petroleum refinery. For the latter test, a gas chromatograph (GC was used as a reference instrument. The test results showed that the detection limit of every component of analyte was less than 10 × 10−6. The maximum test error of every analyte was less than 15 × 10−6 when its practical concentration was no more than 500 × 10−6. A final comparison showed that the result curves of analytes obtained with FT-IR spectrometer almost overlapped with those obtained with GC, and their resulting noise was less than 6.4% when the practical gas concentration was above 100 × 10−6. As a result, our instrument was suitable to be used as a portable instrument for monitoring exhaust gases.

  16. The Local-Cosmopolitan Scientist

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, Ph.D., Hon. Ph.D.

    2011-12-01

    Full Text Available In contrast to previous discussions in the literature treating cosmopolitan and local as two distinct groups of scientists, this paperi demonstrates the notion of cosmopolitan and local as a dual orientation of highly motivated scientists. This dual orientation is derived from institutional motivation, which is a determinant of both high quality basic research and accomplishment of non-research organizational activities. The dual orientation arises in a context of similarity of the institutional goal of science with the goal of the organization; the distinction between groups of locals and cosmopolitans derives from a conflict between two goals.

  17. Award Set for Future Scientists

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thirteen-year-old Zhou Licheng is a pupil at the Beijing Xicheng Experimental School, and recently won second prize in the "Future Scientist Award" for his invention - a device that prevents smoke from coming down the flue. He won a 10,000-yuan cash prize, and his school was also awarded 40,000 yuan. The "Future Scientist Award" was set up through the joint efforts of the Ministry of Education, the China Association for Science and Technology, and the Hong Kong H. S. Chau Foundation. Its aim is to reward

  18. Cygnus Loop Supernova Blast Wave

    Science.gov (United States)

    1993-01-01

    This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to

  19. See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

    Science.gov (United States)

    Hayden, Brian; Perlmutter, Saul; Boone, Kyle; Nordin, Jakob; Rubin, David; Lidman, Chris; Deustua, Susana E.; Fruchter, Andrew S.; Aldering, Greg Scott; Brodwin, Mark; Cunha, Carlos E.; Eisenhardt, Peter R.; Gonzalez, Anthony H.; Jee, James; Hildebrandt, Hendrik; Hoekstra, Henk; Santos, Joana; Stanford, S. Adam; Stern, Daniel; Fassbender, Rene; Richard, Johan; Rosati, Piero; Wechsler, Risa H.; Muzzin, Adam; Willis, Jon; Boehringer, Hans; Gladders, Michael; Goobar, Ariel; Amanullah, Rahman; Hook, Isobel; Huterer, Dragan; Huang, Xiaosheng; Kim, Alex G.; Kowalski, Marek; Linder, Eric; Pain, Reynald; Saunders, Clare; Suzuki, Nao; Barbary, Kyle H.; Rykoff, Eli S.; Meyers, Joshua; Spadafora, Anthony L.; Sofiatti, Caroline; Wilson, Gillian; Rozo, Eduardo; Hilton, Matt; Ruiz-Lapuente, Pilar; Luther, Kyle; Yen, Mike; Fagrelius, Parker; Dixon, Samantha; Williams, Steven

    2017-01-01

    The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.

  20. Scientists and the Selection Task.

    Science.gov (United States)

    Griggs, Richard A.; Ransdell, Sarah E.

    1986-01-01

    Presents findings of a study of scientists on the Wason four-card selection task, finding little understanding of the effect of disconfirmatory data in assessing conditionals. Found performance influenced by problem content. Explains performance as memory-cueing plus reasoning-by-analogy. (JM)

  1. Science, Scientists, and Public Policy.

    Science.gov (United States)

    Schooler, Dean, Jr.

    The politically relevant behavior of scientists in the formulation of public policy by the United States government from 1945-68 is studied. The following types of policy issues are treated: science, space, weather, weapons, deterrence and defense, health, fiscal and monetary, pollution, conservation, antitrust, transportation safety, trade and…

  2. Introductory mathematics for earth scientists

    CERN Document Server

    Yang, Xin-She

    2009-01-01

    Any quantitative work in earth sciences requires mathematical analysis and mathematical methods are essential to the modelling and analysis of the geological, geophysical and environmental processes involved. This book provides an introduction to the fundamental mathematics that all earth scientists need.

  3. Issues in Training Family Scientists.

    Science.gov (United States)

    Ganong, Lawrence H.; And Others

    1995-01-01

    Issues related to graduate education in family science, especially at the doctoral level, are explored. Discusses competencies family scientists should have, as well as experiences necessary to help students acquire them. Proposes ideas for a core curriculum, identifies controversies and unresolved issues, and examines training for the future.…

  4. Comprehensive mathematics for computer scientists

    CERN Document Server

    Mazzola, Guerino; Weissmann, Jody

    2005-01-01

    This two-volume textbook Comprehensive Mathematics for the Working Computer Scientist is a self-contained comprehensive presentation of mathematics including sets, numbers, graphs, algebra, logic, grammars, machines, linear geometry, calculus, ODEs, and special themes such as neural networks, Fourier theory, wavelets, numerical.

  5. Science, Scientists, and Public Policy.

    Science.gov (United States)

    Schooler, Dean, Jr.

    The politically relevant behavior of scientists in the formulation of public policy by the United States government from 1945-68 is studied. The following types of policy issues are treated: science, space, weather, weapons, deterrence and defense, health, fiscal and monetary, pollution, conservation, antitrust, transportation safety, trade and…

  6. The Scientists in Schools Project

    Science.gov (United States)

    Howitt, Christine; Rennie, Leonie; Heard, Marian; Yuncken, Liz

    2009-01-01

    Scientists in Schools is a project funded by the Australian Government Department of Education, Employment, and Workplace Relations and managed by the Commonwealth Scientific and Industrial Research Organisation, Education Section. This paper describes how the project is working to establish and maintain sustained and ongoing partnerships between…

  7. Issues in Training Family Scientists.

    Science.gov (United States)

    Ganong, Lawrence H.; And Others

    1995-01-01

    Issues related to graduate education in family science, especially at the doctoral level, are explored. Discusses competencies family scientists should have, as well as experiences necessary to help students acquire them. Proposes ideas for a core curriculum, identifies controversies and unresolved issues, and examines training for the future.…

  8. Supernova remnants: the X-ray perspective

    NARCIS (Netherlands)

    Vink, J.

    2012-01-01

    Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And i

  9. Single Degenerate Progenitors of Type Ia Supernovae

    Science.gov (United States)

    Bours, Madelon; Toonen, Silvia; Nelemans, Gijs

    2013-01-01

    There is a general agreement that Type Ia supernovae correspond to the thermonuclear runaway of a white dwarf (WD) in a compact binary. The details of these progenitor systems are still unclear. Using the population synthesis code SeBa and several assumption for the WD retention efficiency, we estimate the delay times and supernova rates for the single degenerate scenario.

  10. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    Srubabati Goswami

    2000-01-01

    In this article I review the constraints on neutrino mass and mixing coming from type-II supernovae. The bounds obtained on these parameters from shock reheating, -process nucleosynthesis and from SN1987A are discussed. Given the current constraints on neutrino mass and mixing the effect of oscillations of neutrinos from a nearby supernova explosion in future detectors will also be discussed.

  11. The CHilean Automatic Supernova sEarch

    DEFF Research Database (Denmark)

    Hamuy, M.; Pignata, G.; Maza, J.

    2012-01-01

    The CHilean Automatic Supernova sEarch (CHASE) project began in 2007 with the goal to discover young, nearby southern supernovae in order to (1) better understand the physics of exploding stars and their progenitors, and (2) refine the methods to derive extragalactic distances. During the first...

  12. Cosmic-ray acceleration in supernova remnants

    NARCIS (Netherlands)

    Helder, E.A.

    2010-01-01

    Supernovae are among the most energetic events in the Universe. During the event, they expel their material with enormous speeds into the surroundings. In addition, supernovae are thought to transfer a sizable fraction of their energy into just a few particles: cosmic rays. These cosmic rays acquire

  13. Rates and progenitors of type Ia supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Wood-Vasey, William Michael [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  14. Snapping Supernovae at z>1.7

    CERN Document Server

    Aldering, G; Kowalski, M; Linder, E V; Perlmutter, S; Aldering, Greg; Kim, Alex G.; Kowalski, Marek; Linder, Eric V.; Perlmutter, Saul

    2006-01-01

    We examine the utility of very high redshift Type Ia supernovae for cosmology and systematic uncertainty control. Next generation space surveys such as the Supernova/Acceleration Probe (SNAP) will obtain thousands of supernovae at z>1.7, beyond the design redshift for which the supernovae will be exquisitely characterized. We find that any z\\gtrsim2 standard candles' use for cosmological parameter estimation is quite modest and subject to pitfalls; we examine gravitational lensing, redshift calibration, and contamination effects in some detail. The very high redshift supernovae - both thermonuclear and core collapse - will provide copious interesting information on star formation, environment, and evolution. However, the new observational systematics that must be faced, as well as the limited expansion of SN-parameter space afforded, does not point to high value for 1.7

  15. Supernova shock breakout from a red supergiant.

    Science.gov (United States)

    Schawinski, Kevin; Justham, Stephen; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Röser, Hermann-Josef; Walker, Emma S; Astier, Pierre; Balam, Dave; Balland, Christophe; Carlberg, Ray; Conley, Alex; Fouchez, Dominique; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, D Andrew; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-07-11

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve confirm that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a way to probe the physics of core-collapse supernovae and the internal structures of their progenitor stars.

  16. Supernovae and Cosmology with Future European Facilities

    CERN Document Server

    Hook, I M

    2012-01-01

    Prospects for future supernova surveys are discussed, focusing on the ESA Euclid mission and the European Extremely Large Telescope(E-ELT), both expected to be in operation around the turn of the decade. Euclid is a 1.2m space survey telescope that will operate at visible and near-infrared wavelengths, and has the potential to find and obtain multi-band lightcurves for thousands of distant supernovae. The E-ELT is a planned general-purpose ground-based 40m-class optical-IR telescope with adaptive optics built in, which will be capable of obtaining spectra of Type Ia supernovae to redshifts of at least four. The contribution to supernova cosmology with these facilities will be discussed in the context of other future supernova programs such as those proposed for DES, JWST, LSST and WFIRST.

  17. Injury Prevention for Ski-Area Employees: A Physiological Assessment of Lift Operators, Instructors, and Patrollers

    Directory of Open Access Journals (Sweden)

    Delia Roberts

    2013-01-01

    Full Text Available Background. Momentary lapses in concentration contribute to workplace accidents. Given that blood glucose (BG and hydration levels have been shown to affect vigilance, this study proposed to investigate these parameters and functional movement patterns of ski-resort workers and to determine whether an educational program to stabilize BG and hydration and encourage joint stability had an effect in decreasing occupational injuries. Methods. Seventy-five instructors, patrollers and, lift-operators at five snowsport resorts were evaluated for BG, vigilance, workload, dietary/hydration practices, and functional-movement patterns. Injury rates were tabulated before and after an educational program for nutrition and functional-movement awareness and compared to other resorts. Results. Workers showed poor stability at the lumbar spine, knee, and shoulder. BG levels were normal but variable (%CV = 14±6. Diets were high in sugar and fat and low in water and many nutrients. Medical Aid and Lost Time claims declined significantly by 65.1±20.0% (confidence interval −90.0% ≤μ≤−40.2% in resorts that used the educational program whereas four control resorts not using the program experienced increases of 33.4±42.9% (confidence interval −19.7% ≤μ≤−86.7%; F[2,12] = 21.35, P<0.0001 over the same season. Conclusion. Provision of snowsport resort workers with educational programs encouraging hydration, diet to stabilize BG, and functional-movement awareness was effective in reducing worksite injuries in this population.

  18. Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap

    CERN Document Server

    Arcavi, Iair; Howell, D Andrew; Bildsten, Lars; Leloudas, Giorgos; Hardin, Delphine; Prajs, Szymon; Perley, Daniel A; Svirski, Gilad; Gal-Yam, Avishay; Katz, Boaz; McCully, Curtis; Cenko, S Bradley; Lidman, Chris; Sullivan, Mark; Valenti, Stefano; Astier, Pierre; Balland, Cristophe; Carlberg, Ray G; Conley, Alex; Fouchez, Dominique; Guy, Julien; Pain, Reynald; Palanque-Delabrouille, Nathalie; Perrett, Kathy; Pritchet, Chris J; Regnault, Nicolas; Rich, James; Ruhlmann-Kleider, Vanina

    2015-01-01

    We present observations of four rapidly rising (t_{rise}~10d) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (M_{peak}~-20) - one discovered and followed by the Palomar Transient Factory (PTF) and three by the Supernova Legacy Survey (SNLS). The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as a Type II SN due to broad Halpha emission, but an unusual absorption feature, which can be interpreted as either high velocity Halpha (though deeper than in previously known cases) or Si II (as seen in Type Ia SNe), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM) and magnetar spindown can not r...

  19. Spectroscopy of Type Ia Supernovae by the Carnegie Supernova Project

    CERN Document Server

    Folatelli, Gastón; Phillips, Mark M; Hsiao, Eric; Campillay, Abdo; Contreras, Carlos; Castellón, Sergio; Hamuy, Mario; Krzeminski, Wojtek; Roth, Miguel; Stritzinger, Maximilian; Burns, Christopher R; Freedman, Wendy L; Madore, Barry F; Murphy, David; Persson, S E; Prieto, José L; Suntzeff, Nicholas B; Krisciunas, Kevin; Anderson, Joseph P; Förster, Francisco; Maza, José; Pignata, Giuliano; Rojas, P Andrea; Boldt, Luis; Salgado, Francisco; Wyatt, Pamela; E., Felipe Olivares; Gal-Yam, Avishay; Sako, Masao

    2013-01-01

    This is the first release of optical spectroscopic data of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project including 604 previously unpublished spectra of 93 SNe Ia. The observations cover a range of phases from 12 days before to over 150 days after the time of B-band maximum light. With the addition of 228 near-maximum spectra from the literature we study the diversity among SNe Ia in a quantitative manner. For that purpose, spectroscopic parameters are employed such as expansion velocities from spectral line blueshifts, and pseudo-equivalent widths (pW). The values of those parameters at maximum light are obtained for 78 objects, thus providing a characterization of SNe Ia that may help to improve our understanding of the properties of the exploding systems and the thermonuclear flame propagation. Two objects, namely SNe 2005M and 2006is, stand out from the sample by showing peculiar Si II and S II velocities but otherwise standard velocities for the rest of the ions. We further s...

  20. Carnegie Supernova Project: Observations of Type IIn Supernovae

    CERN Document Server

    Taddia, F; Sollerman, J; Phillips, M M; Anderson, J P; Boldt, L; Campillay, A; Castellón, S; Contreras, C; Folatelli, G; Hamuy, M; Heinrich-Josties, E; Krzeminski, W; Morrell, N; Burns, C R; Freedman, W L; Madore, B F; Persson, S E; Suntzeff, N B

    2013-01-01

    The observational diversity displayed by various Type IIn supernovae (SNe IIn) is explored and quantified. In doing so a more coherent picture ascribing the variety of observed SNe IIn types to particular progenitor scenarios is sought. Carnegie Supernova Project (CSP) optical and near-infrared light curves and visual-wavelength spectroscopy of the Type IIn SNe 2005kj, 2006aa, 2006bo, 2006qq and 2008fq are presented. Combined with previously published observations of the Type IIn SNe 2005ip and 2006jd (Stritzinger et al. 2012), the full CSP sample is used to derive physical parameters which describe the nature of the interaction between the expanding SN ejecta and the circum-stellar material (CSM). For each SN of our sample we find counterparts, identifying objects similar to SNe 1994W (SN 2006bo), 1998S (SN 2008fq) and 1988Z (SN 2006qq). We present the unprecedented initial u-band plateau of SN 2006aa, and its peculiar late-time luminosity and temperature evolution. For each SN, assuming the CSM was formed b...

  1. Statistics of Galactic Supernova Remnants

    Institute of Scientific and Technical Information of China (English)

    Jian-Wen Xu; Xi-Zhen Zhang; Jin-Lin Han

    2005-01-01

    We collected the basic parameters of 231 supernova remnants (SNRs) in our Galaxy, namely, distances (d) from the Sun, linear diameters (D), Galactic heights (Z), estimated ages (t), luminosities (L), surface brightness (∑) and flux densities (Si) at 1-GHz frequency and spectral indices (α). We tried to find possible correlations between these parameters. As expected, the linear diameters were found to increase with ages for the shell-type remnants, and also to have a tendency to increase with the Galactic heights. Both the surface brightness and luminosity of SNRs at 1-GHz tend to decrease with the linear diameter and with age. No other relations between the parameters were found.

  2. Petascale Supernova Simulation with CHIMERA

    Energy Technology Data Exchange (ETDEWEB)

    Messer, Bronson [ORNL; Bruenn, S. W. [Florida Atlantic University; Blondin, J. M. [North Carolina State University; Mezzacappa, Anthony [ORNL; Hix, William Raphael [ORNL; Dirk, Charlotte [Florida Atlantic University

    2007-01-01

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We describe some ma jor algorithmic facets of the code and briefly discuss some recent results. The multi-physics nature of the problem, and the specific implementation of that physics in CHIMERA, provide a rather straightforward path to effective use of multi-core platforms in the near future.

  3. Petascale supernova simulation with CHIMERA

    Energy Technology Data Exchange (ETDEWEB)

    Messer, O E B [National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6008 (United States); Bruenn, S W [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States); Blondin, J M [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Hix, W R [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6354 (United States); Mezzacappa, A [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6354 (United States); Dirk, C J [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States)

    2007-07-15

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We describe some major algorithmic facets of the code and briefly discuss some recent results. The multi-physics nature of the problem, and the specific implementation of that physics in CHIMERA, provide a rather straightforward path to effective use of multi-core platforms in the near future.

  4. Shell-type Supernova Remnants

    OpenAIRE

    Völk, H.

    2006-01-01

    The role of Supernova Remnants (SNRs) for the production of the Galactic Cosmic Rays is reviewed from the point of view of theory and very high energy gamma-ray experiments. The point is made that theory can describe young SNRs very well, if the evidence from the synchrotron emission is used to empirically determine several parameters of the theory, and thus theory can predict the relative contributions of hadronic and leptonic gamma rays at TeV energies. This is exemplified for several objec...

  5. Progress on multi-waveband observations of supernova remnants

    OpenAIRE

    Yang, Xuejuan; Lu, Fangjun; Tian, Wenwu

    2008-01-01

    The development of observational techniques has inriched our knowledge of supernova remnants. In this paper, we review the main progresses in the last decade, including new discoveries of supernova remnants and the associated (rare type of) pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics, and cosmic ray accelerations.

  6. Mathematics for engineers and scientists

    CERN Document Server

    Jeffrey, Alan

    2004-01-01

    Although designed as a textbook with problem sets in each chapter and selected answers at the end of the book, Mathematics for Engineers and Scientists, Sixth Edition serves equally well as a supplemental text and for self-study. The author strongly encourages readers to make use of computer algebra software, to experiment with it, and to learn more about mathematical functions and the operations that it can perform.

  7. Research Integrity of Individual Scientist

    Science.gov (United States)

    Haklak, Rockbill

    We are discussing about many aspects of research integrity of individual scientist, who faces the globalization of research ethics in the traditional culture and custom of Japan. Topics are scientific misconduct (fabrication, falsification, and plagiarism) in writing paper and presenting research results. Managements of research material, research record, grant money, authorship, and conflict of interest are also analyzed and discussed. Finally, we make 5 recommendations to improve research integrity in Japan.

  8. The Scientist as Sentinel (Invited)

    Science.gov (United States)

    Oreskes, N.

    2013-12-01

    Scientists have been warning the world for some time about the risks of anthropogenic interference in the climate system. But we struggle with how, exactly, to express that warning. The norms of scientific behavior enjoin us from the communication strategies normally associated with warnings. If a scientist sounds excited or emotional, for example, it is often assumed that he has lost his capac¬ity to assess data calmly and therefore his conclusions are suspect. If the scientist is a woman, the problem is that much worse. In a recently published article my colleagues and I have shown that scientists have systematically underestimated the threat of climate change (Brysse et al., 2012). We suggested that this occurs for norma¬tive reasons: The scientific values of rationality, dispassion, and self-restraint lead us to demand greater levels of evidence in support of surprising, dramatic, or alarming conclusions than in support of less alarming conclusions. We call this tendency 'err¬ing on the side of least drama.' However, the problem is not only that we err on the side of least drama in our assessment of evidence, it's also that we speak without drama, even when our conclusions are dramatic. We speak without the emotional cadence that people expect to hear when the speaker is worried. Even when we are worried, we don't sound as if we are. In short, we are trying to act as sentinels, but we lack the register with which to do so. Until we find those registers, or partner with colleagues who are able to speak in the cadences that communicating dangers requires, our warnings about climate change will likely continue to go substantially unheeded.

  9. Pavlov as a psychophysiological scientist.

    Science.gov (United States)

    Paré, W P

    1990-05-01

    It is suggested that Pavlov was not only a famous physiologist, but due to his work on the conditional reflex, he could be considered a behavioral scientist. In addition his work on experimental neurosis gives him the distinction of being a pioneer investigator in the area of psychological stress. Pavlov's research is viewed against a background of primitive research tools and unproductive subjective theories. Nineteenth century scientists who influenced Pavlov included Darwin, Botkin, Heidenhain, Gaskell and Bernard. Pavlov's research on the digestive system emphasized the role of the nervous system, launched the field of gastroenterology, and emphasized the concept of the conditional reflex. Pavlov's conditional reflex formulations were based on the theoretical formulations of Sechenov, and possibly the work of David Hartley. The discovery of secretin, by Bayliss and Starling, and its influence on the stomach led Pavlov to diminish his work on the digestive system and to focus his research on the conditional reflex phenomenon. Arguments which suggest that Pavlov worked as a behavioral scientist include his conceptual formulations, his research on traditional psychological topics and his investigation of psychiatric disorders. His conditioning research emphasized the individual differences of his animal subjects which led to his research on typology and experimental neurosis which formed the basis for his work on environmental stressors and psychopathology.

  10. Yuma Border Patrol Area Lighting Retrofit LED System Performance in a Trial Installation – Two Years Later

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, Andrea M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sullivan, Gregory P. [Efficiency Solutions, Inc, Richland, WA (United States); Davis, Robert G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-05-21

    Documentation of the Yuma Sector Border Patrol Area lighting LED trial demonstration continues to provide a better understanding of LED technology performance in a high ambient temperature and high solar radiation environment. Measured data at the project site showed illuminances changing more rapidly than anticipated. As previously predicted, the causes for these observed changes are mostly if not completely explained by dirt accumulation. The laboratory measurements showed not only the effect of dirt on lumen output, but also on the distribution of light exiting the luminaire.

  11. Runaway Stars in Supernova Remnants

    Science.gov (United States)

    Pannicke, Anna; Neuhaeuser, Ralph; Dinçel, Baha

    2016-07-01

    Half of all stars and in particular 70 % of the massive stars are a part of a multiple system. A possible development for the system after the core collapse supernova (SN) of the more massive component is as follows: The binary is disrupted by the SN. The formed neutron star is ejected by the SN kick whereas the companion star either remains within the system and is gravitationally bounded to the neutron star, or is ejected with a spatial velocity comparable to its former orbital velocity (up to 500 km/s). Such stars with a large peculiar space velocity are called runaway stars. We present our observational results of the supernova remnants (SNRs) G184.6-5.8, G74.0-8.5 and G119.5+10.2. The focus of this project lies on the detection of low mass runaway stars. We analyze the spectra of a number of candidates and discuss their possibility of being the former companions of the SN progenitor stars. The spectra were obtained with INT in Tenerife, Calar Alto Astronomical Observatory and the University Observatory Jena. Also we investigate the field stars in the neighborhood of the SNRs G74.0-8.5 and G119.5+10.2 and calculate more precise distances for these SNRs.

