Science.gov

Sample records for 6-m special astrophysical

  1. Safety analysis report for packaging: the ORNL DOT specification 6M - special form package

    SciTech Connect

    Schaich, R.W.

    1982-07-01

    The ORNL DOT Specification 6M - Special Form Package was fabricated at the Oak Ridge Nation al Laboratory (ORNL) for the transport of Type B solid non-fissile radioactive materials in special form. The package was evaluated on the basis of tests performed by the Dow Chemical Company, Rocky Flats Division, on the DOT-6M container and special form tests performed on a variety of stainless steel capsules at ORNL by Operations Division personnel. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of Type B quantities in special form of non-fissile radioactive materials.

  2. Bibliometric Investigations at the Special Astrophysical Observatory RAS

    NASA Astrophysics Data System (ADS)

    Filippova, Ekaterina

    Bibliometric data for the Special Astrophysical Observatory are presented. Statistics and analysis of issues being brought out at SAO are given. Statistical data on publication of SAO research papers from the day of foundation of the observatory through 2000 are presented. The numbers of papers that appeared in domestic and foreign scientific issues are compared. An attempt is made to analyze the correlation of the number of scientific papers with the research of the observatory and also with the economical situation in Russia. It can be seen that the steady rise in publications observed from 1968 to 1991 gave way to an abrupt fall during the first (1991--1995) and second (1998) crises in our country.

  3. Special issue on current research in astrophysical magnetism

    NASA Astrophysics Data System (ADS)

    Kosovichev, Alexander; Lundstedt, Henrik; Brandenburg, Axel

    2012-06-01

    Much of what Hannes Alfvén envisaged some 70 years ago has now penetrated virtually all branches of astrophysical research. Indeed, magnetic fields can display similar properties over a large range of scales. We have therefore been able to take advantage of the transparency of galaxies and the interstellar medium to obtain measurements inside them. On the other hand, the Sun is much closer, allowing us to obtain a detailed picture of the interaction of flows and magnetic fields at the surface, and more recently in the interior by helioseismology. Moreover, the solar timescales are generally much shorter, making studies of dynamical processes more direct. This special issue on current research in astrophysical magnetism is based on work discussed during a one month Nordita program Dynamo, Dynamical Systems and Topology and comprises papers that fall into four different categories (A)-(D). (A) Papers on small-scale magnetic fields and flows in astrophysics 1. E M de Gouveia Dal Pino, M R M Leão, R Santos-Lima, G Guerrero, G Kowal and A Lazarian Magnetic flux transport by turbulent reconnection in astrophysical flows 2. Philip R Goode, Valentyna Abramenko and Vasyl Yurchyshyn New solar telescope in Big Bear: evidence for super-diffusivity and small-scale solar dynamos? 3. I N Kitiashvili, A G Kosovichev, N N Mansour, S K Lele and A A Wray Vortex tubes of turbulent solar convection The above collection of papers begins with a review of astrophysical reconnection and introduces the concept of dynamos necessary to explain the existence of contemporary magnetic fields both on galactic and solar scales (paper 1). This is complemented by observations with the new Big Bear Solar Observatory telescope, allowing us to see magnetic field amplification on small scales (paper 2). This in turn is complemented by realistic simulations of subsurface and surface flow patterns (paper 3). (B) Papers on theoretical approaches to turbulent fluctuations 4. Nathan Kleeorin and Igor

  4. New Master Program of Astrophysics and Specialization Courses for Matriculates of the Yerevan State University

    NASA Astrophysics Data System (ADS)

    Avetissian, Ara K.

    2007-08-01

    The new Master program of Astrophysics had been established for the graduated students of the Department of Astrophysics, Yerevan State University (YSU). The titles of courses and their contents were renewed and reedited based on European Universities' recent achievements. Especially, the new visions of principles, programs, as well as data-bases of Virtual Observatories are now discussing for implementation at the Department of Astrophysics, YSU. In addition to this innovative program, together with the Byurakan Observatory administration and YSU Department of Astrophysics, as well as with invited from BAO professors-teachers we now preparing the popularized fashionable courses for the pre-specialization of so called “matriculates” of YSU (graduated pupils of schools, who will choose specialty in any brunch of natural sciences). The same program with several changes and adaptation will be prepared to represent the public groups or individuals as an educational material for life-long education.

  5. Testing Special Relativity at High Energies with Astrophysical Sources

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    2007-01-01

    Since the group of Lorentz boosts is unbounded, there is a question as to whether Lorentz invariance (LI) holds to infinitely short distances. However, special and general relativity may break down at the Planck scale. Various quantum gravity scenarios such as loop quantum gravity, as well as some forms of string theory and extra dimension models may imply Lorentz violation (LV) at ultrahigh energies. The Gamma-Ray Large Area Space Telescope (GLAST), to be launched in mid-December, will measure the spectra of distant extragalactic sources of high energy gamma-rays, particularly active galactic nuclei and gamma-ray bursts. GLAST can look for energy-dependent gamma-ray propagation effects from such sources as a signal of Lorentz invariance violation. These sources may also exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions with low energy photons having a flux level as determined by various astronomical observations. With LV the threshold for such interactions can be significantly raised, changing the predicted absorption turnover in the observed spectrum of the sources. Stecker and Glashow have shown that the existence such absorption features in the spectra of extragalactic sources puts constraints on LV. Such constraints have important implications for some quantum gravity and large extra dimension models. Future spaceborne detectors dedicated to measuring gamma-ray polarization can look for birefringence effects as a possible signal of loop quantum gravity. A very small LV may also result in the modification or elimination of the GZK effect, thus modifying the spectrum of ultrahigh energy cosmic rays. This possibility can be explored with ground-based arrays such as Auger or with a space based detector system such as the proposed OWL satellite mission.

  6. Conservative special relativistic radiative transfer for multidimensional astrophysical simulations: Motivation and elaboration

    SciTech Connect

    Cardall, Christian Y.; Lentz, Eric J.; Mezzacappa, Anthony

    2005-08-15

    Many astrophysical phenomena exhibit relativistic radiative flows. While velocities in excess of v{approx}0.1c can occur in these systems, it has been common practice to approximate radiative transfer to O(v/c). In the case of neutrino transport in core-collapse supernovas, this approximation gives rise to an inconsistency between lepton number transfer and lab-frame energy transfer, which have different O(v/c) limits. A solution used in spherically symmetric O(v/c) simulations has been to retain, for energy accounting purposes, the O(v{sup 2}/c{sup 2}) terms in the lab-frame energy transfer equation that arise from the O(v/c) neutrino number transport equation. Avoiding the proliferation of such extra O(v{sup 2}/c{sup 2}) terms in the absence of spherical symmetry motivates a special relativistic formalism, which we exhibit in coordinates sufficiently general to encompass Cartesian, spherical, and cylindrical coordinate systems.

  7. Binary star speckle measurements during 1992-1997 from the SAO 6-m and 1-m telescopes in Zelenchuk

    NASA Astrophysics Data System (ADS)

    Balega, I. I.; Balega, Y. Y.; Maksimov, A. F.; Pluzhnik, E. A.; Shkhagosheva, Z. U.; Vasyuk, V. A.

    1999-12-01

    We present the results of speckle interferometric measurements of binary stars made with the television photon-counting camera at the 6-m Big Azimuthal Telescope (BTA) and 1-m telescope of the Special Astrophysical Observatory (SAO) between August 1992 and May 1997. The data contain 89 observations of 62 star systems on the large telescope and 21 on the smaller one. For the 6-m aperture 18 systems remained unresolved. The measured angular separation ranged from 39 mas, two times above the BTA diffraction limit, to 1593 mas.

  8. EMCCD SPECKLE INTERFEROMETRY WITH THE 6 m TELESCOPE: ASTROMETRIC MEASUREMENTS, DIFFERENTIAL PHOTOMETRY, AND ORBITS

    SciTech Connect

    Docobo, Jose A.; Tamazian, Vakhtang S.; Melikian, Norair D. E-mail: vakhtang.tamazian@usc.e E-mail: nmelikia@bao.sci.a

    2010-10-15

    Results of the EMCCD-based speckle interferometric observations and differential photometry for 46 visual binaries obtained in 2007 June and July with the 6 m telescope of the Special Astrophysical Observatory (Russia) are presented. First preliminary orbits for COU 401, COU 1281, and COU 1037 as well as improved orbits for CHR 137, COU 100, COU 1136, COU 798, CHR 51, CHR 55, COU 315, COU 206, and ADS 13961, along with their dynamical mass estimates, are reported. On the basis of dynamical parallax information, first distance estimates for COU 100, COU 1136, COU 798, COU 206, and COU 1037 are calculated.

  9. Special issue: Macroscopic randomness in astrophysical plasmas: The legacy and vision of Ya. B. Zeldovich

    NASA Astrophysics Data System (ADS)

    Shukurov, Anvar; Sokoloff, Dmitry; Schekochihin, Alexander

    2015-08-01

    This issue commemorates an outstanding scientist of the twentieth century, Yakov Borisovich Zeldovich, in connection with the centenary of his birth (8 March 1914), with a collection of reviews and research articles broadly related to large-scale random phenomena in astrophysical plasmas.

  10. The Intersection of NASA Astrophysics Education and Public Outreach and Higher Education: A Special Interest Group Meeting

    NASA Astrophysics Data System (ADS)

    Sharma, M.; Smith, D.; Schultz, G.; Bianchi, L.; Blair, W.

    2011-09-01

    This paper presents highlights from a group discussion on how the NASA Science Mission Directorate (SMD) education and public outreach (EPO) community could better support undergraduate astronomy education through EPO products and resources - current and future - targeted at the college level. The discussion was organized by the SMD Astrophysics EPO Forum through a Special Interest Group Meeting at the 2010 ASP Annual Meeting in Boulder. Our session took advantage of the simultaneous presence of EPO professionals and the Cosmos in the Classroom participants to seek out diverse perspectives on and experiences in higher education.

  11. Detection of spatially extended sources in high energy astrophysics with special application to lunar occultation

    NASA Astrophysics Data System (ADS)

    Jenke, Peter Alexander

    2009-01-01

    Occultation is a technique that enables image reconstruction and source identification with a non-imaging detector. Such an approach is well suited for a future survey mission in nuclear astrophysics. In particular, the Lunar Occultation Technique (LOT) utilizes the Moon as an occulting object and is the basis of a new gamma-ray survey mission concept, the Lunar OCcultation Observer (LOCO). Techniques utilizing the LOT to detect spatially extended emission, from the Galactic plane or Galactic Center region, have been developed. Given knowledge of detector position in lunar orbit, combined with lunar ephemeris and relevant coordinate transformations, occultation time series can be used to reconstruct skymaps of these extended Galactic emitters. Monte-Carlo Markov Chains (MCMC), incorporating the Metropolis-Hastings algorithm for parametric model testing, form the basis of the technique. Performance of the imaging methodology, and its application to nuclear astrophysics will be presented.

  12. A strong astrophysical constraint on the violation of special relativity by quantum gravity.

    PubMed

    Jacobson, T; Liberati, S; Mattingly, D

    2003-08-28

    Special relativity asserts that physical phenomena appear the same to all unaccelerated observers. This is called Lorentz symmetry and relates long wavelengths to short ones: if the symmetry is exact it implies that space-time must look the same at all length scales. Several approaches to quantum gravity, however, suggest that there may be a microscopic structure of space-time that leads to a violation of Lorentz symmetry. This might arise because of the discreteness or non-commutivity of space-time, or through the action of extra dimensions. Here we determine a very strong constraint on a type of Lorentz violation that produces a maximum electron speed less than the speed of light. We use the observation of 100-MeV synchrotron radiation from the Crab nebula to improve the previous limit by a factor of 40 million, ruling out this type of Lorentz violation, and thereby providing an important constraint on theories of quantum gravity. PMID:12944959

  13. Astrophysics and Space Science

    NASA Astrophysics Data System (ADS)

    Mould, Jeremy; Brinks, Elias; Khanna, Ramon

    2015-08-01

    Astrophysics and Space Science publishes original contributions and invited reviews covering the entire range of astronomy, astrophysics, astrophysical cosmology, planetary and space science, and the astrophysical aspects of astrobiology. This includes both observational and theoretical research, the techniques of astronomical instrumentation and data analysis, and astronomical space instrumentation. We particularly welcome papers in the general fields of high-energy astrophysics, astrophysical and astrochemical studies of the interstellar medium including star formation, planetary astrophysics, the formation and evolution of galaxies and the evolution of large scale structure in the Universe. Papers in mathematical physics or in general relativity which do not establish clear astrophysical applications will not longer be considered.The journal also publishes topical collections consisting of invited reviews and original research papers selected special issues in research fields of particular scientific interest. These consist of both invited reviews and original research papers.Conference proceedings will not be considered. All papers published in the journal are subject to thorough and strict peer-reviewing.Astrophysics and Space Science has an Impact Factor of 2.4 and features short editorial turnaround times as well as short publication times after acceptance, and colour printing free of charge. Published by Springer the journal has a very wide online dissemination and can be accessed by researchers at a very large number of institutes worldwide.

  14. Theoretical Astrophysics - Volume 1, Astrophysical Processes

    NASA Astrophysics Data System (ADS)

    Padmanabhan, T.

    2000-12-01

    Preface; 1. Order-of-magnitude astrophysics; 2. Dynamics; 3. Special relativity, electrodynamics and optics; 4. Basics of electromagnetic radiation; 5. Statistical mechanics; 6. Radiative processes; 7. Spectra; 8. Neutral fluids; 9. Plasma physics; 10. Gravitational dynamics; 11. General theory of relativity; 12. Basics of nuclear physics; Notes and References; Index.

  15. The OFP-6M transport jet

    NASA Technical Reports Server (NTRS)

    Alexander, Kelly; Heneghan, Brian; Holmes, Joules; Hughes, Bret; Kettering, Mark; Wells, Jennifer; Whelan, Todd

    1994-01-01

    This report presents a preliminary design of a commercial jet transport that meets the criteria of the Request For Proposal presented by the American Institute of Aeronautics and Astronauts (AIAA). The proposal requires an innovative design of a low cost domestic commercial transport that will reduce operating costs for airline companies while still meeting present and future requirements of the Federal Aviation Regulations for this type of aircraft. Specifications for the design include a mixed class, 153 passenger aircraft, traveling a range of 3000 nm. The intent of the project is to identify factors that reduce cost and to design within the limits of these constraints. The project includes techniques or options that incorporate new technologies but do not override practicality, alternative design approaches, and a comparison between the new design and current aircraft in its class. The OFP-6M is an alternative design approach to the conventional commercial transport jet and is geared towards customer satisfaction through efficiency and reliability. The goals of the OFP-6M transport design are to provide original, sensible, and practical solutions by combining essential preliminary design factors with growing technology. The design focus of the OFP-6M reduces costs by simplifying systems where significant weight or maintenance savings can be achieved, and by integrating advanced technology for improved performance. Key aspects of the OFP-6M design are efficient use of materials like composites, and efficient advanced ducted high bypass turbofan engines. The high bypass engines lower fuel consumption and aid in reducing costs and meeting future noise emission restrictions. Composites are used for most structural components, including flooring and wing box. Although composites are an emerging technology and presently, a high maintenance material, they can be cost effective and an alternative to aluminum structures when correct manufacturing and design strategies

  16. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-12-31

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  17. Nuclear astrophysics

    SciTech Connect

    Haxton, W.C.

    1992-01-01

    The problem of core-collapse supernovae is used to illustrate the many connections between nuclear astrophysics and the problems nuclear physicists study in terrestrial laboratories. Efforts to better understand the collapse and mantle ejection are also motivated by a variety of interdisciplinary issues in nuclear, particle, and astrophysics, including galactic chemical evolution, neutrino masses and mixing, and stellar cooling by the emission of new particles. The current status of theory and observations is summarized.

  18. Detection of an intergalactic meteor particle with the 6-m telescope

    NASA Astrophysics Data System (ADS)

    Afanasiev, V. L.; Kalenichenko, V. V.; Karachentsev, I. D.

    2007-12-01

    On July 28, 2006 the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences recorded the spectrum of a faint meteor. We confidently identify the lines of FeI and MgI, OI, NI and molecular-nitrogen (N2) bands. The entry velocity of the meteor body into the Earth’s atmosphere estimated from radial velocity is equal to 300 km/s. The body was several tens of a millimeter in size, like chondrules in carbon chondrites. The radiant of the meteor trajectory coincides with the sky position of the apex of the motion of the Solar system toward the centroid of the Local Group of galaxies. Observations of faint sporadic meteors with FAVOR TV CCD camera confirmed the radiant at a higher than 96% confidence level. We conclude that this meteor particle is likely to be of extragalactic origin. The following important questions remain open: (1) How metal-rich dust particles came to be in the extragalactic space? (2) Why are the sizes of extragalactic particles larger by two orders of magnitude (and their masses greater by six orders of magnitude) than common interstellar dust grains in our Galaxy? (3) If extragalactic dust surrounds galaxies in the form of dust (or gas-and-dust) aureoles, can such formations now be observed using other observational techniques (IR observations aboard Spitzer satellite, etc.)? (4) If inhomogeneous extragalactic dust medium with the parameters mentioned above actually exists, does it show up in the form of irregularities on the cosmic microwave background (WMAP etc.)?

  19. Relativistic Astrophysics

    NASA Astrophysics Data System (ADS)

    Jones, Bernard J. T.; Markovic, Dragoljub

    1997-06-01

    Preface; Prologue: Conference overview Bernard Carr; Part I. The Universe At Large and Very Large Redshifts: 2. The size and age of the Universe Gustav A. Tammann; 3. Active galaxies at large redshifts Malcolm S. Longair; 4. Observational cosmology with the cosmic microwave background George F. Smoot; 5. Future prospects in measuring the CMB power spectrum Philip M. Lubin; 6. Inflationary cosmology Michael S. Turner; 7. The signature of the Universe Bernard J. T. Jones; 8. Theory of large-scale structure Sergei F. Shandarin; 9. The origin of matter in the universe Lev A. Kofman; 10. New guises for cold-dark matter suspects Edward W. Kolb; Part II. Physics and Astrophysics Of Relativistic Compact Objects: 11. On the unification of gravitational and inertial forces Donald Lynden-Bell; 12. Internal structure of astrophysical black holes Werner Israel; 13. Black hole entropy: external facade and internal reality Valery Frolov; 14. Accretion disks around black holes Marek A. Abramowicz; 15. Black hole X-ray transients J. Craig Wheeler; 16. X-rays and gamma rays from active galactic nuclei Roland Svensson; 17. Gamma-ray bursts: a challenge to relativistic astrophysics Martin Rees; 18. Probing black holes and other exotic objects with gravitational waves Kip Thorne; Epilogue: the past and future of relativistic astrophysics Igor D. Novikov; I. D. Novikov's scientific papers and books.

  20. Astrophysics today

    SciTech Connect

    Cameron, A.G.W.

    1984-01-01

    Examining recent history, current trends, and future possibilities, the author reports the frontiers of research on the solar system, stars, galactic physics, and cosmological physics. The book discusses the great discoveries in astronomy and astrophysics and examines the circumstances in which they occurred. It discusses the physics of white dwarfs, the inflationary universe, the extinction of dinosaurs, black hole, cosmological models, and much more.

  1. Astrophysical symmetries

    PubMed Central

    Trimble, Virginia

    1996-01-01

    Astrophysical objects, ranging from meteorites to the entire universe, can be classified into about a dozen characteristic morphologies, at least as seen by a blurry eye. Some patterns exist over an enormously wide range of distance scales, apparently as a result of similar underlying physics. Bipolar ejection from protostars, binary systems, and active galaxies is perhaps the clearest example. The oral presentation included about 130 astronomical images which cannot be reproduced here. PMID:11607715

  2. Particle astrophysics

    SciTech Connect

    Sadoulet, B. |

    1992-12-31

    In the last few years, particle astrophysics has emerged as a new field at the frontier between high energy astrophysics, cosmology, and particle physics. Two spectacular achievements of this new field in the last decade have been the establishment of neutrino astronomy with the detection of solar neutrinos by two independent experiments and the spectacular observation of the neutrinos from the supernova SN1987A. In addition, the field has produced tantalizing hints of new physics beyond the standard models of astrophysics and particle physics, generating enthusiastic attempts to confirm these potential effects. This new field involves some two hundred experimentalists and a similar number of theorists, most of them coming from particle and nuclear physics, and as scientist will see, their effort is to a large extent complementary to accelerator based high energy physics. This review attempts, at the beginning of this workshop, to capture the excitement of this new field. Summary talks will describe in more detail some of the topics discussed in the study groups.

  3. Results of magnetic field measurements of CP-stars performed with the 6-m telescope. III. Observations in 2009

    NASA Astrophysics Data System (ADS)

    Romanyuk, I. I.; Semenko, E. A.; Kudryavtsev, D. O.; Moiseevaa, A. V.

    2016-07-01

    We present the results of measuring longitudinal magnetic fields ( B e ), rotation velocities ( v e sin i), and radial velocities ( V r ) of 44 stars observed with the Main Stellar Spectrograph (MSS) of the 6-m BTA telescope of the Special Astrophysical Observatory in 2009. For the first time, magnetic fields were detected for the stars HD5441, HD199180, HD225627, and BD+00° 4535. We show that for the same stars, the longitudinal fields B e measured from the H β hydrogen line core and from metal lines can differ by 10% and up to a factor of 2-3. Except in rare cases, magnetic fields measured from the metal lines are stronger. We believe that this phenomenon is of a physical nature and depends on the magnetic field topology and the physical conditions inside a specific star. Observations of standard stars without magnetic fields confirm the absence of systematic errors capable of introducing distortions into the longitudinal-field measurement results. In this work we comment on the results for each of the stars.

  4. Relativistic astrophysics explorer

    NASA Astrophysics Data System (ADS)

    Kaaret, P.

    2004-01-01

    The great success of the Rossi X-Ray Timing Explorer (RXTE) has shown that X-ray timing is an excellent tool for the study of strong gravitational fields and the measurement of fundamental physical properties of black holes and neutron stars. Here, we describe a next-generation X-ray timing mission, the Relativistic Astrophysics Explorer (RAE), designed to fit within the envelope of a medium-sized mission. The instruments will be a narrow-field X-ray detector array with an area of 6 m 2 equal to 10 times that of RXTE and a wide-field X-ray monitor. We describe the science made possible with this mission, the design of the instruments, and results on prototype large-area X-ray detectors.

  5. Laboratory astrophysics

    SciTech Connect

    Springer, P.T.; Goldstein, W.H.; Iglesias, C.A.; Wilson, B.G.; Rogers, F.J.; Stewart, R.E.

    1995-05-01

    We propose an experiment to test opacity models for stellar atmospheres. Particularly important is to perform experiments at very low density and temperature where line shape treatments give large differences in Rosseland mean opacities for astrophysical mixtures, and to test the range of validity for the unresolved transition array treatments. Experimental requirements are ultra high spectral resolution combined with large homogenous plasma sources lasting tens of nanoseconds, and with Planckian radiation fields. These requirements dovetail nicely with emerging pulsed power capabilities. We propose a high resolution measurement of the frequency dependent opacity, for ultra low density iron plasmas in radiatively driven equilibrium plasmas.

  6. Astrophysical cosmology

    SciTech Connect

    Bardeen, J.M.

    1986-01-01

    The last several years have seen a tremendous ferment of activity in astrophysical cosmology. Much of the theoretical impetus has come from particle physics theories of the early universe and candidates for dark matter, but what promise to be even more significant are improved direct observations of high z galaxies and intergalactic matter, deeper and more comprehensive redshift surveys, and the increasing power of computer simulations of the dynamical evolution of large scale structure. Upper limits on the anisotropy of the microwave background radiation are gradually getting tighter and constraining more severely theoretical scenarios for the evolution of the universe. 47 refs.

  7. Computational Astrophysics

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Astsatryan, H. V.

    2015-07-01

    Present astronomical archives that contain billions of objects, both Galactic and extragalactic, and the vast amount of data on them allow new studies and discoveries. Astrophysical Virtual Observatories (VO) use available databases and current observing material as a collection of interoperating data archives and software tools to form a research environment in which complex research programs can be conducted. Most of the modern databases give at present VO access to the stored information, which makes possible also a fast analysis and managing of these data. Cross-correlations result in revealing new objects and new samples. Very often dozens of thousands of sources hide a few very interesting ones that are needed to be discovered by comparison of various physical characteristics. VO is a prototype of Grid technologies that allows distributed data computation, analysis and imaging. Particularly important are data reduction and analysis systems: spectral analysis, SED building and fitting, modelling, variability studies, cross correlations, etc. Computational astrophysics has become an indissoluble part of astronomy and most of modern research is being done by means of it.

  8. Particle astrophysics

    NASA Astrophysics Data System (ADS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  9. Molecular astrophysics

    NASA Astrophysics Data System (ADS)

    Herzberg, G.

    1989-01-01

    A brief history of Molecular Astrophysics is presented. The first molecules in space were identified in the 1920s in comets followed soon after by those in planetary atmospheres. The recent identification by MCKELLAR of the dimer of H 2, that is, (H 2) 2 in the atmosphere of Jupiter as well as the discovery, by DROSSART, MAILLARD, WATSON and others, of the H 3+ ion in the auroral zone of Jupiter are described. In this laboratory there is a continuing interest in interstellar molecules. Several molecules and molecular ions were observed by collaboration of laboratory spectroscopists and astronomers. Only the most recent ones are discussed. Also a few of the molecules not yet observed but likely to be observed are mentioned.

  10. Particle astrophysics

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Cronin, James; Aprile, Elena; Barish, Barry C.; Beier, Eugene W.; Brandenberger, Robert; Cabrera, Blas; Caldwell, David; Cassiday, George; Cline, David B.

    1991-01-01

    The following scientific areas are reviewed: (1) cosmology and particle physics (particle physics and the early universe, dark matter, and other relics); (2) stellar physics and particles (solar neutrinos, supernovae, and unconventional particle physics); (3) high energy gamma ray and neutrino astronomy; (4) cosmic rays (space and ground observations). Highest scientific priorities for the next decade include implementation of the current program, new initiatives, and longer-term programs. Essential technological developments, such as cryogenic detectors of particles, new solar neutrino techniques, and new extensive air shower detectors, are discussed. Also a certain number of institutional issues (the funding of particle astrophysics, recommended funding mechanisms, recommended facilities, international collaborations, and education and technology) which will become critical in the coming decade are presented.

  11. Astrophysics. A primer

    NASA Astrophysics Data System (ADS)

    Kundt, Wolfgang

    For a quantitative understanding of the physics of the universe - from the solar system through the Milky Way to clusters of galaxies all the way to cosmology - these edited lecture notes are perhaps among the most concise and also among the most critical ones: Astrophysics has not yet stood the redundancy test of laboratory physics, hence should be aware of early interpretations. Special chapters are devoted to magnetic and radiation processes, supernovae, disks, black-hole candidacy, bipolar flows, cosmic rays, gamma-ray bursts, image distortions, and special sources. At the same time, planet earth is viewed as the arena for life, with plants and animals having evolved to homo sapiens during cosmic time. This text is unique in covering the basic qualitative and quantitative tools, formulae as well as numbers, needed for the precise interpretation of frontline phenomena. The author compares mainstream interpretations with new and even controversial ones he wishes to emphasize.

  12. Molecular Astrophysics

    NASA Astrophysics Data System (ADS)

    Hartquist, T. W.

    2005-07-01

    Part I. Molecular Clouds and the Distribution of Molecules in the Milky Way and Other Galaxies: 1. Molecular clouds in the Milky Way P. Friberg and A. Hjalmarson; 2. Molecules in galaxies L. Blitz; Part II. Diffuse Molecular Clouds: 3. Diffuse cloud chemistry E. F. Van Dishoeck; 4. Observations of velocity and density structure in diffuse clouds W. D. Langer; 5. Shock chemistry in diffuse clouds T. W. Hartquist, D. R. Flower and G. Pineau des Forets; Part III. Quiescent Dense Clouds: 6. Chemical modelling of quiescent dense interstellar clouds T. J. Millar; 7. Interstellar grain chemistry V. Buch; 8. Large molecules and small grains in astrophysics S. H. Lepp; Part IV. Studies of Molecular Processes: 9. Molecular photoabsorption processes K. P. Kirby; 10. Interstellar ion chemistry: laboratory studies D. Smith, N. G. Adams and E. E. Ferguson; 11. Theoretical considerations on some collisional processes D. R. Bates; 12. Collisional excitation processes E. Roueff; 13. Neutral reactions at Low and High Temperatures M. M. Graff; Part V. Atomic Species in Dense Clouds: 14. Observations of atomic species in dense clouds G. J. Melnick; 15. Ultraviolet radiation in molecular clouds W. G. Roberge; 16. Cosmic ray induced photodissociation and photoionization of interstellar molecules R. Gredel; 17. Chemistry in the molecular cloud Barnard 5 S. B. Charnley and D. A. Williams; 18. Molecular cloud structure, motions, and evolution P. C. Myers; Part VI. H in Regions of Massive Star Formation: 19. Infrared observations of line emission from molecular hydrogen T. R. Geballe; 20. Shocks in dense molecular clouds D. F. Chernoff and C. F. McKee; 21. Dissociative shocks D. A. Neufeld; 22. Infrared molecular hydrogen emission from interstellar photodissociation regions A. Sternberg; Part VII. Molecules Near Stars and in Stellar Ejecta: 23. Masers J. M. Moran; 24. Chemistry in the circumstellar envelopes around mass-losing red giants M. Jura; 25. Atoms and molecules in supernova 1987a R

  13. Planetary rings and astrophysical discs

    NASA Astrophysics Data System (ADS)

    Latter, Henrik

    2016-05-01

    Disks are ubiquitous in astrophysics and participate in some of its most important processes. Of special interest is their role in star, planet and moon formation, the growth of supermassive black holes, and the launching of jets. Although astrophysical disks can be up to ten orders of magnitude larger than planetary rings and differ hugely in composition, all disks share to some extent the same basic dynamics and many physical phenomena. This review explores these areas of overlap. Topics covered include disk formation, accretion, collisions, instabilities, and satellite-disk interactions.

  14. Trends in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Schatz, Hendrik

    2016-06-01

    Nuclear astrophysics is a vibrant field at the intersection of nuclear physics and astrophysics that encompasses research in nuclear physics, astrophysics, astronomy, and computational science. This paper is not a review. It is intended to provide an incomplete personal perspective on current trends in nuclear astrophysics and the specific role of nuclear physics in this field.

  15. Operational guidance for using DOT-6M/2R packaging

    SciTech Connect

    Kelly, D.L.; Hummer, J.H.

    1994-03-01

    The purpose of this paper is to describe a new US Department of Energy (DOE), Transportation Management Division task to create a US Department of Transportation (DOT) Specification 6M/2R packaging configuration user`s guide. The need for a user`s guide was identified because the DOT-6M/2R packaging configuration is widely used by DOE site contractors, and DOE receives many questions about the approved packaging configurations. Currently, two DOE organizations have the authority to approve new DOT-6M/2R configurations. For Defense Programs, the Transportation and Packaging Safety Division (EH-332) administers the program. For Environmental Restoration and Waste Management, the Transportation Management Division (EM-261) administers the program.

  16. The Tapestry of Modern Astrophysics

    NASA Astrophysics Data System (ADS)

    Shore, Steven N.

    2002-10-01

    The scope of modern astrophysics is the entire cosmos and everything in it. As and substantial as its subject, The Tapestry of Modern Astrophysics provides advanced undergraduates or graduate-level students with a comprehensive introduction to the subject. Avoiding axiomatic presentations, the author combines extensive qualitative discussions with analytical treatments so that students develop physical intuition the combination of observations and theoretical "horse sense" that is necessary for research in the field. The text is particularly distinguished by its deep and broad coverage, showing the way apparently different parts of astrophysics are intimately connected. Emphasizing the physical basis of the astrophysical phenomena along with the interpretation of data, Shore covers: The physical processes common to all cosmic bodies gravitation, thermal physics, and the gas laws. Special topics include statistical mechanics of stellar systems, rate equations, and General Relativity

  17. Overview of instrumentation and data analysis methods including calibration, instrumentation, and image formation and reconstruction Radiative transfer and physical processes in stellar and planetary atmospheres. Special topics include spectral classification and techniques for treating scattering Stellar structure and evolution, energy sources, and nucleosynthesis The interstellar medium with a general introduction to radiative and hydrodynamical processes The Milky Way as a galaxy, emphasizing the connection between locally observed phenomena and broader properties of extragalactic systems, active galaxies, and clusters of galaxies Cosmology and structure formation STEVEN N. SHORE is Professor of Physics and Astronomy at Indiana University South Bend. He is a scientific editor of the Astrophysical Journal and a visiting professor at Osservatorio Astrofisico di Arcetri, University of Pisa, University of Notre Dame, and Arizona State University. He is

  18. Specialization.

    ERIC Educational Resources Information Center

    Luna, Pat

    Designed for middle school students, this award winning, six-day teaching unit helped students learn about the concepts of specialization, interdependence, efficiency, and profit. At the onset of the lesson the students were already familiar with the concepts of scarcity, goods, services, profits, supply, demand, and opportunity costs. The unit's…

  19. AUTHORIZING THE DOT SPECIFICATION 6M PACKAGING FOR CONTINUED USE AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Watkins, R.; Loftin, B.; Hoang, D.

    2010-03-04

    The U.S. Department of Transportation (DOT) Specification 6M packaging was in extensive use for more than 40 years for in-commerce shipments of Type B quantities of fissile and radioactive material (RAM) across the USA, among the Department of Energy (DOE) laboratories, and between facilities in the DOE production complex. In January 2004, the DOT Research and Special Programs Administration (RSPA) Agency issued a final rule in the Federal Register to ammend requirements in the Hazardous Materials Regulations (HMR) pertaining to the transportation of radioactive materials. The final rule became effective on October 1, 2004. One of those changes discontinued the use of the DOT specification 6M, along with other DOT specification packagings, on October 1, 2008. A main driver for the change was due to the fact that 6M specification packagings were not supported by a Safety Analysis Report for Packagings (SARP) that was compliant with Title 10 of the Code of Federal Regulations (CFR) Part 71 (10 CFR 71). The regulatory rules for the discontinued use have been edited in Title 49 of the CFR Parts 100-185, 2004 edition and thereafter. Prior to October 1, 2008, the use of the 6M within the boundaries of the Savannah River Site (SRS), called an onsite transfer, was governed by an onsite transportation document that referenced 49 CFR Parts 100-185. SRS had to develop an Onsite Safety Assessment (OSA) which was independent of 49 CFR in order to justify the continued use of the DOT Specification 6M for the transfer of radioactive material (RAM) at the SRS after October 1, 2008. This paper will discuss the methodology for and difficulties associated with authorizing the DOT Specification 6M Packaging for continued use at the Savannah River Site.

  20. CCD polarimetry of distant comets with the 6-m telescope at SAO RAN

    NASA Astrophysics Data System (ADS)

    Ivanova, A.; Dlugach, J.; Afanasiev, V.; Reshetnyk, V.; Korsun, P.

    2014-07-01

    Usually, polarimetric measurements are used to study the physical properties of comets approaching the Sun. Since the dust in distant comets differs from the dust in short-period comets, the study of polarization of the distant comets is very important for the investigation of their physical properties. However, little is known about the dust properties in the cometary coma as well as about the cometary nuclei at large heliocentric distances. So far, there are no comets studied with polarimetric techniques at heliocentric distances more than 4 au. We have started a comprehensive program of polarimetric, photometric, and spectral investigations of active distant comets (or without noticeable activity) with the focal reducer SCORPIO attached in the prime focus of the 6-m telescope BTA (Special Astrophysical Observatory, Russia). We performed broad-band polarimetry and long-slit spectroscopy of comets C/2011 S1 (LINEAR) and C/2010 R1 (LINEAR) in the visible wavelength range. The data were obtained on November 12, 2012, at the phase angle of 10.4°, when the comet C/2011 S1 (LINEAR) was at the heliocentric distance of 6 au, and, on February 6, 2013, at the phase angle of 9.1°, when the comet C/2010 R1 (LINEAR) was at the heliocentric distance of 5.9 au, respectively. The data on the degree of linear polarization of the distant comets C/2011 S1 (LINEAR) and C/2010 R1 (LINEAR) are the first ever obtained at such large heliocentric distances. We present the results and preliminary analysis of imaging polarimetric observations of comets C/2011 S1 (LINEAR) and C/2010 R1 (LINEAR). These comets show considerable levels of activity not only within the zone of water sublimation (up to 3 au), but also at heliocentric distances far exceeding this limit. Molecular emissions are not detected in the observed cometary spectra. The cometary comae display a degree of linear polarization of about -2% and -2.2%, respectively. This value is significantly higher, in absolute terms, than

  21. 0.6-M Antennae for the Amiba Interferometry Array

    NASA Astrophysics Data System (ADS)

    Koch, P.; Raffin, P. A.; Proty Wu, J.-H.; et al.

    2006-10-01

    The Array for Microwave Background Anisotropy (AMiBA) is a hexapod telescope for astronomy. The fully steerable platform can accommodate up to 19 dishes. We present the design, simulation, manufacturing and performance verification for the 0.6m Cassegrain antennae. The primary and secondary mirrors are carbon fiber sandwich structures, manufactured by CoTec Inc., in Taichung, Taiwan. They are aluminium coated with a final surface rms of 20-30 and 10 μm, respectively. Simulated load conditions for the mirrors show maximum rms surface errors of less than 10 μm. The measured antenna beam pattern confirms the expected performance.

  1. Photoneutron reactions in astrophysics

    SciTech Connect

    Varlamov, V. V. Ishkhanov, B. S.; Orlin, V. N.; Peskov, N. N.; Stopani, K. A.

    2014-12-15

    Among key problems in nuclear astrophysics, that of obtaining deeper insight into the mechanism of synthesis of chemical elements is of paramount importance. The majority of heavy elements existing in nature are produced in stars via radiative neutron capture in so-called s- and r processes, which are, respectively, slow and fast, in relation to competing β{sup −}-decay processes. At the same time, we know 35 neutron-deficient so-called bypassed p-nuclei that lie between {sup 74}Se and {sup 196}Hg and which cannot originate from the aforementioned s- and r-processes. Their production is possible in (γ, n), (γ, p), or (γ, α) photonuclear reactions. In view of this, data on photoneutron reactions play an important role in predicting and describing processes leading to the production of p-nuclei. Interest in determining cross sections for photoneutron reactions in the threshold energy region, which is of particular importance for astrophysics, has grown substantially in recent years. The use of modern sources of quasimonoenergetic photons obtained in processes of inverse Compton laser-radiation scattering on relativistic electronsmakes it possible to reveal rather interesting special features of respective cross sections, manifestations of pygmy E1 and M1 resonances, or the production of nuclei in isomeric states, on one hand, and to revisit the problem of systematic discrepancies between data on reaction cross sections from experiments of different types, on the other hand. Data obtained on the basis of our new experimental-theoretical approach to evaluating cross sections for partial photoneutron reactions are invoked in considering these problems.

  2. KATE-140 and MKF-6M space cameras

    NASA Astrophysics Data System (ADS)

    Kuchumov, V.

    1982-07-01

    The KATE-140 large-format topographic camera made it possible to obtain photographs suitable for precision photographic-survey processing. It has a field of vision of 85 deg which makes it possible for a single frame to contain an image of a 450x450-km segment of the Earth's surface from orbital altitude. Precise measurement of the linear dimensions of objects and their mutual positions can be carried out on the photographs. Moreover, the camera's high resolution meets imagery-interpretation requirements. A guidance device provides for both single and strip photographs with a given interval. A punching machine is used to separate the strips. Before being used on the Salyut-6 station, the other fixed camera, the MKF-6M, underwent thorough testing onboard the Soyuz-22 spacecraft. The multispectral MKF-6M camera is designed to obtain information about the spectral characteristics of natural objects in order to increase the reliability of their interpretation. It has six spectral channels, four of which encompass the visible spectra and two of which are in the near-infrared.

  3. Construction of 3.6m ARIES telescope enclosure with eccentric pier at Devasthal, Nainital

    NASA Astrophysics Data System (ADS)

    Bangia, Tarun

    Space optimized enclosure with eccentric pier for 3.6m ARIES telescope presents construction challenges at the unique observing site of Devasthal, Nainital, India. Enclosure comprises of about 16.5m diameter and 14m high insulated steel framed cylindrical dome rotating on a 14m high stationery dome supporting structure and a 24m × 12m extension structure building for accommodating aluminizing plant and ventilation system etc. Great deal of manual and mechanical excavation was carried out at the rocky site using rock breaking and JCB machines. Foundation bolts for columns of dome supporting structure and extension structure building were grouted after alignment with total station. A 7m diameter hollow cylindrical pier isolated from other structures and 1.85m eccentric with dome center designed due to space limitation at site is being casted for mounting 150 MT mass of the largest 3.6m telescope in the country. A 7m diameter template was fabricated for 3.6m pier top. Most of enclosure components are manufactured and tested in works before assembly/erection at site. Dome drive was tested with dummy loads using VVVF drive with 6 drive and 12 idler wheel assemblies at works to simulate dome weight and smooth operation before erection at site. A 4.2m wide motorized windscreen is being manufactured with a special grade synthetic fabric to withstand wind speed up to 15m/s.

  4. Radiative Magnetic Reconnection in Astrophysics

    NASA Astrophysics Data System (ADS)

    Uzdensky, D. A.

    In this chapter we review a new and rapidly growing area of research in high-energy plasma astrophysics—radiative magnetic reconnection, defined here as a regime of reconnection where radiation reaction has an important influence on the reconnection dynamics, energetics, and/or nonthermal particle acceleration. This influence be may be manifested via a variety of radiative effects that are critical in many high-energy astrophysical applications. The most notable radiative effects in astrophysical reconnection include radiation-reaction limits on particle acceleration, radiative cooling, radiative resistivity, braking of reconnection outflows by radiation drag, radiation pressure, viscosity, and even pair creation at highest energy densities. The self-consistent inclusion of these effects into magnetic reconnection theory and modeling sometimes calls for serious modifications to our overall theoretical approach to the problem. In addition, prompt reconnection-powered radiation often represents our only observational diagnostic tool available for studying remote astrophysical systems; this underscores the importance of developing predictive modeling capabilities to connect the underlying physical conditions in a reconnecting system to observable radiative signatures. This chapter presents an overview of our recent theoretical progress in developing basic physical understanding of radiative magnetic reconnection, with a special emphasis on astrophysically most important radiation mechanisms like synchrotron, curvature, and inverse-Compton. The chapter also offers a broad review of key high-energy astrophysical applications of radiative reconnection, illustrated by multiple examples such as: pulsar wind nebulae, pulsar magnetospheres, black-hole accretion-disk coronae and hot accretion flows in X-ray Binaries and Active Galactic Nuclei and their relativistic jets, magnetospheres of magnetars, and Gamma-Ray Bursts. Finally, this chapter discusses the most critical

  5. Future Experiments in Astrophysics

    NASA Technical Reports Server (NTRS)

    Krizmanic, John F.

    2002-01-01

    The measurement methodologies of astrophysics experiments reflect the enormous variation of the astrophysical radiation itself. The diverse nature of the astrophysical radiation, e.g. cosmic rays, electromagnetic radiation, and neutrinos, is further complicated by the enormous span in energy, from the 1.95 Kappa relic neutrino background to cosmic rays with energy greater than 10(exp 20)eV. The measurement of gravity waves and search for dark matter constituents are also of astrophysical interest. Thus, the experimental techniques employed to determine the energy of the incident particles are strongly dependent upon the specific particles and energy range to be measured. This paper summarizes some of the calorimetric methodologies and measurements planned by future astrophysics experiments. A focus will be placed on the measurement of higher energy astrophysical radiation. Specifically, future cosmic ray, gamma ray, and neutrino experiments will be discussed.

  6. Study of astrophysics at the ``Babeş-Bolyai'' University

    NASA Astrophysics Data System (ADS)

    Ureche, Vasile; Roman, Rodica

    2007-03-01

    This paper presents the history of the study of astrophysics at the ``Babeş-Bolyai'' University, from 1945 until now. Some special epochs are analyzed and the contributions of professors of astronomy at the study of astrophysics is put in evidence. The continuity of this study and the collaboration of the ``Babeş-Bolyai'' University with the ``Friedrich Wilhelms'' University of Germany, in the field of astrophysics is emphasized.

  7. Radioactive particulate release associated with the DOT specification 6M container under hypothetical accident conditions

    SciTech Connect

    Taylor, J.M.; Raney, P.J.

    1986-02-01

    A testing program was conducted to determine the leakage of depleted uranium dioxide powder (DUO) from the inner containment components of the US Department of Transportation's (DOT) specification 6M container under hypothetical accident conditions. Depleted uranium dioxide was selected as a surrogate for plutonium oxide because of the similarities in the powder characteristics, density and particle size, and because of the special handling and special facilities required for plutonium oxide. The DUO was packaged inside food pack cans in three different configurations inside the 2R vessel of the 6M container. The amount of DUO powder leakage ranged from none detectable (<2 x 10/sup -7/ g) to a high of 1 x 10/sup -3/ g. The combination of gravity, vibration and pressure produced the highest leakage of DUO. Containers that had hermetic seals (leak rates <6 x 10/sup -4/ atm cc/min) did not leak any detectable amount (<2 x 10/sup -7/ g) of DUO under the test conditions. Impact forces had no effect on the leakage of particles with the packaging configurations used. 23 refs., 24 figs., 3 tabs.

  8. Theory and laboratory astrophysics

    NASA Technical Reports Server (NTRS)

    Schramm, David N.; Mckee, Christopher F.; Alcock, Charles; Allamandola, Lou; Chevalier, Roger A.; Cline, David B.; Dalgarno, Alexander; Elmegreen, Bruce G.; Fall, S. Michael; Ferland, Gary J.

    1991-01-01

    Science opportunities in the 1990's are discussed. Topics covered include the large scale structure of the universe, galaxies, stars, star formation and the interstellar medium, high energy astrophysics, and the solar system. Laboratory astrophysics in the 1990's is briefly surveyed, covering such topics as molecular, atomic, optical, nuclear and optical physics. Funding recommendations are given for the National Science Foundation, NASA, and the Department of Energy. Recommendations for laboratory astrophysics research are given.

  9. High Energy Astrophysics Program

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This report reviews activities performed by members of the USRA (Universities Space Research Association) contract team during the six months during the reporting period (10/95 - 3/96) and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA), X-ray Timing Experiment (XTE), X-ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science, Archive Research Center (HEASARC), and others.

  10. High Energy Astrophysics Program

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This report reviews activities performed-by members of the USRA contract team during the six months of the reporting period and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, visiting the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA); X-ray Timing Experiment (XTE); X-ray Spectrometer (XRS); Astro-E; High Energy Astrophysics Science Archive Research Center (HEASARC), and others.

  11. Polarimetry of major Uranian moons at the 6-m telescope

    NASA Astrophysics Data System (ADS)

    Afanasiev, V. L.; Rosenbush, V. K.; Kiselev, N. N.

    2014-04-01

    We present the results of polarimetric observations of the icymoons of Uranus (Ariel, Titania, Oberon, and Umbriel) performed at the 6-m BTA telescope of the SAO RAS with the SCORPIO-2 focal reducer within the phase angle range of . The parameters of the negative polarization branch (referred to the scattering plane) are obtained in the V filter: for Ariel the maximum branch depth of P min ≈ -1.4% is reached at the phase angle of α min ≈ 1°; for Titania P min ≈ -1.2%, ; for Oberon P min ≈ -1.1%, . For Umbriel the polarization minimum was not reached: for the last measurement point at , polarization amounts to -1.7%. The declining P min and shifting αmin towards larger phase angles correlate with a decrease of the geometric albedo of the Uranian moons. There is no longitudinal dependence of polarization for the moons within the observational errors which indicates a similarity in the physical properties of the leading and trailing hemispheres. The phase-angle dependences of polarization for the major moons of Uranus are quite close to those observed in the group of small trans-Neptunian objects (Ixion, Huya, Varuna, 1999 DE9, etc.), which are characterized by a large gradient of negative polarization, about -1% per degree in the phase-angle range of.

  12. Astrophysical Institute, Potsdam

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Built upon a tradition of almost 300 years, the Astrophysical Institute Potsdam (AIP) is in an historical sense the successor of one of the oldest astronomical observatories in Germany. It is the first institute in the world which incorporated the term `astrophysical' in its name, and is connected with distinguished scientists such as Karl Schwarzschild and Albert Einstein. The AIP constitutes on...

  13. Astrophysics teaching at Assam University, Silchar

    NASA Astrophysics Data System (ADS)

    Das, Himadri Sekhar

    The Department of Physics is established in 1996 and since, then, thirteen batches of students have completed their Master’s programmes in the subject. The Department introduced in the year 2001 Astrophysics as one special paper in PG level (in the second year). The syllabus of Astrophysics is designed to include courses from observational Astronomy to Theoretical Astrophysics and Cosmology. There are two theory papers (in third and fourth semesters), one practical paper (in third semester) and one project or dissertation paper (in fourth semester), each one carries 100 marks. The major instruments available in the department for carrying out the experimental work are Meade-16 inch telescope, Celestron-8 inch inches Telescope, Meade refracting telescopes (4 inches, 2 number), SSP-5, SSP-3 photometer, Sivo Fibre-fed Spectrometer, CCD (Meade 416 XT, ST-6), Goniometer, Limb darkening apparatus etc. The practical paper includes study of the variation of sunspots; measurement of the parallax of distant objects, on moon and on planets like Jupiter and Saturn, measurement of the magnitude of different stars, study of the light scattering properties of rough surfaces, analysis of the image by image processing software (IRAF) etc. The project papers are based on research oriented topics which covers latest trends in Astrophysics including solar system studies, Interstellar medium and star formation studies and some problems in gravito-optics. There are altogether 6 scholars who have been awarded PhD and 10 are registered for PhD in Astrophysics. Besides these, 8 scholars have been awarded M. Phil. in Astrophysics. The broad research area of Astrophysics includes light scattering properties of cosmic dust, star formation, gravito optics, polarization study of comets etc. The Astrophysics group is currently doing research in different fields and have very good publications in several peer reviewed journals of international status.

  14. NASA's Astrophysics Education and Public Outreach

    NASA Astrophysics Data System (ADS)

    Hasan, Hashima

    2011-05-01

    NASA conducts a balanced Astrophysics Education and Public Outreach program over K-12, higher education, informal education and public outreach, with the goal of taking excitement of NASA's scientific discoveries to the public, and generating interest in students in the area of Science, Technology, Education and Mathematics (STEM). Examples of classroom material, innovative research programs for teachers and students, collaborative programs with libraries, museums and planetaria, and programs for special needs individuals are presented. Information is provided on the competitive opportunities provided by NASA for participation in Astrophysics educational programs.

  15. Compressible Astrophysics Simulation Code

    2007-07-18

    This is an astrophysics simulation code involving a radiation diffusion module developed at LLNL coupled to compressible hydrodynamics and adaptive mesh infrastructure developed at LBNL. One intended application is to neutrino diffusion in core collapse supernovae.

  16. Astrophysics and cosmic physics

    NASA Astrophysics Data System (ADS)

    Siuniaev, R. A.

    Recent astrophysical studies undertaken in the Soviet Union are surveyed. Papers are presented on the role of observations of galactic clusters in cosmological studies; photometric observations of active nuclei; investigations of the fine structure of radio sources; and interstellar molecules. Also considered are Type I supernovae, gamma-ray bursts, the motion of the sun in the interstellar medium, and astrophysical observations on Mt. Maidanak in Central Asia.

  17. SPAN: Astronomy and astrophysics

    NASA Technical Reports Server (NTRS)

    Thomas, Valerie L.; Green, James L.; Warren, Wayne H., Jr.; Lopez-Swafford, Brian

    1987-01-01

    The Space Physics Analysis Network (SPAN) is a multi-mission, correlative data comparison network which links science research and data analysis computers in the U.S., Canada, and Europe. The purpose of this document is to provide Astronomy and Astrophysics scientists, currently reachable on SPAN, with basic information and contacts for access to correlative data bases, star catalogs, and other astrophysic facilities accessible over SPAN.

  18. Arcetri Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Arcetri Astrophysical Observatory, a government research institute founded in 1972, is located close to the villa where Galileo spent the last 11 years of his life. Under the directorship of Giorgio Abetti (1921-53) it became the growth point of Italian astrophysics with emphasis on solar physics; a tradition continued by his successor Guglielmo Righini (1953-78). Since 1978 the activities ha...

  19. Laboratory Astrophysics White Paper

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy; Federman, Steve; Kwong, Victor; Salama, Farid; Savin, Daniel; Stancil, Phillip; Weingartner, Joe; Ziurys, Lucy

    2006-01-01

    Laboratory astrophysics and complementary theoretical calculations are the foundations of astronomical and planetary research and will remain so for many generations to come. From the level of scientific conception to that of the scientific return, it is our understanding of the underlying processes that allows us to address fundamental questions regarding the origins and evolution of galaxies, stars, planetary systems, and life in the cosmos. In this regard, laboratory astrophysics is much like detector and instrument development at NASA and NSF; these efforts are necessary for the astronomical research being funded by the agencies. The NASA Laboratory Astrophysics Workshop met at the University of Nevada, Las Vegas (UNLV) from 14-16 February, 2006 to identify the current laboratory data needed to support existing and future NASA missions and programs in the Astrophysics Division of the Science Mission Directorate (SMD). Here we refer to both laboratory and theoretical work as laboratory astrophysics unless a distinction is necessary. The format for the Workshop involved invited talks by users of laboratory data, shorter contributed talks and poster presentations by both users and providers that highlighted exciting developments in laboratory astrophysics, and breakout sessions where users and providers discussed each others' needs and limitations. We also note that the members of the Scientific Organizing Committee are users as well as providers of laboratory data. As in previous workshops, the focus was on atomic, molecular, and solid state physics.

  20. Remarks about the thermodynamics of astrophysical systems in mutual interaction and related notions

    NASA Astrophysics Data System (ADS)

    Velazquez, L.

    2016-03-01

    General aspects about the thermodynamics of astrophysical systems are discussed, overall, those concerning to astrophysical systems in mutual interaction (or the called \\emph{open astrophysical systems}). A special interest is devoted along the paper to clarify several misconceptions that are still common in the recent literature, such as the direct application to the astrophysical scenario of notions and theoretical frameworks that were originally conceived to deal with extensive systems of the everyday practice (large systems with short-range interactions).

  1. Astrophysical observations: lensing and eclipsing Einstein's theories.

    PubMed

    Bennett, Charles L

    2005-02-11

    Albert Einstein postulated the equivalence of energy and mass, developed the theory of special relativity, explained the photoelectric effect, and described Brownian motion in five papers, all published in 1905, 100 years ago. With these papers, Einstein provided the framework for understanding modern astrophysical phenomena. Conversely, astrophysical observations provide one of the most effective means for testing Einstein's theories. Here, I review astrophysical advances precipitated by Einstein's insights, including gravitational redshifts, gravitational lensing, gravitational waves, the Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, from the earliest moments to the ultimate fate of the universe, will require developments in physics beyond Einstein, to a unified theory of gravity and quantum physics. PMID:15705841

  2. Improved Ohmic confinement induced by multipulse turbulent heating in the Hefei Tokamak-6M

    NASA Astrophysics Data System (ADS)

    Xu, Yuhong; Yu, Chang-Xuan; Luo, J. R.; Mao, J. S.; Liu, B. H.; Li, J. G.; Liang, Y. F.; Jie, Y. X.; Wu, Z. W.

    1998-06-01

    The improved Ohmic confinement phase (H-mode) has been observed during the turbulent heating (TH) pulse on the Hefei Tokamak-6M (HT-6M) [World Survey of Activities in Controlled Fusion Research, Nuclear Fusion Special Supplement (International Atomic Energy Agency, Vienna, 1991), p. 190]. The electron temperature and density profiles become steeper, and a more negative radial electric field Er well is developed across the normal Ohmic phase (L-mode) to H-mode transition, at the plasma edge. The edge toroidal and poloidal velocities υφ and υθ and the main ion pressure gradient ∇Pi are substantially enhanced after the TH pulse. It is found that across the transition, υθ, υφ and ∇Pi all play significant roles for regulating the Er profile, and the negative well shape of Er in the H-mode is dominantly maintained by the poloidal rotation. The time evolution indicates that prior to the transition υθ plays a key role in inducing the rapid variations of the Er and its shear. The density fluctuation suppression is independent of the sign of the Er shear(Er') and Er curvature (Er″) and consistent with the theoretical models of Shaing et al. and Zhang and Mahajan, while the Er″ sign has an appreciable effect on the suppression of the plasma potential fluctuations. This fact reveals that the dependence of these two fluctuation suppressions on the Er shear are different, suggesting that the existing L→H transition theories which consider only a single fluctuating field should be improved.

  3. Astrophysics Source Code Library

    NASA Astrophysics Data System (ADS)

    Allen, A.; DuPrie, K.; Berriman, B.; Hanisch, R. J.; Mink, J.; Teuben, P. J.

    2013-10-01

    The Astrophysics Source Code Library (ASCL), founded in 1999, is a free on-line registry for source codes of interest to astronomers and astrophysicists. The library is housed on the discussion forum for Astronomy Picture of the Day (APOD) and can be accessed at http://ascl.net. The ASCL has a comprehensive listing that covers a significant number of the astrophysics source codes used to generate results published in or submitted to refereed journals and continues to grow. The ASCL currently has entries for over 500 codes; its records are citable and are indexed by ADS. The editors of the ASCL and members of its Advisory Committee were on hand at a demonstration table in the ADASS poster room to present the ASCL, accept code submissions, show how the ASCL is starting to be used by the astrophysics community, and take questions on and suggestions for improving the resource.

  4. Augmented Reality in astrophysics

    NASA Astrophysics Data System (ADS)

    Vogt, Frédéric P. A.; Shingles, Luke J.

    2013-09-01

    Augmented Reality consists of merging live images with virtual layers of information. The rapid growth in the popularity of smartphones and tablets over recent years has provided a large base of potential users of Augmented Reality technology, and virtual layers of information can now be attached to a wide variety of physical objects. In this article, we explore the potential of Augmented Reality for astrophysical research with two distinct experiments: (1) Augmented Posters and (2) Augmented Articles. We demonstrate that the emerging technology of Augmented Reality can already be used and implemented without expert knowledge using currently available apps. Our experiments highlight the potential of Augmented Reality to improve the communication of scientific results in the field of astrophysics. We also present feedback gathered from the Australian astrophysics community that reveals evidence of some interest in this technology by astronomers who experimented with Augmented Posters. In addition, we discuss possible future trends for Augmented Reality applications in astrophysics, and explore the current limitations associated with the technology. This Augmented Article, the first of its kind, is designed to allow the reader to directly experiment with this technology.