  12. Dark Matter Triggers of Supernovae

    CERN Document Server

    Graham, Peter W; Varela, Jaime

    2015-01-01

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to $1.25 M_{\\odot}$ rules out primordial black holes with masses $\\sim 10^{19}$ gm - $10^{20}$ gm as a dominant constituent of the local dark matter density. Black holes with masses as large as $10^{24}$ gm will be excluded if recent observations by the NuStar collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range $10^{20}$ gm - $10^{22}$ gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism p...

  13. How supernovae launch galactic winds?

    Science.gov (United States)

    Fielding, Drummond; Quataert, Eliot; Martizzi, Davide; Faucher-Giguère, Claude-André

    2017-09-01

    We use idealized three-dimensional hydrodynamic simulations of global galactic discs to study the launching of galactic winds by supernovae (SNe). The simulations resolve the cooling radii of the majority of supernova remnants (SNRs) and thus self-consistently capture how SNe drive galactic winds. We find that SNe launch highly supersonic winds with properties that agree reasonably well with expectations from analytic models. The energy loading (η _E= \\dot{E}_wind/ \\dot{E}_SN) of the winds in our simulations are well converged with spatial resolution while the wind mass loading (η _M= \\dot{M}_wind/\\dot{M}_\\star) decreases with resolution at the resolutions we achieve. We present a simple analytic model based on the concept that SNRs with cooling radii greater than the local scaleheight break out of the disc and power the wind. This model successfully explains the dependence (or lack thereof) of ηE (and by extension ηM) on the gas surface density, star formation efficiency, disc radius and the clustering of SNe. The winds our simulations are weaker than expected in reality, likely due to the fact that we seed SNe preferentially at density peaks. Clustering SNe in time and space substantially increases the wind power.

  14. Type Ia Supernova Carbon Footprints

    CERN Document Server

    Thomas, R C; Aragon, C; Antilogus, P; Bailey, S; Baltay, C; Bongard, S; Buton, C; Canto, A; Childress, M; Chotard, N; Copin, Y; Fakhouri, H K; Gangler, E; Hsiao, E Y; Kerschhaggl, M; Kowalski, M; Loken, S; Nugent, P; Paech, K; Pain, R; Pecontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Rigault, M; Rubin, D; Runge, K; Scalzo, R; Smadja, G; Tao, C; Weaver, B A; Wu, C; Brown, P J; Milne, P A

    2011-01-01

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of 5 Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 d relative to maximum. Detections are based on the presence of relatively strong C II 6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the 5 SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibits high-velocity (v > 20,000 km/s) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broad band light curve/color behavior: Three of the 5 have relatively narrow light curves but also blue colors, and a fourth may be a dust-reddened member of this family. Accounting for signal-to-noise and phase, we ...

  15. Discovery Prospects for a Biogenic Supernova Signature

    CERN Document Server

    Bishop, Shawn

    2010-01-01

    Within the universe, the astrophysical sites responsible for the production of radioactive 60Fe, of half life 2.62 Myr, are primarily confined to two: Type 1a supernovae and massive stars that end their lives as Type II supernovae. Approximately 2.8 Myr before the present, our planet was subjected to the debris of a supernova explosion. The terrestrial proxy for this event was the discovery of live atoms of 60Fe in a deep sea ferromanganese crust, from which the terrestrial flux of supernova 60Fe was deduced. The signature for this supernova event should also be contained in microfossils produced by magnetotactic bacteria extant at the time of the Earth-supernova interaction. Using estimates for the terrestrial supernova 60Fe flux, combined with our empirically derived microfossil concentrations of a deep sea drill core, we deduce a conservative estimate of the 60Fe fraction as 60Fe/Fe = 3.6 x 10^{-15}; this value sits comfortably within the sensitivity limit of present accelerator mass spectrometry capabilit...

  16. An Open Catalog for Supernova Data

    CERN Document Server

    Guillochon, James; Margutti, Raffaella

    2016-01-01

    We present the Open Supernova Catalog, an online collection of observations and metadata for presently 20,000+ supernovae and related candidates. The catalog is freely available on the web (https://sne.space), with its main interface having been designed to be a user-friendly, rapidly-searchable table accessible on desktop and mobile devices. In addition to the primary catalog table containing supernova metadata, an individual page is generated for each supernova which displays its available metadata, light curves, and spectra spanning X-ray to radio frequencies. The data presented in the catalog is automatically rebuilt on a daily basis and is constructed by parsing several dozen sources, including the data presented in the supernova literature and from secondary sources such as other web-based catalogs. Individual supernova data is stored in the hierarchical, human- and machine-readable JSON format, with the entirety of each supernova's data being contained within a single JSON file bearing its name. The se...

  17. Type Ia Supernova Modeling with Spectrophotometric Data from the Nearby Supernova Factory

    Science.gov (United States)

    Saunders, Clare; Nearby Supernova Factory

    2017-01-01

    Type Ia supernova cosmology is currently limited by dispersion in standardized magnitudes, driven by a combination of calibration uncertainty and so-called ‘intrinsic dispersion.' This intrinsic dispersion is caused by supernova behavior that the current lightcurve fitters do not account for, and it can involve systematic trends. Using data from the Nearby Supernova Factory, we have developed an empirical model that captures a wider range of Type Ia supernova behavior and can be used to improve standardized magnitude dispersion. To do this, Gaussian Processes and Expectation Maximization Factor Analysis are used to generate spectral time series templates that can be combined linearly. Variations of this model are optimized, alternatively for supernova standardization or for maximum accuracy in the description of supernova spectral features. We present these models along with interpretation of the model components. Methods are discussed for the most efficient application of the models in cosmological surveys.

  18. First Results from the La Silla-QUEST Supernova Survey and the Carnegie Supernova Project

    CERN Document Server

    Walker, E S; Campillay, A; Citrenbaum, C; Contreras, C; Ellman, N; Feindt, U; Gonzalez, C; Graham, M L; Hadjiyska, E; Hsiao, E Y; Krisciunas, K; McKinnon, R; Ment, K; Morrell, N; Nugent, P; Phillips, M; Rabinowitz, D; Rostami, S; Seron, J; Stritzinger, M; Sullivan, M; Tucker, B E

    2016-01-01

    The LaSilla/QUEST Variability Survey (LSQ) and the Carnegie Supernova Project (CSP II) are collaborating to discover and obtain photometric light curves for a large sample of low redshift (z < 0.1) Type Ia supernovae. The supernovae are discovered in the LSQ survey using the 1 m ESO Schmidt telescope at the La Silla Observatory with the 10 square degree QUEST camera. The follow-up photometric observations are carried out using the 1 m Swope telescope and the 2.5 m du Pont telescopes at the Las Campanas Observatory. This paper describes the survey, discusses the methods of analyzing the data and presents the light curves for the first 31 Type Ia supernovae obtained in the survey. The SALT 2.4 supernova light curve fitter was used to analyze the photometric data, and the Hubble diagram for this first sample is presented. The measurement errors for these supernovae averaged 4%, and their intrinsic spread was 14%.

  19. An Open Catalog for Supernova Data

    Science.gov (United States)

    Guillochon, James; Parrent, Jerod; Kelley, Luke Zoltan; Margutti, Raffaella

    2017-01-01

    We present the Open Supernova Catalog, an online collection of observations and metadata for presently 36,000+ supernovae and related candidates. The catalog is freely available on the web (https://sne.space), with its main interface having been designed to be a user-friendly, rapidly searchable table accessible on desktop and mobile devices. In addition to the primary catalog table containing supernova metadata, an individual page is generated for each supernova, which displays its available metadata, light curves, and spectra spanning X-ray to radio frequencies. The data presented in the catalog is automatically rebuilt on a daily basis and is constructed by parsing several dozen sources, including the data presented in the supernova literature and from secondary sources such as other web-based catalogs. Individual supernova data is stored in the hierarchical, human- and machine-readable JSON format, with the entirety of each supernova’s data being contained within a single JSON file bearing its name. The setup we present here, which is based on open-source software maintained via git repositories hosted on github, enables anyone to download the entirety of the supernova data set to their home computer in minutes, and to make contributions of their own data back to the catalog via git. As the supernova data set continues to grow, especially in the upcoming era of all-sky synoptic telescopes, which will increase the total number of events by orders of magnitude, we hope that the catalog we have designed will be a valuable tool for the community to analyze both historical and contemporary supernovae.

  20. Postexplosion hydrodynamics of supernovae in red supergiants

    Science.gov (United States)

    Herant, Marc; Woosley, S. E.

    1994-01-01

    Shock propagation, mixing, and clumping are studied in the explosion of red supergiants as Type II supernovae using a two-dimensional smooth particle hydrodynamic (SPH) code. We show that extensive Rayleigh-Talor instabilities develop in the ejecta in the wake of the reverse shock wave. In all cases, the shell structure of the progenitor is obliterated to leave a clumpy, well-mixed supernova remnant. However, the occurrence of mass loss during the lifetime of the progenitor can significantly reduce the amount of mixing. These results are independent of the Type II supernova explosion mechanism.

  1. Chiral transport of neutrinos in supernovae

    Directory of Open Access Journals (Sweden)

    Yamamoto Naoki

    2017-01-01

    Full Text Available The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.

  2. The CHilean Automatic Supernova sEarch

    DEFF Research Database (Denmark)

    Hamuy, M.; Pignata, G.; Maza, J.

    2012-01-01

    The CHilean Automatic Supernova sEarch (CHASE) project began in 2007 with the goal to discover young, nearby southern supernovae in order to (1) better understand the physics of exploding stars and their progenitors, and (2) refine the methods to derive extragalactic distances. During the first...... four years of operation, CHASE has produced more than 130 supernovae, being the most successful project of its type in the southern hemisphere. Here we describe the project and present illustrative examples of CHASE discoveries of particular relevance....

  3. Object Classification at the Nearby Supernova Factory

    Energy Technology Data Exchange (ETDEWEB)

    Aragon, Cecilia R.; Bailey, Stephen; Aragon, Cecilia R.; Romano, Raquel; Thomas, Rollin C.; Weaver, B. A.; Wong, D.

    2007-12-21

    We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of nonsupernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys.

  4. Chiral transport of neutrinos in supernovae

    CERN Document Server

    Yamamoto, Naoki

    2016-01-01

    The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.

  5. A New Supernova Discovery/Classification

    Science.gov (United States)

    Howell, D. A.; Nugent, P. E.; Sullivan, M.; Gal-Yam, A.

    2010-10-01

    The Type Ia supernova science working group of the Palomar Transient Factory (ATEL#1964) reports the discovery of the Type Ia supernova PTF10ygu at RA=09:37:30.30, Dec=+23:09:33.6 (J2000) in the host galaxy NGC 2929 at z=0.025. The supernova was discovered on Oct. 12.5 UT when it was at magnitude 19.2 in R-band (calibrated wrt the USNO catalog). There was nothing at this location on Oct 8.5 UT to a limiting magnitude of 20.3, and a marginal detection (S/N=5) at R=19.6 on Oct.

  6. Supernovae and Gamma-Ray Bursts

    Science.gov (United States)

    Livio, Mario; Panagia, Nino; Sahu, Kailash

    2001-07-01

    Participants; Preface; Gamma-ray burst-supernova relation B. Paczynski; Observations of gamma-ray bursts G. Fishman; Fireballs T. Piran; Gamma-ray mechanisms M. Rees; Prompt optical emission from gamma-ray bursts R. Kehoe, C. Akerlof, R. Balsano, S. Barthelmy, J. Bloch, P. Butterworth, D. Casperson, T. Cline, S. Fletcher, F. Frontera, G. Gisler, J. Heise, J. Hills, K. Hurley, B. Lee, S. Marshall, T. McKay, A. Pawl, L. Piro, B. Priedhorsky, J. Szymanski and J. Wren; X-ray afterglows of gamma-ray bursts L. Piro; The first year of optical-IR observations of SN1998bw I. Danziger, T. Augusteijn, J. Brewer, E. Cappellaro, V. Doublier, T. Galama, J. Gonzalez, O. Hainaut, B. Leibundgut, C. Lidman, P. Mazzali, K. Nomoto, F. Patat, J. Spyromilio, M. Turatto, J. Van Paradijs, P. Vreeswijk and J. Walsh; X-ray emission of Supernova 1998bw in the error box of GRB980425 E. Pian; Direct analysis of spectra of type Ic supernovae D. Branch; The interaction of supernovae and gamma-ray bursts with their surroundings R. Chevalier; Magnetars, soft gamma-ray repeaters and gamma-ray bursts A. Harding; Super-luminous supernova remnants Y. -H. Chu, C. -H. Chen and S. -P. Lai; The properties of hypernovae: SNe Ic 1998bw, 1997ef, and SN IIn 1997cy K. Nomoto, P. Mazzali, T. Nakamura, K. Iwanmoto, K. Maeda, T. Suzuki, M. Turatto, I. Danziger and F. Patat; Collapsars, Gamma-Ray Bursts, and Supernovae S. Woosley, A. MacFadyen and A. Heger; Pre-supernova evolution of massive stars N. Panagia and G. Bono; Radio supernovae and GRB 980425 K. Weiler, N. Panagia, R. Sramek, S. Van Dyk, M. Montes and C. Lacey; Models for Ia supernovae and evolutionary effects P. Hoflich and I. Dominguez; Deflagration to detonation A. Khokhlov; Universality in SN Iae and the Phillips relation D. Arnett; Abundances from supernovae F. -K. Thielemann, F. Brachwitz, C. Freiburghaus, S. Rosswog, K. Iwamoto, T. Nakamura, K. Nomoto, H. Umeda, K. Langanke, G. Martinez-Pinedo, D. Dean, W. Hix and M. Strayer; Sne, GRBs, and the

  7. A Comprehensive Investigation Into Modeling Supernovae Spectra

    Science.gov (United States)

    Hillier, Desmond

    Supernovae are a rich source of information. By studying their light curves and spectra we gain insights into stellar evolution, the nature of the progenitor star, surface abundances at the time of the explosion, whether previous mass-loss episodes have occurred, the physics of the explosion including the amount and type of elements synthesized, and whether the explosion has produced significant mixing between shells of different chemical composition. To maximize the information that can be gleaned from observations of supernovae it is essential that we have the necessary spectroscopic tools. To this end, we are developing a code, CMFGEN, capable of modeling supernova light curves and spectra. The code is currently being used, to study core-collapse supernovae as well as those arising from the nuclear detonation of a White Dwarf star. We wish to extend CMFGEN's capabilities by developing a procedure to handle non-monotonic velocity flows so that we can treat shock breakout and the interaction of supernova ejecta with circumstellar material. We will also investigate magnetar-powered SNe, and explore the connection between Type Ib and Type Ic supernovae and those supernovae associated with long-duration gamma-ray bursters. Through detailed studies of individual supernova, and through the construction of model grids, we are able to infer deficiencies in our modeling, in our atomic data, and in the progenitor models, and hence make refinements so that we can improve our understanding of all SNe classes. Previous (IUE), current (HST, Chandra, GALEX), and future NASA missions (James Webb Telescope) do/will provide a wealth of data on supernovae. The proposed research is related to strategic subgoal 3D: "Discover the origin, structure, evolution, and destiny of the universe, and search for Earth-like planets." Supernovae are inherently coupled to the evolution of the universe and life: They can trigger star formation and they provide the raw materials (e.g., oxygen

  8. Neutrino scattering and flavor transformation in supernovae

    CERN Document Server

    Cherry, John F; Friedland, Alexander; Fuller, George M; Vlasenko, Alexey

    2012-01-01

    We argue that the small fraction of neutrinos that undergo direction-changing scattering outside of the neutrinosphere could have significant influence on neutrino flavor transformation in core-collapse supernova environments. We show that the standard treatment for collective neutrino flavor transformation is adequate at late times, but could be inadequate in the crucial shock revival/explosion epoch of core-collapse supernovae, where the potentials that govern neutrino flavor evolution are affected by the scattered neutrinos. Taking account of this effect, and the way it couples to entropy and composition, will require a new paradigm in supernova modeling.

  9. Excel for Scientists and Engineers

    CERN Document Server

    Verschuuren, Dr Gerard

    2005-01-01

    For scientists and engineers tired of trying to learn Excel with examples from accounting, this self-paced tutorial is loaded with informative samples from the world of science and engineering. Techniques covered include creating a multifactorial or polynomial trendline, generating random samples with various characteristics, and tips on when to use PEARSON instead of CORREL. Other science- and engineering-related Excel features such as making columns touch each other for a histogram, unlinking a chart from its data, and pivoting tables to create frequency distributions are also covered.

  10. A scientist at the seashore

    CERN Document Server

    Trefil, James S

    2005-01-01

    ""A marvelous excursion from the beach to the ends of the solar system . . . captivating.""-The New York Times""So easy to understand yet so dense with knowledge that you'll never look at waves on a beach the same way again.""-San Francisco Chronicle""One of the best popular science books.""-The Kansas City Star""Perfect for the weekend scientist.""-The Richmond News-LeaderA noted physicist and popular science writer heads for the beach to answer common and uncommon questions about the ocean. James S. Trefil, author of Dover Publications' The Moment of Creation: Big Bang Physics from Before th

  11. Radio Supernovae: Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor Stars

    Science.gov (United States)

    2009-02-24

    ar X iv :0 90 2. 40 59 v1 [ as tr o- ph .H E ] 2 4 Fe b 20 09 Radio Supernovae : Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor...FEB 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Radio Supernovae : Circum-Stellar Investigation (C.S.I...of Supernova Progenitor Stars 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f

  12. Observational data on Galactic supernova remnants: II. The supernova remnants within l = 90°-270°

    Directory of Open Access Journals (Sweden)

    Guseinov O.H.

    2004-01-01

    Full Text Available We have collected all the available data on Galactic supernova remnants given in the literature. The data of Galactic supernova remnants located in the Galactic longitude interval l=90° - 270° in all spectral bands are represented in this work. We have adopted distance values for the SNRs by examining these data. The data of various types on neutron stars connected to these supernova remnants are also represented. Remarks of some authors and by ourselves regarding the data and some properties of both the supernova remnants and the point sources are given.

  13. X-ray studies of supernova remnants: a different view of supernova explosions.

    Science.gov (United States)

    Badenes, Carles

    2010-04-20

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research.

  14. Ask a Scientist: What is Color Blindness?

    Science.gov (United States)

    ... Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables Ask a Scientist Video Series Why can’ ... a scientist? Click to Watch What is an optical illusion? Click to Watch What is color blindness? Click ...

  15. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Information Optical Illusions Printables Ask a Scientist Video Series Why can’t you see colors well in ... and more with our Ask a Scientist video series. Dr. Sheldon Miller answers questions about color blindness, ...

  16. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... NEI for Kids > Ask a Scientist Video Series All About Vision About the Eye Ask a Scientist ... have eyelids? Click to Watch Why don’t all animal eyes look the same? Click to Watch ...

  17. Students work as scientists for the summer

    DEFF Research Database (Denmark)

    Ryde, Marianne Vang

    2006-01-01

    Each year, Risø offers its PhD students a course to challenge the natural scientists of the future and to provide them with a more balanced view of their own role as scientists in society.......Each year, Risø offers its PhD students a course to challenge the natural scientists of the future and to provide them with a more balanced view of their own role as scientists in society....

  18. Young scientists in the making

    CERN Multimedia

    Corinne Pralavorio

    2011-01-01

    Some 700 local primary-school children will be trying out the scientific method for themselves from February to June. After "Draw me a physicist", the latest project "Dans la peau d’un chercheur" ("Be a scientist for a day") is designed to give children a taste of what it's like to be a scientist. Both schemes are the fruit of a partnership between CERN, "PhysiScope" (University of Geneva) and the local education authorities in the Pays de Gex and the Canton of Geneva.   Juliette Davenne (left) and Marie Bugnon (centre) from CERN's Communication Group prepare the mystery boxes for primary schools with Olivier Gaumer (right) of PhysiScope. Imagine a white box that rattles and gives off a strange smell when you shake it… How would you go about finding out what's inside it without opening it? Thirty primary-school teachers from the Pays de Gex and the Canton of Geneva tried out this exercise on Wednesday 26 ...

  19. Scientists Discover Sugar in Space

    Science.gov (United States)

    2000-06-01

    The prospects for life in the Universe just got sweeter, with the first discovery of a simple sugar molecule in space. The discovery of the sugar molecule glycolaldehyde in a giant cloud of gas and dust near the center of our own Milky Way Galaxy was made by scientists using the National Science Foundation's 12 Meter Telescope, a radio telescope on Kitt Peak, Arizona. "The discovery of this sugar molecule in a cloud from which new stars are forming means it is increasingly likely that the chemical precursors to life are formed in such clouds long before planets develop around the stars," said Jan M. Hollis of the NASA Goddard Space Flight Center in Greenbelt, MD. Hollis worked with Frank J. Lovas of the University of Illinois and Philip R. Jewell of the National Radio Astronomy Observatory (NRAO) in Green Bank, WV, on the observations, made in May. The scientists have submitted their results to the Astrophysical Journal Letters. "This discovery may be an important key to understanding the formation of life on the early Earth," said Jewell. Conditions in interstellar clouds may, in some cases, mimic the conditions on the early Earth, so studying the chemistry of interstellar clouds may help scientists understand how bio-molecules formed early in our planet's history. In addition, some scientists have suggested that Earth could have been "seeded" with complex molecules by passing comets, made of material from the interstellar cloud that condensed to form the Solar System. Glycolaldehyde, an 8-atom molecule composed of carbon, oxygen and hydrogen, can combine with other molecules to form the more-complex sugars Ribose and Glucose. Ribose is a building block of nucleic acids such as RNA and DNA, which carry the genetic code of living organisms. Glucose is the sugar found in fruits. Glycolaldehyde contains exactly the same atoms, though in a different molecular structure, as methyl formate and acetic acid, both of which were detected previously in interstellar clouds

  20. Still Persistent Global Problem of Scientists' Image

    Science.gov (United States)

    Türkmen, Hakan

    2015-01-01

    Pre-service teachers' views of science and scientists have been widely studied. The purpose of this study is to identify whether there is problem of image of scientists and determine where they receive about scientist image. Three hundred thirty five (105 from Turkey, 162 from Europe, 68 from US) elementary pre-service teachers participated in…

  1. Helping Young People Engage with Scientists

    Science.gov (United States)

    Leggett, Maggie; Sykes, Kathy

    2014-01-01

    There can be multiple benefits of scientists engaging with young people, including motivation and inspiration for all involved. But there are risks, particularly if scientists do not consider the interests and needs of young people or listen to what they have to say. We argue that "dialogue" between scientists, young people and teachers…

  2. Radio emision from supernova remnants

    Science.gov (United States)

    Dubner, G.

    2016-06-01

    The vast majority of supernova remnants (SNRs) in our Galaxy and nearby galaxies have been discovered through radio observations, and only a very small number of the SNRs catalogued in the Milky Way have not been detected in the radio band, or are poorly defined by current radio observations. The study of the radio emission from SNRs is an excellent tool to investigate morphological characteristics, marking the location of shock fronts and contact discontinuities; the presence, orientation and intensity of the magnetic field; the energy spectrum of the emitting particles; and the dynamical consequences of the interaction with the circumstellar and interstellar medium. I will review the present knowledge of different important aspects of radio remnants and their impact on the interstellar gas. Also, new radio studies of the Crab Nebula carried out with the Karl Jansky Very Large Array (JVLA) at 3 GHz and with ALMA at 100 GHz, will be presented.

  3. Supernova 1987A at 30

    Science.gov (United States)

    Spyromilio, J.; Leibundgut, B.; Fransson, C.; Larsson, J.; Migotto, K.; Girard, J.