  5. Astrophysics: An Integrative Course

    ERIC Educational Resources Information Center

    Gutsche, Graham D.

    1975-01-01

    Describes a one semester course in introductory stellar astrophysics at the advanced undergraduate level. The course aims to integrate all previously learned physics by applying it to the study of stars. After a brief introductory section on basic astronomical measurements, the main topics covered are stellar atmospheres, stellar structure, and…

  6. The NASA Astrophysics Program

    NASA Technical Reports Server (NTRS)

    Zebulum, Ricardo S.

    2011-01-01

    NASA's scientists are enjoying unprecedented access to astronomy data from space, both from missions launched and operated only by NASA, as well as missions led by other space agencies to which NASA contributed instruments or technology. This paper describes the NASA astrophysics program for the next decade, including NASA's response to the ASTRO2010 Decadal Survey.

  7. Surprises in astrophysical gasdynamics.

    PubMed

    Balbus, Steven A; Potter, William J

    2016-06-01

    Much of astrophysics consists of the study of ionized gas under the influence of gravitational and magnetic fields. Thus, it is not possible to understand the astrophysical universe without a detailed knowledge of the dynamics of magnetized fluids. Fluid dynamics is, however, a notoriously tricky subject, in which it is all too easy for one's a priori intuition to go astray. In this review, we seek to guide the reader through a series of illuminating yet deceptive problems, all with an enlightening twist. We cover a broad range of topics including the instabilities acting in accretion discs, the hydrodynamics governing the convective zone of the Sun, the magnetic shielding of a cooling galaxy cluster, and the behaviour of thermal instabilities and evaporating clouds. The aim of this review is to surprise and intrigue even veteran astrophysical theorists with an idiosyncratic choice of problems and counterintuitive results. At the same time, we endeavour to bring forth the fundamental ideas, to set out important assumptions, and to describe carefully whatever novel techniques may be appropriate to the problem at hand. By beginning at the beginning, and analysing a wide variety of astrophysical settings, we seek not only to make this review suitable for fluid dynamic veterans, but to engage novice recruits as well with what we hope will be an unusual and instructive introduction to the subject. PMID:27116247

  8. Gamma-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Stecker, F. W. (Editor); Trombka, J. I. (Editor)

    1973-01-01

    Conference papers on gamma ray astrophysics are summarized. Data cover the energy region from about 0.3 MeV to a few hundred GeV and theoretical models of production mechanisms that give rise to both galactic and extragalactic gamma rays.

  9. Surprises in astrophysical gasdynamics

    NASA Astrophysics Data System (ADS)

    Balbus, Steven A.; Potter, William J.

    2016-06-01

    Much of astrophysics consists of the study of ionized gas under the influence of gravitational and magnetic fields. Thus, it is not possible to understand the astrophysical universe without a detailed knowledge of the dynamics of magnetized fluids. Fluid dynamics is, however, a notoriously tricky subject, in which it is all too easy for one’s a priori intuition to go astray. In this review, we seek to guide the reader through a series of illuminating yet deceptive problems, all with an enlightening twist. We cover a broad range of topics including the instabilities acting in accretion discs, the hydrodynamics governing the convective zone of the Sun, the magnetic shielding of a cooling galaxy cluster, and the behaviour of thermal instabilities and evaporating clouds. The aim of this review is to surprise and intrigue even veteran astrophysical theorists with an idiosyncratic choice of problems and counterintuitive results. At the same time, we endeavour to bring forth the fundamental ideas, to set out important assumptions, and to describe carefully whatever novel techniques may be appropriate to the problem at hand. By beginning at the beginning, and analysing a wide variety of astrophysical settings, we seek not only to make this review suitable for fluid dynamic veterans, but to engage novice recruits as well with what we hope will be an unusual and instructive introduction to the subject.

  10. PREFACE: Nuclear Physics in Astrophysics III

    NASA Astrophysics Data System (ADS)

    Bemmerer, D.; Grosse, E.; Junghans, A. R.; Schwengner, R.; Wagner, A.

    2008-01-01

    The Europhysics Conference `Nuclear Physics in Astrophysics III' (NPA3) took place from 26 31 March 2007 in Dresden, Germany, hosted by Forschungszentrum Dresden-Rossendorf. The present special issue of Journal of Physics G: Nuclear and Particle Physics contains all peer-reviewed contributions to the proceedings of this conference. NPA3 is the third conference in the Nuclear Physics in Astrophysics series of conferences devoted to the interplay between nuclear physics and astrophysics. The first and second editions of the series were held in 2002 and 2005 in Debrecen, Hungary. NPA3 has been organized under the auspices of the Nuclear Physics Board of the European Physical Society as its XXI Divisional Conference. The conference marks the 50th anniversary of the landmark paper B2FH published in 1957 by E M Burbidge, G R Burbidge, W A Fowler and F Hoyle. A public lecture by Claus Rolfs (Ruhr-Universität Bochum, Germany) commemorated the progress achieved since 1957. NPA3 aimed to bring together experimental and theoretical nuclear physicists, astrophysicists and astronomers to address the important part played by nuclear physics in current astrophysical problems. A total of 130 participants from 71 institutions in 26 countries attended the conference, presenting 33 invited and 38 contributed talks and 25 posters on six subject areas. The astrophysical motivation and the nuclear tools employed to address it are highlighted by the titles of the subject areas: Big Bang Nucleosynthesis Stellar Nucleosynthesis and Low Cross Section Measurement Explosive Nucleosynthesis and Nuclear Astrophysics with Photons Nuclei far from Stability and Radioactive Ion Beams Dense Matter in Neutron Stars and Relativistic Nuclear Collisions Neutrinos in Nuclear Astrophysics The presentations and discussions proved that Nuclear Astrophysics is a truly interdisciplinary subject. The remarkable progress in astronomical observations achieved in recent years is matched by advances in

  11. LUNA: Nuclear astrophysics underground

    SciTech Connect

    Best, A.

    2015-02-24

    Underground nuclear astrophysics with LUNA at the Laboratori Nazionali del Gran Sasso spans a history of 20 years. By using the rock overburden of the Gran Sasso mountain chain as a natural cosmic-ray shield very low signal rates compared to an experiment on the surface can be tolerated. The cross sectons of important astrophysical reactions directly in the stellar energy range have been successfully measured. In this proceeding we give an overview over the key accomplishments of the experiment and an outlook on its future with the expected addition of an additional accelerator to the underground facilities, enabling the coverage of a wider energy range and the measurement of previously inaccessible reactions.

  12. Astrophysical terms in Armenian

    NASA Astrophysics Data System (ADS)

    Yeghikian, A. G.

    2015-07-01

    There are quite a few astrophysical textbooks (to say nothing about monographs) in Armenian, which are, however out of date and miss all the modern terms concerning space sciences. Many terms have been earlier adopted from English and, especially, from Russian. On the other hand, teachers and lecturers in Armenia need scientific terms in Armenian adequately reproducing either their means when translating from other languages or (why not) creating new ones. In short, a permanently updated astrophysical glossary is needed to serve as explanation of such terms. I am not going here to present the ready-made glossary (which should be a task for a joint efforts of many professionals) but instead just would like to describe some ambiguous examples with comments where possible coming from my long-year teaching, lecturing and professional experience. A probable connection between "iron" in Armenian as concerned to its origin is also discussed.

  13. Nuclear Astrophysics with LUNA

    NASA Astrophysics Data System (ADS)

    Broggini, Carlo

    2016-04-01

    One of the main ingredients of nuclear astrophysics is the knowledge of the thermonuclear reactions which power the stars and synthesize the chemical elements. Deep underground in the Gran Sasso Laboratory the cross section of the key reactions of the proton-proton chain and of the Carbon-Nitrogen-Oxygen (CNO) cycle have been measured right down to the energies of astrophysical interest. The main results obtained during the 'solar' phase of LUNA are reviewed and their influence on our understanding of the properties of the neutrino and of the Sun is discussed. We then describe the current LUNA program mainly devoted to the study of the nucleosynthesis of the light elements in AGB stars and Classical Novae. Finally, the future of LUNA towards the study of helium and carbon burning with a new 3.5 MV accelerator is outlined.

  14. Nuclear astrophysics at DRAGON

    SciTech Connect

    Hager, U.

    2014-05-02

    The DRAGON recoil separator is located at the ISAC facility at TRIUMF, Vancouver. It is designed to measure radiative alpha and proton capture reactions of astrophysical importance. Over the last years, the DRAGON collaboration has measured several reactions using both radioactive and high-intensity stable beams. For example, the 160(a, g) cross section was recently measured. The reaction plays a role in steady-state helium burning in massive stars, where it follows the 12C(a, g) reaction. At astrophysically relevant energies, the reaction proceeds exclusively via direct capture, resulting in a low rate. In this measurement, the unique capabilities of DRAGON enabled determination not only of the total reaction rates, but also of decay branching ratios. In addition, results from other recent measurements will be presented.

  15. CASPAR - Nuclear Astrophysics Underground

    NASA Astrophysics Data System (ADS)

    Strieder, Frank; Robertson, Daniel; Couder, Manoel; Greife, Uwe; Wells, Doug; Wiescher, Michael

    2015-10-01

    The work of the LUNA Collaboration at the Laboratori Nationali del Gran Sasso demonstrated the research potential of an underground accelerator for the field of nuclear astrophysics. Several key reactions could be studied at LUNA, some directly at the Gamow peak for solar hydrogen burning. The CASPAR (Compact Accelerator System for Performing Astrophysical Research) Collaboration will implement a high intensity 1 MV accelerator at the Sanford Underground Research Facility (SURF) and overcome the current limitation at LUNA. The installation of the accelerator in the recently rehabilitated underground cavity at SURF started in Summer 2015 and first beam should be delivered by the end of the year. This project will primarily focus on the neutron sources for the s-process, e.g. 13C(α , n) 16O and 22Ne(α , n) 25Mg , and lead to unprecedented measurements compared to previous studies. A detailed overview of the science goals of CASPAR will be presented.

  16. Extreme Scale Computational Astrophysics

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre

    2009-11-01

    We live in extraordinary times. With increasingly sophisticated observatories opening up new vistas on the universe, astrophysics is becoming more complex and data-driven. The success in understanding astrophysical systems that are inherently multi-physical, nonlinear systems demands realism in our models of the phenomena. We cannot hope to advance the realism of these models to match the expected sophistication of future observations without extreme-scale computation. Just one example is the advent of gravitational wave astronomy. Detectors like LIGO are about to make the first ever detection of gravitational waves. The gravitational waves are produced during violent events such as the merger of two black holes. The detection of these waves or ripples in the fabric of spacetime is a formidable undertaking, requiring innovative engineering, powerful data analysis tools and careful theoretical modeling. I will discuss the computational and theoretical challenges ahead in our new understanding of physics and astronomy where gravity exhibits its strongest grip on our spacetime.

  17. Birth of Neutrino Astrophysics

    ScienceCinema

    None

    2011-10-06

    Based mainly on the results of two experiments, KamiokaNDE and Super-KamiokaNDE, the birth of neutrino astrophysics will be described. At the end, the result of the third generation Kamioka experiment, KamLAND, will be discussed together with the future possibilities.Organiser(s): Daniel Treille / EP DivisionNote: * Tea & coffee will be served at 16:00 hrs. Please note unusual day.

  18. Birth of Neutrino Astrophysics

    SciTech Connect

    2010-05-07

    Based mainly on the results of two experiments, KamiokaNDE and Super-KamiokaNDE, the birth of neutrino astrophysics will be described. At the end, the result of the third generation Kamioka experiment, KamLAND, will be discussed together with the future possibilities.Organiser(s): Daniel Treille / EP DivisionNote: * Tea & coffee will be served at 16:00 hrs. Please note unusual day.

  19. Astrophysical fluid dynamics

    NASA Astrophysics Data System (ADS)

    Ogilvie, Gordon I.

    2016-06-01

    These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

  20. Astrophysical fluid dynamics

    NASA Astrophysics Data System (ADS)

    Ogilvie, Gordon I.

    2016-06-01

    > These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

  1. The Nuclear Astrophysics Explorer

    NASA Technical Reports Server (NTRS)

    Matteson, J. L.; Teegarden, B. J.; Gehrels, N.; Mahoney, W. A.

    1989-01-01

    The Nuclear Astrophysics Explorer was proposed in 1986 for NASA's Explorer Concept Study Program by an international collaboration of 25 scientists from nine institutions. The one-year feasibility study began in June 1988. The Nuclear Astrophysics Explorer would obtain high resolution observations of gamma-ray lines, E/Delta E about 1000, at a sensitivity of about 0.000003 ph/sq cm s, in order to study fundamental problems in astrophysics such as nucleosynthesis, supernovae, neutron star and black-hole physics, and particle acceleration and interactions. The instrument would operate from 15 keV to 10 Mev and use a heavily shielded array of nine cooled Ge spectrometers in a very low background configuration. Its 10 deg FWHM field of view would contain a versatile coded mask system which would provide two-dimensional imaging with 4 deg resolution, one-dimensional imaging with 2 deg resolution, and efficiendt measurements of diffuse emission. An unshielded Ge spectrometer would obtain wide-field measurements of transient gamma-ray sources. The earliest possible mission would begin in 1995.

  2. Advances in Computational Astrophysics

    SciTech Connect

    Calder, Alan C.; Kouzes, Richard T.

    2009-03-01

    I was invited to be the guest editor for a special issue of Computing in Science and Engineering along with a colleague from Stony Brook. This is the guest editors' introduction to a special issue of Computing in Science and Engineering. Alan and I have written this introduction and have been the editors for the 4 papers to be published in this special edition.

  3. The Gaia-ESO Survey Astrophysical Calibration

    NASA Astrophysics Data System (ADS)

    Pancino, E.; Gaia-ESO Survey consortium

    2016-05-01

    The Gaia-ESO Survey is a wide field spectroscopic survey recently started with the FLAMES@VLT in Cerro Paranal, Chile. It will produce radial velocities more accurate than Gaia's for faint stars (down to V ≃ 18), and astrophysical parameters and abundances for approximately 100 000 stars, belonging to all Galactic populations. 300 nights were assigned in 5 years (with the last year subject to approval after a detailed report). In particular, to connect with other ongoing and planned spectroscopic surveys, a detailed calibration program — for the astrophysical parameters derivation — is planned, including well known clusters, Gaia benchmark stars, and special equatorial calibration fields designed for wide field/multifiber spectrographs.

  4. Astrophysical Constraints of Dark Matter Properties

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas A.; Abel, Tom; Brooks, Alyson; Buckley, Matthew; Bullock, James; Collins, Michelle; Cyr-Racine, Francis-Yan; Dawson, William; Drlica-Wagner, Alex; Gaskins, Jennifer; Kaplinghat, Manoj; Keeton, Charles R.; Kim, Stacy; Peter, Annika; Read, Justin; Simon, Joshua D.; Somerville, Rachel S.; Tollerud, Erik Jon; Treu, Tommaso; Wechsler, Risa H.

    2016-01-01

    The nature of the dark matter that fills the universe remains a profound puzzle in physics and astrophysics. Modern astronomical observations have the potential to produce constraints or measurements on properties of dark matter that may have real power for insights into its particle nature. The key lies with understanding what those constraints may be in a way that is interpretable for both the astronomical and particle physics communities, and establishing a community consensus of how diverse astronomical paths can use a common language. The AAS Special Session on the "Astrophysical constraints of dark matter properties" focuses on framing these questions with concrete proposals for astronomical dark matter metrics and potentially figures of merit, and through a series of presentations that serve as points of departure for discussion, ultimately to reach a community consensus that will be useful for current and future pursuits on this topic.

  5. CCD polarimetry of distant comets C/2010 S1 (LINEAR) and C/2010 R1 (LINEAR) at the 6-m telescope of the SAO RAS

    NASA Astrophysics Data System (ADS)

    Ivanova, Oleksandra V.; Dlugach, Janna M.; Afanasiev, Viktor L.; Reshetnyk, Volodymyr M.; Korsun, Pavlo P.

    2015-12-01

    We present first measurements of the degree of linear polarization of distant comets C/2010 S1 (LINEAR) and C/2010 R1 (LINEAR) at heliocentric distances r=5.9-7.0 AU. Observations were carried out with the SCORPIO-2 focal reducer at the 6-m telescope of the Special Astrophysical Observatory (Russia). Both comets showed considerable level of activity (significant dust comae and tails) beyond a zone where water ice sublimation is negligible (up to 5 AU). Significant spatial variations both in the intensity and polarization are found in both the comets. The slope of radial profiles of intensity changes gradually with the distance from the photocenter: from -0.7 near the nucleus up to about -1.3 for larger distances (up to 100,000 km). The variation in polarization profiles indicates the non-uniformity in the polarization distribution over the coma. The polarization degree over the coma gradually increases (in absolute value) with increasing photocentric distance from of about -1.9% up to -3% for comet C/2010 S1 (LINEAR), and from of about -2.5% up to -3.5% for comet C/2010 R1 (LINEAR). These polarization values are significantly higher than typical value of the whole coma polarization (∼-1.5%) for comets at heliocentric distances less than 5 AU. The obtained photometric and polarimetric data are compared with those derived early for other comets at smaller heliocentric distances. Numerical modeling of light scattering characteristics was performed for media composed of particles with different refractive indexes, shapes, and sizes. The computations were made by using the superposition T-matrix method. We obtained that for comet C/2010 S1 (LINEAR), the dust in the form of aggregates of overall radius R~1.3 μm composed of N=1000 spherical monomers with radius a=0.1 μm and refractive index m=1.65+i0.05, allows to obtain a satisfactory agreement between the results of polarimetric observations of comet C/2010 S1 and computations.

  6. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2009-01-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  7. Structure Formation in Astrophysics

    NASA Astrophysics Data System (ADS)

    Chabrier, Gilles

    2011-02-01

    Part I. Physical Processes and Numerical Methods Common to Structure Formations in Astrophysics: 1. The physics of turbulence E. Levêque; 2. The numerical simulation of turbulence W. Schmidt; 3. Numerical methods for radiation magnetohydrodynamics in astrophysics R. Klein and J. Stone; 4. The role of jets in the formation of planets, stars, and galaxies R. Banerjee, R. Pudritz and R. Ouyed; 5. Advanced numerical methods in astrophysical fluid dynamics A. Hujeirat and F. Heitsch; Part II. Structure and Star Formation in the Primordial Universe: 6. New frontiers in cosmology and galaxy formation challenges for the future R. Ellis and J. Silk; 7. Galaxy formation physics T. Abel, G. Bryan and R. Teyssier; 8. First stars formation, evolution, feedback effects V. Bromm, A. Ferrara and A. Heger; Part III. Contemporary Star and Brown Dwarf Formation: a) Cloud Formation and Fragmentation: 9. Diffuse interstellar medium and the formation of molecular clouds P. Hennebelle, M. Mac Low and E. Vazquez-Semadeni; 10. The formation of distributed and clustered stars in molecular clouds T. Megeath, Z. -Y. Li and A. Nordlund; b) Core Fragmentation and Star Formation: 11. The formation and evolution of prestellar cores P. André, S. Basu and S. Inutsuka; 12. Models for the formation of massive stars; Part IV. Protoplanetary Disks and Planet Formation M. Krumholz and I. Bonnell: 13. Observational properties of disks and young stellar objects G. Duchêne, F. Ménard, J. Muzzerolle and S. Mohanty; 14. Structure and dynamics of protoplanetary disks C. Dullemond, R. Durisen and J. Papaloizou; 15. Planet formation and evolution theory and observation Y. Alibert, I. Baraffe, W. Benz, G. Laughlin and S. Udry; 16. Planet formation assembling the puzzle G. Wurm and T. Guillot; Part V. Summary: 17. Open issues in small- and large-scale structure formation R. Klessen and M. Mac Low; 18. Final word E. Salpeter.

  8. Perspectives in astrophysical databases

    NASA Astrophysics Data System (ADS)

    Frailis, Marco; de Angelis, Alessandro; Roberto, Vito

    2004-07-01

    Astrophysics has become a domain extremely rich of scientific data. Data mining tools are needed for information extraction from such large data sets. This asks for an approach to data management emphasizing the efficiency and simplicity of data access; efficiency is obtained using multidimensional access methods and simplicity is achieved by properly handling metadata. Moreover, clustering and classification techniques on large data sets pose additional requirements in terms of computation and memory scalability and interpretability of results. In this study we review some possible solutions.

  9. Astrophysical blast wave data

    SciTech Connect

    Riley, Nathan; Geissel, Matthias; Lewis, Sean M; Porter, John L.

    2015-03-01

    The data described in this document consist of image files of shadowgraphs of astrophysically relevant laser driven blast waves. Supporting files include Mathematica notebooks containing design calculations, tabulated experimental data and notes, and relevant publications from the open research literature. The data was obtained on the Z-Beamlet laser from July to September 2014. Selected images and calculations will be published as part of a PhD dissertation and in associated publications in the open research literature, with Sandia credited as appropriate. The authors are not aware of any restrictions that could affect the release of the data.

  10. The Fermilab Particle Astrophysics Center

    SciTech Connect

    Not Available

    2004-11-01

    The Particle Astrophysics Center was established in fall of 2004. Fermilab director Michael S. Witherell has named Fermilab cosmologist Edward ''Rocky'' Kolb as its first director. The Center will function as an intellectual focus for particle astrophysics at Fermilab, bringing together the Theoretical and Experimental Astrophysics Groups. It also encompasses existing astrophysics projects, including the Sloan Digital Sky Survey, the Cryogenic Dark Matter Search, and the Pierre Auger Cosmic Ray Observatory, as well as proposed projects, including the SuperNova Acceleration Probe to study dark energy as part of the Joint Dark Energy Mission, and the ground-based Dark Energy Survey aimed at measuring the dark energy equation of state.

  11. High Energy Astrophysics Program (HEAP)

    NASA Technical Reports Server (NTRS)

    Angelini, Lorella; Corcoran, Michael; Drake, Stephen; McGlynn, Thomas A.; Snowden, Stephen; Mukai, Koji; Cannizzo, John; Lochner, James; Rots, Arnold; Christian, Eric; Barthelmy, Scott; Palmer, David; Mitchell, John; Esposito, Joseph; Sreekumar, P.; Hua, Xin-Min; Mandzhavidze, Natalie; Chan, Kai-Wing; Soong, Yang; Barrett, Paul

    1998-01-01

    This report reviews activities performed by the members of the USRA contract team during the 6 months of the reporting period and projected activities during the coming 6 months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in astrophysics. Supported missions include advanced Satellite for Cosmology and Astrophysics (ASCA), X-Ray Timing Experiment (XTE), X-Ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science Archive Research Center (HEASARC) and others.

  12. High Energy Astrophysics Program (HEAP)

    NASA Technical Reports Server (NTRS)

    Angelini, L.; Holdridge, David V.; Norris, J. (Technical Monitor)

    1998-01-01

    This report reviews activities performed by members of the USRA contract team during the six months of the reporting period and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA), X-ray Timing Experiment (XTE), X-ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science Archive Research Center (HEASARC), and others.

  13. Frontier Research in Astrophysics

    NASA Astrophysics Data System (ADS)

    Giovanelli, Franco; Sabau-Graziati, Lola

    We want to join about 90 colleagues from the whole world involved in various topics of modern Astrophysics and Particle Physics in order to discuss the most recent experimental and theoretical results for an advance in the comprehension of the Physics governing our Universe. For reaching the aim of the workshop the idea is to use ground- and space-based experimental developments, theoretical developments AND the coming out science results which have already resulted OR WILL result into high impact science papers. The following items will be reviewed: Cosmology: Cosmic Background, Dark Matter, Dark Energy, Clusters of Galaxies. Physics of the Diffuse Cosmic Sources. Physics of Cosmic Rays. Physics of Discrete Cosmic Sources. Extragalactic Sources: Active Galaxies, Normal Galaxies, Gamma-Ray Bursts. Galactic Sources: Star Formation, Pre-Main-Sequence and Main-Sequence Stars, Cataclysmic Variables and Novae, Supernovae and SNRs, X-Ray Binary Systems, Pulsars, Black Holes, Gamma-Ray Sources, Nucleosynthesis. Future Physics and Astrophysics: Ongoing and Planned Ground- and Space-based Experiments. The workshop will include few 40-minute general review talks to introduce the current problems, and typically 20-minute talks discussing new experimental and theoretical results. A series of 15-minute talks will discuss the ongoing and planned ground- and space-based experiments. The cadence of the workshop will be biennial. The participation will be only by invitation. Editors: Franco Giovannelli and Lola Sabau-Graziati

  14. Quantum gravity at astrophysical distances?

    NASA Astrophysics Data System (ADS)

    Reuter, M.; Weyer, H.

    2004-12-01

    Assuming that quantum Einstein gravity (QEG) is the correct theory of gravity on all length scales, we use analytical results from nonperturbative renormalization group (RG) equations as well as experimental input in order to characterize the special RG trajectory of QEG which is realized in Nature and to determine its parameters. On this trajectory, we identify a regime of scales where gravitational physics is well described by classical general relativity. Strong renormalization effects occur at both larger and smaller momentum scales. The latter lead to a growth of Newton's constant at large distances. We argue that this effect becomes visible at the scale of galaxies and could provide a solution to the astrophysical missing mass problem which does not require any dark matter. We show that an extremely weak power law running of Newton's constant leads to flat galaxy rotation curves similar to those observed in Nature. Furthermore, a possible resolution of the cosmological constant problem is proposed by noting that all RG trajectories admitting a long classical regime automatically give rise to a small cosmological constant.

  15. A review of the safety features of 6M packagings for DOE programs

    SciTech Connect

    Not Available

    1988-12-01

    This report, prepared by a US Department of Energy (DOE) Task Force and organized for clarity into two-page modules, argues that the US Department of Transportation (DOT) Specification-6M packagings (hereafter referred to as 6M packaging, or simply 6M) merit continued DOE use and, if necessary, DOE certification. This report is designed to address the specific requirements of a Safety Analysis Report for Packaging (SARP). While not a SARP, this report constitutes a compilation of all available documentation on 6M packagings. The authors individually, and the Task Force collectively, believe their investigation provides justification for the continued use of 6M packagings because they meet criteria for quality assurance and for safety under normal and accident conditions as defined by the US Nuclear Regulatory Commission (NRC) regulations. This report may be used by DOE managers to assist in deliberations on future requirements for 6M packagings as they are required to support DOE programs. For the purpose of ready evaluation, this report includes categorical topics found in Nuclear Regulatory Guide 7.9, the topical guideline for SARPs. The format, however, will (it is hoped) pleasantly surprise customary reader expectations. For, while maintaining categorical headings and subheadings found in SARPs as a skeleton, the Task Force chose to adopt the document design principles developed by Hughes Aircraft in the 1960s, ''Sequential Thematic Organization of Publications'' (STOP). 37 figs.

  16. Lecture Notes and Essays in Astrophysics I. I Astrophysics Symposium of the GEA-RSEF.

    NASA Astrophysics Data System (ADS)

    Ulla, Ana; Manteiga, Minia

    2004-12-01

    This volume entittled "Lecture Notes and Essays in Astrophysics" is the first of a series containing the invited reviews and lectures presented during the biannual meetings of the Astrophysics Group of the spanish RSEF ("Real Sociedad Española de Física"). In particular, it includes the conferences and reviews presented during the meeting held at Madrid (Spain) on July 2003 during the First Centennial of the Spanish RSEF. The book is aimed to offer the specialized public, and particularly the astrophysics postgraduate students, selected comprehensive reviews on hot topics lectured by relevant speakers on the subject ("Lecture Notes"). The issue is complemented by a set of chapters on more specific topics ("Essays"). The turn of century has been rich with new discoveries, from the detections of extrasolar planets to the discovery of the the farthest galaxies ever seen or the detection of acceleration in the expansion of the Universe. Spain is leaving her imprint in the telescope making revolution and is promoting the construction of a 10.4 metre telescope in the ``Roque de Los Muchachos" observatory, in the Island of La Palma, Spain. This book provides an interesting insight on selected topics of modern Astrophysics as developped by Spanish astronomers.

  17. Recognition of compact astrophysical objects

    NASA Technical Reports Server (NTRS)

    Ogelman, H. (Editor); Rothschild, R. (Editor)

    1977-01-01

    NASA's Laboratory for High Energy Astrophysics and the Dept. of Physics and Astrophysics at the Univ. of Md. collaberated on a graduate level course with this title. This publication is an edited version of notes used as the course text. Topics include stellar evolution, pulsars, binary stars, X-ray signatures, gamma ray sources, and temporal analysis of X-ray data.

  18. Learning Astrophysics through Mobile Gaming

    NASA Astrophysics Data System (ADS)

    Massimino, P.; Costa, A.; Becciani, U.; Krokos, M.; Bandieramonte, M.; Petta, C.; Pistagna, C.; Riggi, S.; Sciacca, E.; Vitello, F.

    2013-10-01

    SpaceMission is a mobile application (iOS) offering hands-on experience of astrophysical concepts using scientific simulations. The application is based on VisIVO which is a suite of software tools for visual discovery through 3D views generated from astrophysical datasets.

  19. Important plasma problems in astrophysics

    SciTech Connect

    Kulsrud, R.M.

    1995-01-01

    In astrophysics, plasmas occur under very extreme conditions. For example there are ultra strong magnetic fields in neutron stars) relativistic plasmas around black holes and in jets, extremely energetic particles such as cosmic rays in the interstellar medium, extremely dense plasmas in accretion disks, and extremely large magnetic Reynold`s numbers in the interstellar medium. These extreme limits for astrophysical plasmas make plasma phenomena much simpler to analyze in astrophysics than in the laboratory. An understanding of such phenomena often results in an interesting way, by simply taking the extreme limiting case of a known plasma theory. I will describe one of the more exciting examples. I will attempt to convey the excitement I felt when I was first exposed to it. However, not all plasma astrophysical phenomena are so simple. There are certain important plasma phenomena in astrophysics, which have not been so easily resolved. In fact a resolution of them is blocking significant progress in astrophysical research. They have not yet yielded to attacks by theoretical astrophysicists nor to extensive numerical simulation. I will attempt to describe one of the more important of these plasma-astrophysical problems, and discuss why its resolution is so important to astrophysics. This significant example is fast, magnetic reconnection. Another significant example is the large-magnetic-Reynold`s-number MHD dynamos.

  20. The Relativistic Astrophysics Explorer

    NASA Astrophysics Data System (ADS)

    Kaaret, P.

    The great success of the Rossi X-Ray Timing Explorer (RXTE) has shown that X-ray timing is an excellent tool for the study of strong gravitational fields and the measurement of fundamental physical properties of black holes and neutron stars. Here, we describe a next-generation X-ray timing mission, the Relativistic Astrophysics Explorer (RAE), designed to fit within the envelope of a medium-sized mission. The instruments will be a narrow-field X-ray detector array with an area of 60,000 cm2 equal to ten times that of RXTE and a wide-field X-ray monitor. We describe the science made possible with this mission, the design of the instruments, and results on prototype large-area X-ray detectors.

  1. Theoretical Particle Astrophysics

    SciTech Connect

    Kamionkowski, Marc

    2013-08-07

    Abstract: Theoretical Particle Astrophysics The research carried out under this grant encompassed work on the early Universe, dark matter, and dark energy. We developed CMB probes for primordial baryon inhomogeneities, primordial non-Gaussianity, cosmic birefringence, gravitational lensing by density perturbations and gravitational waves, and departures from statistical isotropy. We studied the detectability of wiggles in the inflation potential in string-inspired inflation models. We studied novel dark-matter candidates and their phenomenology. This work helped advance the DoE's Cosmic Frontier (and also Energy and Intensity Frontiers) by finding synergies between a variety of different experimental efforts, by developing new searches, science targets, and analyses for existing/forthcoming experiments, and by generating ideas for new next-generation experiments.

  2. Astrophysics with MILAGRO

    SciTech Connect

    Not Available

    1993-01-01

    This paper describes how data from a new type of air shower detector, MILAGRO can shed light on a variety of interesting problems in astrophysics. MILAGRO has the capability to make observations of VHE/UHE emission from the recently discovered TeV gamma-ray source Markarian 421, an Active Galactic Nucleus (AGN). An observation of the attenuation of this signal in the range of 1--20 TeV can be used to make the first measurement of the intergalactic infrared radiation. We will also describe how MILAGRO can improve the existing limits on the density of Primordial Black Holes (PBH) by three orders of magnitude. Finally, we will discuss how this instrument can be used to measure the diffuse galactic emission of gamma-rays which must come from the disk.

  3. Black-hole astrophysics

    SciTech Connect

    Bender, P.; Bloom, E.; Cominsky, L.

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  4. Astrophysics with MILAGRO

    SciTech Connect

    The MILAGRO Collaboration

    1993-05-01

    This paper describes how data from a new type of air shower detector, MILAGRO can shed light on a variety of interesting problems in astrophysics. MILAGRO has the capability to make observations of VHE/UHE emission from the recently discovered TeV gamma-ray source Markarian 421, an Active Galactic Nucleus (AGN). An observation of the attenuation of this signal in the range of 1--20 TeV can be used to make the first measurement of the intergalactic infrared radiation. We will also describe how MILAGRO can improve the existing limits on the density of Primordial Black Holes (PBH) by three orders of magnitude. Finally, we will discuss how this instrument can be used to measure the diffuse galactic emission of gamma-rays which must come from the disk.

  5. Theoretical Astrophysics at Fermilab

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Theoretical Astrophysics Group works on a broad range of topics ranging from string theory to data analysis in the Sloan Digital Sky Survey. The group is motivated by the belief that a deep understanding of fundamental physics is necessary to explain a wide variety of phenomena in the universe. During the three years 2001-2003 of our previous NASA grant, over 120 papers were written; ten of our postdocs went on to faculty positions; and we hosted or organized many workshops and conferences. Kolb and collaborators focused on the early universe, in particular and models and ramifications of the theory of inflation. They also studied models with extra dimensions, new types of dark matter, and the second order effects of super-horizon perturbations. S tebbins, Frieman, Hui, and Dodelson worked on phenomenological cosmology, extracting cosmological constraints from surveys such as the Sloan Digital Sky Survey. They also worked on theoretical topics such as weak lensing, reionization, and dark energy. This work has proved important to a number of experimental groups [including those at Fermilab] planning future observations. In general, the work of the Theoretical Astrophysics Group has served as a catalyst for experimental projects at Fennilab. An example of this is the Joint Dark Energy Mission. Fennilab is now a member of SNAP, and much of the work done here is by people formerly working on the accelerator. We have created an environment where many of these people made transition from physics to astronomy. We also worked on many other topics related to NASA s focus: cosmic rays, dark matter, the Sunyaev-Zel dovich effect, the galaxy distribution in the universe, and the Lyman alpha forest. The group organized and hosted a number of conferences and workshop over the years covered by the grant. Among them were:

  6. Differential Control of Interleukin-6 mRNA Levels by Cellular Distribution of YB-1

    PubMed Central

    Kang, Sujin; Lee, Taeyun A.; Ra, Eun A.; Lee, Eunhye; Choi, Hyun jin; Lee, Sungwook; Park, Boyoun

    2014-01-01

    Cytokine production is essential for innate and adaptive immunity against microbial invaders and must be tightly controlled. Cytokine messenger RNA (mRNA) is in constant flux between the nucleus and the cytoplasm and in transcription, splicing, or decay; such processes must be tightly controlled. Here, we report a novel function of Y-box-binding protein 1 (YB-1) in modulating interleukin-6 (IL-6) mRNA levels in a cell type-specific manner. In lipopolysaccharide (LPS)-stimulated macrophages, YB-1 interacts with IL-6 mRNA and actively transports it to the extracellular space by YB-1-enriched vesicles, resulting in the proper maintenance of intracellular IL-6 mRNA levels. YB-1 secretion occurs in a cell type-specific manner. Whereas macrophages actively secret YB-1, dendritic cells maintain it predominantly in the cytoplasm even in response to LPS. Intracellular YB-1 has the distinct function of regulating IL-6 mRNA stability in dendritic cells. Moreover, because LPS differentially regulates the expression of histone deacetylase 6 (HDAC6) in macrophages and dendritic cells, this stimulus might control YB-1 acetylation differentially in both cell types. Taken together, these results suggest a unique feature of YB-1 in controlling intracellular IL-6 mRNA levels in a cell type-specific manner, thereby leading to functions that are dependent on the extracellular and intracellular distribution of YB-1. PMID:25398005

  7. Ultra-narrow Negative Flare Front Observed in Helium-10830 Å Using the 1.6 m New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Cao, Wenda; Ding, Mingde; Kleint, Lucia; Su, Jiangtao; Liu, Chang; Ji, Haisheng; Chae, Jongchul; Jing, Ju; Cho, Kyuhyoun; Cho, Kyungsuk; Gary, Dale; Wang, Haimin

    2016-03-01

    Solar flares are sudden flashes of brightness on the Sun and are often associated with coronal mass ejections and solar energetic particles that have adverse effects on the near-Earth environment. By definition, flares are usually referred to as bright features resulting from excess emission. Using the newly commissioned 1.6 m New Solar Telescope at Big Bear Solar Observatory, we show a striking “negative” flare with a narrow but unambiguous “dark” moving front observed in He i 10830 Å, which is as narrow as 340 km and is associated with distinct spectral characteristics in Hα and Mg ii lines. Theoretically, such negative contrast in He i 10830 Å can be produced under special circumstances by nonthermal electron collisions or photoionization followed by recombination. Our discovery, made possible due to unprecedented spatial resolution, confirms the presence of the required plasma conditions and provides unique information in understanding the energy release and radiative transfer in astronomical objects.

  8. Ultra-Narrow Negative Flare Front Observed in Helium-10830 Å Using the1.6m New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Cao, Wenda; Ding, Mingde; Kleint, Lucia; Su, Jiangtao; Liu, Chang; Ji, Haisheng; Chae, Jongchul; Jing, Ju; Cho, Kyuhyoun; Cho, Kyung-Suk; Gary, Dale E.; Wang, Haimin

    2016-05-01

    Solar flares are sudden flashes of brightness on the Sun and are often associated with coronal mass ejections and solar energetic particles that have adverse effects on the near-Earth environment. By definition, flares are usually referred to as bright features resulting from excess emission. Using the newly commissioned 1.6-m New Solar Telescope at Big Bear Solar Observatory, we show a striking “negative” flare with a narrow but unambiguous “dark” moving front observed in He I 10830 Å, which is as narrow as 340 km and is associated with distinct spectral characteristics in Hα and Mg II lines. Theoretically, such negative contrast in He I 10830 Å can be produced under special circumstances by nonthermal electron collisions or photoionization followed by recombination. Our discovery, made possible due to unprecedented spatial resolution, confirms the presence of the required plasma conditions and provides unique information in understanding the energy release and radiative transfer in solar flares.

  9. Bonding and magnetism in nanosized graphene molecules: Singlet states of zigzag edged hexangulenes C6m2H6m(m =2,3,…,10)

    NASA Astrophysics Data System (ADS)

    Philpott, Michael R.; Kawazoe, Yoshiyuki

    2009-12-01

    A novel molecular phenomenon is predicted on the basis of trends identified in an ab initio density functional theory study of the electronic and geometric structure of the hexagonal shaped zigzag edged graphene hydrocarbon molecules C6m2H6m(m =2,…,10). Electrons in the interior organize to form a graphene core that grows with edge size m. Electrons in the highest occupied molecular orbital levels, localized primarily on the perimeter carbons, polarize the interior atoms with a intensity that decays rapidly with distance from the perimeter. Three distinctive bond length patterns emerge: (i) a central graphene core that grows with size m; (ii) shape-similar transverse and radial bond length patterns on interior rows close to the edges; and (iii) quinoidal bonds radiating from each apex that link adjacent edges. Concomitant with these changes are: (i) a monotonic decrease in atomic charge from center to perimeter and (ii) relegation of spin in diradical states to the outer atomic rows of the bipartite lattice.

  10. Bonding and magnetism in nanosized graphene molecules: Singlet states of zigzag edged hexangulenes C(6m(2) )H(6m)(m=2,3,...,10).

    PubMed

    Philpott, Michael R; Kawazoe, Yoshiyuki

    2009-12-01

    A novel molecular phenomenon is predicted on the basis of trends identified in an ab initio density functional theory study of the electronic and geometric structure of the hexagonal shaped zigzag edged graphene hydrocarbon molecules C(6m(2) )H(6m)(m=2,...,10). Electrons in the interior organize to form a graphene core that grows with edge size m. Electrons in the highest occupied molecular orbital levels, localized primarily on the perimeter carbons, polarize the interior atoms with a intensity that decays rapidly with distance from the perimeter. Three distinctive bond length patterns emerge: (i) a central graphene core that grows with size m; (ii) shape-similar transverse and radial bond length patterns on interior rows close to the edges; and (iii) quinoidal bonds radiating from each apex that link adjacent edges. Concomitant with these changes are: (i) a monotonic decrease in atomic charge from center to perimeter and (ii) relegation of spin in diradical states to the outer atomic rows of the bipartite lattice. PMID:19968359

  11. Atomic processes for astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Badnell, N. R.; Del Zanna, G.; Fernández-Menchero, L.; Giunta, A. S.; Liang, G. Y.; Mason, H. E.; Storey, P. J.

    2016-05-01

    In this review we summarize the recent calculations and improvements of atomic data that we have carried out for the analysis of astrophysical spectroscopy within the atomic processes for astrophysical plasmas network. We briefly discuss the various methods used for the calculations, and highlight several issues that we have uncovered during such extensive work. We discuss the completeness and accuracy of the cross sections for ionic excitation by electron impact for the main isoelectronic sequences, which we have obtained with large-scale calculations. Given its astrophysical importance, we emphasize the work on iron. Some examples on the significant improvement that has been achieved over previous calculations are provided.

  12. Particle Astrophysics Using Balloons

    NASA Astrophysics Data System (ADS)

    Seo, E. S.

    Cosmic rays, energetic particles coming from outer space, bring us information about the physical processes that accelerate particles to relativistic energies, about the effects of those particles in driving dynamical processes in our Galaxy, and about the distribution of matter and fields in interstellar space. Cosmic rays were discovered in the early twentieth century using a balloon-borne electroscope. Balloons are currently being used for answering fundamental questions about the cosmos: (1) Is the Universe symmetric, and if so where is the antimatter? (2) What is the dark matter? (3) How do cosmic rays get their enormous energies? (4) Can the entire energy spectrum of cosmic rays result from a single acceleration mechanism? (5) Are supernovae really the sources of cosmic rays? (6) What is the history of cosmic rays in the Galaxy? (7) What is the origin of the "knee" in the cosmic ray energy spectrum? etc. The status of results from past balloon-borne measurements and expected results from ongoing and planned future balloon-borne particle astrophysics experiments will be reviewed.

  13. Nuclear and particle astrophysics

    SciTech Connect

    Glendenning, N.K.

    1990-10-31

    We discuss the physics of matter that is relevant to the structure of compact stars. This includes nuclear, neutron star matter and quark matter and phase transitions between them. Many aspects of neutron star structure and its dependance on a number of physical assumptions about nuclear matter properties and hyperon couplings are investigated. We also discuss the prospects for obtaining constraints on the equation of state from astrophysical sources. Neuron star masses although few are known at present, provide a very direct constraint in as much as the connection to the equation of state involves only the assumption that Einstein's general of theory of relativity is correct at the macroscopic scale. Supernovae simulations involve such a plethora of physical processes including those involved in the evolution of the precollapse configuration, not all of them known or understood, that they provide no constraint at the present time. Indeed the prompt explosion, from which a constraint had been thought to follow, is now believed not to be mechanism by which most, if any stars, explode. In any case the nuclear equation of state is but one of a multitude on uncertain factors, and possibly one of the least important. The rapid rotation of pulsars is also discussed. It is shown that for periods below a certain limit it becomes increasingly difficult to reconcile them with neutron stars. Strange stars are possible if strange matter is the absolute ground state. We discuss such stars and their compatibility with observation. 112 refs., 37 figs., 6 tabs.

  14. High Energy Astrophysics Mission

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Ormes, Jonathan F. (Technical Monitor)

    2000-01-01

    The nature of gravity and its relationship to the other three forces and to quantum theory is one of the major challenges facing us as we begin the new century. In order to make progress we must challenge the current theories by observing the effects of gravity under the most extreme conditions possible. Black holes represent one extreme, where the laws of physics as we understand them break down. The Universe as whole is another extreme, where its evolution and fate is dominated by the gravitational influence of dark matter and the nature of the Cosmological constant. The early universe represents a third extreme, where it is thought that gravity may somehow be unified with the other forces. NASA's "Cosmic Journeys" program is part of a NASA/NSF/DoE tri-agency initiative designed to observe the extremes of gravity throughout the universe. This program will probe the nature of black holes, ultimately obtaining a direct image of the event horizon. It will investigate the large scale structure of the Universe to constrain the location and nature of dark matter and the nature of the cosmological constant. Finally it will search for and study the highest energy processes, that approach those found in the early universe. I will outline the High Energy Astrophysics part of this program.

  15. Astrophysical implications of periodicity

    NASA Technical Reports Server (NTRS)

    Muller, Richard A.

    1988-01-01

    Two remarkable discoveries of the last decade have profound implications for astrophysics and for geophysics. These are the discovery by Alvarez et al., that certain mass extinctions are caused by the impact on the earth of a large asteroid or comet, and the discovery by Raup and Sepkoski that such extinctions are periodic, with a cycle time of 26 to 30 million years. The validity of both of these discoveries is assumed and the implications are examined. Most of the phenomena described depend not on periodicity, but just on the weaker assumption that the impacts on the earth take place primarily in showers. Proposed explanations for the periodicity include galactic oscillations, the Planet X model, and the possibility of Nemesis, a solar companion star. These hypotheses are critically examined. Results of the search for the solar companion are reported. The Deccan flood basalts of India have been proposed as the impact site for the Cretaceous impact, but this hypotheisis is in contradiction with the conclusion of Courtillot et al., that the magma flow began during a period of normal magnetic field. A possible resolution of this contradiction is proposed.

  16. Relativistic jets in astrophysics

    NASA Astrophysics Data System (ADS)

    Derishev, E. V.; Zheleznyakov, V. V.; Koryagin, S. A.; Kocharovsky, Vl. V.

    The properties of the plasma state of matter are determined by the motion and the electromagnetic emission of the non-bound electrically charged particles --- electrons, positrons, protons and ions. It is not easy to create plasma in a laboratory. However this state is typical for the cosmic conditions --- at the stars and in the interstellar space. The properties of the laboratory as well as the space plasma are investigated at the Institute of Applied Physics of the Russian Academy of Sciences. The research is focused on the mechanisms of generation and propagation of the electromagnetic radiation --- from the radio waves to the gamma-rays --- in the planetary and stellar atmospheres and at the other astrophysical objects. The extreme physical conditions for a plasma are realized near the compact objects like black holes, neutron stars and collapsing nuclei of the massive stars. The plasma could be strongly non-equlibrium and can produce strong electromagnetic fields. Its bulk motion as well as the chaotic motion of the constituting particles can be relativistic, i. e. the motion can achieve velocities close to the speed of light. The relativistic plasma is frequently observed in the form of jets.

  17. Numerical Relativity and Astrophysics

    NASA Astrophysics Data System (ADS)

    Lehner, Luis; Pretorius, Frans

    2014-08-01

    Throughout the Universe many powerful events are driven by strong gravitational effects that require general relativity to fully describe them. These include compact binary mergers, black hole accretion, and stellar collapse, where velocities can approach the speed of light and extreme gravitational fields (ΦNewt/c2≃1) mediate the interactions. Many of these processes trigger emission across a broad range of the electromagnetic spectrum. Compact binaries further source strong gravitational wave emission that could directly be detected in the near future. This feat will open up a gravitational wave window into our Universe and revolutionize our understanding of it. Describing these phenomena requires general relativity, and—where dynamical effects strongly modify gravitational fields—the full Einstein equations coupled to matter sources. Numerical relativity is a field within general relativity concerned with studying such scenarios that cannot be accurately modeled via perturbative or analytical calculations. In this review, we examine results obtained within this discipline, with a focus on its impact in astrophysics.

  18. Neutron reactions in astrophysics

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Lederer, C.; Käppeler, F.

    2014-05-01

    The quest for the origin of matter in the Universe had been the subject of philosophical and theological debates over the history of mankind, but quantitative answers could be found only by the scientific achievements of the last century. A first important step on this way was the development of spectral analysis by Kirchhoff and Bunsen in the middle of the 19th century, which provided first insight in the chemical composition of the sun and the stars. The energy source of the stars and the related processes of nucleosynthesis, however, could be revealed only with the discoveries of nuclear physics. A final break-through came eventually with the compilation of elemental and isotopic abundances in the solar system, which reflect the various nucleosynthetic processes in detail. This review focuses on the mass region above iron, where the formation of the elements is dominated by neutron capture, mainly in the slow (s) and rapid (r) processes. Following a brief historic account and a sketch of the relevant astrophysical models, emphasis is put on the nuclear physics input, where status and perspectives of experimental approaches are presented in some detail, complemented by the indispensable role of theory.

  19. Plasma physics of extreme astrophysical environments.

    PubMed

    Uzdensky, Dmitri A; Rightley, Shane

    2014-03-01

    Among the incredibly diverse variety of astrophysical objects, there are some that are characterized by very extreme physical conditions not encountered anywhere else in the Universe. Of special interest are ultra-magnetized systems that possess magnetic fields exceeding the critical quantum field of about 44 TG. There are basically only two classes of such objects: magnetars, whose magnetic activity is manifested, e.g., via their very short but intense gamma-ray flares, and central engines of supernovae (SNe) and gamma-ray bursts (GRBs)--the most powerful explosions in the modern Universe. Figuring out how these complex systems work necessarily requires understanding various plasma processes, both small-scale kinetic and large-scale magnetohydrodynamic (MHD), that govern their behavior. However, the presence of an ultra-strong magnetic field modifies the underlying basic physics to such a great extent that relying on conventional, classical plasma physics is often not justified. Instead, plasma-physical problems relevant to these extreme astrophysical environments call for constructing relativistic quantum plasma (RQP) physics based on quantum electrodynamics (QED). In this review, after briefly describing the astrophysical systems of interest and identifying some of the key plasma-physical problems important to them, we survey the recent progress in the development of such a theory. We first discuss the ways in which the presence of a super-critical field modifies the properties of vacuum and matter and then outline the basic theoretical framework for describing both non-relativistic and RQPs. We then turn to some specific astrophysical applications of relativistic QED plasma physics relevant to magnetar magnetospheres and to central engines of core-collapse SNe and long GRBs. Specifically, we discuss the propagation of light through a magnetar magnetosphere; large-scale MHD processes driving magnetar activity and responsible for jet launching and propagation in

  20. Plasma physics of extreme astrophysical environments

    NASA Astrophysics Data System (ADS)

    Uzdensky, Dmitri A.; Rightley, Shane

    2014-03-01

    Among the incredibly diverse variety of astrophysical objects, there are some that are characterized by very extreme physical conditions not encountered anywhere else in the Universe. Of special interest are ultra-magnetized systems that possess magnetic fields exceeding the critical quantum field of about 44 TG. There are basically only two classes of such objects: magnetars, whose magnetic activity is manifested, e.g., via their very short but intense gamma-ray flares, and central engines of supernovae (SNe) and gamma-ray bursts (GRBs)—the most powerful explosions in the modern Universe. Figuring out how these complex systems work necessarily requires understanding various plasma processes, both small-scale kinetic and large-scale magnetohydrodynamic (MHD), that govern their behavior. However, the presence of an ultra-strong magnetic field modifies the underlying basic physics to such a great extent that relying on conventional, classical plasma physics is often not justified. Instead, plasma-physical problems relevant to these extreme astrophysical environments call for constructing relativistic quantum plasma (RQP) physics based on quantum electrodynamics (QED). In this review, after briefly describing the astrophysical systems of interest and identifying some of the key plasma-physical problems important to them, we survey the recent progress in the development of such a theory. We first discuss the ways in which the presence of a super-critical field modifies the properties of vacuum and matter and then outline the basic theoretical framework for describing both non-relativistic and RQPs. We then turn to some specific astrophysical applications of relativistic QED plasma physics relevant to magnetar magnetospheres and to central engines of core-collapse SNe and long GRBs. Specifically, we discuss the propagation of light through a magnetar magnetosphere; large-scale MHD processes driving magnetar activity and responsible for jet launching and propagation in

  1. Radiative capture reactions in astrophysics

    SciTech Connect

    Brune, Carl R.; Davids, Barry

    2015-08-07

    Here, the radiative capture reactions of greatest importance in nuclear astrophysics are identified and placed in their stellar contexts. Recent experimental efforts to estimate their thermally averaged rates are surveyed.

  2. Neutrinos in astrophysics and cosmology

    NASA Astrophysics Data System (ADS)

    Balantekin, A. B.

    2016-06-01

    Neutrinos play a crucial role in many aspects of astrophysics and cosmology. Since they control the electron fraction, or equivalently neutron-to-proton ratio, neutrino properties impact yields of r-process nucleosynthesis. Similarly the weak decoupling temperature in the Big Bang Nucleosynthesis epoch is exponentially dependent on the neutron-to-proton ratio. In these conference proceedings, I briefly summarize some of the recent work exploring the role of neutrinos in astrophysics and cosmology.

  3. Highlights of Spanish Astrophysics VII

    NASA Astrophysics Data System (ADS)

    Guirado, J. C.; Lara, L. M.; Quilis, V.; Gorgas, J.

    2013-05-01

    "Highlights of Astronomy and Astrophysics VII" contains the Proceedings of the biannual meeting of the Spanish Astronomical Society held in Valencia from July 9 to 13, 2012. Over 300 astronomer, both national and international researchers, attended to the conference covering a wide variety of astrophysical topics: Galaxies and Cosmology, The Milky Way and Its Components, Planetary Sciences, Solar Physics, Instrumentation and Computation, and Teaching and Outreach of Astronomy.

  4. Minicourses in Astrophysics, Modular Approach, Vol. I.

    ERIC Educational Resources Information Center

    Illinois Univ., Chicago.

    This is the first volume of a two-volume minicourse in astrophysics. It contains chapters on the following topics: planetary atmospheres; X-ray astronomy; radio astrophysics; molecular astrophysics; and gamma-ray astrophysics. Each chapter gives much technical discussion, mathematical treatment, diagrams, and examples. References are included with…

  5. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  6. Solar astrophysical fundamental parameters

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Irbah, A.; Hauchecorne, A.

    2014-08-01

    The accurate determination of the solar photospheric radius has been an important problem in astronomy for many centuries. From the measurements made by the PICARD spacecraft during the transit of Venus in 2012, we obtained a solar radius of 696,156±145 kilometres. This value is consistent with recent measurements carried out atmosphere. This observation leads us to propose a change of the canonical value obtained by Arthur Auwers in 1891. An accurate value for total solar irradiance (TSI) is crucial for the Sun-Earth connection, and represents another solar astrophysical fundamental parameter. Based on measurements collected from different space instruments over the past 35 years, the absolute value of the TSI, representative of a quiet Sun, has gradually decreased from 1,371W.m-2 in 1978 to around 1,362W.m-2 in 2013, mainly due to the radiometers calibration differences. Based on the PICARD data and in agreement with Total Irradiance Monitor measurements, we predicted the TSI input at the top of the Earth's atmosphere at a distance of one astronomical unit (149,597,870 kilometres) from the Sun to be 1,362±2.4W.m-2, which may be proposed as a reference value. To conclude, from the measurements made by the PICARD spacecraft, we obtained a solar photospheric equator-to-pole radius difference value of 5.9±0.5 kilometres. This value is consistent with measurements made by different space instruments, and can be given as a reference value.

  7. NASA's Astrophysics Education and Public Outreach: Selected Highlights

    NASA Astrophysics Data System (ADS)

    Hasan, H.; Smith, D.; Sharma, M.

    2013-04-01

    NASA's rich portfolio of Astrophysics Education and Public Outreach (EPO) programs spans formal and informal education from K-12, addresses diverse audiences, and takes the latest NASA scientific discoveries to the public through science museums, planetaria, exhibitions, and other outlets. Public outreach activities use NASA Astrophysics scientific discoveries and technology to inspire students to undertake scientific careers and enhance public understanding of science and technology. Examples of noteworthy activities in the past year include Hubble, Chandra, JWST exhibits at the Intrepid Museum, New York, community collaborations such as the Multiwavelength Universe online course, and a variety of Citizen Science projects associated with robotic telescopes and with flight missions such as HST and Kepler. Special EPO programs have been developed to reach out to girls and underrepresented minorities. NASA's Astrophysics Science Education and Public Outreach Forum (SEPOF) has developed resources to assist the scientific community in participating in education and public outreach.