    2017-03-01

    Thirty years on, SN 1987A continues to develop and, over the last decade in particular, has: revealed the presence of a large centrally concentrated reservoir of dust; shown the presence of molecular species within the ejecta; expanded such that the ejecta structure is angularly resolved; begun the destruction of the circumstellar ring and transitioned to being dominated by energy sources external to the ejecta. We are participating in a live experiment in the creation of a supernova remnant and here the recent progress is briefly overviewed. Exciting developments can be expected as the ejecta and the reverse shock continue their interaction, the X-rays penetrate into the cold molecular core and we observe the return of the material into the interstellar medium. We anticipate that the nature of the remnant of the leptonisation event in the centre will also be revealed.

  4. Progenitors of Supernovae Type Ia

    CERN Document Server

    Toonen, S; Bours, M; Zwart, S Portegies; Claeys, J; Mennekens, N; Ruiter, A

    2013-01-01

    Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. The standard scenarios involve thermonuclear explosions of carbon/oxygen white dwarfs approaching the Chandrasekhar mass; either by accretion from a companion or by a merger of two white dwarfs. We investigate the contribution from both channels to the SNIa rate with the binary population synthesis (BPS) code SeBa in order to constrain binary processes such as the mass retention efficiency of WD accretion and common envelope evolution. We determine the theoretical rates and delay time distribution of SNIa progenitors and in particular study how assumptions affect the predicted rates.

  5. ANTIPROTONS PRODUCED IN SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E. G.; Ksenofontov, L. T., E-mail: ksenofon@ikfia.sbras.ru [Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue, 677891 Yakutsk (Russian Federation)

    2014-08-20

    We present the energy spectrum of an antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNRs). The model includes the reacceleration of antiprotons already existing in the interstellar medium as well as the creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shocks. It is shown that the production of antiprotons in SNRs produces a considerable effect in their resultant energy spectrum, making it essentially flatter above 10 GeV so that the spectrum at TeV energies increases by a factor of 5. The calculated antiproton spectrum is consistent with the PAMELA data, which correspond to energies below 100 GeV. As a consistency check, we have also calculated within the same model the energy spectra of secondary nuclei and show that the measured boron-to-carbon ratio is consistent with the significant SNR contribution.

  6. Progenitors of type Ia supernovae

    CERN Document Server

    Maeda, Keiichi

    2016-01-01

    Natures of progenitors of type Ia Supernovae (SNe Ia) have not yet been clarified. There has been long and intensive discussion on whether the so-called single degenerate (SD) scenario or the double degenerate (DD) scenario, or anything else, could explain a major population of SNe Ia, but the conclusion has not yet been reached. With rapidly increasing observational data and new theoretical ideas, the field of studying the SN Ia progenitors has been quickly developing, and various new insights have been obtained in recent years. This article aims at providing a summary of the current situation regarding the SN Ia progenitors, both in theory and observations. It seems difficult to explain the emerging diversity seen in observations of SNe Ia by a single population, and we emphasize that it is important to clarify links between different progenitor scenarios and different sub-classes of SNe Ia.

  7. Mass extinctions and supernova explosions

    CERN Document Server

    Korschinek, Gunther

    2016-01-01

    A nearby supernova (SN) explosion could have negatively influenced life on Earth, maybe even been responsible for mass extinctions. Mass extinction poses a significant extinction of numerous species on Earth, as recorded in the paleontologic, paleoclimatic, and geological record of our planet. Depending on the distance between the Sun and the SN, different types of threats have to be considered, such as ozone depletion on Earth, causing increased exposure to the Sun's ultraviolet radiation, or the direct exposure of lethal x-rays. Another indirect effect is cloud formation, induced by cosmic rays in the atmosphere which result in a drop in the Earth's temperature, causing major glaciations of the Earth. The discovery of highly intensive gamma ray bursts (GRBs), which could be connected to SNe, initiated further discussions on possible life-threatening events in Earth's history. The probability that GRBs hit the Earth is very low. Nevertheless, a past interaction of Earth with GRBs and/or SNe cannot be exclude...

  8. Bangladesh women scientists' association honours ICDDR,B scientist.

    Science.gov (United States)

    1984-01-01

    Dr. Ayesha Molla, an ICDDR,B biochemist-nutritionist, was awarded a gold medal by the Bangladesh Women Scientists' Association and named Best Woman Scientist of the Year. She was honored for outstanding achievements in diarrhea/nutrition research especially in her classic studies on nutrient absorption during diarrhea. Her recent work has focused on the diarrhea/malnutrition mechanism in children. Her findings indicate that eating during acute diarrhea should be encouraged to reduce post-diarrhea malnutriton in vulnerable developing country children. In another study in collaboration with her husband, a pediatrician and gastroenterologist, it was found that diarrhea has a negligible effect on secretion of digestive enzymes which partially explains why significant digestion and absorption continue during diarrhea. Dr. Molla was also honored for related studies on the vitamin A/diarrhea/malnutrition mechanism. This is of immense importance in developing countries since repeated diarrheal infections in children aggravate malnutrition and lead to vitamin A deficiency blindness. Most blindness seems to be associated with or preceded by recurrent diarrheal infections. Dr. Molla found that water-soluble vitamin A administrated orally was associated with rapid improvement of deteriorating eye conditions. A brief outline of her background is given and her current work discussed. She is presently involved in seeking the best possible diet for children suffering from severe protein energy malnutrition (PEM). This problem results in coincident lack of varying proportions of protein and energy. Dr. Molla is attempting to determine the fastest, most tolerable, low cost, readily available and culturally acceptable diet. Maternal training in feeding practices will be provided. In collaboration with her husband, Dr. Molla is also studying the 2nd generation Oral Rehydration Solution (ORS). They are working to substitute rice or other staples for the traditional sugar in ORS.

  9. Astrophysics: Echo from an ancient supernova

    Science.gov (United States)

    Pastorello, Andrea; Patat, Ferdinando

    2008-12-01

    Light reflected off a dust cloud in the vicinity of the relic of Tycho Brahe's supernova, whose light first swept past Earth more than four centuries ago, literally sheds light on the nature of this cosmic explosion.

  10. The Supernova Impostor SN 2010da

    Science.gov (United States)

    Binder, Breanna A.; Williams, Benjamin F.; Kong, Albert K. H.; Plucinsky, Paul P.; Gaetz, Terrance J.; Skillman, Evan D.; Dolphin, Andrew E.

    2016-01-01

    Supernova impostors are optical transients that, despite being assigned a supernova designation, do not signal the death of a massive star or accreting white dwarf. Instead, many impostors are thought to be major eruptions from luminous blue variables. Although the physical cause of these eruptions is still debated, tidal interactions from a binary companion has recently gained traction as a possible explanation for observations of some supernova impostors. In this talk, I will discuss the particularly interesting impostor SN 2010da, which exhibits high-luminosity, variable X-ray emission. The X-ray emission is consistent with accretion onto a neutron star, making SN 2010da a likely high mass X-ray binary in addition to a supernova impostor. SN 2010da is a unique laboratory for understanding both binary interactions as drivers of massive star eruptions and the evolutionary processes that create high mass X-ray binaries.

  11. Physical processes in collapse driven supernova

    Energy Technology Data Exchange (ETDEWEB)

    Mayle, R.W.

    1985-11-01

    A model of the supernova explosion is discussed. The method of neutrino transport is discussed, since the explosive mechanism depends on neutrino heating of the material behind the accretion shock. The core region of these exploding stars becomes unstable to convective motions during the supernova evolution. Convective mixing allows more neutrinos to escape from under the neutrinosphere, and thus increases the amount of heating by neutrinos. An approximate method of incorporating convection is described, and some results of including convection in a computer model is presented. Another phenomena is seen in computer simulations of supernova, oscillations in the neutrino luminosity and mass accretion rate onto the protoneutron star. The last topic discussed in this thesis describes the attempt to understand this oscillation by perturbation of the steady state solution to equations approximating the complex physical processes occurring in the late time supernova. 42 refs., 31 figs.

  12. Inside the supernova a powerful convective engine

    CERN Document Server

    Herant, M; Hix, W R; Fryer, C F; Colgate, S A; Marc Herant; Willy Benz; Chris F Fryer; Stirling Colgate

    1994-01-01

    We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 Msun and 25 Msun) in two dimensions. Our calculations begin at the onset of core collapse and stop several 100 ms after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. (...) Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. (...) In essence, a Carnot cycle is established in which convection allows out-of-equilibrium heat transfer mediated by neutrinos to drive low entropy matter to higher entropy and therefore extracts mechanical energy from the heat generated by gravitational collapse. We argue that supernova explosions are ne...

  13. Detecting supernovae neutrino with Earth matter effect

    CERN Document Server

    Liao, Wei

    2016-01-01

    We study Earth matter effect in oscillation of supernovae neutrinos. We show that detecting Earth matter effect gives an independent measurement of spectra of supernovae neutrinos, i.e. the flavor difference of the spectra of supernovae neutrinos. We study the effect of energy resolution and angular resolution of final electron or positron on detecting the signal of Earth matter effect. We show that varying the widths of energy bins in analysis can change the signal strength of Earth matter effect and the statistical fluctuation. A reasonable choice of energy bins can both suppress the statistical fluctuation and make out a good signal strength relative to the statistical fluctuation. Neutrino detectors with good energy resolution and good angular resolution are therefore preferred so that there are more freedom to vary energy bins and to optimize the signal of Earth matter effect in analyzing events of supernovae neutrinos.

  14. Gravitational wave triggered searches for failed supernovae

    Science.gov (United States)

    Annis, James; Dark Energy Survey Collaboration

    2016-03-01

    Stellar core collapses occur to all stars of sufficiently high mass and often result in supernovae. A small fraction of supergiant stars, however, are thought to collapse directly into black holes without producing supernovae. A survey of such ``failed'' supernovae would require monitoring millions of supergiants for several years. That is very challenging even for current surveys. With the start of the Advanced LIGO science run, we investigate the possibility of detecting failed supernovae by looking for missing supergiants associated with gravitational wave triggers. We use the Dark Energy Camera (DECam). Our project is a joint effort between the community and the Dark Energy Survey (DES) collaboration. In this talk we report on our ongoing efforts and discuss prospects for future searches.

  15. Supernovae, dark energy and the accelerating universe

    CERN Document Server

    Perlmutter, Saul

    1999-01-01

    Based on an analysis of 42 high-redshift supernovae discovered by the supernovae cosmology project, we have found evidence for a positive cosmological constant, Lambda, and hence an accelerating universe. In particular, the data are strongly inconsistent with a Lambda=0 flat cosmology, the simplest inflationary universe model. The size of our supernova sample allows us to perform a variety of statistical tests to check for possible systematic errors and biases. We will discuss results of these and other studies and the ongoing hunt for further loopholes to evade the apparent consequences of the measurements. We will present further work that begins to constrain the alternative physics theories of "dark energy" that have been proposed to explain these results. Finally, we propose a new concept for a definitive supernova measurement of the cosmological parameters.

  16. Shock Heated Dust in Young Supernova Remnants

    Science.gov (United States)

    Braun, R.; Strom, R. G.; van der Laan, H.; Greidanus, H.

    Infrared emission in young supernova remnants is interpreted as coming from shock-heated dust. Using models and data from other wavelength regimes, many physical parameters of the remnants can accurately be derived.

  17. Cosmic ray escape from supernova remnants

    CERN Document Server

    Gabici, Stefano

    2011-01-01

    Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the cosmic rays which are eventually injected in the interstellar medium is more uncertain and depends on the details of the process of particle escape from the shock. Knowing the spectral shape of these escaping particles is of crucial importance in order to assess the validity of the supernova remnant paradigm for cosmic ray origin. Moreover, after escaping from a supernova remnant, cosmic rays interact with the surrounding ambient gas and produce gamma rays in the vicinity of the remnant itself. The detection of this radiation can be used as an indirect proof of the fact that the supernova remnant was indeed accelerating cosmic rays in the past.

  18. An "archaeological" quest for galactic supernova neutrinos

    CERN Document Server

    Lazauskas, Rimantas; Volpe, Cristina

    2009-01-01

    We explore the possibility to observe the effects of electron neutrinos from past galactic supernovae, through a geochemical measurement of the amount of Technetium 97 produced by neutrino-induced reactions in a Molybdenum ore. The calculations we present take into account the recent advances in our knowledge of neutrino interactions, of neutrino oscillations inside a supernova, of the solar neutrino flux at Earth and of possible failed supernovae. The predicted Technetium 97 abundance is of the order of 10^7 atoms per 10 kilotons of ore, which is close to the current geochemical experimental sensitivity. Of this, 10-20% is from supernovae. Considering the comparable size of uncertainties, more precision in the modeling of neutrino fluxes as well as of neutrino cross sections is required for a meaningful measurement.

  19. A review of type Ia supernova spectra

    CERN Document Server

    Parrent, J; Parthasarathy, M

    2014-01-01

    SN 2011fe was the nearest and best-observed type Ia supernova in a generation, and brought previous incomplete datasets into sharp contrast with the detailed new data. In retrospect, documenting spectroscopic behaviors of type Ia supernovae has been more often limited by sparse and incomplete temporal sampling than by consequences of signal-to-noise ratios, telluric features, or small sample sizes. As a result, type Ia supernovae have been primarily studied insofar as parameters discretized by relative epochs and incomplete temporal snapshots near maximum light. Here we discuss a necessary next step toward consistently modeling and directly measuring spectroscopic observables of type Ia supernova spectra. In addition, we analyze current spectroscopic data in the parameter space defined by empirical metrics, which will be relevant even after progenitors are observed and detailed models are refined.

  20. SN 1054: A pulsar-powered supernova?

    Science.gov (United States)

    Li, Shao-Ze; Yu, Yun-Wei; Huang, Yan

    2015-11-01

    The famous ancient supernova SN 1054 could have been too bright to be explained in the “standard” radioactive-powered supernova scenario. As an alternative attempt, we demonstrate that the spin-down of the newly born Crab pulsar could provide a sufficient energy supply to make SN 1054 visible at daytime for 23 days and at night for 653 days, where a one-zone semi-analytical model is employed. Our results indicate that SN 1054 could be a “normal” cousin of magnetar-powered superluminous supernovae. Therefore, SN 1054-like supernovae could be a probe to uncover the properties of newly born neutron stars, which provide initial conditions for studies on neutron star evolutions.

  1. Diffuse supernova neutrinos at underground laboratories

    Science.gov (United States)

    Lunardini, Cecilia

    2016-06-01

    I review the physics of the Diffuse Supernova Neutrino flux (or Background, DSNB), in the context of future searches at the next generation of neutrino observatories. The theory of the DSNB is discussed in its fundamental elements, namely the cosmological rate of supernovae, neutrino production inside a core collapse supernova, redshift, and flavor oscillation effects. The current upper limits are also reviewed, and results are shown for the rates and energy distributions of the events expected at future liquid argon and liquid scintillator detectors of O(10) kt mass, and water Cherenkov detectors up to a 0.5 Mt mass. Perspectives are given on the significance of future observations of the DSNB, both at the discovery and precision phases, for the investigation of the physics of supernovae and of the properties of the neutrino.

  2. Supernova Shock Breakout from a Red Supergiant

    CERN Document Server

    Schawinski, Kevin; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Roeser, Hermann-Josef; Walker, Emma; Astier, Pierre; Balam, Dave; Balland, Christophe; Basa, Stephane; Carlberg, Ray; Conley, Alex; Fouchez, Dominque; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, Andy; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-01-01

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic `core-collapse' supernova. Such events are usually detected long after the star has exploded. Here we report the first detection of the radiative precursor from a supernova shock before it has reached the surface of a star followed by the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve show that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a promising and novel way to probe the physics of core-collapse supernovae and the internal structures of their progenitors.

  3. Supernova Classification Using Swift UVOT Photometry

    Science.gov (United States)

    Smith, Madison; Brown, Peter J.

    2017-01-01

    With the great influx of supernova discoveries over the past few years, the observation time needed to acquire the spectroscopic data needed to classify supernova by type has become unobtainable. Instead, using the photometry of supernovae could greatly reduce the amount of time between discovery and classification. For this project we looked at the relationship between colors and supernova types through machine learning packages in Python. Using data from the Swift Ultraviolet/Optical Telescope (UVOT), each photometric point was assigned values corresponding to colors, absolute magnitudes, and the relative times from the peak brightness in several filters. These values were fed into three classifying methods, the nearest neighbors, decision tree, and random forest methods. We will discuss the success of these classification systems, the optimal filters for photometric classification, and ways to improve the classification.

  4. MDM OSMOS Spectroscopic classification of Supernovae

    Science.gov (United States)

    Bose, Subhash; Dong, Subo; Chen, Ping; Klusmeyer, J.; Prieto, Jose Luis; Shappee, B.; Shields, J.; Brown, J.; Stanek, K. Z.; Kochanek, C.

    2016-11-01

    We report optical spectroscopic classification of supernova candidates 2016hgd (ATel #9651), 2016hli (ATel #9685), CSS161013:015319+171853 and CSS161013:020130+141534 (http://nesssi.cacr.caltech.edu/catalina/AllSN.html).

  5. TYPE Ia SUPERNOVA CARBON FOOTPRINTS

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. C.; Nugent, P. [Computational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94611 (United States); Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Hsiao, E. Y.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Antilogus, P.; Bongard, S.; Canto, A. [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05 (France); Baltay, C. [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States); Buton, C.; Kerschhaggl, M.; Kowalski, M.; Paech, K. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622 Lyon (France); and others

    2011-12-10

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II {lambda}6580 absorption 'notches' in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s{sup -1}) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22{sup +10}{sub -6%} of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II {lambda}6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a 'carbon blobs' hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

  6. Neutrino-nucleus reactions in supernovae

    Science.gov (United States)

    Dzhioev, Alan A.; Vdovin, A. I.

    2016-01-01

    We study thermal effects on neutrino-nucleus reactions occurring under supernova conditions. The approach we use is based on the QRPA extended to finite temperature by the thermofield dynamics formalism. For the relevant supernova conditions we calculate inelastic neutrino scattering and neutrino absorption cross sections for two sample nuclei, 56Fe and 82Ge. In addition, we apply the approach to examine the rate of neutrino-antineutrino pair emission by hot nuclei.

  7. Neutrino-nucleus reactions in supernovae

    Directory of Open Access Journals (Sweden)

    Dzhioev Alan A.

    2016-01-01

    Full Text Available We study thermal effects on neutrino-nucleus reactions occurring under supernova conditions. The approach we use is based on the QRPA extended to finite temperature by the thermofield dynamics formalism. For the relevant supernova conditions we calculate inelastic neutrino scattering and neutrino absorption cross sections for two sample nuclei, 56Fe and 82Ge. In addition, we apply the approach to examine the rate of neutrino-antineutrino pair emission by hot nuclei.

  8. Supernova neutrino oscillations: What do we understand?

    Energy Technology Data Exchange (ETDEWEB)

    Dighe, Amol, E-mail: amol@theory.tifr.res.i [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2010-01-01

    We summarize our current understanding of the neutrino flavor conversions inside a core collapse supernova, clarifying the important role played by the 'collective effects' in determining flavor conversion probabilities. The potentially observable {nu}{sub e} and {nu}-bar {sub e} spectra may help us identify the neutrino mixing scenario, distinguish between primary flux models, and learn more about the supernova explosion.

  9. Collective flavor transitions of supernova neutrinos

    CERN Document Server

    Sigl, Guenter; Esteban-Pretel, Andreu; Pastor, Sergio; Mirizzi, Alessandro; Raffelt, Georg G; Serpico, Pasquale D

    2009-01-01

    We give a very brief overview of collective effects in neutrino oscillations in core collapse supernovae where refractive effects of neutrinos on themselves can considerably modify flavor oscillations, with possible repercussions for future supernova neutrino detection. We discuss synchronized and bipolar oscillations, the role of energy and angular neutrino modes, as well as three-flavor effects. We close with a short summary and some open questions.

  10. The SuperNova Early Warning System

    OpenAIRE

    Scholberg, K.

    2008-01-01

    A core collapse in the Milky Way will produce an enormous burst of neutrinos in detectors world-wide. Such a burst has the potential to provide an early warning of a supernova's appearance. I will describe the nature of the signal, the sensitivity of current detectors, and SNEWS, the SuperNova Early Warning System, a network designed to alert astronomers as soon as possible after the detected neutrino signal.

  11. Close binary white dwarfs and supernovae IA

    Directory of Open Access Journals (Sweden)

    R. Napiwotzki

    2004-01-01

    Full Text Available Informamos sobre el estado actual de los \\surveys" de velocidades radiales para binarias de enanas blancas (degeneradas dobles - DDs incluyendo SPY (Exploraci on ESO de progenitoras de supernovas Ia que recien- temente se llevaron a cabo en el VLT. Una amplia muestra de DDs nos permitir a poner fuertes restricciones sobre las fases evolutivas de los sistemas progenitores de binarias cercanas y tambi en llevar a cabo pruebas observacionales del escenario DD para supernovas de tipo Ia.

  12. Overview of the nearby supernova factory

    Energy Technology Data Exchange (ETDEWEB)

    Aldering, Greg; Adam, Gilles; Antilogus, Pierre; Astier, Pierre; Bacon, Roland; Bongard, S.; Bonnaud, C.; Copin, Yannick; Hardin, D.; Howell, D. Andy; Lemmonnier, Jean-Pierre; Levy, J.-M.; Loken, S.; Nugent, Peter; Pain, Reynald; Pecontal, Arlette; Pecontal, Emmanuel; Perlmutter, Saul; Quimby, Robert; Schahmaneche, Kyan; Smadja, Gerard; Wood-Vasey, W. Michael

    2002-07-29

    The Nearby Supernova Factory (SNfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The SNfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000 {angstrom} for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the SNfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The SNfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.

  13. Neutrino oscillations in core-collapse supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng-Ru [TU Darmstadt (Germany); University of Minnesota, MN (United States); Huther, Lutz [TU Darmstadt (Germany); Fischer, Tobias; Martinez-Pinedo, Gabriel [TU Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Qian, Yong-Zhong [University of Minnesota, MN (United States)

    2013-07-01

    Neutrino oscillations play an important role in determining the spectra of neutrinos emitted from core-collapse supernova and must be considered in the analysis of supernova neutrino detection to understand both the supernova dynamics and the unknown neutrino mass hierarchy. We have studied neutrino oscillations in supernovae using the emission spectra of neutrinos and the dynamically evolving supernova density profile from a state-of-the-art supernova model. We find that in this model, different regions of neutrino oscillations are well separated. Collective neutrino oscillations happen at the innermost part such that the spectra of electron neutrinos and mu/tau neutrinos are partly swapped for the first few seconds in the cooling phase. Then, the high and low MSW resonances that occur after collective oscillations are both adiabatic. Using these results, we find that in this model, neutrino oscillations have little effect on the nucleosynthesis in the neutrino-driven winds. However, the detection of such a signal could possibly allow us to differentiate the neutrino mass hierarchy and to extract the shock revival time.

  14. The Distant Type Ia Supernova Rate

    Science.gov (United States)

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R. S.; Aldering, G.; Astier, P.; Deustua, S. E.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M. J.; Kim, A. G.; Kim, M. Y.; Knop, R. A.; Lee, J. C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N. A.