  8. Stellar Astrophysical Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Thompson, Michael J.; Christensen-Dalsgaard, Jørgen

    2003-05-01

    Preface; 1. A selective overview Jørgen Christensen-Dalsgaard and Michael J. Thompson; Part I. Stellar Convection and Oscillations: 2. On the diversity of stellar pulsations Wojciech A. Dziembowski; 3. Acoustic radiation and mode excitation by turbulent convection Günter Houdek; 4. Understanding roAp stars Margarida S. Cunha; 5. Waves in the magnetised solar atmosphere Colin S. Rosenthal; Part II. Stellar Rotation and Magnetic Fields: 6. Stellar rotation: a historical survey Leon Mestel; 7. The oscillations of rapidly rotating stars Michel Rieutord; 8. Solar tachocline dynamics: eddy viscosity, anti-friction, or something in between? Michael E. McIntyre; 9. Dynamics of the solar tachocline Pascale Garaud; 10. Dynamo processes: the interaction of turbulence and magnetic fields Michael Proctor; 11. Dynamos in planets Chris Jones; Part III. Physics and Structure of Stellar Interiors: 12. Solar constraints on the equation of state Werner Däppen; 13. 3He transport and the solar neutrino problem Chris Jordinson; 14. Mixing in stellar radiation zones Jean-Paul Zahn; 15. Element settling and rotation-induced mixing in slowly rotating stars Sylvie Vauclair; Part IV. Helio- and Asteroseismology: 16. Solar structure and the neutrino problem Hiromoto Shibahashi; 17. Helioseismic data analysis Jesper Schou; 18. Seismology of solar rotation Takashi Sekii; 19. Telechronohelioseismology Alexander Kosovichev; Part V. Large-Scale Numerical Experiments: 20. Bridges between helioseismology and models of convection zone dynamics Juri Toomre; 21. Numerical simulations of the solar convection zone Julian R. Elliott; 22. Modelling solar and stellar magnetoconvection Nigel Weiss; 23. Nonlinear magnetoconvection in the presence of a strong oblique field Keith Julien, Edgar Knobloch and Steven M. Tobias; 24. Simulations of astrophysical fluids Marcus Brüggen; Part VI. Dynamics: 25. A magic electromagnetic field Donald Lynden-Bell; 26. Continuum equations for stellar dynamics Edward A

  9. Stellar Astrophysical Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Thompson, Michael J.; Christensen-Dalsgaard, Jørgen

    2008-02-01

    Preface; 1. A selective overview Jørgen Christensen-Dalsgaard and Michael J. Thompson; Part I. Stellar Convection and Oscillations: 2. On the diversity of stellar pulsations Wojciech A. Dziembowski; 3. Acoustic radiation and mode excitation by turbulent convection Günter Houdek; 4. Understanding roAp stars Margarida S. Cunha; 5. Waves in the magnetised solar atmosphere Colin S. Rosenthal; Part II. Stellar Rotation and Magnetic Fields: 6. Stellar rotation: a historical survey Leon Mestel; 7. The oscillations of rapidly rotating stars Michel Rieutord; 8. Solar tachocline dynamics: eddy viscosity, anti-friction, or something in between? Michael E. McIntyre; 9. Dynamics of the solar tachocline Pascale Garaud; 10. Dynamo processes: the interaction of turbulence and magnetic fields Michael Proctor; 11. Dynamos in planets Chris Jones; Part III. Physics and Structure of Stellar Interiors: 12. Solar constraints on the equation of state Werner Däppen; 13. 3He transport and the solar neutrino problem Chris Jordinson; 14. Mixing in stellar radiation zones Jean-Paul Zahn; 15. Element settling and rotation-induced mixing in slowly rotating stars Sylvie Vauclair; Part IV. Helio- and Asteroseismology: 16. Solar structure and the neutrino problem Hiromoto Shibahashi; 17. Helioseismic data analysis Jesper Schou; 18. Seismology of solar rotation Takashi Sekii; 19. Telechronohelioseismology Alexander Kosovichev; Part V. Large-Scale Numerical Experiments: 20. Bridges between helioseismology and models of convection zone dynamics Juri Toomre; 21. Numerical simulations of the solar convection zone Julian R. Elliott; 22. Modelling solar and stellar magnetoconvection Nigel Weiss; 23. Nonlinear magnetoconvection in the presence of a strong oblique field Keith Julien, Edgar Knobloch and Steven M. Tobias; 24. Simulations of astrophysical fluids Marcus Brüggen; Part VI. Dynamics: 25. A magic electromagnetic field Donald Lynden-Bell; 26. Continuum equations for stellar dynamics Edward A

  10. Exotic nuclei in astrophysics

    NASA Astrophysics Data System (ADS)

    Penionzhkevich, Yu. E.

    2012-07-01

    Recently the academic community has marked several anniversaries connected with discoveries that played a significant role in the development of astrophysical investigations. The year 2009 was proclaimed by the United Nations the International Year of Astronomy. This was associated with the 400th anniversary of Galileo Galilei's discovery of the optical telescope, which marked the beginning of regular research in the field of astronomy. An important contribution to not only the development of physics of the microcosm, but also to the understanding of processes occurring in the Universe, was the discovery of the atomic nucleus made by E. Rutherford 100 years ago. Since then the investigations in the fields of physics of particles and atomic nuclei have helped to understand many processes in the microcosm. Exactly 80 years ago, K. Yanski used a radio-telescope in order to receive the radiation from cosmic objects for the first time, and at the present time this research area of physics is the most efficient method for studying the properties of the Universe. Finally, the April 12, 1961 (50 years ago) launching of the first sputnik into space with a human being onboard, the Russian cosmonaut Yuri Gagarin, marked the beginning of exploration of the Universe with the direct participation of man. All these achievements considerably extended our ideas about the Universe. This work is an attempt to present some problems on the evolution of the Universe: the nucleosynthesis and cosmochronology from the standpoint of physics of particles and nuclei, in particular with the use of the latest results, obtained by means of radioactive nuclear beams. The comparison is made between the processes taking place in the Universe and the mechanisms of formation and decay of nuclei, as well as of their interaction at different energies. Examples are given to show the capabilities of nuclear-physics methods for studying cosmic objects and properties of the Universe. The results of

  11. BOOK REVIEW: Particle Astrophysics (Second Edition)

    NASA Astrophysics Data System (ADS)

    Bell, Nicole

    2009-07-01

    Particle astrophysics, the interface of elementary particle physics with astrophysics and cosmology, is a rapidly evolving field. Perkins' book provides a nice introduction to this field, at a level appropriate for senior undergraduate students. Perkins develops the foundations underlying both the particle and astrophysics areas, and also covers some of the most recent developments in this field. The latter is an appealing feature, as students rarely encounter topics of current research in their undergraduate textbooks. Part 1 of the text introduces the elementary particle content, and interactions, of the standard model of particle physics. Relativity is addressed at the level of special relativistic kinematics, the equivalence principle and the Robertson-Walker metric. Part 2 covers cosmology, starting with the expansion of the Universe and basic thermodynamics. It then moves on to primordial nucleosynthesis, baryogenesis, dark matter, dark energy, structure formation and the cosmic microwave background. Part 3 covers cosmic rays, stellar evolution, and related topics. Cutting edge topics include the use of the cosmological large scale structure power spectrum to constrain neutrino mass, the creation of the baryon asymmetry via leptogenesis, and the equation of state for dark energy. While the treatment of many topics is quite brief, the level of depth is about right for undergraduates who are being exposed to these topics for the first time. The breadth of topics spanned is excellent. Perkins does a good job connecting theory with the experimental underpinnings, and of simplifying the theoretical presentation of complex subjects to a level that senior undergraduate students should find accessible. Each chapter includes a number of exercises. Brief solutions are provided for all the exercises, while fully worked solutions are provided for a smaller subset.

  12. Effects of high Z probe on plasma behavior in HT-6M tokamak

    NASA Astrophysics Data System (ADS)

    Li, J.; Gong, X.; Luo, L.; Yin, F. X.; Noda, N.; Wan, B.; Xu, W.; Gao, X.; Yin, F.; Jiang, J. G.; Wu, Z.; Zhao, J. Y.; Wu, M.; Liu, S.; Han, Y.

    1997-02-01

    Molybdenum and tungsten probes have been tested in HT-6M tokamak under various discharge conditions aiming to find out the conditions in which high Z PFC can be used without serious degradation of core plasma performance. In normal OH discharges, the degradation of core plasma performance was found only when the probe was inserted beyond 3.0 cm inside the last closed flux surface (LCFS). The plasma performance did not change with positive biasing to the probe, whereas central Te degraded during negative biasing of -100 V. The insertion of the Mo probe to 1.5 cm inside the LCFS made a change in the threshold power of the L-H transition in EOH discharges. These results suggest a certain operation range of the H-mode in the EOH discharge with the Mo probe in HT-6M.

  13. Enclosure design for the ARIES 3.6m optical telescope

    NASA Astrophysics Data System (ADS)

    Pandey, A. K.; Shukla, Vishal; Bangia, Tarun; Raskar, R. D.; Kulkarni, R. R.; Ghanti, A. S.

    2012-09-01

    A 3.6-m, f/9 optical telescope is planned to be installed at Devasthal, India (Latitude:29° 21' 40'' N, Longitude: 79° 41' 04'' E, Altitude: 2450 m above msl). The telescope has Cassegrain focus and alt-azimuth mount. The design of the telescope enclosure and the auxiliary building includes a fixed base enclosure, a telescope pier, a rotating dome structure, an auxiliary building, ventilation and component handling systems. The design is optimized for thermal, mechanical, structural, as well as for telescope installation and maintenance requirements. The design aims to provide seeing limited images within the telescope enclosure. This paper presents design of the 3.6m telescope enclosure.

  14. EVALUATION OF RADIOLYSIS INDUCED HYDROGEN GENERATION IN DOT 6M DRUMS FROM INTEC

    SciTech Connect

    Vinson, D

    2007-06-18

    Three DOT 6M 30-gallon drums are scheduled to be shipped from the Idaho Nuclear Technology Engineering Center (INTEC) at the Idaho National Laboratory (INL) to L-Area at the Savannah River Site (SRS). These three drums contain radioactive materials that resulted from the material recovery effort following a small explosion that had occurred in the Idaho Chemical Processing Plant (ICPP) hot chemistry laboratory (HCL). In support of the shipment and subsequent storage of the three DOT 6M drums, an evaluation of the potential for molecular hydrogen production in the drums has been completed and documented herein. The potential sources of hydrogen evaluated in the current report include radiolytic decomposition of polymeric materials in the DOT 6M drums No.3031 and No.3598 and the radiolytic decomposition of water in drum No.20102. No other potential sources have been identified based upon reported drum contents and packaging configuration. A parametric approach was used to evaluate the maximum quantity of molecular hydrogen that can be expected to evolve in two DOT 6M 30-gallon drums in support of receipt and subsequent interim storage prior to canyon processing. These drums are two of three drums scheduled for shipment from INTEC to SRS as part of the decommissioning effort of the INTEC facility. The three DOT 6M drums will be received at L-Area in SRS and stored for up to 13-years prior to final disposition at HB-Line in 2020. Results of the current analysis do not include parametric analysis of drum No.20102 containing 114/133 SAL (salvage) which contains UO{sub 3} powder. This drum has not been identified as containing polymeric materials and a conservative calculation indicates that the maximum gross molecular hydrogen production due to the radiolysis of adsorbed moisture would yield a production rate of 5.1-cm{sup 3}/yr, driven primarily by the large surface are to volume ratio of the oxide powder. The remaining two drums, No.3031 and No.3598 contain polymer

  15. The Next Century Astrophysics Program

    NASA Technical Reports Server (NTRS)

    Swanson, Paul N.

    1991-01-01

    The Astrophysics Division within the NASA Office of Space Science and Applications (OSSA) has defined a set of major and moderate missions that are presently under study for flight sometime within the next 20 years. These programs include the: Advanced X Ray Astrophysics Facility; X Ray Schmidt Telescope; Nuclear Astrophysics Experiment; Hard X Ray Imaging Facility; Very High Throughput Facility; Gamma Ray Spectroscopy Observatory; Hubble Space Telescope; Lunar Transit Telescope; Astrometric Interferometer Mission; Next Generation Space Telescope; Imaging Optical Interferometer; Far Ultraviolet Spectroscopic Explorer; Gravity Probe B; Laser Gravity Wave Observatory in Space; Stratospheric Observatory for Infrared Astronomy; Space Infrared Telescope Facility; Submillimeter Intermediate Mission; Large Deployable Reflector; Submillimeter Interferometer; and Next Generation Orbiting Very Long Baseline Interferometer.

  16. High Energy Density Laboratory Astrophysics

    SciTech Connect

    Remington, B A

    2004-11-11

    High-energy-density (HED) physics refers broadly to the study of macroscopic collections of matter under extreme conditions of temperature and density. The experimental facilities most widely used for these studies are high-power lasers and magnetic-pinch generators. The HED physics pursued on these facilities is still in its infancy, yet new regimes of experimental science are emerging. Examples from astrophysics include work relevant to planetary interiors, supernovae, astrophysical jets, and accreting compact objects (such as neutron stars and black holes). In this paper, we will review a selection of recent results in this new field of HED laboratory astrophysics and provide a brief look ahead to the coming decade.

  17. Experimental High Energy Neutrino Astrophysics

    SciTech Connect

    Distefano, Carla

    2005-10-12

    Neutrinos are considered promising probes for high energy astrophysics. More than four decades after deep water Cerenkov technique was proposed to detect high energy neutrinos. Two detectors of this type are successfully taking data: BAIKAL and AMANDA. They have demonstrated the feasibility of the high energy neutrino detection and have set first constraints on TeV neutrino production astrophysical models. The quest for the construction of km3 size detectors have already started: in the South Pole, the IceCube neutrino telescope is under construction; the ANTARES, NEMO and NESTOR Collaborations are working towards the installation of a neutrino telescope in the Mediterranean Sea.

  18. Heavy elements in astrophysical nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Sun, Bao-Hua; Niu, Zhong-Ming

    With the many successes of covariant density functional theory (CDFT) as seen in the previous chapters, there has been growing interest over the last years to examine directly their applicability in astrophysical nucleosynthesis simulations. This chapter thus concentrates on the very recent applications of CDFT in astrophysics nucleosynthesis, ranging from the calculations of nuclear physics inputs -- masses and beta-decay half-lives -- for rapid-neutron (r-) and rapid-proton (rp-) capture processes, to the nucleosynthesis studies that employed these inputs and to nuclear cosmochronology. The concepts of nucleosynthesis process and formulas on beta-decays are sketched briefly.

  19. The Astrophysics of the Sun

    NASA Astrophysics Data System (ADS)

    Zirin, H.

    1998-06-01

    This is an entirely new edition of Harold Zirin's classic text on the solar atmosphere. Combining an introductory course in astrophysics with a comprehensive treatment of the theoretical and observational aspects of our present knowledge of the sun, the book has been completely updated. It includes a large number of spectacular new photographs, including many of the best solar pictures from the world's observatories. Professor Zirin is one of the leading scientists in his field. His lucid writing style, combined with considerable teaching experience, has resulted in a valuable and important textbook of astrophysics.

  20. HOPE: Just-in-time Python compiler for astrophysical computations

    NASA Astrophysics Data System (ADS)

    Akeret, Joel; Gamper, Lukas; Amara, Adam; Refregier, Alexandre

    2014-11-01

    HOPE is a specialized Python just-in-time (JIT) compiler designed for numerical astrophysical applications. HOPE focuses on a subset of the language and is able to translate Python code into C++ while performing numerical optimization on mathematical expressions at runtime. To enable the JIT compilation, the user only needs to add a decorator to the function definition. By using HOPE, the user benefits from being able to write common numerical code in Python while getting the performance of compiled implementation.

  1. Zn/gelled 6 M KOH/O 2 zinc-air battery

    NASA Astrophysics Data System (ADS)

    Mohamad, A. A.

    The gel electrolyte for the zinc-air cell was prepared by mixing hydroponics gel with a 6 M potassium hydroxide aqueous solution. The self-discharge of cells was characterized by measuring the open-circuit voltage. The effect of a discharge rate of 50 mA constant current on cell voltage and plateau hour, as well as the voltage-current and current density-power density were measured and analysed. The electrode degradation after discharge cycling was characterized by structural and surface methods. The oxidation of the electrode surface further blocked the utilization of the Zn anode and was identified as a cause for the failure of the cell.

  2. High-resolution fibre-fed spectrograph for the 6-m telescope. Polarimetric unit

    NASA Astrophysics Data System (ADS)

    Kukushkin, D. E.; Sazonenko, D. A.; Bakholdin, A. V.; Yushkin, M. V.; Bychkov, V. D.

    2016-04-01

    We report the computation of the design of a polarimetric unit for the optical scheme of the fiberfed high-resolution spectrograph for the 6-m Russian telescope.We discuss a variant of its integration into the design of conversion optics at the input of the fiber path if the instrument and estimate the efficiency of the entire pre-fiber optical system. The luminous efficiency of the assembly is equal to 80 and 90% when operated in the polarimetry and normal spectroscopic modes, respectively.We estimate the lower limit for the distorting instrumental effects of the polarimetric unit.

  3. Structural Testing of a 6m Hypersonic Inflatable Aerodynamic Decelerator System

    NASA Technical Reports Server (NTRS)

    Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.

    2015-01-01

    NASA is developing low ballistic coefficient technologies to support the Nations long-term goal of landing humans on Mars. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current and future launch vehicle fairing limitations. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) are being developed to circumvent this limitation and are now considered a leading technology to enable landing of heavy payloads on Mars. At the beginning of 2014, a 6m diameter HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify its structural performance under flight-relevant loads. The inflatable structure was constructed into a 60 degree sphere-cone configuration using nine inflatable torus segments composed of fiber-reinforced thin films. The inflatable tori were joined together using adhesives and high-strength textile woven structural straps. These straps help distribute the load throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials that are designed to protect the inflatable structure from heat loads that would be seen in flight during atmospheric entry. A custom test fixture was constructed to perform the static load test series. The fixture consisted of a round structural tub with enough height and width to allow for displacement of the HIAD test article as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The rigid centerbody of the HIAD was mounted to a pedestal in the center of the structural tub. Using an impermeable membrane draped over the HIAD test article, an airtight seal was created with the top rim of the static load tub. This seal allowed partial vacuum to be pulled beneath the HIAD resulting in a uniform static pressure load applied to the outer surface. Using this technique, the test article

  4. Spectral monitoring of NGC 4151 and 3C 390.3 at the 6 m telescope.

    NASA Astrophysics Data System (ADS)

    Shapovalova, A. I.; Burenkov, A. N.; Bochkarev, N. G.

    The results of spectral monitoring of the Seyfert galaxies NGC 4151 (1986 - 96) and 3C 390.3 (1995 - 96) obtained at the 6 m telescope are presented. The behaviour of the broad component profiles of Hβ and continuum is studied. Quasisimultaneous variations of the fluxes in the blue and red wings of Hβ in both galaxies are detected, which is indicative of the absence of considerable radial motions in BLR. The authors confirm the obtained by Veilleux and Zheng (1991) sinusoidal dependence with a period of ≡10 years for the ratios of the observed fluxes of the blue and red wings of Hβ in 3C 390.3 spectra.

  5. Condensation Processes in Astrophysical Environments

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Rietmeijer, Frans J. M.; Hill, Hugh G. M.

    2002-01-01

    Astrophysical systems present an intriguing set of challenges for laboratory chemists. Chemistry occurs in regions considered an excellent vacuum by laboratory standards and at temperatures that would vaporize laboratory equipment. Outflows around Asymptotic Giant Branch (AGB) stars have timescales ranging from seconds to weeks depending on the distance of the region of interest from the star and, on the way significant changes in the state variables are defined. The atmospheres in normal stars may only change significantly on several billion-year timescales. Most laboratory experiments carried out to understand astrophysical processes are not done at conditions that perfectly match the natural suite of state variables or timescales appropriate for natural conditions. Experimenters must make use of simple analog experiments that place limits on the behavior of natural systems, often extrapolating to lower-pressure and/or higher-temperature environments. Nevertheless, we argue that well-conceived experiments will often provide insights into astrophysical processes that are impossible to obtain through models or observations. This is especially true for complex chemical phenomena such as the formation and metamorphism of refractory grains under a range of astrophysical conditions. Data obtained in our laboratory has been surprising in numerous ways, ranging from the composition of the condensates to the thermal evolution of their spectral properties. None of this information could have been predicted from first principals and would not have been credible even if it had.

  6. The Wisconsin Plasma Astrophysics Laboratory

    NASA Astrophysics Data System (ADS)

    Forest, C. B.; Flanagan, K.; Brookhart, M.; Clark, M.; Cooper, C. M.; Désangles, V.; Egedal, J.; Endrizzi, D.; Khalzov, I. V.; Li, H.; Miesch, M.; Milhone, J.; Nornberg, M.; Olson, J.; Peterson, E.; Roesler, F.; Schekochihin, A.; Schmitz, O.; Siller, R.; Spitkovsky, A.; Stemo, A.; Wallace, J.; Weisberg, D.; Zweibel, E.

    2015-10-01

    > provide an ideal testbed for a range of astrophysical experiments, including self-exciting dynamos, collisionless magnetic reconnection, jet stability, stellar winds and more. This article describes the capabilities of WiPAL, along with several experiments, in both operating and planning stages, that illustrate the range of possibilities for future users.

  7. Astrophysics on the Lab Bench

    ERIC Educational Resources Information Center

    Hughes, Stephen W.

    2010-01-01

    In this article some basic laboratory bench experiments are described that are useful for teaching high school students some of the basic principles of stellar astrophysics. For example, in one experiment, students slam a plastic water-filled bottle down onto a bench, ejecting water towards the ceiling, illustrating the physics associated with a…

  8. Astronomy & Astrophysics: an international journal

    NASA Astrophysics Data System (ADS)

    Bertout, C.

    2011-07-01

    After a brief historical introduction, we review the scope, editorial process, and production organization of A&A, one of the leading journals worldwide dedicated to publishing the results of astrophysical research. We then briefly discuss the economic model of the Journal and some current issues in scientific publishing.

  9. Astrophysical Bounds on Particle Properties

    NASA Astrophysics Data System (ADS)

    Raffelt, G.; Murdin, P.

    2000-11-01

    Ever since NEWTON proposed that the Moon on its orbit follows the same laws of motion as an apple falling from a tree, the heavens have been a favorite laboratory for testing the fundamental laws of physics, notably Newton's and EINSTEIN's theories of gravity. More recently, astrophysics and cosmology have become crucial testing grounds for the microcosm of elementary particles. This area of scie...

  10. Astronomy and Astrophysics in India

    NASA Astrophysics Data System (ADS)

    Narlikar, J.; Murdin, P.

    2001-07-01

    The growth in astronomy and astrophysics (A&A) in India has been mostly since the country achieved independence in 1947. The present work is carried out in a few select research institutes and in some university departments. The Astronomical Society of India has around 300 working A&A scientists as members, with another 50-60 graduate students....

  11. Indirect methods in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Bertulani, C. A.; Shubhchintak; Mukhamedzhanov, A.; Kadyrov, A. S.; Kruppa, A.; Pang, D. Y.

    2016-04-01

    We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions.

  12. Time Ordered Astrophysics Scalable Tools

    2011-12-14

    This software package provides tools for astrophysical experiments which record data in the form of individual time streams from discrete detectors. TOAST provides tools from meta-data manipulation and job set up, I/O operation, telescope pointing reconstruction, and map-making. It also provides tools for constructing simulated observations.

  13. Nuclear astrophysics of supernovae

    SciTech Connect

    Cooperstein, J.

    1988-01-01

    In this paper, I'll give a general introduction to Supernova Theory, beginning with the presupernova evolution and ending with the later stages of the explosion. This will be distilled from a colloquium type of talk. It is necessary to have the whole supernova picture in one's mind's eye when diving into some of its nooks and crannies, as it is quite a mess of contradictory ingredients. We will have some discussion of supernova 1987a, but will keep our discussion more general. Second, we'll look at the infall and bounce of the star, seeing why it goes unstable, what dynamics it follows as it collapses, and how and why it bounces back. From there, we will go on to look at the equation of state (EOS) in more detail. We'll consider the cases T = 0 and T > 0. We'll focus on /rho/ < /rho//sub 0/, and then /rho/ > /rho//sub 0/ and the EOS of neutron stars, and whether or not they contain cores of strange matter. There are many things we could discuss here and not enough time. If I had more lectures, the remaining time would focus on two more questions of special interest to nuclear physicists: the electron capture reactions and neutrino transport. If time permitted, we'd have some discussion of the nucleosynthetic reactions in the explosion's debris as well. However, we cannot cover such material adequately, and I have chosen these topics because they are analytically tractable, pedagogically useful, and rather important. 23 refs., 14 figs., 3 tabs.

  14. Symposium on Recent Results in Infrared Astrophysics

    NASA Technical Reports Server (NTRS)

    Dyal, P. (Editor)

    1977-01-01

    Abstracts of papers presented at a symposium titled Recent Results in Infrared Astrophysics are set forth. The abstracts emphasize photometric, spectroscopic, polarization, and theoretical results on a broad range of current topics in infrared astrophysics.

  15. Introducing Astrophysics Research to High School Students.

    ERIC Educational Resources Information Center

    Etkina, Eugenia; Lawrence, Michael; Charney, Jeff

    1999-01-01

    Presents an analysis of an astrophysics institute designed for high school students. Investigates how students respond cognitively in an active science-learning environment in which they serve as apprentices to university astrophysics professors. (Author/CCM)

  16. International Olympiad on Astronomy and Astrophysics

    ERIC Educational Resources Information Center

    Soonthornthum, B.; Kunjaya, C.

    2011-01-01

    The International Olympiad on Astronomy and Astrophysics, an annual astronomy and astrophysics competition for high school students, is described. Examples of problems and solutions from the competition are also given. (Contains 3 figures.)

  17. Computational Infrastructure for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Smith, M. S.; Lingerfelt, E. J.; Scott, J. P.; Nesaraja, C. D.; Hix, W. R.; Bardayan, D. W.; Blackmon, J. C.; Chae, K.; Guidry, M. W.; Hard, C. C.; Sharp, J. E.; Kozub, R. L.; Meyer, R. A.

    2004-12-01

    The Computational Infrastructure for Nuclear Astrophysics is a platform-independent, online suite of computer codes developed by the ORNL Nuclear Data Project that makes a rapid connection between laboratory nuclear physics results and astrophysical models. It enables users to evaluate cross sections, process them into thermonuclear reaction rates, and parameterize (with a few percent accuracy) these rates that vary by up to 30 orders of magnitude over the temperatures of interest. Users can then properly format these rates for input into astrophysical computer simulations, create and manipulate libraries of rates, as well as run and visualize sample post-processing nucleosynthesis calculations. For example, we have developed animated nuclide charts that show how predicted abundances (represented by a user-defined color scale) change in time. With this unique suite, users can within a very short time quantify the astrophysical impact of a newly measured or calculated cross section, or a newly created customized reaction rate library, and then document and share their results with the scientific community. The suite has a straightforward interface with a "Windows Wizard" motif whereby users progress through complicated calculations in a step-by-step fashion. Users can upload their own files for processing and save their work on our server, as well as work with files that other users wish to share. These tools are currently being used to investigate novae and X-ray bursts. The suite is available through nucastrodata.org, a website that also hyperlinks available nuclear data sets relevant for nuclear astrophysics research. New features are continually being added to this software, which is funded by the U.S. Department of Energy Low Energy Nuclear Physics and Nuclear Data Programs. ORNL is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.

  18. Progress in the 1.6 m New Solar Telescope in Big Bear

    NASA Astrophysics Data System (ADS)

    Goode, Philip R.; NST Team

    2006-06-01

    Progress in building the NST (New Solar Telescope) will be reported. The NST is a 1.6 m clear aperture, off-axis solar telescope. The telescope is scheduled to see first light at Big Bear Solar Observatory (BBSO) in April 2007, and is a joint effort of BBSO, the University of Hawaii, the Korea Astronomy & Space Science Institute and the University of Arizona.The telescope is off-axis to optimize low-contrast imaging, and will have a 3 arcminute field of view. Figuring and testing the figure of the large off-axis primary mirror presented unique problems. The NST (New Solar Telescope) will have wavefront sensor controlled, real-time active optics, and its light will feed BBSO's adaptive optics system, which in turn feeds infrared and visible light Fabry-Perot based polarimeters, as well as a real-time image processing system utilizing parallel processing.The NST replaces the current 0.6 m solar telescope at BBSO, and required a new, larger, vented dome with new thermal and telescope control systems.The complementary value of the telescope for upcoming space missions, such as SOLAR-B, STEREO and SDO will be discussed.

  19. Influence of Wind Buffeting on the 3.6 m Telescope

    NASA Astrophysics Data System (ADS)

    Griffin, S.; Haar, S.; Walker, E.; Whiting, A.; Williams, S.

    2013-09-01

    Unsteady wind loading is the largest dynamic loading on most large ground telescopes. The maximum operational windspeed not only sets requirements on the wind load rejection performance of the mount control system but also is a significant driver for tracker error rejection. In addition, turbulence due to the wind contributes to wavefront distortion. With the recent interest in daylight imaging, introduction of a baffle that reduces background light during the day may further accentuate wind loading on the 3.6 m telescope. The initial daylight configuration of the telescope has been to operate without a baffle and to use operational constraints to avoid angles close to the sun. This configuration offers reasonable daylight performance but is susceptible to stray light that limits achievable signal-to-noise ratio. Also under test is a unique baffled configuration where the telescope is shrouded to increase target signal-to-noise ratio. Traditional baffles increase jitter and wind loading due to increased exposed area to the wind and increase wavefront distortion due to thermal gradients introduced by the baffle. The 3.6 m telescope baffle has been designed out of an opaque fabric to limit the negative impacts on jitter and wavefront distortion while increasing signal-to-noise ratio for daylight imaging. The intent of the design is to limit high frequency transmission of wind loading by the relatively compliant fabric and to allow some circulation using the fabric's porosity to limit thermal gradients. The fabric design also facilitates the extension to a deployable design, since it is relatively easy to deploy and stow compared to a traditional approach. This paper will present analytical results predicting jitter and mount control performance with and without the baffle as well as signal-to-noise ratio predictions with and without the baffle. The jitter results will use measured wind loading in conjunction with a system line-of-sight model for performance

  20. Laboratory Astrophysics White Paper: Summary of Laboratory Astrophysics Needs

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The NASA Laboratory Astrophysics Workshop (NASA LAW) met at NASA Ames Research Center from 1-3 May 2002 to assess the role that laboratory astrophysics plays in the optimization of NASA missions, both at the science conception level and at the science return level. Space missions provide understanding of fundamental questions regarding the origin and evolution of galaxies, stars, and planetary systems. In all of these areas the interpretation of results from NASA's space missions relies crucially upon data obtained from the laboratory. We stress that Laboratory Astrophysics is important not only in the interpretation of data, but also in the design and planning of future missions. We recognize a symbiosis between missions to explore the universe and the underlying basic data needed to interpret the data from those missions. In the following we provide a summary of the consensus results from our Workshop, starting with general programmatic findings and followed by a list of more specific scientific areas that need attention. We stress that this is a 'living document' and that these lists are subject to change as new missions or new areas of research rise to the fore.

  1. PREFACE: Nuclear Physics in Astrophysics VI (NPA6)

    NASA Astrophysics Data System (ADS)

    2016-01-01

    The Nuclear Physics in Astrophysics VI conference was the 6th event of the NPA biannual conference series. Previous events of this series were held at the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen, Hungary, in 2002 and 2005; at the Forschungszentrum Dresden-Rossendorf, Dresden, Germany, in 2007; at the Laboratori Nazionali del Gran Sasso (LNGS), L'Aquila, Italy, in 2009; and in Eilat, Israel, in 2011. This edition of the NPA conference series was organized by the European Physical Society (EPS) through its Nuclear Physics Division, corresponding to the 26th edition of the Topical Conferences of the EPS. As in previous editions, the goal of the NPA conference was to bring together the specialists in the fields of Nuclear Physics (theory and experiment) and Nuclear Astrophysics (theory and observation), providing the appropriate forum for review and discussion of the status and prospects of the field of Nuclear Astrophysics. During the discussions, special attention was given to the Nuclear Physics aspects that have an impact in Astrophysics.

  2. Queue observing at the Observatoire du Mont-Mégantic 1.6-m telescope

    NASA Astrophysics Data System (ADS)

    Artigau, Étienne; Lamontagne, Robert; Doyon, René; Malo, Lison

    2010-07-01

    Queue planning of observation and service observing are generally seen as specific to large, world-class, astronomical observatories that draw proposal from a large community. One of the common grievance, justified or not, against queue planning and service observing is the fear of training a generation of astronomers without hands-on observing experience. At the Observatoire du Mont-Mégantic (OMM) 1.6-m telescope, we are developing a student-run service observing program. Queue planning and service observing are used as training tools to expose students to a variety of scientific project and instruments beyond what they would normally use for their own research project. The queue mode at the OMM specifically targets relatively shallow observations that can be completed in less than a few hours and are too short to justify a multi-night classical observing run.

  3. The 3,6 m Indo-Belgian Devasthal Optical Telescope: general description

    NASA Astrophysics Data System (ADS)

    Ninane, Nathalie; Flebus, Carlo; Kumar, Brijesh

    2012-09-01

    AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation (Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT). The telescope has Ritchey-Chrétien optical configuration with one axial and two side Cassegrain ports. The meniscus primary mirror is active and it is supported by pneumatic actuators. The azimuth axis system is equipped with hydrostatic bearing. The telescope was completely assembled and tested in AMOS workshop. This step is completed and successful. The telescope is now ready for shipment to Nainital. This paper describes the telescope and summarizes the test results performed at AMOS to demonstrate that the telescope satisfies the main system requirements.

  4. Mechanical characteristics of alloy AMg6M in broad temperature and strain-rate ranges

    SciTech Connect

    Krashchenko, V.P.; Dvoeglazov, G.A.; Ermolaev, G.V.; Rudnitskii, N.P.

    1986-02-01

    The authors study the mechanical properties of an aluminum-magnesium alloy in broad ranges of temperature and strain rate, and the change in hardness and dynamic modulus of elasticity in relation to temperature. The material chosen for study was alloy AMg6M. The heat treating process is described. The experimental data obtained on Micro-6, UVT-2, and UP-7 units is shown graphically. It is apparent that an increase in temperature is accompanied by a decrease in hardness, elastic modulus, and strength in general. Models are obtained and additional tests of specimens at the strain rate 3.3 X 10/sup -2/ sec/sup -1/ and different temperatures are conducted. The dependences must be calculated using all possible models, and the lowest resulting value must be chosen.

  5. Drop Simulation of 6M Drum with Locking-Ring Closure and Liquid Contents

    SciTech Connect

    Wu, T

    2006-04-17

    This paper presents the dynamic simulation of the 6M drum with a locking-ring type closure subjected to a 4.9-foot drop. The drum is filled with water to 98 percent of overflow capacity. A three dimensional finite-element model consisting of metallic, liquid and rubber gasket components is used in the simulation. The water is represented by a hydrodynamic material model in which the material's volume strength is determined by an equation of state. The explicit numerical method based on the theory of wave propagation is used to determine the combined structural response to the torque load for tightening the locking-ring closure and to the impact load due to the drop.

  6. The 1.6 m New Solar Telescope (NST) in Big Bear

    NASA Astrophysics Data System (ADS)

    Cao, W.

    2012-12-01

    The 1.6 m clear aperture, off-axis New Solar Telescope (NST) is in regular operation in Big Bear Solar Observatory. The NST is the first facility-class solar telescope built in the U.S. in a generation. The NST provides high resolution and high sensitivity observations of the solar photosphere and chromosphere in the visible and near infrared (NIR). A high order adaptive optics system delivers corrected light to an ensemble of state-of-the-art scientific instruments in the coude laboratory including the Broad-band Filter Imagers (BFIs), NIR Imaging Spectro-polarimeter (NIRIS), Visible Imaging Spectro-polarimeter (VIS) and Fast Imaging Solar Spectrograph (FISS). Some early scientific results from the NST will be presented, followed by a progress report on NST instrument development projects, as well as upgrades to existing instruments.

  7. Control and operation of the 1.6 m New Solar Telescope in Big Bear

    NASA Astrophysics Data System (ADS)

    Varsik, J.; Plymate, C.; Goode, P.; Kosovichev, A.; Cao, W.; Coulter, R.; Ahn, K.; Gorceix, N.; Shumko, S.

    2014-08-01

    The 1.6m New Solar Telescope (NST) has developed a modern and comprehensive suite of instruments which allow high resolution observations of the Sun. The current instrument package comprises diffraction limited imaging, spectroscopic and polarimetric instruments covering the wavelength range from 0.4 to 5.0 microns. The instruments include broadband imaging, visible and near-infrared scanning Fabry-Perot interferometers, an imaging spectropolarimeter, a fast visible-light imaging spectrograph, and a unique new scanning cryogenic infrared spectrometer/spectropolarimeter that is nearing completion. Most instruments are operated with a 308 subaperture adaptive optics system, while the thermal-IR spectrometer has a correlation tracker. This paper reports on the current observational programs and operational performance of the telescope and instrumentation. The current control, data processing, and archiving systems are also briefly discussed.

  8. The 1.6 m off-axis New Solar Telescope (NST) in Big Bear

    NASA Astrophysics Data System (ADS)

    Goode, Philip R.; Cao, Wenda

    2012-09-01

    The 1.6-m New Solar Telescope (NST) has been used to observe the Sun for more than three years with ever increasing capabilities as its commissioning phase winds down. The NST is the first facility-class solar telescope built in the U.S. in a generation, and it has an off-axis design as is planned for the 4 m Advanced Technology Solar Telescope. Lessons learned will be discussed. Current NST post-focus instrumentation includes adaptive optics (AO) feeding photometric and near-IR polarimetric sytems, as well as an imaging spectrograph. On-going instrumentation projects will be sketched, including Multi-Conjugate AO (MCAO), next generation (dual Fabry- Perot) visible light and near-IR polarimeters and a fully cryogenic spectrograph. Finally, recent observational results illustrating the high resolution capabilities of the NST will be shown.

  9. The EMCCD-based speckle interferometer of the BTA 6-m telescope: Description and first results

    NASA Astrophysics Data System (ADS)

    Maksimov, A. F.; Balega, Yu. Yu.; Dyachenko, V. V.; Malogolovets, E. V.; Rastegaev, D. A.; Semernikov, E. A.

    2009-07-01

    The description is given for the speckle interferometer of the BTA 6-m telescope of the SAO RAS based on a new detector with an electron multiplication CCD. The main components of the instrument are microscope objectives, interference filters and atmospheric dispersion correction prisms. The PhotonMAX-512B CCD camera using a back-illuminated CCD97 allows up to 20 speckle images (with 512×512 pix resolution) per second storage on the hard drive. Due to high quantum efficiency (93% in the maximum at 550 nm), and high transmission of its optical elements, the new camera can be used for diffraction-limited (0.02″) image reconstruction of 15 m stars under good seeing conditions. The main advantages of the new system over the previous generation BTA speckle interferometer are examined.

  10. Active optics correction forces for the VST 2.6m primary mirror

    NASA Astrophysics Data System (ADS)

    Schipani, P.; Perrotta, F.; Marty, L.

    2006-06-01

    In active optics systems obviously a fundamental role is played be the choice of polynomials to describe the primary mirror deformations. The well known Zernike polynomials are widely used because of their immediate interpretation in terms of optical aberrations. Nevertheless in an active optics correction system context, the choice of the so called "minimum energy modes" as the polynomials to represent the mechanical deformations is best justified by their derivation from mechanical properties. This is the approach followed for the 2.6m primary mirror of the VST telescope, to be hosted on top of the Cerro Paranal ESO observatory. The calibration forces to compensate a given amount of each aberration mode are computed and discussed.

  11. Structure and wear resistance of R6M5 steel based coatings

    NASA Astrophysics Data System (ADS)

    Gnyusov, S. F.; Ignatov, A. A.; Durakov, V. G.

    2010-08-01

    Features of the structure of R6M5 steel based coatings obtained by multiscan electron-beam fusion of a hardening composition in vacuum have been studied. It is established that the carbide subsystem of the hardened layer is characterized by a multimodal distribution of carbide particles with d 1 = 3.8 μm, d 2 = 0.65 μm, and d 3 < 0.25 μm. The volume fraction of M6C secondary carbide and retained matrix austenite can be controlled within broad limits by varying thermal parameters of the electron-beam fusion. An increase in the retained austenite fraction in the coating leads to improved wear resistance due to the γ → α' marten-site transformation during friction and the presence of dispersed secondary carbides inside the matrix grains.

  12. Hypothetical accident conditions, free drop and thermal tests: Specification 6M

    SciTech Connect

    Blankenship, R.W.

    1980-05-01

    The 30 gallon Specification 6M shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UO/sub 2/ was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UO/sub 2/ for the following week was 3.2 ..mu..g. This leakage is well below the allowable leakage per week for most plutonium isotopic mixtures. Using the examples provided, any plutonium isotopic mixture can be easily compared with the allowable leakage per week. Test conditions and results are reported.

  13. Construction and Test of 3.6 m Nb3Sn Racetrack Coils for LARP

    SciTech Connect

    Wanderer, P.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Cheng, D. W.; Cozzolino, J.; Dietderich, D.R.; Escallier, J.; Feher, S.; Ferracin, P.; Ganetis, G.; Ghosh, A. K.; Gupta, R. C.; Hafalia,, A. R.; Hannaford, C. R.; Joshi, P.; Kovach, P.; Lietzke, A. F.; Lizarazo, J.; Louie, W.; Marone, A.; McInturff, A.D.; Muratore, J.; Nobrega, F.; Sabbi, G.; Schmalzle, J.; Thomas, R.; Turrioni, D.

    2008-06-01

    Development of high-performance Nb{sub 3}Sn quadrupoles is one of the major goals of the LHC Accelerator Research Program (LARP). As part of this program, long racetrack magnets were made in order to check the fabrication steps for long Nb{sub 3}Sn coils, that the changes in coil length that take place during reaction and cooldown are correctly accounted for in the quadrupole design, and the use of a long aluminum shell for the support structure. This paper reports the construction of the first long Nb{sub 3}Sn magnet with racetrack coils 3.6 m long. The magnet reached a nominal 'plateau' at 9596 A after five quenches. This is about 90% of the estimated conductor limit. The peak field in the coils at this current was 11 T.

  14. Astrophysical Applications of Fractional Calculus

    NASA Astrophysics Data System (ADS)

    Stanislavsky, Aleksander A.

    The paradigm of fractional calculus occupies an important place for the macroscopic description of subdiffusion. Its advance in theoretical astrophysics is expected to be very attractive too. In this report we discuss a recent development of the idea to some astrophysical problems. One of them is connected with a random migration of bright points associated with magnetic fields at the solar photosphere. The transport of the bright points has subdiffusive features that require the fractional generalization of the Leighton's model. Another problem is related to the angular distribution of radio beams, being propagated through a medium with random inhomogeneities. The peculiarity of this medium is that radio beams are trapped because of random wave localization. This idea can be useful for the diagnostics of interplanetary and interstellar turbulent media.

  15. Astrophysical processes on the Sun

    PubMed Central

    Parnell, Clare E.

    2012-01-01

    Over the past two decades, there have been a series of major solar space missions, namely Yohkoh, SOHO, TRACE, and in the past 5 years, STEREO, Hinode and SDO, studying various aspects of the Sun and providing images and spectroscopic data with amazing temporal, spatial and spectral resolution. Over the same period, the type and nature of numerical models in solar physics have been completely revolutionized as a result of widespread accessibility to parallel computers. These unprecedented advances on both observational and theoretical fronts have led to significant improvements in our understanding of many aspects of the Sun's behaviour and furthered our knowledge of plasma physics processes that govern solar and other astrophysical phenomena. In this Theme Issue, the current perspectives on the main astrophysical processes that shape our Sun are reviewed. In this Introduction, they are discussed briefly to help set the scene. PMID:22665891

  16. MHD scaling: from astrophysics to the laboratory

    NASA Astrophysics Data System (ADS)

    Ryutov, Dmitri

    2000-10-01

    During the last few years, considerable progress has been made in simulating astrophysical phenomena in laboratory experiments with high power lasers [1]. Astrophysical phenomena that have drawn particular interest include supernovae explosions; young supernova remnants; galactic jets; the formation of fine structures in late supernova remnants by instabilities; and the ablation driven evolution of molecular clouds illuminated by nearby bright stars, which may affect star formation. A question may arise as to what extent the laser experiments, which deal with targets of a spatial scale 0.01 cm and occur at a time scale of a few nanoseconds, can reproduce phenomena occurring at spatial scales of a million or more kilometers and time scales from hours to many years. Quite remarkably, if dissipative processes (like, e.g., viscosity, Joule dissipation, etc.) are subdominant in both systems, and the matter behaves as a polytropic gas, there exists a broad hydrodynamic similarity (the ``Euler similarity" of Ref. [2]) that allows a direct scaling of laboratory results to astrophysical phenomena. Following a review of relevant earlier work (in particular, [3]-[5]), discussion is presented of the details of the Euler similarity related to the presence of shocks and to a special case of a strong drive. After that, constraints stemming from possible development of small-scale turbulence are analyzed. Generalization of the Euler similarity to the case of a gas with spatially varying polytropic index is presented. A possibility of scaled simulations of ablation front dynamics is one more topic covered in this paper. It is shown that, with some additional constraints, a simple similarity exists. This, in particular, opens up the possibility of scaled laboratory simulation of the aforementioned ablation (photoevaporation) fronts. A nonlinear transformation [6] that establishes a duality between implosion and explosion processes is also discussed in the paper. 1. B.A. Remington et

  17. Astrophysics with Microarcsecond Accuracy Astrometry

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.

    2008-01-01

    Space-based astrometry promises to provide a powerful new tool for astrophysics. At a precision level of a few microarcsonds, a wide range of phenomena are opened up for study. In this paper we discuss the capabilities of the SIM Lite mission, the first space-based long-baseline optical interferometer, which will deliver parallaxes to 4 microarcsec. A companion paper in this volume will cover the development and operation of this instrument. At the level that SIM Lite will reach, better than 1 microarcsec in a single measurement, planets as small as one Earth can be detected around many dozen of the nearest stars. Not only can planet masses be definitely measured, but also the full orbital parameters determined, allowing study of system stability in multiple planet systems. This capability to survey our nearby stellar neighbors for terrestrial planets will be a unique contribution to our understanding of the local universe. SIM Lite will be able to tackle a wide range of interesting problems in stellar and Galactic astrophysics. By tracing the motions of stars in dwarf spheroidal galaxies orbiting our Milky Way, SIM Lite will probe the shape of the galactic potential history of the formation of the galaxy, and the nature of dark matter. Because it is flexibly scheduled, the instrument can dwell on faint targets, maintaining its full accuracy on objects as faint as V=19. This paper is a brief survey of the diverse problems in modern astrophysics that SIM Lite will be able to address.

  18. Optical Quantum Entanglement in Astrophysics

    NASA Astrophysics Data System (ADS)

    Gómez, J.; Peimbert, A.; Echevarría, J.

    2009-10-01

    The theories of quantum entanglement between two distant particles, which clearly confirm the non-local nature of Quantum Mechanics, are applied to naturally produced particles in astrophysical objects. We study the production and reception of the cases of optical quantum entanglement most feasible to be observed: the two-photon spontaneous transition of the hydrogen 2 ^{2}S_{1/2} metastable level, which is known to be one of the components of the continuous spectra of ionized regions. We obtain the two-photon emission rate for four astrophysical objects: the Orion Nebula, two nearby planetary nebulae IC 2149 and NGC 7293, and the solar corona. The production of entangled pairs per second is 5.80×10^48, 9.39×10^45, 9.77×10^44, and 1.46×10^16 respectively. The distribution of the propagation directions of both emitted photons does not vanish at any angle; therefore it is possible to observe the entangled pair at an angles θ ≈ 0°. Because the number of two-photon coincidences goes as the fourth power of the ratio between the detector size and the distance from the astrophysical object, coincidences are scarce; for its detection we require receivers much larger than those currently available.

  19. NASA Astrophysics E/PO Impact: The Astrophysics Educator Ambassador Program

    NASA Astrophysics Data System (ADS)

    Cominsky, Lynn R.; McLin, Kevin M.; SSU E/PO Team

    2015-01-01

    The NASA Astrophysics Educator Ambassador (EA) Program began in 2001 as part of the GLAST (now Fermi) E/PO effort at Sonoma State University. The program currently supports 15 EAs, sponsored by either Fermi, Swift, XMM-Newton or NuSTAR. This group of master educators work with mission scientists and E/PO personnel to develop curricula and train teachers; they also do workshops for students and outreach events with the general public. We have held six bi-annual weeklong trainings at SSU: each has had a different focus. Special topics of study have included the Dark Universe, Particle Physics and Gravitation. Additionally, time is given for the EAs to share ideas from their own workshops. In the 14 years of the program, the total number of teachers attending EA-run workshops is over 65,000. Over 1500 workshops have been evaluated by participants, and these evaluation scores and comments have been further analyzed by external experts at WestEd. The WestEd report summarizes the results: "Almost universally high ratings are obtained even though a wide range of participants by grade level, teaching experience or interest typically attends EA conference sessions, and they can bring quite different needs or perspectives." In this talk, I will report details of the impacts of the Astrophysics EA program.

  20. Implications of Ultrahigh Energy Air Showers for Physics and Astrophysics

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    The primary ultrahigh energy particles which produce giant extensive air showers in the Earth atmosphere present an intriguing mystery from two points of view: (1) How are the base particles produced with such astounding energies, eight orders of magnitude higher than those produced by the best man-made terrestrial accelerators? (2) Since they are most likely extragalactic in origin, how do they reach us from extragalactic distances without suffering the severe losses expected from interactions with the 2.7 K thermal cosmic background photons, the so called GZK effect? The answers to these questions may involve new physics: violations of special relativity, grand unification theories, and quantum gravity theories involving large extra dimensions. They may involve new astrophysical sources, "zevatrons". Or some heretofore totally unknown physics or astrophysics may hold the answer. I will discuss here the mysteries involving the production and extragalactic propagation of ultrahigh energy cosmic rays and some suggested possible solutions.

  1. Blazar variability studies with the 1.3m Robotically Controlled Telescope and the automated 0.6m Bell Observatory telescope

    NASA Astrophysics Data System (ADS)

    Carini, M. T.; Barnaby, D.; Mattox, J. R.; Walters, R.; Poteet, C.; Wills, W.; Gelderman, R.; Davis, D.; Everett, M.; Guinan, E.; Howell, S.; McGruder, C. H., III

    2004-10-01

    One of the key programs on the 1.3m Robotically Controlled Telescope (RCT) located at Kitt Peak National Observatory and the 0.6m telescope at the Bell Observatory operated by Western Kentucky University is a study of the variability of the class of Active Galactic Nuclei (AGN) known as Blazars. Blazars are highly variable on timescales of minutes to decades and this variability is seen across the electromagnetic spectrum. In addition, they display a featureless spectrum, thus continuum variability provides the only diagnostic of these objects. Variability provides information on the size of the emission region responsible for the observed variations and when observations are obtained at multiple wavelengths, it can be used to discriminate between emission models. However, traditional ground based observations are limited in a variety of ways. We will discuss how an automated facility, with time dedicated to this astrophysically interesting problem, can overcome many of these limitations, and we show results from the Bell Observatory as well as some of the first results of Blazar observations from the RCT.

  2. The 3,6 m Indo-Belgian Devasthal Optical Telescope: the hydrostatic azimuth bearing

    NASA Astrophysics Data System (ADS)

    de Ville, Jonathan; Piérard, Maxime; Bastin, Christian

    2012-09-01

    AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation (Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT). The telescope has a Ritchey-Chrétien optical configuration with a Cassegrain focus equipped with one axial port and two side ports. The primary mirror is a meniscus active mirror. The mount is an Alt-Az type with for the azimuth axis a 5 m diameter hydrostatic track. This paper presents the solution adopted by AMOS to meet the specific requirements for the azimuth axis. The track is designed to be able to control the positioning of the telescope around the azimuth axis with an accuracy of 0.05 arc second for all tracking configurations. The challenge came from this tight accuracy with a mass in rotation weighting 125 tons. The azimuth track was mounted and tested in AMOS workshop; the tests and performances are also discussed.

  3. First Results from 1.6 m Off-Axis Solar Telescope in Big Bear (Invited)

    NASA Astrophysics Data System (ADS)

    Goode, P. R.

    2009-12-01

    In early 2009 at Big Bear Solar Observatory, first light science observations were made with BBSO's NST (New Solar Telescope), which has a 1.6m clear aperture (0.06” resolution at 500 nm). After a brief introduction to some of the lessons learned in making the telescope, first light observations in TiO, Halpha, G-Band and 1.56 micron lines will be introduced with detailed results presented in other talks in this session, including joint observations with Hinode and other satellites. The NST has an off-axis Gregorian configuration consisting of a parabolic primary, heat-stop, elliptical secondary and diagonal flats. The focal ratio of the primary mirror is f/2.4, and the final ratio is f/50. The working wavelength range covers from 0.4 to 1.7 microns in the Coude Lab beneath the telescope and all wavelengths including the far infrared at the Nasmyth focus on the dome floor. Plans for the on-going commissioning phase will be sketched.

  4. Half sandwich structures of MCF6- (M = Ag and Au): An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Sun, Zhang; Tang, Zichao; Gao, Zhen

    2013-01-01

    The metal-hexafluorobenzene anionic complexes of [MC6F6]- (M = Ag and Au) were produced from the reactions between metal cluster generated by laser ablation and the hexafluorobenzene seeded in argon carrier gas, and were studied by photoelectron spectroscopy (PES) and density functional theory (DFT). The adiabatic electron affinities (EAs) of these corresponding complexes are measured from the experimental PE spectra at 193 nm photon energy. Also, the calculated EAs and the calculated density of states (DOS) spectra of these complexes in the ground state are conducted, which are in good agreement with their experimental PE spectra. The most possible structures of the anions [AgC6F6]- and [AuC6F6]- are the half-sandwich structures with C6v symmetry, in which the metal atom is above the center of the C6F6 plane. Furthermore, the molecular orbital (MO) analysis of these species indicates that the additional electron of the anions binds on the metal.

  5. Imaging polarimetry of distant comets at the 6-m BTA telescope of the SAO RAS

    NASA Astrophysics Data System (ADS)

    Ivanova, Oleksandra; Afanasiev, Viktor; Rosenbush, Vera; Kiselev, Nikolai

    2016-07-01

    Results of the recent polarimetric observations of distant comets C/2013 V4 (Catalina), C/2014 A4 (SONEAR), C/2010 S1 (LINEAR), C/2010 R1 (LINEAR), and 29P/Schwassmann-Wachmann 1 are presented together with analysis of their photometry and spectroscopy. Observations were carried out at the 6-m telescope BTA of the SAO RAS with the multi-mode focal reducer SCORPIO-2 from 2011 to 2015. Comets were observed in the range of heliocentric distances from 4.2 to 7.0 AU and phase angles from 4.9 to 9.4 degrees. The maps of intensity and linear polarization over the coma are derived. The comets observed show a considerable activity at heliocentric distances far exceeding a zone of water sublimation. Molecular emissions were only detected in the spectra of comet 29P/Schwassmann-Wachmann 1. The linear polarization of distant comets with a high level of activity is the first ever measured at the heliocentric distances larger than 5 AU. The degree of linear polarization (from -2 to -3.7%) for these comets is significantly higher (in absolute value) than the typical value of the whole coma polarization (about -1.5 %) at the minimum of negative polarization branch for close to the Sun comets.

  6. Continuous synthesis process of hexagonal nanoplates of P6m ordered mesoporous silica.

    PubMed

    Jammaer, Jasper; van Erp, Titus S; Aerts, Alexander; Kirschhock, Christine E A; Martens, Johan A

    2011-08-31

    Hexagonally ordered mesoporous silica coined COK-12 was synthesized in a continuous process by combining streams of sodium silicate and citric acid/sodium citrate buffered solution of (ethylene oxide)(20)-(propylene oxide)(70)-(ethylene oxide)(20) triblock copolymer (Pluronic P123) from separate reservoirs. COK-12 precipitated spontaneously upon combining both streams at nearly neutral pH and ambient temperature. Stable intermediates of the COK-12 formation process could be prepared by limiting sodium silicate addition. Investigation of these intermediates using small-angle X-ray scattering revealed COK-12 formed via an assembly process departing from spherical uncharged core-shell P123-silica micelles. The sterical stabilization of these micelles decreased upon accumulation of silicate oligomers in their shell. Aggregation of the spherical micelles led to cylindrical micelles, which aligned and adopted the final hexagonal organization. This unprecedentedly fast formation of P6m ordered mesoporous silica was caused by two factors in the synthesis medium: the neutral pH favoring uncharged silicate oligomers and the high salt concentration promoting hydrophobic interactions with surfactant micelles leading to silica accumulation in the PEO shell. The easy continuous synthesis process is convenient for large-scale production. The platelet particle morphology with short and identical internal channels will be advantageous for many applications such as pore replication, nanotube or fiber growth, catalytic functionalization, drug delivery, film and sensor development, and in nano dyes as well as for investigation of pore diffusion phenomena. PMID:21790195

  7. PREFACE: International Conference on Particle Physics and Astrophysics (ICPPA-2015)

    NASA Astrophysics Data System (ADS)

    2016-02-01

    The International Conference on Particle Physics and Astrophysics (ICPPA-2015) was held in Moscow, Russia, from October 5 to 10, 2015. The conference is organized by Center of Fundamental Research and Particle Physics of National Research Nuclear University ''MEPhI''. The aim of the Conference is to promote contacts between scientists and development of new ideas in fundamental research. We bring together experts and young scientists working on experimental and theoretical aspects of nuclear, particle, astroparticle physics and cosmology. The conference covers a wide range of topics such as accelerator physics, (astro) particle physics, cosmic rays, cosmology and methods of experimental physics - detectors and instruments. These directions are unified by development of the Standard Model (SM) which is evidently not complete. There are deviations from the Standard Model - neutrino oscillations, the dark matter existence. Together with strong interactions, they are main subjects of the Conference. New results from LHC collider as well as its future upgrade are discussed with the Higgs as the main point for discussion. Substantial development of experimental tools for astrophysical observations and new results from cosmic ray experiments is one of the main subjects of the conference. Various aspects of strong interaction are discussed. Among them: Charmonium and Bottomonium states, Flavor physics at Super B factories, Exotic Nuclei in Astrophysics. Another subject for discussion is the neutrino physics, promising and unique way to get new knowledge. In this content, several talks on BOREXINO experiment where new results in neutrino oscillations are presented. Special session is devoted to PAMELA experiment - 9 years in orbit and to the future GAMMA-400 gamma-ray telescope with following main scientific goals: indirect dark matter origin study by the gamma-ray astronomy methods, discrete astrophysical sources observations, diffuse background γ-emission analysis

  8. Einstein Toolkit for Relativistic Astrophysics

    NASA Astrophysics Data System (ADS)

    Collaborative Effort

    2011-02-01

    The Einstein Toolkit is a collection of software components and tools for simulating and analyzing general relativistic astrophysical systems. Such systems include gravitational wave space-times, collisions of compact objects such as black holes or neutron stars, accretion onto compact objects, core collapse supernovae and Gamma-Ray Bursts. The Einstein Toolkit builds on numerous software efforts in the numerical relativity community including CactusEinstein, Whisky, and Carpet. The Einstein Toolkit currently uses the Cactus Framework as the underlying computational infrastructure that provides large-scale parallelization, general computational components, and a model for collaborative, portable code development.

  9. Astrophysics on the lab bench

    NASA Astrophysics Data System (ADS)

    Hughes, Stephen W.

    2010-05-01

    In this article some basic laboratory bench experiments are described that are useful for teaching high school students some of the basic principles of stellar astrophysics. For example, in one experiment, students slam a plastic water-filled bottle down onto a bench, ejecting water towards the ceiling, illustrating the physics associated with a type II supernova explosion. In another experiment, students roll marbles up and down a double ramp in an attempt to get a marble to enter a tube halfway up the slope, which illustrates quantum tunnelling in stellar cores. The experiments are reasonably low cost to either purchase or manufacture.

  10. Astrophysics Source Code Library Enhancements

    NASA Astrophysics Data System (ADS)

    Hanisch, R. J.; Allen, A.; Berriman, G. B.; DuPrie, K.; Mink, J.; Nemiroff, R. J.; Schmidt, J.; Shamir, L.; Shortridge, K.; Taylor, M.; Teuben, P. J.; Wallin, J.