    2002-05-28

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  15. The distant Type Ia supernova rate

    CERN Document Server

    Pain, R; Sullivan, M; Ellis, Richard S; Aldering, G; Astier, Pierre; Duestua, S E; Fruchter, A S; Goldhaber, Gerson; Goobar, A; Groom, D E; Hardin, D; Hook, I M; Howell, D A; Irwin, M J; Kim, A G; Kim, M Y; Knop, R A; Lee, J C; Lidman, C E; McMahon, R G; Nugent, P; Panagia, N; Pennypacker, C R; Perlmutter, S; Ruiz-Lapuente, P; Schahmaneche, K; Schaefer, B; Walton, N A

    2001-01-01

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially-flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean redshift $z\\simeq0.55$ of $1.53 {^{+0.28}_{-0.25}} {^{+0.32}_{-0.31}} 10^{-4} h^3 {\\rm Mpc}^{-3} {\\rm yr}^{-1}$ or $0.58 {^{+0.10}_{-0.09}} {^{+0.10}_{-0.09}} h^2 {\\rm SNu}$ (1 SNu = 1 supernova per century per $10^{10}$\\Lbsun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  16. Type Ia supernova rate at a redshift of ­0.1

    DEFF Research Database (Denmark)

    Blanc ...[et al], G.; Andersen, J.

    2004-01-01

    stars: supernovae: general; galaxies: evolution; cosmology: miscellaneous; methods: observational......stars: supernovae: general; galaxies: evolution; cosmology: miscellaneous; methods: observational...

  17. Supernova remnants: the X-ray perspective

    Science.gov (United States)

    Vink, Jacco

    2012-12-01

    Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And in particular the advances made in X-ray imaging spectroscopy over the last two decades has greatly increased our knowledge about supernova remnants. It has made it possible to map the products of fresh nucleosynthesis, and resulted in the identification of regions near shock fronts that emit X-ray synchrotron radiation. Since X-ray synchrotron radiation requires 10-100 TeV electrons, which lose their energies rapidly, the study of X-ray synchrotron radiation has revealed those regions where active and rapid particle acceleration is taking place. In this text all the relevant aspects of X-ray emission from supernova remnants are reviewed and put into the context of supernova explosion properties and the physics and evolution of supernova remnants. The first half of this review has a more tutorial style and discusses the basics of supernova remnant physics and X-ray spectroscopy of the hot plasmas they contain. This includes hydrodynamics, shock heating, thermal conduction, radiation processes, non-equilibrium ionization, He-like ion triplet lines, and cosmic ray acceleration. The second half offers a review of the advances made in field of X-ray spectroscopy of supernova remnants during the last 15 year. This period coincides with the availability of X-ray imaging spectrometers. In addition, I discuss the results of high resolution X-ray spectroscopy with the Chandra and XMM-Newton gratings. Although these instruments are not ideal for studying extended sources, they nevertheless provided interesting results for a limited number of remnants. These results provide a glimpse of what may be achieved with future microcalorimeters that will be available on board future X

  18. Is evaluation of scientist's objective

    CERN Document Server

    Wold, A

    2000-01-01

    There is ample data demonstrating that female scientists advance at a far slower rate than their male colleagues. The low numbers of female professors in European and North American universities is, thus, not solely an effect of few women in the recruitment pool but also to obstacles specific to the female gender. Together with her colleague Christine Wennerås, Agnes Wold conducted a study of the evaluation process at the Swedish Medical Research Council. Evaluators judged the "scientific competence", "research proposal" and "methodology" of applicants for post-doctoral positions in 1995. By relating the scores for "scientific competence" to the applicants' scientific productivity and other factors using multiple regression, Wennerås and Wold demonstrated that the applicant's sex exerted a strong influence on the "competence" score so that male applicants were perceived as being more competent than female applicants of equal productivity. The study was published in Nature (vol 387, p 341-3, 1997) and inspir...

  19. LHCb Early Career Scientist Awards

    CERN Multimedia

    Patrick Koppenburg for the LHCb Collaboration

    2016-01-01

    On 15 September 2016, the LHCb collaboration awarded the first set of prizes for outstanding contributions of early career scientists.   From left to right: Guy Wilkinson (LHCb spokesperson), Sascha Stahl, Kevin Dungs, Tim Head, Roel Aaij, Conor Fitzpatrick, Claire Prouvé, Patrick Koppenburg (chair of committee) and Sean Benson. Twenty-five nominations were submitted and considered by the committee, and 5 prizes were awarded to teams or individuals for works that had a significant impact within the last year. The awardees are: Roel Aaij, Sean Benson, Conor Fitzpatrick, Rosen Matev and Sascha Stahl for having implemented and commissioned the revolutionary changes to the LHC Run-2 high-level-trigger, including the first widespread deployment of real-time analysis techniques in High Energy Physics;   Kevin Dungs and Tim Head for having launched the Starterkit initiative, a new style of software tutorials based on modern programming methods. “Starterkit is a group of ph...

  20. Data Scientist Training for Librarians

    Science.gov (United States)

    Erdmann, C.

    2015-04-01

    Recent studies suggest that there will be a shortfall in the near future of skilled talent available to help take advantage of big data in organizations. Meanwhile, government initiatives have encouraged the research community to share their data more openly, raising new challenges for researchers. Librarians can assist in this new data-driven environment. Data Scientist Training for Librarians (or Data Savvy Librarians) is an experimental course being offered by the Harvard Library to train librarians to respond to the growing data needs of their communities. In the course, librarians familiarize themselves with the research data lifecycle, working hands-on with the latest tools for extracting, wrangling, storing, analyzing, and visualizing data. By experiencing the research data lifecycle themselves, and becoming data savvy and embracing the data science culture, librarians can begin to imagine how their services might be transformed.

  1. Special Functions for Applied Scientists

    CERN Document Server

    Mathai, A M

    2008-01-01

    Special Functions for Applied Scientists provides the required mathematical tools for researchers active in the physical sciences. The book presents a full suit of elementary functions for scholars at the PhD level and covers a wide-array of topics and begins by introducing elementary classical special functions. From there, differential equations and some applications into statistical distribution theory are examined. The fractional calculus chapter covers fractional integrals and fractional derivatives as well as their applications to reaction-diffusion problems in physics, input-output analysis, Mittag-Leffler stochastic processes and related topics. The authors then cover q-hypergeometric functions, Ramanujan's work and Lie groups. The latter half of this volume presents applications into stochastic processes, random variables, Mittag-Leffler processes, density estimation, order statistics, and problems in astrophysics. Professor Dr. A.M. Mathai is Emeritus Professor of Mathematics and Statistics, McGill ...

  2. Neutrinos from type-II supernovae and the neutrino-driven supernova mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Janka, H.T. [Max-Planck-Institut fuer Astrophysik, Garching (Germany)

    1996-11-01

    Supernova 1987A has confirmed fundamental aspects of our theoretical view of type-II supernovae: Type-II supernovae are a consequence of the collapse of the iron core of a massive evolved star and lead to the formation of a neutron star or black hole. This picture is most strongly supported by the detection of electron antineutrinos in the IMB and Kamiokande II experiments in connection with SN 1987A. However, the mechanism causing the supernova explosion is not yet satisfactorily understood. In this paper the properties of the neutrino emission from supernovae and protoneutron stars will be reviewed; analytical estimates will be derived and results of numerical simulations will be shown. It will be demonstrated that the spectral distributions of the emitted neutrinos show clear and systematic discrepancies compared with thermal (black body-type) emission. This must be taken into account when neutrino observations from supernovae are to be interpreted, or when implications of the neutrino emission on nucleosynthesis processes in mantle and envelope of the progenitor star are to be investigated. Furthermore, the influence of neutrinos on the supernova dynamics will be discussed, in particular their crucial role in causing the explosion by Wilson`s neutrino-driven delayed mechanism. Possible implications of convection inside the newly born neutron star and between surface and the supernova shock will be addressed and results of multi-dimensional simulations will be presented. (author) 7 figs., 1 tab., refs.

  3. PREFACE: FAIRNESS 2014: FAIR Next Generation ScientistS 2014

    Science.gov (United States)

    2015-04-01

    FAIRNESS 2014 was the third edition in a series of workshops designed to bring together excellent international young scientists with research interests focused on physics at FAIR (Facility for Antiproton and Ion Research) and was held on September 22-27 2014 in Vietri sul Mare, Italy. The topics of the workshops cover a wide range of aspects in both theoretical developments and current experimental status, concentrated around the four scientific pillars of FAIR. FAIR is a new accelerator complex with brand new experimental facilities, that is currently being built next to the existing GSI Helmholtzzentrum for Schwerionenforschung close to Darmstadt, Germany. The spirit of the conference is to bring together young scientists, e.g. advanced PhD students and postdocs and young researchers without permanent position to present their work, to foster active informal discussions and build up of networks. Every participant in the meeting with the exception of the organizers gives an oral presentation, and all sessions are followed by an hour long discussion period. During the talks, questions are anonymously collected in a box to stimulate discussions. The broad physics program at FAIR is reflected in the wide range of topics covered by the workshop: • Physics of hot and dense nuclear matter, QCD phase transitions and critical point • Nuclear structure, astrophysics and reactions • Hadron Spectroscopy, Hadrons in matter and Hypernuclei • New developments in atomic and plasma physics • Special emphasis is put on the experiments CBM, HADES, PANDA, NUSTAR, APPA and related experiments For each of these different areas one invited speaker was selected to give a longer introductory presentation. The write-ups of the talks presented at FAIRNESS 2014 are the content of this issue of Journal of Physics: Conference Series and have been refereed according to the IOP standard for peer review. This issue constitutes therefore a collection of the forefront of research that

  4. Effects of Patrol Operation on Hydration Status and Autonomic Modulation of Heart Rate of Brazilian Peacekeepers in Haiti.

    Science.gov (United States)

    Duarte, Antonio F A; Morgado, Jairo J M

    2015-11-01

    The stress of operational missions may challenge the maintenance of body homeostasis, affecting soldiers' cardiac autonomic control, promoting dehydration, and compromising performance. Therefore, we aimed to determine the effects of peacekeeper patrol operation in Haiti on soldiers' hydration status and cardiac autonomic modulation, and to determine whether fluctuations in autonomic modulation were associated with changes in hydration status, energy expenditure (EE), and aerobic fitness (V[Combining Dot Above]O2max). A group of 20 soldiers (23.5 ± 4.7 years; V[Combining Dot Above]O2max 52.9 ± 4.5 ml·kg⁻¹·min⁻¹) completed an operational patrol mission with a mean duration of 160.6 ± 28.6 minutes. Before (Pre) and after (Post) the operation, the soldiers' body masses (BMs) were measured and 5-minute heart rate interbeat (R-R) intervals were recorded at rest to estimate heart rate variability (low-frequency [LF] and high-frequency [HF] power, and sympathovagal balance [LF/HF]). During the mission, EE was estimated using heart rate (HR) monitors. Changes from Pre to Post in BM (%BM loss) and LF/HF (ΔLF/HF) were used to evaluate the soldiers' dehydration levels and autonomic modulation, respectively. The mean EE was 711.0 ± 208.7 kcal. From pre to post, increases (p < 0.01) were noted in LF normalized units (n.u.) and LF/HF and decreases (p < 0.01) were noted in BM, R-R interval, and HF n.u. The variation in ΔLF/HF correlated with EE (r = 0.49; p = 0.02), V[Combining Dot Above]O2max (r = -0.42; p = 0.05), and %BM loss (r = 0.53; p = 0.02). The results demonstrated that an operational peacekeeper patrol with an approximate duration of 160 minutes promoted both dehydration and an imbalance in the autonomic modulation of soldiers' HR. The reduction in sympathovagal balance correlated with EE, dehydration, and aerobic conditioning.

  5. Supernova Remnant Observations with Micro-X

    Science.gov (United States)

    Figueroa, Enectali

    explosion mechanisms of supernovae and their roles in energy and heavy-element injection into galaxies, their evolution into SNRs, their interactions with their environments, and finally their roles as particle accelerators. For the first flight, we will observe an ejecta region in the Puppis A SNR. The Puppis A bright eastern knot (BEK), is the target of second flight in 2014. The third flight, in late 2015 or early 2016, will make an observation of the Cas A SNR. We will continue to advance the technology readiness of TES microcalorimeters while enhancing the science capability of the payload by implementing a series of improvements for the third flight. For the observation of Cas A in the third flight, we will upgrade from the 128-pixel array with 1 arcminute pixels used in the first two flights to a higher-energy resolution (1 eV FWHM) 256-pixel array with 20 arcsecond pixels and a new 30 arcsecond HPD mirror to enable improved imaging spectroscopy with our payload. The Micro-X team includes leaders in the development of microcalorimeters, SQUID readout systems, and segmented and full-shell grazing incidence X-ray optics, as well as highly experienced sounding rocket instrument developers, and scientific experts on supernova remnants. These investigators are located at institutions with strong space instrumentation traditions with the infrastructure to ensure a successful flight program. With Micro-X, we have designed a versatile payload capable of providing high-resolution science and a testbed for new technology. The first flight this year will make significant scientific contributions well ahead of the Astro-H mission. The program will also aid in the understanding and development of future flight-qualified microcalorimeter systems for larger orbiting missions. Finally, it will continue to attract talented young scientists to X-ray astrophysics and thus serve as a direct pipeline of future leaders of NASA missions.

  6. Patterns of citation when Korean scientists cite other Korean scientists

    Directory of Open Access Journals (Sweden)

    Yeonok Chung

    2016-08-01

    Full Text Available Citation patterns of Korean scientists are investigated by analyzing the references of the papers authored by Korean chemists and published in two journals of different standing. Particular interest is given to how frequently Korean researchers quote the papers written by other Korean researchers and whether there is any difference in the citation pattern when Korean researchers publish their papers in a top international journal or in a domestic journal. Two journals in the category of multidisciplinary chemistry, the Journal of the American Chemical Society and the Bulletin of the Korean Chemical Society, are chosen and a detailed analysis of the references of the papers written by Korean authors in 2015 was performed. The author self-citation rate is found to be much larger than the citation rate of other Korean authors. It is also found that the percentage of self-citations and the percentage of the references by Korean authors excluding self-citations are both significantly larger in the Bulletin of the Korean Chemical Society than in the Journal of the American Chemical Society. Interpretations of the results based on social exchange theory are proposed.

  7. The Carnegie Supernova Project: Intrinsic Colors of Type Ia Supernovae

    CERN Document Server

    Burns, Christopher R; Phillips, M M; Hsiao, E Y; Contreras, Carlos; Persson, S E; Folatelli, Gaston; Boldt, Luis; Campillay, Abdo; Catellón, Sergio; Freedman, Wendy L; Madore, Barry F; Morrell, Nidia; Salgado, Francisco; Suntzeff, Nicholas B

    2014-01-01

    We present an updated analysis of the intrinsic colors of SNe Ia using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of "normal" SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B-V color-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of Rv, though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, Rv, and the color excess, E(B-V), such t...

  8. Type Ia Supernova Progenitors, Environmental Effects and Cosmic Supernova Rates

    CERN Document Server

    Nomoto, K; Hachisu, I; Kato, M; Kobayashi, C; Tsujimoto, T; Nomoto, Ken'ichi; Umeda, Hideyuki; Hachisu, Izumi; Kato, Mariko; Kobayashi, Chiaki; Tsujimoto, Takuji

    1999-01-01

    Relatively uniform light curves and spectral evolution of Type Ia supernovae (SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting white dwarfs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metalli...

  9. Supernovae under microscope: how supernovae overlap to form superbubbles

    CERN Document Server

    Yadav, Naveen; Sharma, Prateek; Nath, Biman B

    2016-01-01

    We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use total energy conserving, 3-D hydrodynamic simulations to study how SNe correlated in space and time create superbubbles. While isolated SNe fizzle out completely by $\\sim 1$ Myr due to radiative losses, for a realistic cluster size it is likely that subsequent SNe go off within the hot/dilute bubble and sustain the shock till the cluster lifetime. We scan the parameter space of ISM density ($n_{g0}$), number of SNe ($N_{\\rm OB}$), and star cluster radius ($r_{\\rm cl}$) to study the conditions for the formation of an overpressured (super)bubble. For realistic cluster sizes, we find that the bubble remains overpressured only if, for a given $n_{g0}$, $N_{\\rm OB}$ is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to $\\sim 5-10\\%$ of the input energy in form of kinetic+thermal energy till 10 Myr for ISM density $n_{g0} \\approx 1$ cm$^...

  10. The End of Days -- Chandra Catches X-ray Glow From Supernova

    Science.gov (United States)

    1999-12-01

    Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

  11. Collaborative Patrol or Joint Patrol: Cooperative Mechanism of Waterway Security in Malacca Straits%从协作巡逻、联合巡逻之区别看马六甲海峡航道安全合作机制

    Institute of Scientific and Technical Information of China (English)

    杨仁飞

    2005-01-01

    Since the beginning of 2005, the security of Malacca Straits has been a worldwide focus not only because of frequent occurrences of five piracy and kidnap cases in several months, but also of the attitudes and stands of major powers and the littoral countries such as Indonesia, Malaysia and Singapore. Though the littoral governments express their wills of coping with the serious piracy threats by themselves, Japan uses the occurrences as a pretext to send troops to assist the patrol. The paper, focusing on the difference of collaborative patrol and joint patrol and the formulation of the cooperative mechanism by the three littoral countries in the present Malacca Straits maritime security, analyzes their advantages, shortcomings and potential ways among the littoral countries and the international community.

  12. The physics of core collapse supernovae

    Science.gov (United States)

    Swesty, Frank Douglas

    1993-01-01

    I have developed an equation of state (EOS) for hot, dense matter that is intended specifically for use in radiation hydrodynamic simulations of supernovae, proto-neutron star cooling, and neutron stars. This EOS makes use of an adjustable nucleon-nucleon interaction that allows for the input of various nuclear force parameters that are not well determined by laboratory measurements. Properties of the EOS as a function of these input parameters were studied and comparisons were made to another EOS that is currently used in stellar collapse simulations. Using this EOS I have conducted simulations of core collapse supernovae with several ideas in mind. First, I have attempted to delineate role of the incompressibility of dense matter in supernovae. I have conducted a parameter study in which the compression modulous of bulk nuclear matter was varied and have found some new and surprising results. When the EOS is constrained by the observed mass of 1.44M(solar mass) for one of the components of the binary pulsar system PSR1913+16, the 'stiffness' of the EOS no longer plays a role in the shock dynamics of the supernova. Secondly, I varied the symmetry energy coefficients in the EOS to determine the role of these coefficients in supernovae. I have found that the symmetry energy behavior of the EOS has potentially observable effects and may play an important role in determining the efficacy of the late-time heating mechanism for the explosion and the stability of the post-bounce core against convection. Finally, I have developed an implicit, general relativistic, radiation hydrodynamics algorithm for the numerical simulation of supernovae. By allowing simulation timesteps to exceed the Courant timescale, this algorithm makes practical high resolution simulations of supernovae to late times. I discuss this algorithm and the associated computer code along with code verification tests and an example of a late-time calculation.

  13. Supernova Dust at Sub-micrometer Scales

    Science.gov (United States)

    Nittler, Larry; Stroud, R. M.

    2006-06-01

    Meteorites contain nanometer to micrometer stardust grains, which formed in pre-solar generations of stars and exhibit large isotopic anomalies that reflect the nuclear processes that occurred in their individual parent stars [1]. Supernovae of Type II have been identified as the sources of much of the stardust, including grains of SiC, Si3N4, graphite and Mg2SiO4. Although, the isotopic compositions of many elements in these grains point unambiguously to supernova nucleosynthesis processes [2], the data require extensive and heterogeneous mixing of disparate nuclear burning zones. A recent study found that individual 200 nm TiC sub-grains within a 12 micron supernova graphite grain have uniform Ti isotopic composition but a range of O isotopic ratios [3]. New microanalysis techniques allow us to correlate the physical microstructures of supernova grains with isotopic composition, e.g., SiC and Si3N4, providing a sub-micron view of condensation processes in supernova ejecta. Results on two SiC grains indicate that micron-sized SiC grains from supernovae consist of assemblages of smaller crystallites with some evidence of radiation and/or shock processing. This is in strong contrast to SiC grains from AGB stars, which are typically single euhedral crystals [4]. The Si, C and N isotopic compositions of the grains are highly uniform, in contrast to the model of [5], which predicts strong isotopic gradients in supernova-derived SiC grains.This work is supported by NASA.[1] Clayton D. D. and Nittler L. R. (2004) ARAA, 42, 39-78.[2] Nittler L. R., et al. (1996) ApJ, 462, L31-34.[3] Stadermann F. J., et al. (2005) GCA, 69, 177-188.[4] Daulton T. L., et al. (2002) Science, 296, 1852-1855.[5] Deneault E. A.-N., et al. (2003) ApJ, 594, 312-325.

  14. ANALISA PERUBAHAN KECEPATAN DAN KEKUATAN MEMANJANG AKIBAT PERUBAHAN BENTUK LAMBUNG PADA PATROL SPEED BOAT “GRASS CARP” DI RAWAPENING

    Directory of Open Access Journals (Sweden)

    Ari Wibawa BS

    2012-02-01

    Full Text Available Pada penelitian ini, sebuah Fibreglass Patrol Speed Boat GRASS CARP yang dioperasikan di wilayah perairan Rawapening Kab. Semarang dihitung dan dianalisa kecepatannya menggunakan Maxsurf Hullspeed version 11.03 dan untuk analisa dan perhitungan kekuatan memanjang menggunakan Maxsurf Hidromax version 11.03. Perhitungan dan analisa kecepatan dilakukan untuk mengetahui hambatan total yang yang diterima baik kapal rancangan maupun kapal sesungguhnya, daya yang dibutuhkan untuk mencapai kecepatan maksimal yang sama dengan kapal rancangan yaitu 13 knot, serta penyebab terjadinya perbedaan kecepatan. Sedangkan analisa pada kekuatan memanjang dilakukan untuk mengetahui apakah GRASS CARP telah memenuhi syarat BKI dilihat dari segi tegangan perhitungan, faktor keamanan kondisi air tenang dan sagging serta hogging, dan nilai modulus serta momen inersianya.

  15. Gifted and Talented Students’ Images of Scientists

    Directory of Open Access Journals (Sweden)

    Sezen Camcı-Erdoğan

    2013-06-01

    Full Text Available The purpose of this study was to investigate gifted students’ images of scientists. The study involved 25 students in grades 7 and 8. The Draw-a-Scientist Test (DAST (Chamber, 183 was used to collect data. Drawings were eval-uated using certain criterion such as a scien-tist’s appearance and investigation, knowledge and technology symbols and gender and working style, place work, expressions, titles-captions-symbols and alternative images and age. The results showed that gifted students’ perceptions about scientists were stereotypical, generally with glasses and laboratory coats and working with experiment tubes, beakers indoors and using books, technological tools and dominantly lonely males. Most gifted stu-dents drew male scientists. Although females drew male scientists, none of the boys drew female scientist.

  16. Exploring Scientists' Working Timetable: A Global Survey

    CERN Document Server

    Wang, Xianwen; Zhang, Chunbo; Xu, Shenmeng; Wang, Zhi; Wang, Chuanli; Wang, Xianbing

    2013-01-01

    In our previous study (Wang et al., 2012), we analyzed scientists' working timetable of 3 countries, using realtime downloading data of scientific literatures. In this paper, we make a through analysis about global scientists' working habits. Top 30 countries/territories from Europe, Asia, Australia, North America, Latin America and Africa are selected as representatives and analyzed in detail. Regional differences for scientists' working habits exists in different countries. Besides different working cultures, social factors could affect scientists' research activities and working patterns. Nevertheless, a common conclusion is that scientists today are often working overtime. Although scientists may feel engaged and fulfilled about their hard working, working too much still warns us to reconsider the work - life balance.