    2015-09-01

    The Astrophysics Source Code Library (ASCL)1 is a free online registry of codes used in astronomy research; it currently contains over 900 codes and is indexed by ADS. The ASCL has recently moved a new infrastructure into production. The new site provides a true database for the code entries and integrates the WordPress news and information pages and the discussion forum into one site. Previous capabilities are retained and permalinks to ascl.net continue to work. This improvement offers more functionality and flexibility than the previous site, is easier to maintain, and offers new possibilities for collaboration. This paper covers these recent changes to the ASCL.

  11. Astrophysics and Cosmology: International Partnerships

    NASA Astrophysics Data System (ADS)

    Blandford, Roger

    2015-04-01

    Most large projects in astrophysics and cosmology are international. This raises many challenges including: • Aligning the sequence of: proposal, planning, selection, funding, construction, deployment, operation, data mining in different countries • Managing to minimize cost growth through reconciling different practices • Communicating at all levels to ensure a successful outcome • Stabilizing long term career opportunities. There has been considerable progress in confronting these challenges. Lessons learned from past collaborations are influencing current facilities but much remains to be done if we are to optimize the scientific and public return on the expenditure of financial and human resources.

  12. High-energy spectroscopic astrophysics

    NASA Astrophysics Data System (ADS)

    Güdel, Manuel; Walter, Roland

    After three decades of intense research in X-ray and gamma-ray astronomy, the time was ripe to summarize basic knowledge on X-ray and gamma-ray spectroscopy for interested students and researchers ready to become involved in new high-energy missions. This volume exposes both the scientific basics and modern methods of high-energy spectroscopic astrophysics. The emphasis is on physical principles and observing methods rather than a discussion of particular classes of high-energy objects, but many examples and new results are included in the three chapters as well.

  13. Astrophysical constraints on dark energy

    NASA Astrophysics Data System (ADS)

    Ho, Chiu Man; Hsu, Stephen D. H.

    2016-02-01

    Dark energy (i.e., a cosmological constant) leads, in the Newtonian approximation, to a repulsive force which grows linearly with distance and which can have astrophysical consequences. For example, the dark energy force overcomes the gravitational attraction from an isolated object (e.g., dwarf galaxy) of mass 107M⊙ at a distance of 23 kpc. Observable velocities of bound satellites (rotation curves) could be significantly affected, and therefore used to measure or constrain the dark energy density. Here, isolated means that the gravitational effect of large nearby galaxies (specifically, of their dark matter halos) is negligible; examples of isolated dwarf galaxies include Antlia or DDO 190.

  14. Astrophysics and Cosmology: International Partnerships

    NASA Astrophysics Data System (ADS)

    Blandford, Roger

    2016-03-01

    Most large projects in astrophysics and cosmology are international. This raises many challenges including: --Aligning the sequence of: proposal, planning, selection, funding, construction, deployment, operation, data mining in different countries --Managing to minimize cost growth through reconciling different practices --Communicating at all levels to ensure a successful outcome --Stabilizing long term career opportunities. There has been considerable progress in confronting these challenges. Lessons learned from past collaborations are influencing current facilities but much remains to be done if we are to optimize the scientific and public return on the expenditure of financial and human resources.

  15. Scientific instrumentation for the 1.6 m New Solar Telescope in Big Bear

    NASA Astrophysics Data System (ADS)

    Cao, W.; Gorceix, N.; Coulter, R.; Ahn, K.; Rimmele, T. R.; Goode, P. R.

    2010-06-01

    The NST (New Solar Telescope), a 1.6 m clear aperture, off-axis telescope, is in its commissioning phase at Big Bear Solar Observatory (BBSO). It will be the most capable, largest aperture solar telescope in the US until the 4 m ATST (Advanced Technology Solar Telescope) comes on-line late in the next decade. The NST will be outfitted with state-of-the-art scientific instruments at the Nasmyth focus on the telescope floor and in the Coudé Lab beneath the telescope. At the Nasmyth focus, several filtergraphs already in routine operation have offered high spatial resolution photometry in TiO 706 nm, H\\alpha 656 nm, G-band 430 nm and the near infrared (NIR), with the aid of a correlation tracker and image reconstruction system. Also, a Cryogenic Infrared Spectrograph (CYRA) is being developed to supply high signal-to-noise-ratio spectrometry and polarimetry spanning 1.0 to 5.0 μm. The Coudé Lab instrumentation will include Adaptive Optics (AO), InfraRed Imaging Magnetograph (IRIM), Visible Imaging Magnetograph (VIM), and Fast Imaging Solar Spectrograph (FISS). A 308 sub-aperture (349-actuator deformable mirror) AO system will enable nearly diffraction limited observations over the NST's principal operating wavelengths from 0.4 μm through 1.7 μm. IRIM and VIM are Fabry-Pérot based narrow-band tunable filters, which provide high resolution two-dimensional spectroscopic and polarimetric imaging in the NIR and visible respectively. FISS is a collaboration between BBSO and Seoul National University focussing on chromosphere dynamics. This paper reports the up-to-date progress on these instruments including an overview of each instrument and details of the current state of design, integration, calibration and setup/testing on the NST.

  16. 1.6 m Off-Axis Solar Telescope at Big Bear Solar Observatory

    NASA Astrophysics Data System (ADS)

    Goode, P. R.; BBSO/NJIT Team; Mees Solar Obs./U. Hawaii Team

    2003-05-01

    New Jersey Institute of Technology (NJIT), in collaboration with the University of Hawaii (UH), is upgrading Big Bear Solar Observatory (BBSO) by replacing its principal, 65 cm aperture telescope with a modern, off-axis 1.6 m clear aperture instrument from a 1.7 m blank. The new telescope offers a significant incremental improvement in ground-based infrared and high angular resolution capabilities, and enhances our continuing program to understand photospheric magneto-convection and chromospheric dynamics. These are the drivers for what is broadly called space weather -- an important problem, which impacts human technologies and life on earth. This New Solar Telescope (NST) will use the existing BBSO pedestal, pier and observatory building, which will be modified to accept the larger open telescope structure. It will be operated together with our 10 inch (for larger field-of-view vector magnetograms, Ca II K and Hα observations) and Singer-Link (full disk Hα , Ca II K and white light) synoptic telescopes. The NST optical and software control design will be similar to the existing SOLARC (UH) and the planned Advanced Technology Solar Telescope (ATST) facility led by the National Solar Observatory (NSO) -- all three are off-axis designs. The highest resolution solar telescopes currently operating are in the sub-meter class, and have diffraction limits which allow them to resolve features larger than 100 km in size on the sun. They are often photon-starved in the study of dynamic events because of the competing need for diffraction limited spatial resolution, short exposure times to minimize seeing effects, and high spectral resolution to resolve line profiles. Thus, understanding many significant and dynamic solar phenomena remains tantalizingly close, but just beyond our grasp. Research supported in part by NASA grant NAG5-12782 and NSF grant ATM-0086999.

  17. 1.6 M Solar Telescope in Big Bear -- The NST

    NASA Astrophysics Data System (ADS)

    Goode, Philip R.; Denker, Carsten J.; Didkovsky, Leonid I.; Kuhn, J. R.; Wang, Haimin

    2003-06-01

    New Jersey Institute of Technology (NJIT), in collaboration with the University of Hawaii (UH), is upgrading Big Bear Solar Observatory (BBSO) by replacing its principal, 65 cm aperture telescope with a modern, off-axis 1.6 m clear aperture instrument from a 1.7 m blank. The new telescope offers a significant incremental improvement in ground-based infrared and high angular resolution capabilities, and enhances our continuing program to understand photospheric magneto-convection and chromospheric dynamics. These are the drivers for what is broadly called space weather -- an important problem, which impacts human technologies and life on earth. This New Solar Telescope (NST) will use the existing BBSO pedestal, pier and observatory building, which will be modified to accept the larger open telescope structure. It will be operated together with our 10 inch (for larger field-of-view vector magnetograms, Ca II K and Hα observations) and Singer-Link (full disk Hα, Ca II K and white light) synoptic telescopes. The NST optical and software control design will be similar to the existing SOLARC (UH) and the planned Advanced Technology Solar Telescope (ATST) facility led by the National Solar Observatory (NSO) -- all three are off-axis designs. The NST will be available to guest observers and will continue BBSO's open data policy. The polishing of the primary will be done in partnership with the University of Arizona Mirror Lab, where their proof-of-concept for figuring 8 m pieces of 20 m nighttime telescopes will be the NST's primary mirror. We plan for the NST's first light in late 2005. This new telescope will be the largest aperture solar telescope, and the largest aperture off-axis telescope, located in one of the best observing sites. It will enable new, cutting edge science. The scientific results will be extremely important to space weather and global climate change research.

  18. A Ribonucleoprotein Complex Protects the Interleukin-6 mRNA from Degradation by Distinct Herpesviral Endonucleases

    PubMed Central

    Muller, Mandy; Hutin, Stephanie; Marigold, Oliver; Li, Kathy H.; Burlingame, Al; Glaunsinger, Britt A.

    2015-01-01

    During lytic Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, the viral endonuclease SOX promotes widespread degradation of cytoplasmic messenger RNA (mRNA). However, select mRNAs escape SOX-induced cleavage and remain robustly expressed. Prominent among these is interleukin-6 (IL-6), a growth factor important for survival of KSHV infected B cells. IL-6 escape is notable because it contains a sequence within its 3’ untranslated region (UTR) that can confer protection when transferred to a SOX-targeted mRNA, and thus overrides the endonuclease targeting mechanism. Here, we pursued how this protective RNA element functions to maintain mRNA stability. Using affinity purification and mass spectrometry, we identified a set of proteins that associate specifically with the protective element. Although multiple proteins contributed to the escape mechanism, depletion of nucleolin (NCL) most severely impacted protection. NCL was re-localized out of the nucleolus during lytic KSHV infection, and its presence in the cytoplasm was required for protection. After loading onto the IL-6 3’ UTR, NCL differentially bound to the translation initiation factor eIF4H. Disrupting this interaction, or depleting eIF4H, reinstated SOX targeting of the RNA, suggesting that interactions between proteins bound to distant regions of the mRNA are important for escape. Finally, we found that the IL-6 3’ UTR was also protected against mRNA degradation by the vhs endonuclease encoded by herpes simplex virus, despite the fact that its mechanism of mRNA targeting is distinct from SOX. These findings highlight how a multitude of RNA-protein interactions can impact endonuclease targeting, and identify new features underlying the regulation of the IL-6 mRNA. PMID:25965334

  19. A ribonucleoprotein complex protects the interleukin-6 mRNA from degradation by distinct herpesviral endonucleases.

    PubMed

    Muller, Mandy; Hutin, Stephanie; Marigold, Oliver; Li, Kathy H; Burlingame, Al; Glaunsinger, Britt A

    2015-05-01

    During lytic Kaposi's sarcoma-associated herpesvirus (KSHV) infection, the viral endonuclease SOX promotes widespread degradation of cytoplasmic messenger RNA (mRNA). However, select mRNAs escape SOX-induced cleavage and remain robustly expressed. Prominent among these is interleukin-6 (IL-6), a growth factor important for survival of KSHV infected B cells. IL-6 escape is notable because it contains a sequence within its 3' untranslated region (UTR) that can confer protection when transferred to a SOX-targeted mRNA, and thus overrides the endonuclease targeting mechanism. Here, we pursued how this protective RNA element functions to maintain mRNA stability. Using affinity purification and mass spectrometry, we identified a set of proteins that associate specifically with the protective element. Although multiple proteins contributed to the escape mechanism, depletion of nucleolin (NCL) most severely impacted protection. NCL was re-localized out of the nucleolus during lytic KSHV infection, and its presence in the cytoplasm was required for protection. After loading onto the IL-6 3' UTR, NCL differentially bound to the translation initiation factor eIF4H. Disrupting this interaction, or depleting eIF4H, reinstated SOX targeting of the RNA, suggesting that interactions between proteins bound to distant regions of the mRNA are important for escape. Finally, we found that the IL-6 3' UTR was also protected against mRNA degradation by the vhs endonuclease encoded by herpes simplex virus, despite the fact that its mechanism of mRNA targeting is distinct from SOX. These findings highlight how a multitude of RNA-protein interactions can impact endonuclease targeting, and identify new features underlying the regulation of the IL-6 mRNA. PMID:25965334

  20. High-Energy Astrophysics: An Overview

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.

    2007-01-01

    High-energy astrophysics is the study of objects and phenomena in space with energy densities much greater than that found in normal stars and galaxies. These include black holes, neutron stars, cosmic rays, hypernovae and gamma-ray bursts. A history and an overview of high-energy astrophysics will be presented, including a description of the objects that are observed. Observing techniques, space-borne missions in high-energy astrophysics and some recent discoveries will also be described. Several entirely new types of astronomy are being employed in high-energy astrophysics. These will be briefly described, along with some NASA missions currently under development.

  1. High Energy Astrophysics Research and Programmatic Support

    NASA Technical Reports Server (NTRS)

    Angelini, Lorella

    1998-01-01

    This report reviews activities performed by members of the USRA contract team during the six months of the reporting period and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA), X-ray Timing Experiment (XTE), X-ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science Archive Research Center (HEASARC), and others.

  2. High Energy Astrophysics Research and Programmatic Support

    NASA Technical Reports Server (NTRS)

    Angelini, L. (Editor)

    1997-01-01

    This report reviews activities performed by members of the USRA contract team during the six months of the reporting period and projected activities during the coming six months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in Astrophysics. Missions supported include: Advanced Satellite for Cosmology and Astrophysics (ASCA), X-ray Timing Experiment (XTE), X-ray Spectrometer (XRS), Astro-E, High Energy Astrophysics Science Archive Research Center (HEASARC), and others.

  3. Working Papers: Astronomy and Astrophysics Panel Reports

    NASA Technical Reports Server (NTRS)

    Bahcall, John N.; Beichman, Charles A.; Canizares, Claude; Cronin, James; Heeschen, David; Houck, James; Hunten, Donald; Mckee, Christopher F.; Noyes, Robert; Ostriker, Jeremiah P.

    1991-01-01

    The papers of the panels appointed by the Astronomy and Astrophysics survey Committee are compiled. These papers were advisory to the survey committee and represent the opinions of the members of each panel in the context of their individual charges. The following subject areas are covered: radio astronomy, infrared astronomy, optical/IR from ground, UV-optical from space, interferometry, high energy from space, particle astrophysics, theory and laboratory astrophysics, solar astronomy, planetary astronomy, computing and data processing, policy opportunities, benefits to the nation from astronomy and astrophysics, status of the profession, and science opportunities.

  4. The next century astrophysics program

    NASA Technical Reports Server (NTRS)

    Swanson, Paul N.

    1992-01-01

    The Astrophysics Division within the NASA Office of Space Science and Applications (OSSA) has defined a set of flagship and intermediate missions that are presently under study for possible launch during the next 20 years. These missions and tentative schedules, referred to as the Astrotech 21 Mission Set, are summarized. The missions are in three groups corresponding to the cognizant science branch within the Astrophysics Division. Phase C/D refers to the pre-launch construction and delivery of the spacecraft, and the Operations Phase refers to the period when the mission is active in space. Approximately 1.5 years before the start of Phase C/D, a non-advocate review (NAR) is held to ensure that the mission/system concept and the requisite technology are at an appropriate stage of readiness for full scale development to begin. Therefore, technology development is frozen (usually) as of the date of a successful NAR. An overview of the technology advances required for each of the three wavelength groups is provided in the following paragraphs, along with a brief description of the individual missions.

  5. Libstatmech and applications to astrophysics

    NASA Astrophysics Data System (ADS)

    Yu, Tianhong

    In this work an introduction to Libstatmech is presented and applications especially to astrophysics are discussed. Libstatmech is a C toolkit for computing the statistical mechanics of fermions and bosons, written on top of libxml and gsl (GNU Scientific Library). Calculations of Thomas-Fermi Screening model and Bose-Einstein Condensate based on libstatmech demonstrate the expected results. For astrophysics application, a simple Type Ia Supernovae model is established to run the network calculation with weak reactions, in which libstatmech contributes to compute the electron chemical potential and allows the weak reverse rates to be calculated from detailed balance. Starting with pure 12C and T9=1.8, we find that at high initial density (rho~ 9x 109 g/cm3) there are relatively large abundances of neutron-rich iron-group isotopes (e.g. 66Ni, 50Ti, 48Ca) produced during the explosion, and Y e can drop to ~0.4, which indicates that the rare, high density Type Ia supernovae may help to explain the 48Ca and 50Ti effect in FUN CAIs.

  6. Analytic studies in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Pizzochero, Pierre

    Five studies are presented in nuclear astrophysics, which deal with different stages of stellar evolution and which use analytic techniques as opposed to numerical ones. Two problems are described in neutrino astrophysics: the solar-neutrino puzzle is analyzed in the framework of the MSW mechanism for the enhancement of neutrino oscillations in matter; and the cooling of neutron stars is studied by calculating the neutrino emissivity from strangeness condensation. Radiative transfer is then examined as applied to SN1987A: its early spectrum and bolometric corrections are calculated by developing an analytic model which can describe both the extended nature of the envelope and the non-LTE state of the radiation field in the scattering-dominated early atmosphere; and a model-independent relation is derived between mass and kinetic energy for the hydrogen envelope of SN1987A, using only direct observations of its luminosity and photospheric velocity. Finally, an analytic approach is presented to relate the softness of the EOS of dense nuclear matter in the core of a supernova, the hydrostatic structure of such core and the initial strength of the shock wave.

  7. Transient dynamics of perturbations in astrophysical disks

    NASA Astrophysics Data System (ADS)

    Razdoburdin, D. N.; Zhuravlev, V. V.

    2015-11-01

    We review some aspects of a major unsolved problem in understanding astrophysical (in particular, accretion) disks: whether the disk interiors can be effectively viscous in spite of the absence of magnetorotational instability. A rotational homogeneous inviscid flow with a Keplerian angular velocity profile is spectrally stable, making the transient growth of perturbations a candidate mechanism for energy transfer from regular motion to perturbations. Transient perturbations differ qualitatively from perturbation modes and can grow substantially in shear flows due to the nonnormality of their dynamical evolution operator. Because the eigenvectors of this operator, also known as perturbation modes, are not pairwise orthogonal, they can mutually interfere, resulting in the transient growth of their linear combinations. Physically, a growing transient perturbation is a leading spiral whose branches are shrunk as a result of the differential rotation of the flow. We discuss in detail the transient growth of vortex shearing harmonics in the spatially local limit, as well as methods for identifying the optimal (fastest growth) perturbations. Special attention is given to obtaining such solutions variationally by integrating the respective direct and adjoint equations forward and backward in time. The presentation is intended for experts new to the subject.

  8. Nuclear astrophysics studies by recoil mass separators.

    NASA Astrophysics Data System (ADS)

    Gialanella, L.; Brand, K.; Campajola, L.; D'Onofrio, A.; Greife, U.; Morone, M. C.; Oliviero, G.; Ordine, A.; Roca, V.; Rolfs, C.; Romano, M.; Romoli, M.; Schmidt, S.; Schulte, W. H.; Strieder, F.; Terrasi, F.; Trautvetter, H. P.; Zahnow, D.

    1997-11-01

    It has been recently demonstrated that an accelerator mass spectrometry (AMS) system, used as a recoil separator in conjunction with a windowless gas target, can yield the high suppression factor needed to dispersively analyze radiative capture residues, with the aim of measuring cross sections in the sub-microbarn range. An experiment is underway utilizing a radioactive 7Be beam for the measurement of the cross section of the astrophysically important reaction 7Be(p, γ)8B at a center of mass energy ECM = 1 MeV. Preliminary results of this experiment are presented. The extension of the method to another reaction playing a key role in stellar evolution, i.e. 12C(α, γ)16O, requires an improvement of the angle- and momentum-acceptance of the recoil separator, the use of a jet gas target and of a specially designed low-threshold detector. The solutions proposed by a joint Italian-German project are discussed.

  9. Recent astrophysical applications of the Trojan Horse Method to nuclear astrophysics

    SciTech Connect

    Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.; Fu, C.; Tribble, R.; Banu, A.; Al-Abdullah, T.; Goldberg, V.; Mukhamedzhanov, A.; Tabacaru, G.; Trache, L.

    2008-05-21

    The Trojan Horse Method (THM) is an unique indirect technique allowing to measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the recent applications of the Trojan Horse Method are presented. The applications aiming to the extraction of the bare astrophysical S{sub b}(E) for some two-body processes are discussed.

  10. Scientific Instruments of 1.6 m New Solar Telescope in Big Bear

    NASA Astrophysics Data System (ADS)

    Cao, W.

    2009-12-01

    The NST (New Solar Telescope) is in its commissioning phase at Big Bear Solar Observatory (BBSO). It will be the most capable, largest aperture solar telescope in the US until the 4 m ATST (Advanced Technology Solar Telescope) comes on-line in the middle of the next decade. The NST will be outfitted with state-of-the-art post-focus instrumentations at the Nasmyth focus on the dome floor and in the Coude Lab beneath the telescope. At the Nasmyth focus, several filter-based systems already in routine operation offer high spatial resolution photometry in TiO 704 nm, Hα 656 nm, G-band 430 nm and near infrared 1.56 μm & 2.2 μm, with the assistance of local correlation tracking and image reconstruction. As well, a Cryogenic InfraRed Spectrograph (CIRS) is being developed to supply high signal-to-noise-ratio spectrometry and polarimetry spanning 1.0 to 5.0 μm. The Coudé-lab instrumentations will include Adaptive Optics system (AO), InfraRed Imaging Magnetograph (IRIM), Visible Imaging Magnetograph (VIM), Real-time Image Reconstruction System (RIRS), and Fast Imaging Solar Spectrograph (FISS) -- most of these instruments operated on the old 0.6 m BBSO telescope. AO is being upgraded to a 308 sub-aperture (349-actuator Deformable Mirror) AO system that will enable diffraction limited observations over the NST's principal operating wavelengths from 0.4 through 1.7 μm. IRIM and VIM are Fabry-Pérot based narrow-band tunable filter, which provide high resolution two-dimensional spectroscopic and polarimetric imaging in the near infrared and visible respectively. Using a 32-node parallel computing system, RIRS is capable of performing real-time image reconstruction with one image every minute. FISS is a collaboration between BBSO and Seoul National University to focus on chromosphere dynamics. Key tasks including optical design, hardware/software integration and subsequent setup/testing on the NST, will be presented here. Some preliminary observation results in the near

  11. Flexible, Mastery-Oriented Astrophysics Sequence.

    ERIC Educational Resources Information Center

    Zeilik, Michael, II

    1981-01-01

    Describes the implementation and impact of a two-semester mastery-oriented astrophysics sequence for upper-level physics/astrophysics majors designed to handle flexibly a wide range of student backgrounds. A Personalized System of Instruction (PSI) format was used fostering frequent student-instructor interaction and role-modeling behavior in…

  12. Proceedings of the NASA Laboratory Astrophysics Workshop

    NASA Technical Reports Server (NTRS)

    Weck, Phillippe F. (Editor); Kwong, Victor H. S. (Editor); Salama, Farid (Editor)

    2006-01-01

    This report is a collection of papers presented at the 2006 NASA Workshop on Laboratory Astrophysics held in the University of Nevada, Las Vegas (UNLV) from February 14 to 16, 2006. This workshop brings together producers and users of laboratory astrophysics data so that they can understand each other's needs and limitations in the context of the needs for NASA's missions. The last NASA-sponsored workshop was held in 2002 at Ames Research Center. Recent related meetings include the Topical Session at the AAS meeting and the European workshop at Pillnitz, Germany, both of which were held in June 2005. The former showcased the importance of laboratory astrophysics to the community at large, while the European workshop highlighted a multi-laboratory approach to providing the needed data. The 2006 NASA Workshop on Laboratory Astrophysics, sponsored by the NASA Astrophysics Division, focused on the current status of the field and its relevance to NASA. This workshop attracted 105 participants and 82 papers of which 19 were invited. A White Paper identifying the key issues in laboratory astrophysics during the break-out sessions was prepared by the Scientific Organizing Committee, and has been forwarded to the Universe Working Group (UWG) at NASA Headquarters. This White Paper, which represented the collective inputs and opinions from experts and stakeholders in the field of astrophysics, should serve as the working document for the future development of NASA's R&A program in laboratory astrophysics.

  13. Astrophysics at the Highest Energy Frontiers

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    I discuss recent advances being made in the physics and astrophysics of cosmic rays and cosmic gamma-rays at the highest observed energies as well as the related physics and astrophysics of very high energy cosmic neutrinos. I also discuss the connections between these topics.

  14. Nuclear Astrophysics with the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spitaleri, C.; Lamia, L.; Pizzone, R. G.; Cherubini, S.; Gulino, M.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.

    2016-01-01

    The Trojan Horse Method (THM) represents the indirect path to determine the bare nucleus astrophysical S(E) factor for reactions between charged particles at astrophysical energies. This is done by measuring the quasi free cross section of a suitable three body process. The basic features of the THM will be presented together with some applications to demonstrate its practical use.

  15. Overview of NASA Astrophysics Program Analysis Groups

    NASA Astrophysics Data System (ADS)

    Sanders, Wilton T.; Sambruna, Rita M.; Perez, Mario R.; Hudgins, Douglas M.

    2015-01-01

    NASA Astrophysics Program Analysis Groups (PAGs) are responsible for facilitating and coordinating community input into the development and execution of NASAs three astrophysics science themes: Cosmic Origins (COPAG), Exoplanet Exploration (ExoPAG), and Physics of the Cosmos (PhysPAG). The PAGs provide a community-based, interdisciplinary forum for analyses that support and inform planning and prioritization of activities within the Astrophysics Division programs. Operations and structure of the PAGs are described in their Terms of Reference (TOR), which can be found on the three science theme Program Office web pages. The Astrophysics PAGs report their input and findings to NASA through the Astrophysics Subcommittee of the NASA Advisory Council, of which all the PAG Chairs are members. In this presentation, we will provide an overview of the ongoing activities of NASAs Astrophysics PAGs in the context of the opportunities and challenges currently facing the Astrophysics Division. NASA Headquarters representatives for the COPAG, ExoPAG, and PhysPAG will all be present and available to answer questions about the programmatic role of the Astrophysics PAGs.

  16. Overview of NASA Astrophysics Program Analysis Groups

    NASA Astrophysics Data System (ADS)

    Garcia, Michael R.; Hudgins, D. M.; Sambruna, R. M.

    2014-01-01

    NASA Astrophysics Program Analysis Groups (PAGs) are responsible for facilitating and coordinating community input into the developmentand execution of NASAs three astrophysics science themes: Cosmic Origins (COPAG), Exoplanet Exploration (ExoPAG), and Physics of the Cosmos (PhysPAG). The PAGs provide a community-based, interdisciplinary forum for analyses that support and inform planning and prioritization of activities within the Astrophysics Division programs. Operations and structure of the PAGs are described in the Terms of Reference (TOR) which can be found on the three science theme Program Office web pages. The Astrophysics PAGs report their input and findings to NASA through the Astrophysics Subcommittee of the NASA Advisory Council, of which all the PAG Chairs are members. In this presentation, we will provide an overview of the ongoing activities of NASAs Astrophysics PAGs in the context of the opportunities and challenges currently facing the Astrophysics Division. NASA Headquarters representatives for the COPAG, ExoPAG, and PhysPAG will all be present and available to answer questions about the programmatic role of the Astrophysics PAGs.

  17. Atoms and molecules in astrophysics

    SciTech Connect

    Lepp, S.

    1993-05-01

    In 1987 supernova was observed in the Large Magellanic Cloud. The supernova, the explosion of a massive star following core collapse, releases a expanding cloud of gas called the ejecta. Because this supernova occured so close to our own galaxy it was the first chance to get high resolution spectra from a supernova ejecta. There have been a few molecular species (CO and SiO) and many more atomic species observed in the ejecta of Supernova 1987a. The ejecta represents an evolving laboratory for atomic and molecular physics. This paper will review models of the ejecta of Supernova 1987a and some other astrophysical objects with a particular emphasis on the atomic and molecular processes involved.

  18. Astrophysically Interesting Resonances; Another Approach

    NASA Astrophysics Data System (ADS)

    Austin, Roby; Jenkins, David

    2008-10-01

    R.A.E. Austin, R. Kanungo, A. Campbell, S. Colosimo, S. Reeve Saint Mary's University; D.G. Jenkins, C.Aa.Diget, A. Robinson, University of York, UK; P.J. Woods T. Davinson University of Edinburgh; C.-Y. Wu A. Hurst J.A. Becker Lawrence Livermore National Laboratory; G.C. Ball M. Djongolov G. Hackman A.C. Morton, C. Pearson, S.J. Williams TRIUMF; A.A. Phillips, M. Schumaker, University of Guelph H.Boston, A. Grint, D. Oxley, University of Liverpool; D. Cline, A. Hayes, University of Rochester; We describe a prototype experiment to measure resonances of interest in astrophysical reactions. We use the TIGRESS to detect gamma rays in coincidence with charged particles, inelastically scattered in inverse kinematics. The particles are detected with the Bambino detector modified to a δE-E silicon telescope spanning 15-40 degrees in the lab.

  19. Axions in astrophysics and cosmology

    SciTech Connect

    Sikivie, P.