  17. Walter sutton: physician, scientist, inventor.

    Science.gov (United States)

    Ramirez, Gregory J; Hulston, Nancy J; Kovac, Anthony L

    2015-01-01

    Walter S. Sutton (1877-1916) was a physician, scientist, and inventor. Most of the work on Sutton has focused on his recognition that chromosomes carry genetic material and are the basis for Mendelian inheritance. Perhaps less well known is his work on rectal administration of ether. After Sutton's work on genetics, he completed his medical degree in 1907 and began a 2-year surgical fellowship at Roosevelt Hospital, New York City, NY, where he was introduced to the technique of rectal administration of ether. Sutton modified the work of others and documented 100 cases that were reported in his 1910 landmark paper "Anaesthesia by Colonic Absorption of Ether". Sutton had several deaths in his study, but he did not blame the rectal method. He felt that his use of rectal anesthesia was safe when administered appropriately and believed that it offered a distinct advantage over traditional pulmonary ether administration. His indications for its use included (1) head and neck surgery; (2) operations when ether absorption must be minimized due to heart, lung, or kidney problems; and (3) preoperative pulmonary complications. His contraindications included (1) cases involving alimentary tract or weakened colon; (2) laparotomies, except when the peritoneal cavity was not opened; (3) incompetent sphincter or anal fistula; (4) orthopnea; and (5) emergency cases. Sutton wrote the chapter on "Rectal Anesthesia" in one of the first comprehensive textbooks in anesthesia, James Tayloe Gwathmey's Anesthesia. Walter Sutton died of a ruptured appendix in 1916 at age 39.

  18. The Supernovae Analysis Application (SNAP)

    Science.gov (United States)

    Bayless, Amanda J.; Fryer, Chris L.; Wollaeger, Ryan; Wiggins, Brandon; Even, Wesley; de la Rosa, Janie; Roming, Peter W. A.; Frey, Lucy; Young, Patrick A.; Thorpe, Rob; Powell, Luke; Landers, Rachel; Persson, Heather D.; Hay, Rebecca

    2017-09-01

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of a publicly available relational database with observational light curve, theoretical light curve, and correlation table sets with statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users upload new SN models or new SN observations and run the comparison software to determine correlations via the website. There are problems looming on the horizon that SNAP is beginning to solve. For example, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Second, there is no rapidly available, systematic way to determine degeneracies between parameters, or even what physics is needed to model a realistic SN. The correlations made within the SNAP system are beginning to solve these problems.

  19. The Supernovae Analysis Application (SNAP)

    CERN Document Server

    Bayless, Amanda J; Wiggins, Brandon; Even, Wesley; Wollaeger, Ryan; de la Rosa, Janie; Roming, Peter W A; Frey, Lucy; Young, Patrick A; Thorpe, Rob; Powell, Luke; Landers, Rachel; Persson, Heather D; Hay, Rebecca

    2016-01-01

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of an open source relational database with (a) observational light curve, (b) theoretical light curve, and (c) correlation table sets, statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users to upload new SN models or new SN observations and run the comparison software to determine correlations via the web site. There are looming problems on the horizon that SNAP begins to solve. Namely, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Secondly, there is not a rapidly available, systematic way to determine degeneracie...

  20. Fingerprints of a Local Supernova

    CERN Document Server

    Manuel, Oliver

    2009-01-01

    The results of precise analysis of elements and isotopes in meteorites, comets, the Earth, the Moon, Mars, Jupiter, the solar wind, solar flares, and the solar photosphere since 1960 reveal fingerprints of a local supernova (SN), undiluted by interstellar material. Heterogeneous SN debris formed the planets. The Sun formed on the neutron (n) rich SN core. The ground-state masses of nuclei reveal repulsive n-n interactions that trigger n-emission and a series of nuclear reactions that generate solar luminosity, the solar wind, and the measured flux of solar neutrinos. The location of the Sun's high-density core shifts relative to the solar surface as gravitational forces exerted by the major planets cause the Sun to experience abrupt acceleration and deceleration, like a yoyo on a string, in its orbit about the ever-changing centre-of-mass of the solar system. Solar cycles (surface magnetic activity, solar eruptions, and sunspots) and major climate changes arise from changes in the depth of the energetic SN co...

  1. Asymmetric Explosions of Thermonuclear Supernovae

    CERN Document Server

    Ghezzi, C R; Horváth, J E

    2004-01-01

    A type Ia supernova explosion starts in a white dwarf as a laminar deflagration at the center of the star and soon several hydrodynamic instabilities (in particular, the Rayleigh-Taylor (R-T) instability) begin to act. In previous work (Ghezzi, de Gouveia Dal Pino, & Horvath 2001), we addressed the propagation of an initially laminar thermonuclear flame in presence of a magnetic field assumed to be dipolar. We were able to show that, within the framework of a fractal model for the flame velocity, the front is affected by the field through the quenching of the R-T instability growth in the direction perpendicular to the field lines. As a consequence, an asymmetry develops between the magnetic polar and the equatorial axis that gives a prolate shape to the burning front. We have here computed numerically the total integrated asymmetry as the flame front propagates outward through the expanding shells of decreasing density of the magnetized white dwarf progenitor, for several chemical compositions, and found...

  2. Short-term effects of supernova explosions on radiocarbon production

    Energy Technology Data Exchange (ETDEWEB)

    Povinec, P. (Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta)

    1980-01-01

    The short-term increase in cosmic ray intensity caused by a supernova gamma-ray burst as well as the long-term increase resulting from corpuscular particles accelerated during the supernova explosion may be investigated by cosmogenic radiocarbon. It is shown that o.alactic supernovae exploding at distances up to 1 kpc from the Earth could cause a measurable increase in radiocarbon concentration in the past. Radiocarbon measurements for the period of the Tycho de Brahe supernova showed negative results.

  3. Progress in multi-waveband observations of supernova remnants

    Institute of Scientific and Technical Information of China (English)

    Xuejuan Yang; Fangjun Lu; Wenwu Tian

    2008-01-01

    The development of observational techniques has enriched our knowledge of supernova remnants.In this paper,we review the main progresses in the last decade,including new discoveries of supernova remnants and the associated(rare type of pulsars,nucleosynthesis,the interaction between supernova remnants and molecular clouds,dust in the supernova remnants,shock physics,and cosmic ray accelerations.

  4. GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

    Directory of Open Access Journals (Sweden)

    Manami Sasaki

    2013-12-01

    Full Text Available Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

  5. Exploring Scientists' Working Timetable: A Global Survey

    OpenAIRE

    Wang, Xianwen; Peng, Lian; Zhang, Chunbo; Xu, Shenmeng; Wang, Zhi; Wang, Chuanli; Wang, Xianbing

    2013-01-01

    In our previous study (Wang et al., 2012), we analyzed scientists' working timetable of 3 countries, using realtime downloading data of scientific literatures. In this paper, we make a through analysis about global scientists' working habits. Top 30 countries/territories from Europe, Asia, Australia, North America, Latin America and Africa are selected as representatives and analyzed in detail. Regional differences for scientists' working habits exists in different countries. Besides differen...

  6. Superluminous Supernovae: No Threat from Eta Carinae

    Science.gov (United States)

    Thomas, Brian; Melott, A. L.; Fields, B. D.; Anthony-Twarog, B. J.

    2008-05-01

    Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of 1044 Joules. It was proposed that the progenitor may have been a massive evolved star similar to η Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. η Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, η Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over 104 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous” for other reasons. However, due to reddening and extinction by the interstellar medium, η Carinae is unlikely to trigger such effects to any significant degree.

  7. Snapping Supernovae at z>1.7

    Energy Technology Data Exchange (ETDEWEB)

    Aldering, Greg; Kim, Alex G.; Kowalski, Marek; Linder, Eric V.; Perlmutter, Saul

    2006-07-03

    We examine the utility of very high redshift Type Ia supernovae for cosmology and systematic uncertainty control. Next generation space surveys such as the Supernova/Acceleration Probe (SNAP) will obtain thousands of supernovae at z>1.7, beyond the design redshift for which the supernovae will be exquisitely characterized. We find that any z gtrsim 2 standard candles' use for cosmological parameter estimation is quite modest and subject to pitfalls; we examine gravitational lensing, redshift calibration, and contamination effects in some detail. The very high redshift supernovae - both thermonuclear and core collapse - will provide copious interesting information on star formation, environment, and evolution. However, the new observational systematics that must be faced, as well as the limited expansion of SN-parameter space afforded, does not point to high value for 1.7

  8. A solar-type star polluted by calcium-rich supernova ejecta inside the supernova remnant RCW 86

    Science.gov (United States)

    Gvaramadze, Vasilii V.; Langer, Norbert; Fossati, Luca; Bock, Douglas C.-J.; Castro, Norberto; Georgiev, Iskren Y.; Greiner, Jochen; Johnston, Simon; Rau, Arne; Tauris, Thomas M.

    2017-06-01

    When a massive star in a binary system explodes as a supernova, its companion star may be polluted with heavy elements from the supernova ejecta. Such pollution has been detected in a handful of post-supernova binaries 1 , but none of them is associated with a supernova remnant. We report the discovery of a binary G star strongly polluted with calcium and other elements at the position of the candidate neutron star [GV2003] N within the young galactic supernova remnant RCW 86. Our discovery suggests that the progenitor of the supernova that produced RCW 86 could have been a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass because of common-envelope evolution shortly before core collapse, and that the supernova explosion might belong to the class of calcium-rich supernovae — faint and fast transients 2,3 , the origin of which is strongly debated 4-6 .

  9. Investigations of supernovae and supernova remnants in the era of SKA

    CERN Document Server

    Wang, Lingzhi; Zhu, Hui; Tian, Wenwu; Wang, Xiaofeng

    2015-01-01

    Two main physical mechanisms are used to explain supernova explosions: thermonuclear explosion of a white dwarf(Type Ia) and core collapse of a massive star (Type II and Type Ib/Ic). Type Ia supernovae serve as distance indicators that led to the discovery of the accelerating expansion of the Universe. The exact nature of their progenitor systems however remain unclear. Radio emission from the interaction between the explosion shock front and its surrounding CSM or ISM provides an important probe into the progenitor star's last evolutionary stage. No radio emission has yet been detected from Type Ia supernovae by current telescopes. The SKA will hopefully detect radio emission from Type Ia supernovae due to its much better sensitivity and resolution. There is a 'supernovae rate problem' for the core collapse supernovae because the optically dim ones are missed due to being intrinsically faint and/or due to dust obscuration. A number of dust-enshrouded optically hidden supernovae should be discovered via SKA1-...

  10. Supernova remnants, pulsar wind nebulae and their interaction

    NARCIS (Netherlands)

    Swaluw, E. van der

    2001-01-01

    A supernova explosion marks the end of the evolution of a massive star. What remains of the exploded star is a high density neutron star or a black hole. The material which has been ejected by the supernova explosion will manifest itself as a supernova remnant: a hot bubble of gas expanding in the

  11. The destruction of cosmological minihalos by primordial supernovae

    NARCIS (Netherlands)

    Whalen, D.; van Veelen, B.; O'Shea, B.W.; Norman, M.L.

    2008-01-01

    We present numerical simulations of primordial supernovae in cosmological minihalos at z ~ 20. We consider Type II supernovae, hypernovae, and pair instability supernovae (PISN) in halos from 6.9 × 105 to 1.2 × 107 M, those in which Population III stars are expected to form via H2 cooling. Our simul

  12. A 3D View of a Supernova Remnant

    Science.gov (United States)

    Kohler, Susanna

    2017-06-01

    The outlined regions mark the 57 knots in Tycho selected by the authors for velocity measurements. Magenta regions have redshifted line-of-sight velocities (moving away from us); cyan regions have blueshifted light-of-sight velocities (moving toward us). [Williams et al. 2017]The Tycho supernova remnant was first observed in the year 1572. Nearly 450 years later, astronomers have now used X-ray observations of Tycho to build the first-ever 3D map of a Type Ia supernova remnant.Signs of ExplosionsSupernova remnants are spectacular structures formed by the ejecta of stellar explosions as they expand outwards into the surrounding interstellar medium.One peculiarity of these remnants is that they often exhibit asymmetries in their appearance and motion. Is this because the ejecta are expanding into a nonuniform interstellar medium? Or was the explosion itself asymmetric? The best way we can explore this question is with detailed observations of the remnants.Histograms of the velocity in distribution of the knots in the X (green), Y (blue) and Z (red) directions (+Z is away from the observer). They show no evidence for asymmetric expansion of the knots. [Williams et al. 2017]Enter TychoTo this end, a team of scientists led by Brian Williams (Space Telescope Science Institute and NASA Goddard SFC) has worked to map out the 3D velocities of the ejecta in the Tycho supernova remnant. Tycho is a Type Ia supernova thought to be caused by the thermonuclear explosion of a white dwarf in a binary system that was destabilized by mass transfer from its companion.After 450 years of expansion, the remnant now has the morphological appearance of a roughly circular cloud of clumpy ejecta. The forward shock wave from the supernova, however, is known to have twice the velocity on one side of the shell as on the other.To better understand this asymmetry, Williams and collaborators selected a total of 57 knots in Tychos ejecta, spread out around the remnant. They then used 12 years of

  13. Electron capture in carbon dwarf supernovae

    Science.gov (United States)

    Mazurek, T. J.; Truran, J. W.; Cameron, A. G. W.

    1974-01-01

    The rates of electron capture on heavier elements under the extreme conditions predicted for dwarf star supernovae have been computed, incorporating modifications that seem to be indicated by present experimental results. An estimate of the maximum possible value of such rates is also given. The distribution of nuclei in nuclear statistical equilibrium has been calculated for the range of expected supernovae conditions, including the effects of the temperature dependence of nuclear partition functions. These nuclide abundance distributions are then used to compute nuclear equilibrium thermodynamic properties. The effects of the electron capture on such equilibrium matter are discussed. In the context of the 'carbon detonation' supernova model, the dwarf central density required to ensure core collapse to a neutron star configuration is found to be slightly higher than that obtained by Bruenn (1972) with the electron capture rates of Hansen (1966).-

  14. Supernova Recognition using Support Vector Machines

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Raquel A.; Aragon, Cecilia R.; Ding, Chris

    2006-10-01

    We introduce a novel application of Support Vector Machines(SVMs) to the problem of identifying potential supernovae usingphotometric and geometric features computed from astronomical imagery.The challenges of this supervised learning application are significant:1) noisy and corrupt imagery resulting in high levels of featureuncertainty,2) features with heavy-tailed, peaked distributions,3)extremely imbalanced and overlapping positiveand negative data sets, and4) the need to reach high positive classification rates, i.e. to find allpotential supernovae, while reducing the burdensome workload of manuallyexamining false positives. High accuracy is achieved viaasign-preserving, shifted log transform applied to features with peaked,heavy-tailed distributions. The imbalanced data problem is handled byoversampling positive examples,selectively sampling misclassifiednegative examples,and iteratively training multiple SVMs for improvedsupernovarecognition on unseen test data. We present crossvalidationresults and demonstrate the impact on a largescale supernova survey thatcurrently uses the SVM decision value to rank-order 600,000 potentialsupernovae each night.

  15. Probing Exotic Physics With Supernova Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Chris; Hooper, Dan

    2010-09-01

    Future galactic supernovae will provide an extremely long baseline for studying the properties and interactions of neutrinos. In this paper, we discuss the possibility of using such an event to constrain (or discover) the effects of exotic physics in scenarios that are not currently constrained and are not accessible with reactor or solar neutrino experiments. In particular, we focus on the cases of neutrino decay and quantum decoherence. We calculate the expected signal from a core-collapse supernova in both current and future water Cerenkov, scintillating, and liquid argon detectors, and find that such observations will be capable of distinguishing between many of these scenarios. Additionally, future detectors will be capable of making strong, model-independent conclusions by examining events associated with a galactic supernova's neutronization burst.

  16. Supernova Neutrinos: Production, Oscillations and Detection

    CERN Document Server

    Mirizzi, Alessandro; Janka, Hans-Thomas; Saviano, Ninetta; Scholberg, Kate; Bollig, Robert; Hudepohl, Lorenz; Chakraborty, Sovan

    2015-01-01

    Neutrinos play a crucial role in the collapse and explosion of massive stars, governing the infall dynamics of the stellar core, triggering and fueling the explosion and driving the cooling and deleptonization of the newly formed neutron star. Due to their role neutrinos carry information from the heart of the explosion and, due to their weakly interacting nature, offer the only direct probe of the dynamics and thermodynamics at the center of a supernova. In this paper, we review the present status of modelling the neutrino physics and signal formation in collapsing and exploding stars. We assess the capability of current and planned large underground neutrino detectors to yield faithful information of the time and flavor dependent neutrino signal from a future Galactic supernova. We show how the observable neutrino burst would provide a benchmark for fundamental supernova physics with unprecedented richness of detail. Exploiting the treasure of the measured neutrino events requires a careful discrimination o...

  17. Supernova discoveries 2010: statistics and trends

    CERN Document Server

    Gal-Yam, Avishay

    2013-01-01

    We have inspected all supernova discoveries reported during 2010, a total of 538 events. This number includes a small number of "supernova impostors" (bright extragalactic eruptions) but not novae or events that turned out to be Galactic stars. We examine the statistics of all discovered objects, as well as those of the subset of spectroscopically-confirmed events. This year shows the rise of wide-field non-targeted supernova surveys to prominence, with the largest numbers of events contributed by the CRTS and PTF surveys (189 and 88 events respectively), followed by the integrated contribution of numerous amateurs (82 events). Among spectroscopically-confirmed events the PTF (88 events) leads, before amateur discoveries (69 events), closely followed by the CRTS and PS1 surveys (67 and 63 events, respectively). Traditional galaxy-targeted surveys such as LOSS and CHASE, maintain a strong contribution (50 and 36 events, respectively) with high spectroscopic completeness (96% for LOSS). It is interesting to not...

  18. Deep Recurrent Neural Networks for Supernovae Classification

    Science.gov (United States)

    Charnock, Tom; Moss, Adam

    2017-03-01

    We apply deep recurrent neural networks, which are capable of learning complex sequential information, to classify supernovae (code available at https://github.com/adammoss/supernovae). The observational time and filter fluxes are used as inputs to the network, but since the inputs are agnostic, additional data such as host galaxy information can also be included. Using the Supernovae Photometric Classification Challenge (SPCC) data, we find that deep networks are capable of learning about light curves, however the performance of the network is highly sensitive to the amount of training data. For a training size of 50% of the representational SPCC data set (around 104 supernovae) we obtain a type-Ia versus non-type-Ia classification accuracy of 94.7%, an area under the Receiver Operating Characteristic curve AUC of 0.986 and an SPCC figure-of-merit F 1 = 0.64. When using only the data for the early-epoch challenge defined by the SPCC, we achieve a classification accuracy of 93.1%, AUC of 0.977, and F 1 = 0.58, results almost as good as with the whole light curve. By employing bidirectional neural networks, we can acquire impressive classification results between supernovae types I, II and III at an accuracy of 90.4% and AUC of 0.974. We also apply a pre-trained model to obtain classification probabilities as a function of time and show that it can give early indications of supernovae type. Our method is competitive with existing algorithms and has applications for future large-scale photometric surveys.

  19. THE LOW-REDSHIFT CARNEGIE SUPERNOVA PROJECT

    Directory of Open Access Journals (Sweden)

    G. Folatelli

    2009-01-01

    Full Text Available We present the low-redshift Carnegie Supernova Project (CSP, an undergoing program to follow up about 250 nearby supernovae (SNe of all types. We brie y describe the observations which yield well-sampled, highly precise optical and near-infrared light curves in a well-understood photometric system, complemented with optical spectroscopy. As one of the main goals of the CSP, we preliminarily present the rst Hubble diagram using a sample of 30 Type-Ia SNe (SNe Ia.

  20. Spectroscopy of superluminous supernova host galaxies

    DEFF Research Database (Denmark)

    Leloudas, G.; Kruehler, T.; Schulze, S

    2015-01-01

    Superluminous supernovae (SLSNe) are very bright explosions that were only discovered recently and that show a preference for occurring in faint dwarf galaxies. Understanding why stellar evolution yields different types of stellar explosions in these environments is fundamental in order to both...... uncover the elusive progenitors of SLSNe and to study star formation in dwarf galaxies. In this paper, we present the first results of our project to study SUperluminous Supernova Host galaxIES, focusing on the sample for which we have obtained spectroscopy. We show that SLSNe-I and SLSNe-R (hydrogen...

  1. Collective Oscillations and Diffuse Supernova Neutrino Background

    Science.gov (United States)

    Kar, Kamales; Chakraborty, Sovan; Choubey, Sandhya

    2012-01-01

    Core-collapse supernova explosions give rise to the emission of a huge flux of neutrinos of all flavors. In this article we describe the phenomenon neutrino-neutrino interaction of these weakly interacting particles at the very high density central region of the stellar core giving rise to non-linear collective oscillations in both the neutrino and antineutrino sectors. The effect of the collective oscillations on the Diffuse Supernova Neutrino Background is elaborated with emphasis on its future detection and the connection of that to neutrino mass hierarchy.

  2. Absolute-Magnitude Distributions of Supernovae

    CERN Document Server

    Richardson, Dean; Wright, John; Maddox, Larry

    2014-01-01

    The absolute-magnitude distributions of seven supernova types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (M_B -15) make up about 3%. The normal Ia distribution was the brightest with a mean absolute blue magnitude of -19.25. The IIP distribution was the dimmest at -16.75.

  3. Formation of Nuclear "Pasta" in Supernovae

    CERN Document Server

    Watanabe, Gentaro; Maruyama, Toshiki; Sato, Katsuhiko; Yasuoka, Kenji; Ebisuzaki, Toshikazu

    2009-01-01

    In supernova cores, nuclear "pasta" phases such as triangular lattice of rod-like nuclei and layered structure of slab-like nuclei are considered to exist. However, it is still unclear whether or not they are actually formed in collapsing supernova cores. Using {\\it ab-initio} numerical simulations called the Quantum Molecular Dynamics (QMD), we here solve this problem by demonstrating that a lattice of rod-like nuclei is formed from a bcc lattice by compression. We also find that, in the transition process, the system undergoes zigzag configuration of elongated nuclei, which are formed by a fusion of two original spherical nuclei.

  4. Deflagrations and Detonations in Thermonuclear Supernovae

    CERN Document Server

    Gamezo, V N; Oran, E S; Gamezo, Vadim N.; Khokhlov, Alexei M.; Oran, Elaine S.

    2004-01-01

    We study a type Ia supernova explosion using three-dimensional numerical simulations based on reactive fluid dynamics. We consider a delayed-detonation model that assumes a deflagration-to-detonation transition. In contrast to the pure deflagration model, the delayed-detonation model releases enough energy to account for a healthy explosion, and does not leave carbon, oxygen, and intermediate-mass elements in central parts of a white dwarf. This removes the key disagreement between simulations and observations, and makes a delayed detonation the mostly likely mechanism for type Ia supernovae.

  5. Analysis as border patrol: chemists along the boundary between pure food and real adulteration.

    Science.gov (United States)

    Cohen, Benjamin R

    2011-06-01

    A disputed butter competition in Pennsylvania in 1895 brought the cultural, environmental, and scientific character of the Era of Adulteration to the fore. The incident put a spotlight on the confusing character of adulteration and the increasingly prominent role of chemical analysts in arbitrating that confusion. This article uses the case to explore the role scientific analysts played on the border between pure food products and adulterated ones, arguing that the scientists fighting adulteration gained credibility within a cultural environment where trust and confidence were problematic and an agricultural environment where spatial connections between producers and consumers were difficult to see. They were not just detectors of chemical impurities, but participants in a vital cultural arbitration. Characterizing them for their cultural role helps demonstrate that their practices and identity were (and remain) relevant for more than just detection and eradication, then and in the future. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. How Middle Schoolers Draw Engineers and Scientists

    Science.gov (United States)

    Fralick, Bethany; Kearn, Jennifer; Thompson, Stephen; Lyons, Jed

    2009-01-01

    The perceptions young students have of engineers and scientists are often populated with misconceptions and stereotypes. Although the perceptions that young people have of engineers and of scientists have been investigated separately, they have not been systematically compared. The research reported in this paper explores the question "How are…

  7. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables Ask a Scientist Video Series ...

  8. Chinese, US scientists find new particle

    CERN Multimedia

    2003-01-01

    "Chinese and US scientists have discovered a new particle at the Beijing Electron Position Collider, which is hard to be explained with any known particles, according to scientists from the Institute of High Energy Physics under the Chinese Academy of Sciences Wednesday" (1/2 page).

  9. Tens of Romanian scientists work at CERN

    CERN Multimedia

    Silian, Sidonia

    2007-01-01

    "The figures regarding the actual number of Romanian scientists working at the European Center for Nuclear Research, or CERN, differ. The CERN data base lists some 30 Romanians on its payroll, while the scientists with the Nuclear Center at Magurele, Romania, say they should be around 50." (1 page)

  10. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables Ask a Scientist Video Series ...

  11. How Scientists Develop Competence in Visual Communication

    Science.gov (United States)

    Ostergren, Marilyn

    2013-01-01

    Visuals (maps, charts, diagrams and illustrations) are an important tool for communication in most scientific disciplines, which means that scientists benefit from having strong visual communication skills. This dissertation examines the nature of competence in visual communication and the means by which scientists acquire this competence. This…

  12. Response: Training Doctoral Students to Be Scientists

    Science.gov (United States)

    Pollio, David E.

    2012-01-01

    The purpose of this article is to begin framing doctoral training for a science of social work. This process starts by examining two seemingly simple questions: "What is a social work scientist?" and "How do we train social work scientists?" In answering the first question, some basic assumptions and concepts about what constitutes a "social work…

  13. Reducing Zero-point Systematics in Dark Energy Supernova Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, Lorenzo; Kim, Alex G; Miquel, Ramon; Bernstein, Gary; Bonissent, Alain; Brown, Matthew; Carithers, William; Christiansen, Jodi; Connolly, Natalia; Deustua, Susana; Gerdes, David; Gladney, Larry; Kushner, Gary; Linder, Eric; McKee, Shawn; Mostek, Nick; Shukla, Hemant; Stebbins, Albert; Stoughton, Chris; Tucker, David

    2011-04-01

    We study the effect of filter zero-point uncertainties on future supernova dark energy missions. Fitting for calibration parameters using simultaneous analysis of all Type Ia supernova standard candles achieves a significant improvement over more traditional fit methods. This conclusion is robust under diverse experimental configurations (number of observed supernovae, maximum survey redshift, inclusion of additional systematics). This approach to supernova fitting considerably eases otherwise stringent mission cali- bration requirements. As an example we simulate a space-based mission based on the proposed JDEM satellite; however the method and conclusions are general and valid for any future supernova dark energy mission, ground or space-based.

  14. Type Ia supernova rate studies from the SDSS-II Supernova Study

    Energy Technology Data Exchange (ETDEWEB)

    Dilday, Benjamin [Univ. of Chicago, IL (United States)

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  15. SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators

    CERN Document Server

    Guy, J; Baumont, S; Hardin, D; Pain, R; Regnault, N; Basa, S; Carlberg, R G; Conley, A; Fabbro, S; Fouchez, D; Hook, I M; Howell, D A; Perrett, K; Pritchet, C J; Rich, J; Sullivan, M; Antilogus, P; Aubourg, E; Bazin, G; Bronder, J; Filiol, M; Palanque-Delabrouille, Nathalie; Ripoche, P; Ruhlmann-Kleider, V

    2007-01-01

    We present an empirical model of Type Ia supernovae spectro-photometric evolution with time. The model is built using a large data set including light-curves and spectra of both nearby and distant supernovae, the latter being observed by the SNLS collaboration. We derive the average spectral sequence of Type Ia supernovae and their main variability components including a color variation law. The model allows us to measure distance moduli in the spectral range 2500-8000 A with calculable uncertainties, including those arising from variability of spectral features. Thanks to the use of high-redshift SNe to model the rest-frame UV spectral energy distribution, we are able to derive improved distance estimates for SNe Ia in the redshift range 0.8supernovae.

  16. Analyzing Prospective Teachers' Images of Scientists Using Positive, Negative and Stereotypical Images of Scientists

    Science.gov (United States)

    Subramaniam, Karthigeyan; Harrell, Pamela Esprivalo; Wojnowski, David

    2013-01-01

    Background and purpose: This study details the use of a conceptual framework to analyze prospective teachers' images of scientists to reveal their context-specific conceptions of scientists. The conceptual framework consists of context-specific conceptions related to positive, stereotypical and negative images of scientists as detailed in the…

  17. Echoes from Ancient supernovae in the Large Magellanic Cloud

    Energy Technology Data Exchange (ETDEWEB)

    Rest, A; Suntzeff, N B; Olsen, K; Prieto, J L; Smith, R C; Welch, D L; Becker, A; Bergmann, M; Clocchiatti, A; Cook, K; Garg, A; Huber, M; Miknaitis, G; Minniti, D; Nikolaev, S; Stubbs, C

    2005-06-15

    In principle, historical supernovae could still be visible as scattered-light echoes even centuries later [1, 2]. Searches for surface brightness variations using photographic plates have not recovered any echoes in the regions of historical Galactic supernovae [3]. Using differenced images, our SuperMACHO collaboration has discovered three faint new variable surface brightness complexes with high apparent proper motion pointing back to well-defined positions in the Large Magellanic Cloud (LMC). These correspond to three of the six smallest (and likely youngest) supernova remnants believed to be due to thermonuclear (Type Ia) supernovae [4]. A lower limit to the age of these remnants and echoes is 200 years given the lack of any reported LMC supernovae until 1987. The discovery of historical supernova echoes in the LMC suggests that similar echoes for Galactic supernovae such as Tycho, Kepler, Cas A, or SN1006 could be visible using standard image differencing techniques.

  18. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.

  19. The ASAS-SN Bright Supernova Catalog $-$ II. 2015

    CERN Document Server

    Holoien, T W -S; Stanek, K Z; Kochanek, C S; Shappee, B J; Prieto, J L; Dong, Subo; Brimacombe, J; Bishop, D W; Basu, U; Beacom, J F; Bersier, D; Chen, Ping; Danilet, A B; Falco, E; Godoy-Rivera, D; Goss, N; Pojmanski, G; Simonian, G V; Skowron, D M; Thompson, Todd A; Woźniak, P R; Avíla, C G; Bock, G; Carballo, J -L G; Conseil, E; Contreras, C; Cruz, I; andújar, J M F; Guo, Zhen; Hsiao, E Y; Kiyota, S; Koff, R A; Krannich, G; Madore, B F; Marples, P; Masi, G; Morrell, N; Monard, L A G; Munoz-Mateos, J C; Nicholls, B; Nicolas, J; Wagner, R M; Wiethoff, W S

    2016-01-01

    This manuscript presents information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during 2015, its second full year of operations. The same information is presented for bright ($m_V\\leq17$), spectroscopically confirmed supernovae discovered by other sources in 2015. As with the first ASAS-SN bright supernova catalog, we also present redshifts and near-UV through IR magnitudes for all supernova host galaxies in both samples. Combined with our previous catalog, this work comprises a complete catalog of 455 supernovae from multiple professional and amateur sources, allowing for population studies that were previously impossible. This is the second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

  20. The ASAS-SN Bright Supernova Catalog - II. 2015

    Science.gov (United States)

    Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Basu, U.; Beacom, J. F.; Bersier, D.; Chen, Ping; Danilet, A. B.; Falco, E.; Godoy-Rivera, D.; Goss, N.; Pojmanski, G.; Simonian, G. V.; Skowron, D. M.; Thompson, Todd A.; Woźniak, P. R.; Ávila, C. G.; Bock, G.; Carballo, J.-L. G.; Conseil, E.; Contreras, C.; Cruz, I.; Andújar, J. M. F.; Guo, Zhen; Hsiao, E. Y.; Kiyota, S.; Koff, R. A.; Krannich, G.; Madore, B. F.; Marples, P.; Masi, G.; Morrell, N.; Monard, L. A. G.; Munoz-Mateos, J. C.; Nicholls, B.; Nicolas, J.; Wagner, R. M.; Wiethoff, W. S.

    2017-01-01

    This manuscript presents information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during 2015, its second full year of operations. The same information is presented for bright (mV ≤ 17), spectroscopically confirmed supernovae discovered by other sources in 2015. As with the first ASAS-SN bright supernova catalog, we also present redshifts and near-UV through IR magnitudes for all supernova host galaxies in both samples. Combined with our previous catalog, this work comprises a complete catalog of 455 supernovae from multiple professional and amateur sources, allowing for population studies that were previously impossible. This is the second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

  1. Supernova Feedback in Molecular Clouds: Global Evolution and Dynamics

    CERN Document Server

    Körtgen, Bastian; Banerjee, Robi; Vázquez-Semadeni, Enrique; Zamora-Avilés, Manuel

    2016-01-01

    We use magnetohydrodynamical simulations of converging warm neutral medium flows to analyse the formation and global evolution of magnetised and turbulent molecular clouds subject to supernova feedback from massive stars. We show that supernova feedback alone fails to disrupt entire, gravitationally bound, molecular clouds, but is able to disperse small--sized (~10 pc) regions on timescales of less than 1 Myr. Efficient radiative cooling of the supernova remnant as well as strong compression of the surrounding gas result in non-persistent energy and momentum input from the supernovae. However, if the time between subsequent supernovae is short and they are clustered, large hot bubbles form that disperse larger regions of the parental cloud. On longer timescales, supernova feedback increases the amount of gas with moderate temperatures (T~300-3000 K). Despite its inability to disrupt molecular clouds, supernova feedback leaves a strong imprint on the star formation process. We find an overall reduction of the ...

  2. The Carnegie Supernova Project: The Low-Redshift Survey

    CERN Document Server

    Hamuy, M; Morrell, N I; Phillips, M M; Suntzeff, N B; Persson, S E; Roth, M; González, S; Krzeminski, W; Contreras, C S; Freedman, W L; Murphy, D C; Madore, B F; Wyatt, P; Maza, J; Filippenko, A V; Li, W; Pinto, P A; Hamuy, Mario; Folatelli, Gast\\'on; Morrell, Nidia I.; Phillips, Mark M.; Suntzeff, Nicholas B.; Roth, Miguel; Gonzalez, Sergio; Krzeminski, Wojtek; Contreras, Carlos; Freedman, Wendy L.; Madore, Barry F.; Maza, Jos\\'{e}; Filippenko, Alexei V.; Li, Weidong

    2005-01-01

    Supernovae are essential to understanding the chemical evolution of the Universe. Type Ia supernovae also provide the most powerful observational tool currently available for studying the expansion history of the Universe and the nature of dark energy. Our basic knowledge of supernovae comes from the study of their photometric and spectroscopic properties. However, the presently available data sets of optical and near-infrared light curves of supernovae are rather small and/or heterogeneous, and employ photometric systems that are poorly characterized. Similarly, there are relatively few supernovae whose spectral evolution has been well sampled, both in wavelength and phase, with precise spectrophotometric observations. The low-redshift portion of the Carnegie Supernova Project (CSP) seeks to remedy this situation by providing photometry and spectrophotometry of a large sample of supernovae taken on telescope/filter/detector systems that are well understood and well characterized. During a five-year program w...

  3. X-ray studies of supernova remnants: A different view of supernova explosions

    OpenAIRE

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent data sets accumulated on young, ejecta dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints o...

  4. Supernova 1987A: a Template to Link Supernovae to their Remnants

    CERN Document Server

    Orlando, S; Pumo, M L; Bocchino, F

    2015-01-01

    The emission of supernova remnants reflects the properties of both the progenitor supernovae and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the supernova. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15000 after the supernova. We demonstrated that the physical model reproducing the main observables of SN 1987A during the first 250 days of evolution reproduces also the X-ray emission of the subsequent expanding remnant, thus bridging the gap between supernovae and supernova remnants. By comparing model results with observations, we constrained the explosion energy in the range $1.2-1.4\\times 10^{51}$~erg and the envelope mass in the rang...

  5. A capability-based approach to analyzing the effectiveness and robustness of an offshore patrol vessel in the search and rescue mission

    OpenAIRE

    Ashpari, Mohammad

    2012-01-01

    Approved for public release; distribution is unlimited. In this thesis, a model of effectiveness for an offshore patrol vessel conducting search and rescue missions is developed and described. Beginning with a brief overview of work done by colleagues from the University of Genoa, Italy, as well as documents currently in use by the United States Navy and Coast Guard for search and rescue, this thesis provides a link between physical ship design factors and the operational effectiveness of ...

  6. The ultraviolet properties of supernovae

    Science.gov (United States)

    Brown, Peter J.

    2009-09-01

    Ultraviolet (UV) observations of supernovae (SNe) probe an important wavelength region where hot temperatures, extinction, and metallicity have strong effects. In addition, they provide a comparison set against which to compare and better understand rest frame UV observations of high redshift SNe observed in the optical. UV observations, however, are rare due to the need for telescopes above the atmosphere and the difficulty in observing transient objects with space based observatories. Limited observations with space based observatories, primarily the International Ultraviolet Explorer and the Hubble Space Telescope, are reviewed, after which the Ultra-Violet/Optical Telescope (UVOT) on the Swift spacecraft is introduced. With Swift we have observed more SNe than all previous UV missions combined. Case studies of two individual SNe are first presented: SNe 2005am and 2005cs. SN 2005am is the first young SN observed with Swift, and the near-UV (uvw1: central wavelength ~ 2600 λ) light curve is consistent with the previous "template" derived from IUE and HST observations of SNe 1990N and 1992A. SN 2005cs is the first plateau-type II (IIP) with a well observed UV light curve. UVOT observations show a dramatic drop in the UV brightness and shift in the spectral energy distribution from blue to red caused by the dropping temperature and resulting line blanketing in the UV. These case studies demonstrate the information available from the UV data for individual SNe. A photometry method for proper accounting of coincidence loss, aperture corrections, and subtraction of the underlying galaxy is detailed. This method is then applied to a large sample of SNe observed with UVOT. We present 25 light curves and compare SNe by type and across types. The SNe Ia, with a few exceptions, are shown to have very similar light curves in the near UV, whereas, the three SNe Ib/c we have observed are very different. The SNe IIP all have rapidly fading UV light curves, though with

  7. Probable Bright Supernova discovered by PSST

    Science.gov (United States)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Young, D. R.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-09-01

    A bright transient, which is a probable supernova, has been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  8. Explosions inside Ejecta and Most Luminous Supernovae

    CERN Document Server

    Blinnikov, S I

    2008-01-01

    The extremely luminous supernova SN2006gy is explained in the same way as other SNIIn events: light is produced by a radiative shock propagating in a dense circumstellar envelope formed by a previous weak explosion. The problems in the theory and observations of multiple-explosion SNe IIn are briefly reviewed.

  9. Did Egret Detect Distant Supernova Remnants?

    CERN Document Server

    Torres, D F; Dame, T M; Combi, J A; Butt, Y M; Torres, Diego F.; Romero, Gustavo E.; Dame, Thomas M.; Combi, Jorge A.; Butt, Yousaf M.

    2004-01-01

    It might be thought that supernova remnants (SNRs) more distant than a few kiloparsec from Earth could not have been detected by the EGRET experiment. This work analyzes the observational status of this statement in the light of new CO studies of SNRs.

  10. Multipole expansion method for supernova neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Huaiyu; Shalgar, Shashank, E-mail: duan@unm.edu, E-mail: shashankshalgar@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-10-01

    We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.

  11. Ultraviolet diversity of Type Ia Supernovae

    DEFF Research Database (Denmark)

    Foley, Ryan J.; Pan, Yen-Chen; Brown, P.;

    2016-01-01

    Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the outermost layers of the explosion, and UV spectra of SNe Ia are expected to be extremely sensitive to differences in progenitor composition and the details of the explosion. Here, we present the first study of a sample of high...

  12. First stars, hypernovae, and superluminous supernovae

    Science.gov (United States)

    Nomoto, Ken'Ichi

    2016-07-01

    After the big bang, production of heavy elements in the early universe takes place starting from the formation of the first (Pop III) stars, their evolution, and explosion. The Pop III supernova (SN) explosions have strong dynamical, thermal, and chemical feedback on the formation of subsequent stars and evolution of galaxies. However, the nature of Pop III stars/supernovae (SNe) have not been well-understood. The signature of nucleosynthesis yields of the first SN can be seen in the elemental abundance patterns observed in extremely metal-poor (EMP) stars. We show that the abundance patterns of EMP stars, e.g. the excess of C, Co, Zn relative to Fe, are in better agreement with the yields of hyper-energetic explosions (Hypernovae, (HNe)) rather than normal supernovae. We note the large variation of the abundance patterns of EMP stars propose that such a variation is related to the diversity of the GRB-SNe and posssibly superluminous supernovae (SLSNe). For example, the carbon-enhanced metal-poor (CEMP) stars may be related to the faint SNe (or dark HNe), which could be the explosions induced by relativistic jets. Finally, we examine the various mechanisms of SLSNe.

  13. Einstein Observations of Galactic supernova remnants

    Science.gov (United States)

    Seward, Frederick D.

    1990-01-01

    This paper summarizes the observations of Galactic supernova remnants with the imaging detectors of the Einstein Observatory. X-ray surface brightness contours of 47 remnants are shown together with gray-scale pictures. Count rates for these remnants have been derived and are listed for the HRI, IPC, and MPC detectors.

  14. Are Ti44-Producing Supernovae Exceptional?

    CERN Document Server

    The, L S; Diehl, R; Hartmann, D H; Iyudin, A F; Leising, M D; Meyer, B S; Motizuki, Y; Schönfelder, V

    2006-01-01

    According to standard models supernovae produce radioactive $^{44}$Ti, which should be visible in gamma-rays following decay to $^{44}$Ca for a few centuries. $^{44}Ti production is believed to be the source of cosmic $^{44}$Ca, whose abundance is well established. Yet, gamma-ray telescopes have not seen the expected young remnants of core collapse events. The $^{44}$Ti mean life of $\\tau \\simeq$ 89 y and the Galactic supernova rate of $\\simeq$ 3/100 y imply $\\simeq$ several detectable $^{44}Ti gamma-ray sources, but only one is clearly seen, the 340-year-old Cas A SNR. Furthermore, supernovae which produce much $^{44}Ti are expected to occur primarily in the inner part of the Galaxy, where young massive stars are most abundant. Because the Galaxy is transparent to gamma-rays, this should be the dominant location of expected gamma-ray sources. Yet the Cas A SNR as the only one source is located far from the inner Galaxy (at longitude 112 degree). We evaluate the surprising absence of detectable supernovae fro...

  15. Deep Recurrent Neural Networks for Supernovae Classification

    CERN Document Server

    Charnock, Tom

    2016-01-01

    We apply deep recurrent neural networks, which are capable of learning complex sequential information, to classify supernovae. The observational time and filter fluxes are used as inputs to the network, but since the inputs are agnostic additional data such as host galaxy information can also be included. Using the Supernovae Photometric Classification Challenge (SPCC) data, we find that deep networks are capable of learning about light curves, however the performance of the network is highly sensitive to the amount of training data. For a training size of 50% of the representational SPCC dataset (around 104 supernovae) we obtain a type Ia vs non type Ia classification accuracy of 94.8%, an area under the Receiver Operating Characteristic curve AUC of 0.986 and a SPCC figure-of-merit F1 = 0.64. We also apply a pre-trained model to obtain classification probabilities as a function of time, and show it can give early indications of supernovae type. Our method is competitive with existing algorithms and has appl...

  16. Essential ingredients in core-collapse supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Hix, W. Raphael [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Lentz, Eric J.; Chertkow, M. Austin; Harris, J. Austin [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Endeve, Eirik [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Baird, Mark [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6003 (United States); Messer, O. E. Bronson [Physics Division, Oak Ridge National Laboratory, Oak Ridge TN 37831-6354 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831-6008 (United States); Mezzacappa, Anthony [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Joint Institute for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6173 (United States); Bruenn, Stephen [Department of Physics, Florida Atlantic University, 777 W Glades Road, Boca Raton, FL 33431-0991 (United States); Blondin, John [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States)

    2014-04-15

    Carrying 10{sup 44} joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  17. Supernovae and high density nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state (EOS) in producing prompt supernova explosions is examined. Results of calculations of Baron, Cooperstein, and Kahana incorporating general relativity and a new high density EOS are presented, and the relevance of these calculations to laboratory experiments with heavy ions considered. 31 refs., 6 figs., 2 tabs.

  18. Essential ingredients in core-collapse supernovae

    Directory of Open Access Journals (Sweden)

    W. Raphael Hix

    2014-03-01

    Full Text Available Carrying 1044 joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  19. Mutual influence of supernovae and molecular clouds

    CERN Document Server

    Iffrig, Olivier

    2014-01-01

    Context. Molecular clouds are known to be turbulent and strongly affected by stellar feedback. Moreover, stellar feedback is believed to be driving turbulence at large scales in galaxies. Aims. We study the role played by supernovae in molecular clouds and the influence of the magnetic field on this process. Methods. We perform three-dimensional numerical simulations of supernova explosions, in and near turbulent self-gravitating molecular clouds. In order to study the influence of the magnetic field, we perform both hydrodynamical and MHD simulations. We also run a series of simple uniform density medium simulations and develop a simple analytical model. Results. We find that the total amount of momentum that is delivered during supernova explosions typically varies by a factor of about 2 even when the gas density changes by 3 orders of magnitude. However, the amount of momentum delivered to the dense gas varies by almost a factor 10 if the supernova explodes within or outside the molecular cloud. The magnet...

  20. A catalogue of 294 Galactic supernova remnants

    CERN Document Server

    Green, D A

    2014-01-01

    A revised catalogue of 294 Galactic supernova remnants (SNRs) is presented, along with some simple statistics. This catalogue has twenty more entries than did the previous version (from 2009), as 21 new remnants have been added, and one object has been removed as it has been identified as an HII region.

  1. Rayleigh-Taylor mixing in supernova experiments

    Energy Technology Data Exchange (ETDEWEB)

    Swisher, N. C.; Abarzhi, S. I., E-mail: snezhana.abarzhi@gmail.com [Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Kuranz, C. C. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Arnett, D. [University of Arizona, Tucson, Arizona 85721 (United States); Hurricane, O.; Remington, B. A.; Robey, H. F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-10-15

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order.

  2. Evidence for strange matter in supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, O.G.; Horvath, J.E. (Facultad de Ciencias Astronomicas y Geofiiaasicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina de La Plata, Calle 49 y 115, Casilla de Correo 67, 1900 La Plata, Argentina (AR))

    1989-08-14

    With the aim of overcoming the present energetic difficulties in getting type-II supernovae explosions, we present a possible scenario based on strange-matter formation. The observational expectations of this picture are discussed and the predictions of the model for SN 1987A neutrinos and remnant pulsar are examined.

  3. Classification of 9 DES supernova by Magellan

    Science.gov (United States)

    Challis, P.; Kirshner, R.; Mandel, K.; Avelino, A.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.

    2016-09-01

    We report optical spectroscopy of 9 supernovae discovered by the Dark Energy Survey (ATel #4668). The spectra were obtained using LDSS-3C (covering 420-950nm) on the 6.5m Clay telescope at the Las Campanas Observatory.

  4. Clustering of supernova Ia host galaxies

    CERN Document Server

    Carlberg, R G; Le Borgne, D; Conley, A; Howell, D A; Perrett, K; Astier, Pierre; Balam, D; Balland, C; Basa, S; Hardin, D; Fouchez, D; Guy, J; Hook, I; Pain, R; Pritchet, C J; Regnault, N; Rich, J; Perlmutter, S

    2008-01-01

    For the first time the cross-correlation between type Ia supernova host galaxies and surrounding field galaxies is measured using the Supernova Legacy Survey sample. Over the z=0.2 to 0.9 redshift range we find that supernova hosts are correlated an average of 60% more strongly than similarly selected field galaxies over the 3-100 arcsec range and about a factor of 3 more strongly below 10 arcsec. The correlation errors are empirically established with a jackknife analysis of the four SNLS fields. The hosts are more correlated than the field at a significance of 99% in the fitted amplitude and slope, with the point-by-point difference of the two correlation functions having a reduced $\\chi^2$ for 8 degrees of freedom of 4.3, which has a probability of random occurrence of less than 3x10^{-5}. The correlation angle is 1.5+/-0.5 arcsec, which deprojects to a fixed co-moving correlation length of approximately 6.5+/- 2/h mpc. Weighting the field galaxies with the mass and star formation rate supernova frequencie...

  5. The Extreme Hosts of Extreme Supernovae

    CERN Document Server

    Neill, James D; Gal-Yam, Avishay; Quimby, Robert; Ofek, Eran; Wyder, Ted K; Howell, D Andrew; Nugent, Peter; Seibert, Mark; Martin, D Christopher; Overzier, Roderik; Barlow, Tom A; Foster, Karl; Friedman, Peter G; Morrissey, Patrick; Neff, Susan G; Schiminovich, David; Bianchi, Luciana; Donas, José; Heckman, Timothy M; Lee, Young-Wook; Madore, Barry F; Milliard, Bruno; Rich, R Michael; Szalay, Alex S

    2010-01-01

    We use GALEX ultraviolet (UV) and optical integrated photometry of the hosts of seventeen luminous supernovae (LSNe, having peak M_V 100 M_sun), by appearing in low-SFR hosts, are potential tests for theories of the initial mass function that limit the maximum mass of a star based on the S FR.

  6. UAV Patrolling Based on Stochastic Strategy%基于随机策略的无人机巡逻路径规划

    Institute of Scientific and Technical Information of China (English)

    曹攀峰; 崔升

    2011-01-01

    Multiple Unmanned Aerial Vehicles (UAVs) cooperative patroling is an important research area in cooperative control. In the presence of an adversary trying to penetrate the area, an efficient patrolling path requires enough unpredictability in order to prevent the intruder to predict the schedule. An algorithm of stochastic path planning is presented to achieve cooperative patrol in adversarial environments. Computer simulations show the performance of this strategy.%多无人机协同巡逻是多无人机协同控制的重要内容之一.在敌对情况下固定周期性的巡逻路径容易被敌方预测到而失去巡逻效果.提出了一种以随机策略为基础的巡逻路径的规划方法,实现了敌对环境下分布式的多无人机协同巡逻.用仿真算例研究了算法的性能.

  7. Swimming between the flags: a preliminary exploration of the influences on Australians' intentions to swim between the flags at patrolled beaches.

    Science.gov (United States)

    White, Katherine M; Hyde, Melissa K

    2010-11-01

    Swimming at patrolled beaches reduces the likelihood of drownings and near-drownings. The present study tested the Theory of Planned Behaviour (TPB), with the addition of risk perceptions, in predicting people's intentions to swim between the flags at patrolled beaches. We examined also the predictors of people's willingness to swim [1] up to 10 m and [2] more than 10 m outside of the patrol flags. Participants (N=526) completed measures of attitudes, subjective norm, perceived behavioural control (PBC), intentions/willingness, and both objective and subjective risk perceptions. Two weeks later, a sub-sample of participants reported on their beach swimming behaviour for the previous fortnight. Attitude and subjective norm predicted intentions to swim between and willingness to swim outside of the flags. Age and PBC influenced willingness to swim beyond the flags. Objective risk predicted willingness to swim beyond the flags (both distances) while subjective risk predicted willingness to swim up to 10 m outside the flags. People's intentions to swim between the flags were correlated with their behaviour at follow-up. This study provides a preliminary investigation into an important safety behaviour and identifies factors to target when promoting safe swimming behaviours to prevent drowning deaths on Australian beaches.

  8. Reinventing Biostatistics Education for Basic Scientists.

    Science.gov (United States)

    Weissgerber, Tracey L; Garovic, Vesna D; Milin-Lazovic, Jelena S; Winham, Stacey J; Obradovic, Zoran; Trzeciakowski, Jerome P; Milic, Natasa M

    2016-04-01

    Numerous studies demonstrating that statistical errors are common in basic science publications have led to calls to improve statistical training for basic scientists. In this article, we sought to evaluate statistical requirements for PhD training and to identify opportunities for improving biostatistics education in the basic sciences. We provide recommendations for improving statistics training for basic biomedical scientists, including: 1. Encouraging departments to require statistics training, 2. Tailoring coursework to the students' fields of research, and 3. Developing tools and strategies to promote education and dissemination of statistical knowledge. We also provide a list of statistical considerations that should be addressed in statistics education for basic scientists.

  9. Social media for engineers and scientists

    CERN Document Server

    DiPietro, Jon

    2011-01-01

    This book explores the rising phenomena of internet-based social networking and discusses the particular challenges faced by engineers and scientists in adapting to this new, content-centric environment. Social networks are both a blessing and a curse to the engineer and scientist. The blessings are apparent: the abundance of free applications and their increasing mobility and transportability. The curse is that creating interesting and compelling content on these user-driven systems is best served by right-brain skills. But most engineers and scientists are left-brain oriented, have genera

  10. Scaling supernova hydrodynamics to the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kane, J.O.

    1999-06-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane et al., Astrophys. J.478, L75 (1997) The Nova laser is used to shock two-layer targets, producing Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities at the interfaces between the layers, analogous to instabilities seen at the interfaces of SN 1987A. Because the hydrodynamics in the laser experiments at intermediate times (3-40 ns) and in SN 1987A at intermediate times (5 s-10{sup 4} s) are well described by the Euler equations, the hydrodynamics scale between the two regimes. The experiments are modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS, thus serving as a benchmark for PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike and bubble velocities in the experiment using potential flow theory and a modified Ott thin shell theory is presented. A numerical study of 2D vs. 3D differences in instability growth at the O-He and He-H interface of SN 1987A, and the design for analogous laser experiments are presented. We discuss further work to incorporate more features of the SN in the experiments, including spherical geometry, multiple layers and density gradients. Past and ongoing work in laboratory and laser astrophysics is reviewed, including experimental work on supernova remnants (SNRs). A numerical study of RM instability in SNRs is presented.

  11. Infrared Light Curves of Type Ia Supernovae

    Science.gov (United States)

    Friedman, Andrew Samuel

    2012-05-01

    This thesis presents the CfAIR2 data set, which includes over 4000 near-Infrared (NIR) JHK8-band measurements of 104 Type Ia Supernovae (SN Ia) observed from 2005-2011 using PAIRITEL, the 1.3-m Peters Automated InfraRed Imaging TELescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona. While the discovery of dark energy and most subsequent supernova cosmology has been performed using optical and Ultraviolet wavelength observations of SN Ia, a growing body of evidence suggests that NIR SN Ia observations will be crucial for future cosmological studies. Whereas SN Ia observed at optical wavelengths have been shown to be excellent standardizeable candles, using empirical correlations between luminosity, light curve shape, and color, the CfAIR2 data set strengthens the evidence that SN Ia at NIR wavelengths are essentially standard candles, even without correction for light-curve shape or for reddening. CfAIR2 was obtained as part of the CfA Supernova Program, an ongoing multi-wavelength follow-up effort at FLWO designed to observe high-quality, densely sampled light curves and spectra of hundreds of low-redshift SN Ia. CfAIR2 is the largest homogeneously observed and processed NIR data set of its kind to date, nearly tripling the number of individual JHK8-band observations and nearly doubling the set of SN Ia with published NIR light curves in the literature. Matched only by the recently published Carnegie Supernova Project sample, CfAIR2 complements the large and growing set of low-redshift optical and NIR SN Ia observations obtained by the CfA and other programs, making this data set a unique and particularly valuable local universe anchor for future supernova cosmology.

  12. Education and Outreach: Advice to Young Scientists

    Science.gov (United States)

    Lopes, R. M. C.

    2005-08-01

    Carl Sagan set an example to all scientists when he encouraged us to reach out to the public and share the excitement of discovery and exploration. The prejudice that ensued did not deter Sagan and, with the passing of years, more and more scientists have followed his example. Although at present scientists at all ranks are encouraged by their institutions to do outreach, the balancing of a successful scientific career with teaching and outreach is often not an easy one. Young scientists, in particular, may worry about how their outreach efforts are viewed in the community and how they will find the time and energy for these efforts. This talk will offer suggestions on how to balance an active science research program with outreach activities, the many different ways to engage in education and public outreach, and how the rewards are truly priceless.

  13. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home > NEI for Kids > Ask a Scientist Video Series ... can see clearly from 25 feet away. NEI Home Contact Us A-Z Site Map NEI on ...

  14. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Links to More Information Optical Illusions Printables Ask a Scientist Video Series Why can’t you see ... eyelids? Why does saltwater sting your eyes? Select a video below to get answers to questions like ...

  15. Women scientists reflections, challenges, and breaking boundaries

    CERN Document Server

    Hargittai, Magdolna

    2015-01-01

    Magdolna Hargittai uses over fifteen years of in-depth conversation with female physicists, chemists, biomedical researchers, and other scientists to form cohesive ideas on the state of the modern female scientist. The compilation, based on sixty conversations, examines unique challenges that women with serious scientific aspirations face. In addition to addressing challenges and the unjustifiable underrepresentation of women at the higher levels of academia, Hargittai takes a balanced approach by discussing how some of the most successful of these women have managed to obtain professional success and personal happiness. Women Scientists portrays scientists from different backgrounds, different geographical regions-eighteen countries from four continents-and leaders from a variety of professional backgrounds, including eight Nobel laureate women. The book is divided into three sections: "Husband and Wife Teams," "Women at the Top," and "In High Positions." Hargittai uses her own experience to introduce her fi...

  16. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Printables Ask a Scientist Video Series Why can’t you see colors well in the dark? Do ... fish have eyelids? Click to Watch Why don’t all animal eyes look the same? Click to ...

  17. Scientists Spot Genes Behind Crohn's, Ulcerative Colitis

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_166957.html Scientists Spot Genes Behind Crohn's, Ulcerative Colitis Large study finds key ... Researchers say they've come closer to pinpointing genes linked with inflammatory bowel diseases such as Crohn's ...

  18. Scientists Discover More Clues to Stuttering

    Science.gov (United States)

    ... fullstory_162368.html Scientists Discover More Clues to Stuttering MRI shows involvement of brain areas controlling speech, ... speech, attention and emotion are all linked to stuttering. Stuttering is characterized by involuntarily repeating certain sounds, ...

  19. Scientists Design Heat-Activated Penis Implant

    Science.gov (United States)

    ... news/fullstory_162815.html Scientists Design Heat-Activated Penis Implant Device an improvement on current implants, researchers ... News) -- Doctors report that they have crafted a penis implant that becomes erect when heated. Dubbed by ...

  20. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Links to More Information Optical Illusions Printables Ask a Scientist Video Series Why can’t you see ... eyelids? Why does saltwater sting your eyes? Select a video below to get answers to questions like ...

  1. Elements of ethics for physical scientists

    CERN Document Server

    Greer, Sandra C

    2017-01-01

    This book offers the first comprehensive guide to ethics for physical scientists and engineers who conduct research. Written by a distinguished professor of chemistry and chemical engineering, the book focuses on the everyday decisions about right and wrong faced by scientists as they do research, interact with other people, and work within society. The goal is to nurture readers’ ethical intelligence so that they know an ethical issue when they see one, and to give them a way to think about ethical problems. After introductions to the philosophy of ethics and the philosophy of science, the book discusses research integrity, with a unique emphasis on how scientists make mistakes and how they can avoid them. It goes on to cover personal interactions among scientists, including authorship, collaborators, predecessors, reviewers, grantees, mentors, and whistle-blowers. It considers underrepresented groups in science as an ethical issue that matters not only to those groups but also to the development of scien...

  2. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Illusions Printables Ask a Scientist Video Series Why can’t you see colors well in the dark? ... Miller answers questions about color blindness, whether it can be treated, and how people become color blind. ...

  3. Scientists Create Clothing with 'Knitted' Muscle Power

    Science.gov (United States)

    ... 163272.html Scientists Create Clothing With 'Knitted' Muscle Power Fabric reacts to low voltage charge and could ... techniques that one day might help provide muscle power to disabled people or seniors who have trouble ...

  4. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Printables Ask a Scientist Video Series Why can’t you see colors well in the dark? Do ... fish have eyelids? Click to Watch Why don’t all animal eyes look the same? Click to ...

  5. Ask a Scientist: What is Color Blindness?

    Medline Plus

    Full Text Available ... Scientist Video Series Why can’t you see colors well in the dark? Do fish have eyelids? ... video series. Dr. Sheldon Miller answers questions about color blindness, whether it can be treated, and how ...

  6. Exploring evolutionary biology: readings from American Scientist

    National Research Council Canada - National Science Library

    Slatkin, M

    1995-01-01

    The articles in this collection are taken from the pages of American Scientist, an interdisciplinary magazine of science and technology published by Sigma Xi, the scientific Research Society. Contents...

  7. Thermal effects in supernova matter

    Science.gov (United States)

    Constantinou, Constantinos

    A crucial ingredient in simulations of core collapse supernova (SN) explosions is the equation of state (EOS) of nucleonic matter for densities extending from 10-7 fm-3 to 1 ffm-3, temperatures up to 50 MeV, and proton-to-baryon fraction in the range 0 to 1/2. SN explosions release 99% of the progenitor star's gravitational potential energy in the form of neutrinos and, additionally, they are responsible for populating the universe with elements heavier than 56Fe. Therefore, the importance of understanding this phenomenon cannot be overstated as it could shed light onto the underlying nuclear and neutrino physics. A realistic EOS of SN matter must incorporate the nucleon-nucleon interaction in a many-body environment. We treat this problem with a non-relativistic potential model as well as relativistic mean-field theoretical one. In the former approach, we employ the Skyrme-like Hamiltonian density constructed by Akmal, Pandharipande, and Ravenhall which takes into account the long scattering lengths of nucleons that determine the low density characteristics. In the latter, we use a Walecka-like Lagrangian density supplemented by non-linear interactions involving scalar, vector, and isovector meson exchanges, calibrated so that known properties of nuclear matter are reproduced. We focus on the bulk homogeneous phase and calculate its thermodynamic properties as functions of baryon density, temperature, and proton-to-baryon ratio. The exact numerical results are then compared to those in the degenerate and non-degenerate limits for which analytical formulae have been derived. We find that the two models bahave similarly for densities up to nuclear saturation but exhibit differences at higher densities most notably in the isospin susceptibilities, the chemical potentials, and the pressure. The importance of the correct momentum dependence in the single particle potential that fits optical potentials of nucleon-nucleus scattering was highlighted in the context of

  8. Type Ia supernovae: explosions and progenitors

    Science.gov (United States)

    Kerzendorf, Wolfgang Eitel

    2011-08-01

    Supernovae are the brightest explosions in the universe. Supernovae in our Galaxy, rare and happening only every few centuries, have probably been observed since the beginnings of mankind. At first they were interpreted as religious omens but in the last half millennium they have increasingly been used to study the cosmos and our place in it. Tycho Brahe deduced from his observations of the famous supernova in 1572, that the stars, in contrast to the widely believe Aristotelian doctrine, were not immutable. More than 400 years after Tycho made his paradigm changing discovery using SN 1572, and some 60 years after supernovae had been identified as distant dying stars, two teams changed the view of the world again using supernovae. The found that the Universe was accelerating in its expansion, a conclusion that could most easily be explained if more than 70% of the Universe was some previously un-identified form of matter now often referred to as `Dark Energy'. Beyond their prominent role as tools to gauge our place in the Universe, supernovae themselves have been studied well over the past 75 years. We now know that there are two main physical causes of these cataclysmic events. One of these channels is the collapse of the core of a massive star. The observationally motivated classes Type II, Type Ib and Type Ic have been attributed to these events. This thesis, however is dedicated to the second group of supernovae, the thermonuclear explosions of degenerate carbon and oxygen rich material and lacking hydrogen - called Type Ia supernovae (SNe Ia). White dwarf stars are formed at the end of a typical star's life when nuclear burning ceases in the core, the outer envelope is ejected, with the degenerate core typically cooling for eternity. Theory predicts that such stars will self ignite when close to 1.38 Msun (called the Chandrasekhar Mass). Most stars however leave white dwarfs with 0.6 Msun, and no star leaves a remnant as heavy as 1.38 M! sun, which suggests

  9. Intelligent OkiKoSenPBX1 Security Patrol Robot via Network and Map-Based Route Planning

    Directory of Open Access Journals (Sweden)

    Mbaïtiga Zacharie

    2009-01-01

    Full Text Available Problem statement: With an increased demand for security and limited numbers of trained security personnel, some security mangers have a lot of ground to police and limited staff to cover it. To compensate for shortages of security staff and to reduce the stress of security managers, we have developed an intelligent patrol robot system called "OkiKoSenPBX1". The system integrates a variety of sensors to gather environmental information and to detect abnormal events including intruders. Approach: In our approach, the route planning procedure was based on determining a sequence of intermediary goal points or coordinates x and y composing the robot trajectory. Results: A qualitative running experimental evaluation had been performed on the 1st floor of the Okinawa national college of technology as a preliminary practical implementation and its real-time performance was excellent, where a student like-guard can take control of the camera pan and tilt functions remotely. Conclusion: The real-time performance of the developed system that can leave security personnel hands-free for other important tasks is an irresistible system that can be put into practical use in a public offices facility, manufacturing facilities and various construction sites-everywhere there’s a need for advanced frontline security.

  10. Development of a Data Reduction Algorithm for Optical Wide Field Patrol (OWL) II: Improving Measurement of Lengths of Detected Streaks

    Science.gov (United States)

    Park, Sun-Youp; Choi, Jin; Roh, Dong-Goo; Park, Maru; Jo, Jung Hyun; Yim, Hong-Suh; Park, Young-Sik; Bae, Young-Ho; Park, Jang-Hyun; Moon, Hong-Kyu; Choi, Young-Jun; Cho, Sungki; Choi, Eun-Jung

    2016-09-01

    As described in the previous paper (Park et al. 2013), the detector subsystem of optical wide-field patrol (OWL) provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time) data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.

  11. Development of a Reduction Algorithm of GEO Satellite Optical Observation Data for Optical Wide Field Patrol (OWL)

    Science.gov (United States)

    Park, Sun-youp; Choi, Jin; Jo, Jung Hyun; Son, Ju Young; Park, Yung-Sik; Yim, Hong-Suh; Moon, Hong-Kyu; Bae, Young-Ho; Choi, Young-Jun; Park, Jang-Hyun

    2015-09-01

    An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous orbit satellites (GOS satellites) is developed. The optical wide-field patrol system is capable of automatic observation using a pre-arranged schedule. Therefore, if this type of automatic analysis algorithm is available, daily unmanned monitoring of GEO satellites can be possible. For data acquisition for development, the COMS1 satellite was observed with 1-s exposure time and 1-m interval. The images were grouped and processed in terms of ¡°action¡±, and each action was composed of six or nine successive images. First, a reference image with the best quality in one action was selected. Next, the rest of the images in the action were geometrically transformed to fit in the horizontal coordinate system (expressed in azimuthal angle and elevation) of the reference image. Then, these images were median-combined to retain only the possible non-moving GEO candidates. By reverting the coordinate transformation of the positions of these GEO satellite candidates, the final coordinates could be calculated.

  12. Cosmic Forensics Confirms Gamma-Ray Burst And Supernova Connection

    Science.gov (United States)

    2003-03-01

    Scientists announced today that they have used NASA's Chandra X-ray Observatory to confirm that a gamma-ray burst was connected to the death of a massive star. This result is an important step in understanding the origin of gamma-ray bursts, the most violent events in the present-day universe. "If a gamma-ray burst were a crime, then we now have strong circumstantial evidence that a supernova explosion was at the scene," said Nathaniel Butler of Massachusetts Institute of Technology in Cambridge, lead author of a paper presented today at the meeting of the High Energy Division of the American Astronomical Society. Chandra was able to obtain an unusually long observation (approximately 21 hours) of the afterglow of GRB 020813 (so named because the High-Energy Transient Explorer, HETE, discovered it on August 13, 2002.) A grating spectrometer aboard Chandra revealed an overabundance of elements characteristically dispersed in a supernova explosion. Narrow lines, or bumps, due to silicon and sulfur ions (atoms stripped of most of their electrons) were clearly identified in the X-ray spectrum of GRB 020813. "Our observation of GRB 020813 supports two of the most important features of the popular supra-nova model for gamma-ray bursts," said Butler. "An extremely massive star likely exploded less than two months prior to the gamma-ray burst, and the radiation from the gamma-ray burst was beamed into a narrow cone." An analysis of the data showed that the ions were moving away from the site of the gamma-ray burst at a tenth the speed of light, probably as part of a shell of matter ejected in the supernova explosion. The line features were observed to be sharply peaked, indicating that they were coming from a narrow region of the expanding shell. This implies that only a small fraction of the shell was illuminated by the gamma-ray burst, as would be expected if the burst was beamed into a narrow cone. The observed duration of the afterglow suggests a delay of about 60 days

  13. A supernova feedback implementation for the astrophysical simulation software Arepo

    CERN Document Server

    Bubel, André-Patrick

    2016-01-01

    Supernova (SN) explosions play an important role in the development of galactic structures. The energy and momentum imparted on the interstellar medium (ISM) in so called "supernova feedback" drives turbulence, heats the gas, enriches it with heavy elements, can lead to the formation of new stars or even suppress star formation by disrupting stellar nurseries. In the numerical simulation at the sub-galactic level, not including the energy and momentum of supernovas in the physical description of the problem can also lead to several problems that might partially be resolved by including a description of supernovas. In this thesis such an implementation is attempted for the combined numerical hydrodynamics and N-body simulation software Arepo (Springel, 2010). In a stochastic process a large amount of thermal energy is imparted on a number of neighbouring cells, mimicking the effect of a supernova explosions. We test this approach by modelling the explosion of a single supernova in a uniform density medium and ...

  14. Semi-supervised Learning for Photometric Supernova Classification

    CERN Document Server

    Richards, Joseph W; Freeman, Peter E; Schafer, Chad M; Poznanski, Dovi

    2011-01-01

    We present a semi-supervised method for photometric supernova typing. Our approach is to first use the nonlinear dimension reduction technique diffusion map to detect structure in a database of supernova light curves and subsequently employ random forest classification on a spectroscopically confirmed training set to learn a model that can predict the type of each newly observed supernova. We demonstrate that this is an effective method for supernova typing. As supernova numbers increase, our semi-supervised method efficiently utilizes this information to improve classification, a property not enjoyed by template based methods. Applied to supernova data simulated by Kessler et al. (2010b) to mimic those of the Dark Energy Survey, our methods achieve (cross-validated) 96% Type Ia purity and 86% Type Ia efficiency on the spectroscopic sample, but only 56% Type Ia purity and 48% efficiency on the photometric sample due to their spectroscopic followup strategy. To improve the performance on the photometric sample...

  15. Spectroscopic observations of eight supernovae at intermediate redshift

    CERN Document Server

    Balland, C; Amanullah, R; Astier, Pierre; Fabbro, S; Folatelli, G; Garavini, G; Goobar, A; Hardin, D; Irwin, M J; McMahon, R G; Mourão, A M; Nobili, S; Pain, R; Pascoal, R; Raux, J; Sainton, G; Schahmaneche, K; Walton, N A

    2007-01-01

    We present spectra of six Type Ia and two Type II supernovae obtained in June 2002 at the William Herschel Telescope during a search for Type Ia supernovae (SNIa) at intermediate redshift. Supernova type identification and phase determination are performed using a fitting technique based on a Xi2 minimization against a series of model templates. The spectra range from z=0.033 to z=0.328, including one spectroscopically underluminous SNIa at z=0.033. This set of spectra significantly increases the sample of well-observed type SNIa supernovae available in the range 0.15< z <0.35. Together with the twelve supernovae observed by our team in 1999 in the same redshift range, they form an homogeneous sample of seventeen type Ia supernovae with comparable signal-to-noise ratio and regular phase sampling in a still largely unexplored region of the redshift space.

  16. Type Ia supernova rate at $z \\sim 0.1$

    CERN Document Server

    Hardin, D P; Alard, C; Albert, J N; Amadon, A; Andersen, J; Ansari, R; Aubourg, E; Bareyre, P; Bauer, F; Beaulieu, J P; Blanc, G; Bouquet, A; Char, S; Charlot, X; Couchot, F; Coutures, C; Derue, F; Ferlet, R; Glicenstein, J F; Goldman, B; Gould, A; Graff, D; Gros, M H; Haïssinski, J; Hamilton, J C; Kat, J; Kim, A; Lasserre, T; Lesquoy, E; Loup, C; Magneville, C; Mansoux, B; Marquette, J B; Maurice, E; Milshtein, A I; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Prévôt, L; Regnault, N; Rich, J; Spiro, Michel; Vidal-Madjar, A; Vigroux, L; Zylberajch, S

    2000-01-01

    We present the EROS nearby supernova ($z \\sim 0.02 - 0.2$) search and the analysis of the first year of data (1997). A total of 80 square degrees were surveyed. Eight supernov{\\ae} were detected, four of which were spectroscopically identified as type Ia supernov{\\ae}. The search efficiency was determined with a Monte-Carlo simulation taking into account the efficiencies for both supernova detection and host galaxy identification. Assuming that for a given galaxy the supernova rate is proportional to the galactic luminosity, we compute a type Ia supernova explosion rate of: ${\\cal R} = 0.44 {}_{-0.21}^{+0.35} {}_{-0.07}^{+0.13} h^2: / 10^{10} \\lbsun / 100 {\\rm yrs}$ at an average redshift of $\\sim 0.1$ where the errors are respectively statistical and systematic (type misidentification included).

  17. The Supernova Legacy Survey 3-year sample: Type Ia Supernovae photometric distances and cosmological constraints

    CERN Document Server

    Guy, J; Conley, A; Regnault, N; Astier, P; Balland, C; Basa, S; Carlberg, R G; Fouchez, D; Hardin, D; Hook, I M; Howell, D A; Pain, R; Palanque-Delabrouille, N; Perrett, K M; Pritchet, C J; Rich, J; Ruhlmann-Kleider, V; Balam, D; Baumont, S; Ellis, R S; Fabbro, S; Fakhouri, H K; Fourmanoit, N; Gonzalez-Gaitan, S; Graham, M L; Hsiao, E; Kronborg, T; Lidman, C; Mourao, A M; Perlmutter, S; Ripoche, P; Suzuki, N; Walker, E S

    2010-01-01

    We present photometric properties and distance measurements of 252 high redshift Type Ia supernovae (0.15 < z < 1.1) discovered during the first three years of the Supernova Legacy Survey (SNLS). These events were detected and their multi-colour light curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshifts. Systematic uncertainties arising from light curve modeling are studied, making use of two techniques to derive the peak magnitude, shape and colour of the supernovae, and taking advantage of a precise calibration of the SNLS fields. A flat LambdaCDM cosmological fit to 231 SNLS high redshift Type Ia supernovae alone gives Omega_M = 0.211 +/- 0.034(stat) +/- 0.069(sys). The dominant systematic uncertainty comes from uncertainties in the photometri...

  18. Photometric selection of Type Ia supernovae in the Supernova Legacy Survey

    CERN Document Server

    Bazin, G; Palanque-Delabrouille, N; Rich, J; Aubourg, E; Astier, P; Balland, C; Basa, S; Carlberg, R G; Conley, A; Fouchez, D; Guy, J; Hardin, D; Hook, I M; Howell, D A; Pain, R; Perrett, K; Pritchet, C J; Regnault, N; Sullivan, M; Fourmanoit, N; Gonzalez-Gaitan, S; Lidman, C; Perlmutter, S; Ripoche, P; Walker, E S

    2011-01-01

    We present a sample of 485 photometrically identified Type Ia supernova candidates mined from the first three years of data of the CFHT SuperNova Legacy Survey (SNLS). The images were submitted to a deferred processing independent of the SNLS real-time detection pipeline. Light curves of all transient events were reconstructed in the g_M, r_M, i_M and z_M filters and submitted to automated sequential cuts in order to identify possible supernovae. Pure noise and long-term variable events were rejected by light curve shape criteria. Type Ia supernova identification relied on event characteristics fitted to their light curves assuming the events to be normal SNe Ia. The light curve fitter SALT2 was used for this purpose, assigning host galaxy photometric redshifts to the tested events. The selected sample of 485 candidates is one magnitude deeper than that allowed by the SNLS spectroscopic identification. The contamination by supernovae of other types is estimated to be 4%. Testing Hubble diagram residuals with ...

  19. Two superluminous supernovae from the early universe discovered by the Supernova Legacy Survey

    CERN Document Server

    Howell, D A; Lidman, C; Sullivan, M; Conley, A; Astier, P; Carlberg, C Balland R G; Fouchez, D; Guy, J; Hardin, D; Pain, R; Palanque-Delabrouille, N; Perrett, K; Pritchet, C J; Regnault, N; Rich, J; Ruhlmann-Kleider, V

    2013-01-01

    We present spectra and lightcurves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M_U = -22.7 is one of the most luminous SNe ever observed, and gives a rare glimpse into the restframe ultraviolet where these supernovae put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but based on the supernova spectrum, we estimate it to be at z ~ 1.5. Both supernovae have similar observer-frame griz lightcurves, which map to restframe lightcurves in the U-band and UV, rising in ~ 20 restframe days or longer, and declining over a similar timescale. The lightcurves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra to theoretical models, and identify lines of C II, C III, Fe III, and Mg II in the spectrum of SNLS 06D4eu and SCP 06F6...

  20. Nobelist TD LEE Scientist Cooperation Network and Scientist Innovation Ability Model

    OpenAIRE

    2013-01-01

    Nobelist TD Lee scientist cooperation network (TDLSCN) and their innovation ability are studied. It is found that the TDLSCN not only has the common topological properties both of scale-free and small-world for a general scientist cooperation networks, but also appears the creation multiple-peak phenomenon for number of published paper with year evolution, which become Nobelist TD Lee’s significant mark distinguished from other scientists. This new phenomenon has not been revealed in the scie...

  1. Improving Communication Skills in Early Career Scientists

    Science.gov (United States)

    Saia, S. M.

    2013-12-01

    The AGU fall meeting is a time for scientists to share what we have been hard at work on for the past year, to share our trials and tribulations, and of course, to share our science (we hope inspirational). In addition to sharing, the AGU fall meeting is also about collaboration as it brings old and new colleagues together from diverse communities across the planet. By sharing our ideas and findings, we build new relationships with the potential to cross boundaries and solve complex and pressing environmental issues. With ever emerging and intensifying water scarcity, extreme weather, and water quality issues across the plant, it is especially important that scientists like us share our ideas and work together to put these ideas into action. My vision of the future of water sciences embraces this fact. I believe that better training is needed to help early career scientists, like myself, build connections within and outside of our fields. First and foremost, more advanced training in effective storytelling concepts and themes may improve our ability to provide context for our research. Second, training in the production of video for internet-based media (e.g. YouTube) may help us bring our research to audiences in a more personalized way. Third, opportunities to practice presenting at highly visible public events such as the AGU fall meeting, will serve to prepare early career scientists for a variety of audiences. We hope this session, ';Water Sciences Pop-Ups', will provide the first steps to encourage and train early career scientists as they share and collaborate with scientists and non-scientists around the world.

  2. Ejection of Supernova-Enriched Gas From Dwarf Disk Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Fragile, P C; Murray, S D; Lin, D C

    2004-06-15

    We examine the efficiency with which supernova-enriched gas may be ejected from dwarf disk galaxies, using a methodology previously employed to study the self-enrichment efficiency of dwarf spheroidal systems. Unlike previous studies that focused on highly concentrated starbursts, in the current work we consider discrete supernova events spread throughout various fractions of the disk. We model disk systems having gas masses of 10{sup 8} and 10{sup 9} M{sub {circle_dot}} with supernova rates of 30, 300, and 3000 Myr{sup -1}. The supernova events are confined to the midplane of the disk, but distributed over radii of 0, 30, and 80% of the disk radius, consistent with expectations for Type II supernovae. In agreement with earlier studies, we find that the enriched material from supernovae is largely lost when the supernovae are concentrated near the nucleus, as expected for a starburst event. In contrast, we find the loss of enriched material to be much less efficient (as low as 21%) when the supernovae occur over even a relatively small fraction of the disk. The difference is due to the ability of the system to relax following supernova events that occur over more extended regions. Larger physical separations also reduce the likelihood of supernovae going off within low-density ''chimneys'' swept out by previous supernovae. We also find that, for the most distributed systems, significant metal loss is more likely to be accompanied by significant mass loss. A comparison with theoretical predications indicates that, when undergoing self-regulated star formation, galaxies in the mass range considered shall efficiently retain the products of Type II supernovae.

  3. The Frequency of Supernovae in the Early Universe

    Science.gov (United States)

    Melinder, Jens

    Supernovae are cosmic explosions of cataclysmic proportion that signify the death of a star. While being interesting phenomena in their own right, their brightness also make them excellent probes of the early universe. Depending on the type of the progenitor star and the origin of the explosion different subjects can be investigated. In this dissertation the work I have done on the detection, characterisation and rate measurements of supernovae in the Stockholm VIMOS Supernova Search is presented. We have discovered 16 supernovae that exploded billions of years ago (or, equivalently, at high redshift, z). The observed brightness and colour evolution have been used to classify the supernovae into either thermonuclear (type Ia) or core collapse (type II) supernovae. The accuracy of the classification code is high, only about 5% of the supernovae are mistyped, similar to other codes of the same kind. By comparing the observed frequency of supernovae to simulations the underlying supernova rate at these high redshifts have been measured. The main result reported in this thesis is that the core collapse supernova rate at high redshift matches the rates estimated from looking at the star formation history of the universe, and agree well with previous studies. The rate of Ia supernovae at high redshift have been investigated by several projects, our results show a somewhat higher rate of Ia supernovae than expected. Proper estimates of the systematic errors of rate measurements are found to be very important. Furthermore, by using novel techniques for reducing and stacking images, we have obtained a galaxy sample containing approximately 50,000 galaxies. Photometric redshifts have been obtained for most of the galaxies, the resulting accuracy below z=1 is on the order of 10%. The galaxy sample has also been used to find high redshift sources, so called Lyman Break Galaxies, at z=3-5.

  4. Vivid View of Tycho's Supernova Remnant

    Science.gov (United States)

    2008-01-01

    This composite image of the Tycho supernova remnant combines infrared and X-ray observations obtained with NASA's Spitzer and Chandra space observatories, respectively, and the Calar Alto observatory, Spain. It shows the scene more than four centuries after the brilliant star explosion witnessed by Tycho Brahe and other astronomers of that era. The explosion has left a blazing hot cloud of expanding debris (green and yellow). The location of the blast's outer shock wave can be seen as a blue sphere of ultra-energetic electrons. Newly synthesized dust in the ejected material and heated pre-existing dust from the area around the supernova radiate at infrared wavelengths of 24 microns (red). Foreground and background stars in the image are white.

  5. Tycho Brahe's supernova: light from centuries past

    CERN Document Server

    Ruiz-Lapuente, P

    2003-01-01

    The light curve of SN 1572 is described in the terms used nowadays to characterize SNeIa. By assembling the records of the observations done in 1572--74 and evaluating their uncertainties, it is possible to recover the light curve and the color evolution of this supernova. It is found that, within the SNe Ia family, the event should have been a SNIa with a normal rate of decline, its stretch factor being {\\it s} $\\sim$ 0.9. Visual light curve near maximum, late--time decline and the color evolution sustain this conclusion. After correcting for extinction, the luminosity of this supernova is found to be M$_{V}$ $=$ --19.58 --5 log (D/3.5 kpc) $\\pm$ 0.42.

  6. Nucleosynthesis Basics and Applications to Supernovae

    CERN Document Server

    Thielemann, F K; Freiburghaus, C; Nomoto, K; Hashimoto, M; Pfeiffer, B; Kratz, K L

    1998-01-01

    This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary...

  7. Impacto ambiental de los remanentes de supernova

    Science.gov (United States)

    Dubner, G. M.

    2015-08-01

    The explosion of a supernovae (SN) represents the sudden injection of about ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

  8. Photometric Supernova Classification With Machine Learning

    CERN Document Server

    Lochner, Michelle; Peiris, Hiranya V; Lahav, Ofer; Winter, Max K

    2016-01-01

    Automated photometric supernova classification has become an active area of research in recent years in light of current and upcoming imaging surveys such as the Dark Energy Survey (DES) and the Large Synoptic Telescope (LSST), given that spectroscopic confirmation of type for all supernovae discovered with these surveys will be impossible. Here, we develop a multi-faceted classification pipeline, combining existing and new approaches. Our pipeline consists of two stages: extracting descriptive features from the light curves and classification using a machine learning algorithm. Our feature extraction methods vary from model-dependent techniques, namely SALT2 fits, to more independent techniques fitting parametric models to curves, to a completely model-independent wavelet approach. We cover a range of representative machine learning algorithms, including naive Bayes, k-nearest neighbors, support vector machines, artificial neural networks and boosted decision trees. We test the pipeline on simulated multi-ba...

  9. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    CERN Document Server

    Sieverding, A; Langanke, K; Martínez-Pinedo, G; Heger, A

    2015-01-01

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z < 76 $ and ii) by considering modern supernova neutrino spectra which have substantially lower average energies compared to those previously adopted in neutrino nucleosynthesis studies. We confirm the production of $^7$Li, $^{11}$B, $^{138}$La, and $^{180}$Ta by neutrino nucleosynthesis, albeit at slightly smaller abundances due to the changed neutrino spectra. We find that for stars with a mass smaller than 20 M$_\\odot$, $^{19}$F is produced mainly by explosive nucleosynthesis while for higher mass stars it is produced by the $\

  10. Prospects for Neutrino Spin Coherence in Supernovae

    CERN Document Server

    Tian, James

    2016-01-01

    We present neutrino bulb model simulations of majorana neutrino coherent spin transformation (i.e., neutrino-antineutrino transformation) for conditions corresponding to the neutronization burst epoch of an O-Ne-Mg core collapse supernova. Significant neutrino spin transformation, in e.g. the neutronization burst, could alter the fluence of neutrinos and antineutrinos in a way which is potentially detectable for a galactic core collapse supernova. Our calculations for the first time treat geometric dilution in the spin evolution of the neutrinos and combine two-flavor and three-flavor neutrino flavor evolution with spin mixing physics. We find that significant spin transformations can occur, but only with an electron fraction profile which facilitates adiabatic conditions for the spin-channel resonance. Using our adopted parameters of neutrino energy spectra, luminosity, density and electron fraction profiles, our calculations require an unrealistically large neutrino rest mass to sustain the spin transformat...

  11. Multi-Wavelength Observations of Supernova Remnants

    Science.gov (United States)

    Williams, B.

    2012-01-01

    Supernova remnants (SNRs) provide a laboratory for studying various astrophysical processes, including particle acceleration, thermal and non thermal emission processes across the spectrum, distribution of heavy elements, the physics of strong shock waves, and the progenitor systems and environments of supernovae. Long studied in radio and X-rays, the past decade has seen a dramatic increase in the detection and subsequent study of SNRs in the infrared and gamma-ray regimes. Understanding the evolution of SNRs and their interaction with the interstellar medium requires a multi-wavelength approach. I will review the various physical processes observed in SNRs and how these processes are intertwined. In particular, I will focus on X-ray and infrared observations, which probe two very different but intrinsically connected phases of the ISM: gas and dust. I will discuss results from multi-wavelength studies of several SNRs at various stages of evolution, including Kepler, RCW 86, and the Cygnus Loop.

  12. SNCosmo: Python library for supernova cosmology

    Science.gov (United States)

    Barbary, Kyle; Barclay, Tom; Biswas, Rahul; Craig, Matt; Feindt, Ulrich; Friesen, Brian; Goldstein, Danny; Jha, Saurabh; Rodney, Steve; Sofiatti, Caroline; Thomas, Rollin C.; Wood-Vasey, Michael

    2016-11-01

    SNCosmo synthesizes supernova spectra and photometry from SN models, and has functions for fitting and sampling SN model parameters given photometric light curve data. It offers fast implementations of several commonly used extinction laws and can be used to construct SN models that include dust. The SNCosmo library includes supernova models such as SALT2, MLCS2k2, Hsiao, Nugent, PSNID, SNANA and Whalen models, as well as a variety of built-in bandpasses and magnitude systems, and provides convenience functions for reading and writing peculiar data formats used in other packages. The library is extensible, allowing new models, bandpasses, and magnitude systems to be defined using an object-oriented interface.

  13. Merging White Dwarfs and Thermonuclear Supernovae

    CERN Document Server

    van Kerkwijk, Marten H

    2012-01-01

    Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure, and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and our suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar mass remnants. I then turn to possible observational tests, in particular those that test the absence or presence of electron captures during the burning.

  14. Supernova Feedback in an Inhomogeneous Interstellar Medium

    CERN Document Server

    Martizzi, Davide; Quataert, Eliot

    2014-01-01

    Supernova (SN) feedback is one of the key processes shaping the interstellar medium (ISM) of galaxies. SNe contribute to (and in some cases may dominate) driving turbulence in the ISM and accelerating galactic winds. Modern cosmological simulations have sufficient resolution to capture the main structures in the ISM of galaxies, but are typically still not capable of explicitly resolving all of the small-scale stellar feedback processes, including the expansion of supernova remnants (SNRs). We perform a series of controlled three-dimensional hydrodynamic (adaptive mesh refinement, AMR) simulations of single SNRs expanding in an inhomogeneous density field with statistics motivated by those of the turbulent ISM. We use these to quantify the momentum and thermal energy injection from SNe as a function of spatial scale and the density, metallicity, and structure of the ambient medium. Using these results, we develop an analytic sub-resolution model for SN feedback for use in galaxy formation simulations. We then...

  15. An Unusually Fast-Evolving Supernova

    CERN Document Server

    Poznanski, Dovi; Nugent, Peter E; Bloom, Joshua S; Ganeshalingam, Mohan; Leonard, Douglas C; Li, Weidong; Thomas, Rollin C

    2009-01-01

    Analyses of supernovae (SNe) have revealed two main types of progenitors: exploding white dwarfs and collapsing massive stars. We present SN2002bj, which stands out as different from any SN reported to date. Its light curve rises and declines very rapidly, yet reaches a peak intrinsic brightness greater than -18 mag. A spectrum obtained 7 days after discovery shows the presence of helium and intermediate-mass elements, yet no clear hydrogen or iron-peak elements. The spectrum only barely resembles that of a Type Ia supernova, with added carbon and helium. Its properties suggest that SN2002bj may be representative of a class of progenitors that previously has been only hypothesized: a helium detonation on a white dwarf, ejecting a small envelope of material. New surveys should find many such objects, despite their scarcity.

  16. Nuclear pasta in supernovae and neutron stars

    CERN Document Server

    Watanabe, Gentaro

    2011-01-01

    In supernova cores and neutron star crusts, nuclei with exotic shapes such as rod-like and slab-like nuclei are expected to exist. These nuclei are collectively called nuclear "pasta". For the past decades, existence of the pasta phases in the equilibrium state has been studied using various methods. Recently, the formation process of the pasta phases, which has been a long-standing problem, has been unveiled using molecular dynamics simulations. In this review, we first provide the astrophysical background of supernovae and neutron stars and overview the history of the study of the pasta phases. We then focus on the recent study on the formation process of the pasta phases. Finally, we discuss future important issues related to the pasta phases: their astrophysical evidence and consequences.

  17. Cosmogenic Secondary Radiation from a Nearby Supernova

    Science.gov (United States)

    Overholt, Andrew

    2017-01-01

    Increasing evidence has been found for multiple supernovae within 100 pc of the solar system. Supernovae produce large amounts of cosmic rays which upon striking Earth's atmosphere, produce a cascade of secondary particles. Among these cosmic ray secondaries are neutrons and muons, which penetrate far within the atmosphere to sea level and even below sea level. Muons and neutrons are both forms of ionizing radiation which have been linked to increases in cancer, congenital malformations, and other maladies. This work focuses on the impact of muons, as they penetrate into ocean water to impact the lowest levels of the aquatic food chain. We have used monte carlo simulations (CORSIKA, MCNPx, and FLUKA) to determine the ionizing radiation dose due to cosmic ray secondaries. This information shows that although most astrophysical events do not supply the necessary radiation flux to prove dangerous; there may be other impacts such as an increase to mutation rate.

  18. Core-Collapse Supernovae: Reflections and Directions

    CERN Document Server

    Janka, H -Thomas; Huedepohl, Lorenz; Marek, Andreas; Mueller, Bernhard; Obergaulinger, Martin

    2012-01-01

    Core-collapse supernovae are among the most fascinating phenomena in astrophysics and provide a formidable challenge for theoretical investigation. They mark the spectacular end of the lives of massive stars and, in an explosive eruption, release as much energy as the sun produces during its whole life. A better understanding of the astrophysical role of supernovae as birth sites of neutron stars, black holes, and heavy chemical elements, and more reliable predictions of the observable signals from stellar death events are tightly linked to the solution of the long-standing puzzle how collapsing stars achieve to explode. In this article our current knowledge of the processes that contribute to the success of the explosion mechanism are concisely reviewed. After a short overview of the sequence of stages of stellar core-collapse events, the general properties of the progenitor-dependent neutrino emission will be briefly described. Applying sophisticated neutrino transport in axisymmetric (2D) simulations with ...

  19. The supernova cosmology cookbook: Bayesian numerical recipes

    CERN Document Server

    Karpenka, N V

    2015-01-01

    Theoretical and observational cosmology have enjoyed a number of significant successes over the last two decades. Cosmic microwave background measurements from the Wilkinson Microwave Anisotropy Probe and Planck, together with large-scale structure and supernova (SN) searches, have put very tight constraints on cosmological parameters. Type Ia supernovae (SNIa) played a central role in the discovery of the accelerated expansion of the Universe, recognised by the Nobel Prize in Physics in 2011. The last decade has seen an enormous increase in the amount of high quality SN observations, with SN catalogues now containing hundreds of objects. This number is expected to increase to thousands in the next few years, as data from next-generation missions, such as the Dark Energy Survey and Large Synoptic Survey Telescope become available. In order to exploit the vast amount of forthcoming high quality data, it is extremely important to develop robust and efficient statistical analysis methods to answer cosmological q...

  20. SUPERNOVA 1987A: CELEBRATING A SILVER JUBILEE

    Directory of Open Access Journals (Sweden)

    Nino Panagia

    2013-12-01

    Full Text Available The story of the SN 1987A explosion is briefly reviewed. Although this supernova was somewhat peculiar, the study of SN 1987A has clarified quite a number of important aspects of the nature and the properties of supernovae, such as the confirmation of the core collapse of a massive star as the cause of the explosion, as well the confirmation that the decays 56Ni–56Co–56Fe at early times and 44Ti–44Sc at late times, are the main sources of the energy radiated by the ejecta. Still we have not been able to ascertain whether the progenitor was a single star or a binary system, nor have we been able to detect the stellar remnant, a neutron star that should be produced in the core collapse process.