    1984-07-01

    Axion models often have a spontaneously broken exact discrete symmetry. In that case, they have discretely degenerate vacua and hence domain walls. The properties of the domain walls, the cosmological catastrophe they produce and the ways in which this catastrophe may be avoided are explained. Cosmology and astrophysics provide arguments that imply the axion decay constant should lie in the range 10/sup 8/ GeV less than or equal to f/sub a/ less than or equal to 10/sup 12/ GeV. Reasons are given why axions are an excellent candidate to constitute the dark matter of galactic halos. Using the coupling of the axions to the electromagnetic field, detectors are described to look for axions floating about in the halo of our galaxy and for axions emitted by the sun. (LEW)

  20. Reaction models in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Descouvemont, Pierre

    2016-05-01

    We present different reaction models commonly used in nuclear astrophysics, in particular for the nucleosynthesis of light elements. Pioneering works were performed within the potential model, where the internal structure of the colliding nuclei is completely ignored. Significant advances in microscopic cluster models provided the first microscopic description of the 3He(α,&gamma)7 Be reaction more than thirty years ago. In this approach, the calculations are based on an effective nucleon-nucleon interaction, but the cluster approximation should be made to simplify the calculations. Nowadays, modern microscopic calculations are able to go beyond the cluster approximation, and aim at finding exact solutions of the Schrödinger equation with realistic nucleon-nucleon interactions. We discuss recent examples on the d+d reactions at low energies.

  1. Transfer reactions in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Bardayan, D. W.

    2016-08-01

    To a high degree many aspects of the large-scale behavior of objects in the Universe are governed by the underlying nuclear physics. In fact the shell structure of nuclear physics is directly imprinted into the chemical abundances of the elements. The tranquility of the night sky is a direct result of the relatively slow rate of nuclear reactions that control and determines a star’s fate. Understanding the nuclear structure and reaction rates between nuclei is vital to understanding our Universe. Nuclear-transfer reactions make accessible a wealth of knowledge from which we can extract much of the required nuclear physics information. A review of transfer reactions for nuclear astrophysics is presented with an emphasis on the experimental challenges and opportunities for future development.

  2. Hard X-ray astrophysics

    NASA Technical Reports Server (NTRS)

    Rothschild, R. E.

    1981-01-01

    Past hard X-ray and lower energy satellite instruments are reviewed and it is shown that observation above 20 keV and up to hundreds of keV can provide much valuable information on the astrophysics of cosmic sources. To calculate possible sensitivities of future arrays, the efficiencies of a one-atmosphere inch gas counter (the HEAO-1 A-2 xenon filled HED3) and a 3 mm phoswich scintillator (the HEAO-1 A-4 Na1 LED1) were compared. Above 15 keV, the scintillator was more efficient. In a similar comparison, the sensitivity of germanium detectors did not differ much from that of the scintillators, except at high energies where the sensitivity would remain flat and not rise with loss of efficiency. Questions to be addressed concerning the physics of active galaxies and the diffuse radiation background, black holes, radio pulsars, X-ray pulsars, and galactic clusters are examined.

  3. Underground Nuclear Astrophysics at LUNA

    SciTech Connect

    Junker, Matthias

    2008-01-24

    Nuclear cross sections play a key role in understanding stellar evolution and elemental synthesis. Also in the field of astroparticle physics precise knowledge on thermonuclear cross sections is needed to extract the particle properties from the experimental data. While it is desirable to directly measure the relevant cross sections in the energy range of interest for the specific stellar environment this proves to be difficult, if not impossible, due to the effect of the Coulomb barrier, which causes an exponential drop of the cross sections at stellar energies. Consequently direct measurements are hampered by low counting rates and background caused by cosmic rays and environmental radioactivity. In addition background induced by the beam or the target itself can disturb the measurements.In this contribution I will discuss some of the reactions studied by LUNA in the past years to illustrate important aspects underground nuclear astrophysics.

  4. Overview of the Astrophysics Data System

    NASA Technical Reports Server (NTRS)

    Good, John C.; Pomphrey, Richard B.

    1990-01-01

    The Astrophysics Division of NASA has built a geographically- and logically-distributed heterogeneous information system for the dissemination and coordinated multispectral analysis of data from astrophysics missions. The Astrophysics Data System (ADS) is a truly distributed system in which the data and the required processing are physically distributed. To accommodate the anticipated growth and changes in both requirements and technology, the ADS employs a server/client architecture which allows services and data to be added or replaced without having to change the basic architecture or interfaces. Current datasets accessible through the system include all the tabular astronomical data available at each of six existing astrophysics data centers. Additional data nodes, at both NASA data centers and academic institutions, will be added shortly. The future evolution of the system will be driven in large part by user services mounted both by the ADS project itself and by members of the astrophysics community.

  5. Overview of the Astrophysics Data System

    NASA Technical Reports Server (NTRS)

    Good, John C.; Pomphrey, Richard B.

    1991-01-01

    The Astrophysics Division of NASA has built a geographically and logically distributed heterogeneous information system for the dissemination and coordinated multispectral analysis of data from astrophysics missions. The Astrophysics Data System (ADS) is a truly distributed system in which the data and the required processing are physically distributed. To accommodate the anticipated growth and changes in both requirements and technology, the ADS employs a server/client architecture which allows services and data to be added or replaced without having to change the basic architecture or interfaces. Current datasets accessible through the system include all the tabular astronomical data available at each of six existing astrophysics data centers. Additional data nodes, at both NASA data centers and academic institutions, will be added shortly. The future evolution of the system will be driven in large part by user services mounted both by the ADS project itself and by members of the astrophysics community.

  6. Large-Scale Astrophysical Visualization on Smartphones

    NASA Astrophysics Data System (ADS)

    Becciani, U.; Massimino, P.; Costa, A.; Gheller, C.; Grillo, A.; Krokos, M.; Petta, C.

    2011-07-01

    Nowadays digital sky surveys and long-duration, high-resolution numerical simulations using high performance computing and grid systems produce multidimensional astrophysical datasets in the order of several Petabytes. Sharing visualizations of such datasets within communities and collaborating research groups is of paramount importance for disseminating results and advancing astrophysical research. Moreover educational and public outreach programs can benefit greatly from novel ways of presenting these datasets by promoting understanding of complex astrophysical processes, e.g., formation of stars and galaxies. We have previously developed VisIVO Server, a grid-enabled platform for high-performance large-scale astrophysical visualization. This article reviews the latest developments on VisIVO Web, a custom designed web portal wrapped around VisIVO Server, then introduces VisIVO Smartphone, a gateway connecting VisIVO Web and data repositories for mobile astrophysical visualization. We discuss current work and summarize future developments.

  7. Magnetic Reconnection in Extreme Astrophysical Environments

    NASA Astrophysics Data System (ADS)

    Uzdensky, Dmitri A.

    2011-10-01

    Magnetic reconnection is a fundamental plasma physics process in which ideal-MHD's frozen-in constraints are broken and the magnetic field topology is dramatically re-arranged, which often leads to a violent release of the free magnetic energy. Most of the magnetic reconnection research done to date has been motivated by the applications to systems such as the solar corona, Earth's magnetosphere, and magnetic confinement devices for thermonuclear fusion. These environments have relatively low energy densities and the plasma is adequately described as a mixture of equal numbers of electrons and ions and where the dissipated magnetic energy always stays with the plasma. In contrast, in this paper I would like to introduce a different, new direction of research—reconnection in high energy density radiative plasmas, in which photons play as important a role as electrons and ions; in particular, in which radiation pressure and radiative cooling become dominant factors in the pressure and energy balance. This research is motivated in part by rapid theoretical and experimental advances in High Energy Density Physics, and in part by several important problems in modern high-energy astrophysics. I first discuss some astrophysical examples of high-energy-density reconnection and then identify the key physical processes that distinguish them from traditional reconnection. Among the most important of these processes are: special-relativistic effects; radiative effects (radiative cooling, radiation pressure, and radiative resistivity); and, at the most extreme end—QED effects, including pair creation. The most notable among the astrophysical applications are situations involving magnetar-strength fields (1014-1015 G, exceeding the quantum critical field B ∗≃4×1013 G). The most important examples are giant flares in soft gamma repeaters (SGRs) and magnetic models of the central engines and relativistic jets of Gamma Ray Bursts (GRBs). The magnetic energy density in

  8. Studying Nuclear Astrophysics at NIF

    SciTech Connect

    Boyd, R; Bernstein, L; Brune, C

    2009-07-01

    The National Ignition Facility's primary goal is to generate fusion energy. But the starlike conditions that it creates will also enable NIF scientists to study astrophysically important nuclear reactions. When scientists at the stadium-sized National Ignition Facility attempt to initiate fusion next year, 192 powerful lasers will direct 1.2 MJ of light energy toward a two-mm-diameter pellet of deuterium ({sup 2}H, or D) and tritium ({sup 3}H, or T). Some of that material will be gaseous, but most will be in a frozen shell. The idea is to initiate 'inertial confinement fusion', in which the two hydrogen isotopes fuse to produce helium-4, a neutron, and 17.6 MeV of energy. The light energy will be delivered to the inside walls of a hohlraum, a heavy-metal, centimeter-sized cylinder that houses the pellet. The container's heated walls will produce x rays that impinge on the pellet and ablate its outer surface. The exiting particles push inward on the pellet and compresses the DT fuel. Ultimately a hot spot develops at the pellet's center, where fusion produces {sup 4}He nuclei that have sufficient energy to propagate outward, trigger successive reactions, and finally react the frozen shell. Ignition should last several tens of picoseconds and generate more than 10 MJ of energy and roughly 10{sup 19} neutrons. The temperature will exceed 10{sup 8} K and fuel will be compressed to a density of several hundred g/cm{sup 3}, both considerably greater than at the center of the Sun. The figure shows a cutaway view of NIF. The extreme conditions that will be produced there simulate those in nuclear weapons and inside stars. For that reason, the facility is an important part of the US stockpile stewardship program, designed to assess the nation's aging nuclear stockpile without doing nuclear tests. In this Quick Study we consider a third application of NIF - using the extraordinary conditions it will produce to perform experiments in basic science. We will focus on

  9. Proceedings of the NASA Laboratory Astrophysics Workshop

    NASA Technical Reports Server (NTRS)

    Salama, Farid (Editor)

    2002-01-01

    This document is the proceedings of the NASA Laboratory Astrophysics Workshop, convened May 1-3, 2002 at NASA's Ames Research Center. Sponsored by the NASA Office of Space Science (OSS), this programmatic workshop is held periodically by NASA to discuss the current state of knowledge in the interdisciplinary field of laboratory astrophysics and to identify the science priorities (needs) in support of NASA's space missions. An important goal of the Workshop is to provide input to OSS in the form of a white paper for incorporation in its strategic planning. This report comprises a record of the complete proceedings of the Workshop and the Laboratory Astrophysics White Paper drafted at the Workshop.

  10. Scaling Extreme Astrophysical Phenomena to the Laboratory

    SciTech Connect

    Remington, B A

    2007-11-01

    High-energy-density (HED) physics refers broadly to the study of macroscopic collections of matter under extreme conditions of temperature and density. The experimental facilities most widely used for these studies are high-power lasers and magnetic-pinch generators. The HED physics pursued on these facilities is still in its infancy, yet new regimes of experimental science are emerging. Examples from astrophysics include work relevant to planetary interiors, supernovae, astrophysical jets, and accreting compact objects (such as neutron stars and black holes). In this paper, we review a selection of recent results in this new field of HED laboratory astrophysics and provide a brief look ahead to the coming decade.

  11. Astrophysics at RIA (ARIA) Working Group

    SciTech Connect

    Smith, Michael S.; Schatz, Hendrik; Timmes, Frank X.; Wiescher, Michael; Greife, Uwe

    2006-07-12

    The Astrophysics at RIA (ARIA) Working Group has been established to develop and promote the nuclear astrophysics research anticipated at the Rare Isotope Accelerator (RIA). RIA is a proposed next-generation nuclear science facility in the U.S. that will enable significant progress in studies of core collapse supernovae, thermonuclear supernovae, X-ray bursts, novae, and other astrophysical sites. Many of the topics addressed by the Working Group are relevant for the RIKEN RI Beam Factory, the planned GSI-Fair facility, and other advanced radioactive beam facilities.

  12. Astrophysics at RIA (ARIA) Working Group

    NASA Astrophysics Data System (ADS)

    Smith, Michael S.; Schatz, Hendrik; Timmes, Frank X.; Wiescher, Michael; Greife, Uwe

    2006-07-01

    The Astrophysics at RIA (ARIA) Working Group has been established to develop and promote the nuclear astrophysics research anticipated at the Rare Isotope Accelerator (RIA). RIA is a proposed next-generation nuclear science facility in the U.S. that will enable significant progress in studies of core collapse supernovae, thermonuclear supernovae, X-ray bursts, novae, and other astrophysical sites. Many of the topics addressed by the Working Group are relevant for the RIKEN RI Beam Factory, the planned GSI-Fair facility, and other advanced radioactive beam facilities.

  13. Development of the fully digital dc speed regulation system in 8-mX6-m wind tunnel

    NASA Astrophysics Data System (ADS)

    Li, Dexiang; Ye, Jicheng; You, Xi; Zhang, Xiande

    2000-05-01

    The old analog system of speed regulation of 8 m X 6 m wind tunnel has been successfully reformed recently. The new system realized fully digital control on 2600 kW DC motor, through rebuilding two sets of 485 V and 30 A speed regulation equipment used in controlling large power thyristor rectifier of 2-stage serial.

  14. Proton beam of 2 MeV 1.6 mA on a tandem accelerator with vacuum insulation

    NASA Astrophysics Data System (ADS)

    Kasatov, D.; Kuznetsov, A.; Makarov, A.; Shchudlo, I.; Sorokin, I.; Taskaev, S.

    2014-12-01

    A source of epithermal neutrons based on a tandem accelerator with vacuum insulation for boron neutron capture therapy of malignant tumors was proposed and constructed. Stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity and 0.5% current stability has just been obtained.

  15. Environmental Effects for Gravitational-wave Astrophysics

    NASA Astrophysics Data System (ADS)

    Barausse, Enrico; Cardoso, Vitor; Pani, Paolo

    2015-05-01

    The upcoming detection of gravitational waves by terrestrial interferometers will usher in the era of gravitational-wave astronomy. This will be particularly true when space-based detectors will come of age and measure the mass and spin of massive black holes with exquisite precision and up to very high redshifts, thus allowing for better understanding of the symbiotic evolution of black holes with galaxies, and for high-precision tests of General Relativity in strong-field, highly dynamical regimes. Such ambitious goals require that astrophysical environmental pollution of gravitational-wave signals be constrained to negligible levels, so that neither detection nor estimation of the source parameters are significantly affected. Here, we consider the main sources for space-based detectors - the inspiral, merger and ringdown of massive black-hole binaries and extreme mass-ratio inspirals - and account for various effects on their gravitational waveforms, including electromagnetic fields, cosmological evolution, accretion disks, dark matter, “firewalls” and possible deviations from General Relativity. We discover that the black-hole quasinormal modes are sharply different in the presence of matter, but the ringdown signal observed by interferometers is typically unaffected. The effect of accretion disks and dark matter depends critically on their geometry and density profile, but is negligible for most sources, except for few special extreme mass-ratio inspirals. Electromagnetic fields and cosmological effects are always negligible. We finally explore the implications of our findings for proposed tests of General Relativity with gravitational waves, and conclude that environmental effects will not prevent the development of precision gravitational-wave astronomy.

  16. Two LANL laboratory astrophysics experiments

    SciTech Connect

    Intrator, Thomas P.

    2014-01-24

    Two laboratory experiments are described that have been built at Los Alamos (LANL) to gain access to a wide range of fundamental plasma physics issues germane to astro, space, and fusion plasmas. The overarching theme is magnetized plasma dynamics which includes significant currents, MHD forces and instabilities, magnetic field creation and annihilation, sheared flows and shocks. The Relaxation Scaling Experiment (RSX) creates current sheets and flux ropes that exhibit fully 3D dynamics, and can kink, bounce, merge and reconnect, shred, and reform in complicated ways. Recent movies from a large data set describe the 3D magnetic structure of a driven and dissipative single flux rope that spontaneously self-saturates a kink instability. Examples of a coherent shear flow dynamo driven by colliding flux ropes will also be shown. The Magnetized Shock Experiment (MSX) uses Field reversed configuration (FRC) experimental hardware that forms and ejects FRCs at 150km/sec. This is sufficient to drive a collision less magnetized shock when stagnated into a mirror stopping field region with Alfven Mach number MA=3 so that super critical shocks can be studied. We are building a plasmoid accelerator to drive Mach numbers MA >> 3 to access solar wind and more exotic astrophysical regimes. Unique features of this experiment include access to parallel, oblique and perpendicular shocks, shock region much larger than ion gyro radii and ion inertial length, room for turbulence, and large magnetic and fluid Reynolds numbers.

  17. Recoil Separators for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Blackmon, J. C.

    2004-10-01

    Hydrogen and helium capture reactions are important in many astrophysical environments. Measurements in inverse kinematics using recoil separators have demonstrated a particularly sensitive technique for studying low-yield capture reactions.(M. S. Smith, C. E. Rolfs, and C. A. Barnes, Nucl. Instrum. Meth. Phys. Res. A306) (1991) 233. This approach allows a low background rate to be achieved with a high detection efficiency (about 50%) for the particles of interest using a device with only modest acceptance. Recoil separators using a variety of ion-optic configurations have been installed at numerous accelerator facilities in the past decade and have been used to measure, for example, alpha capture reactions using stable beams(D. Rogalla et al.), Eur. Phys. J. 6 (1999) 471. and proton capture reactions using radioactive ion beams.(S. Bishop et al.), Phys. Rev. Lett. 90 (2003) 162501. Measurements in inverse kinematics are the only viable means for studying reactions on short-lived nuclei that are crucial for understanding stellar explosions, and a recoil separator optimized for the measurement of capture reactions with radioactive ion beams figures prominently into the design of the low energy experimental area at the Rare Isotope Accelerator (RIA). The operational requirements for such a device will be outlined, and recoil separator designs and characteristics will be presented.

  18. Relativistic opacities for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Fontes, C. J.; Fryer, C. L.; Hungerford, A. L.; Hakel, P.; Colgan, J.; Kilcrease, D. P.; Sherrill, M. E.

    2015-09-01

    We report on the use of the Los Alamos suite of relativistic atomic physics codes to generate radiative opacities for the modeling of astrophysically relevant plasmas under local thermodynamic equilibrium (LTE) conditions. The atomic structure calculations are carried out in fine-structure detail, including full configuration interaction. Three example applications are considered: iron opacities at conditions relevant to the base of the solar convection zone, nickel opacities for the modeling of stellar envelopes, and samarium opacities for the modeling of light curves produced by neutron star mergers. In the first two examples, comparisons are made between opacities that are generated with the fully and semi-relativistic capabilities in the Los Alamos suite of codes. As expected for these highly charged, iron-peak ions, the two methods produce reasonably similar results, providing confidence that the numerical methods have been correctly implemented. However, discrepancies greater than 10% are observed for nickel and investigated in detail. In the final application, the relativistic capability is used in a preliminary investigation of the complicated absorption spectrum associated with cold lanthanide elements.

  19. NASA Astrophysics Educator Ambassador Program

    NASA Astrophysics Data System (ADS)

    McLin, K. M.; Cominsky, L. R.

    2014-07-01

    The NASA Astrophysics Educator Ambassador (EA) Program began in 2001 as part of the GLAST (now Fermi) EPO effort at Sonoma State University. The program currently supports 15 EAs, sponsored by either Fermi (10), Swift (3), XMM-Newton (1) or NuSTAR (1). This group of master educators work with mission scientists and EPO personnel to develop curricula and train teachers; they also do workshops for students and outreach events with the general public. Every other year since 2002 the EAs assemble for a week of training at SSU. Each training has had a different focus. Additionally, time is given for the EAs to share ideas from their own workshops. In the dozen years of the program, the total number of teachers attending EA-run workshops is over 60,000, and EA workshops have received outstanding positive reviews from participants according to surveys conducted by our external evaluator, WestEd. This poster gives an overview of the program and its nationwide impact.

  20. Mass-23 nuclei in astrophysics

    NASA Astrophysics Data System (ADS)

    Fraser, P. R.; Amos, K.; Canton, L.; Karataglidis, S.; Svenne, J. P.; van der Kniff, D.

    2015-09-01

    The formation of mass-23 nuclei by radiative capture is of great interest in astrophysics. A topical problem associated with these isobars is the so-called 22Na puzzle of ONe white dwarf novae, where the abundance of 22Na observed is not as is predicted by current stellar models, indicating there is more to learn about how the distribution of elements in the universe occurred. Another concerns unexplained variations in elements abundance on the surface of aging red giant stars. One method for theoretically studying nuclear scattering is the Multi-Channel Algebraic Scattering (MCAS) formalism. Studies to date have used a simple collective-rotor prescription to model the target states which couple to projectile nucleons. While, in general, the target states considered all belong to the ground state rotor band, for some systems it is necessary to include coupling to states outside of this band. Herein we discuss an extension of MCAS to allow coupling of different strengths between such states and the ground state band. This consideration is essential when studying the scattering of neutrons from 22Ne, a necessary step in studying the mass-23 nuclei mentioned above.

  1. NASA's Research Programs in Astrophysics

    NASA Astrophysics Data System (ADS)

    Hasan, H.

    2006-08-01

    The motivation for this paper is to present to the scientific community the current status of research in Astrophysics being funded by NASA in support of its strategic objectives, in order to foster a dialog with the international space science community. Research investigations selected by NASA via a peer review process, are conducted at universities, NASA centers, other U.S. Government institutions, and private institutions. Non U.S. participation is permitted. The research program is an incubator for new ideas. A major component is technology development in the area of astronomical detectors; instruments flown on rockets, balloons and other suborbital platforms; supporting technology such as development of gratings, mirror coatings, mission concepts; laboratory experiments to produce atomic and molecular data to support spectroscopic observations from space missions; study if ice and dust in a space environment to understand planet formation. There is also a data analysis program which is complemented by a robust theory program. The poster paper will give an overview and present specific examples of research in each of the areas listed above. Areas of international collaboration will be highlighted.

  2. The molecular astrophysics of stars and galaxies.

    NASA Astrophysics Data System (ADS)

    Hartquist, T. W.; Williams, D. A.

    This book provides a comprehensive survey of modern molecular astrophysics. It gives an introduction to molecular spectroscopy and then addresses the main areas of current molecular astrophysics, including galaxy formation, star forming regions, mass loss from young as well as highly evolved stars and supernovae, starburst galaxies plus the tori and discs near the central engines of active galactic nuclei. With chapters written by leading experts, the book is unique in giving a detailed view of this wide-ranging subject. It will provide the standard introduction for research students in molecular astrophysics; it will also enable chemists to learn the astrophysics most related to chemistry as well as instruct physicists about the molecular processes most important in astronomy. This volume is dedicated to Alexander Dalgarno.

  3. Advances in instrumentation for nuclear astrophysics

    SciTech Connect

    Pain, S. D.

    2014-04-15

    The study of the nuclear physics properties which govern energy generation and nucleosynthesis in the astrophysical phenomena we observe in the universe is crucial to understanding how these objects behave and how the chemical history of the universe evolved to its present state. The low cross sections and short nuclear lifetimes involved in many of these reactions make their experimental determination challenging, requiring developments in beams and instrumentation. A selection of developments in nuclear astrophysics instrumentation is discussed, using as examples projects involving the nuclear astrophysics group at Oak Ridge National Laboratory. These developments will be key to the instrumentation necessary to fully exploit nuclear astrophysics opportunities at the Facility for Rare Isotope Beams which is currently under construction.

  4. Underground nuclear astrophysics: Why and how

    NASA Astrophysics Data System (ADS)

    Best, A.; Caciolli, A.; Fülöp, Zs.; Gyürky, Gy.; Laubenstein, M.; Napolitani, E.; Rigato, V.; Roca, V.; Szücs, T.

    2016-04-01

    The goal of nuclear astrophysics is to measure cross-sections of nuclear physics reactions of interest in astrophysics. At stars temperatures, these cross-sections are very low due to the suppression of the Coulomb barrier. Cosmic-ray-induced background can seriously limit the determination of reaction cross-sections at energies relevant to astrophysical processes and experimental setups should be arranged in order to improve the signal-to-noise ratio. Placing experiments in underground sites, however, reduces this background opening the way towards ultra low cross-section determination. LUNA (Laboratory for Underground Nuclear Astrophysics) was pioneer in this sense. Two accelerators were mounted at the INFN National Laboratories of Gran Sasso (LNGS) allowing to study nuclear reactions close to stellar energies. A summary of the relevant technology used, including accelerators, target production and characterisation, and background treatment is given.

  5. High Energy Astrophysics Research and Programmatic Support

    NASA Technical Reports Server (NTRS)

    Angellini, L.

    1994-01-01

    This report reviews activities performed by members of the USRA contract team during the three months of the reporting period. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics.

  6. Thermal analysis of the 10-gallon and the 55-gallon DOT-6M containers with thermal boundary conditions corresponding to 10CFR71 normal transport and accident conditions

    SciTech Connect

    Sanchez, L.C.; Longenbaugh, R.S.; Moss, M.; Haseman, G.M.; Fowler, W.E.; Roth, E.P.

    1988-03-01

    This report describes the heat transfer analysis of the 10-gallon and 55-gallon 6M containers. The analysis was performed with boundary conditions corresponding to a normal transport condition and a hypothetical accident condition. Computational results indicated that the insulation material in the 6M containers will adequately protect the payload region of the 6M containers. 26 refs., 26 figs., 8 tabs.

  7. Special Days, Special Ways.

    ERIC Educational Resources Information Center

    Clarke, Jacqueline

    2001-01-01

    Presents unique ways to create special rituals that recognize individual students' achievements and milestones. Ideas include throwing a send-off party for a student who is moving; holding monthly birthday luncheons; choosing an ambassador to accompany new students around school; and making a lost tooth container that students can use to safely…

  8. Indirect techniques for astrophysical reaction rates determinations

    NASA Astrophysics Data System (ADS)

    Hammache, F.; Oulebsir, N.; Benamara, S.; De Séréville, N.; Coc, A.; Laird, A.; Stefan, I.; Roussel, P.

    2016-05-01

    Direct measurements of nuclear reactions of astrophysical interest can be challenging. Alternative experimental techniques such as transfer reactions and inelastic scattering reactions offer the possibility to study these reactions by using stable beams. In this context, I will present recent results that were obtained in Orsay using indirect techniques. The examples will concern various astrophysical sites, from the Big-Bang nucleo synthesis to the production of radioisotopes in massive stars.

  9. The Trojan Horse Method in Nuclear Astrophysics

    SciTech Connect

    Spitaleri, C.

    2010-11-24

    The Trojan Horse Method allows for the measurements of cross section in nuclear reaction between charged particles at astrophysical energies. The basic features of the method are discussed in the non resonant reactions case. A review of applications aimed to extract the bare nucleus astrophysical S{sub b}(E) factor for two body processes are presented. The information on electron screening potential U{sub e} were obtained from comparison with direct experiments of fusion reactions.

  10. Research in cosmic and gamma ray astrophysics

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1989-01-01

    Research activities in cosmic rays, gamma rays, and astrophysical plasmas are covered. The activities are divided into sections and described, followed by a bibliography. The astrophysical aspects of cosmic rays, gamma rays, and of the radiation and electromagnetic field environment of the Earth and other planets are investigated. These investigations are performed by means of energetic particle and photon detector systems flown on spacecraft and balloons.

  11. EMPIRE: A code for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Palumbo, A.

    2016-01-01

    The nuclear reaction code EMPIRE is presented as a useful tool for nuclear astrophysics. EMPIRE combines a variety of the reaction models with a comprehensive library of input parameters providing a diversity of options for the user. With exclusion of the direct- semidirect capture all reaction mechanisms relevant to the nuclear astrophysics energy range of interest are implemented in the code. Comparison to experimental data show consistent agreement for all relevant channels.

  12. Handbook of Space Astronomy and Astrophysics

    NASA Astrophysics Data System (ADS)

    Zombeck, Martin V.

    2006-11-01

    Foreword; Preface; 1. General data; 2. Astronomy and astrophysics; 3. Radio astronomy; 4. Infrared and submillimeter astronomy; 5. Ultraviolet astronomy; 6. X-ray astronomy; 7. Gamma-ray astronomy; 8. Cosmic rays; 9. Earth's atmosphere and environment; 10. Relativity and cosmology; 11. Atomic physics; 12. Electromagnetic radiation; 13. Plamsa physics; 14. Experimental astronomy and astrophysics; 15. Astronautics; 16. Mathematics; 17. Probability and statistics; 18. Radiation safety; 19. Astronomical catalogs; 20. Computer science; 21. Glossary of abbreviations and symbols; Appendices; Index.

  13. VAMDC Consortium: A Service to Astrophysics

    NASA Astrophysics Data System (ADS)

    L Dubernet, M.; Moreau, N.; Zwoelf, C. M.; Ba, Y. A.

    2015-12-01

    The VAMDC Consortium is a worldwide consortium which federates Atomic and Molecular databases through an e-science infrastructure and a political organisation. About 90% of the inter-connected databases handle data that are used for the interpretation of spectra and for the modelisation of media of many fields of astrophysics. This paper presents how the VAMDC Consortium is organised in order to provide a ``service'' to the astrophysics community.

  14. Distance Measurement Solves Astrophysical Mysteries

    NASA Astrophysics Data System (ADS)

    2003-08-01

    Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of

  15. Gas leak characteristics of inner packaging components used in the D0T-Spec 6M container

    SciTech Connect

    Taylor, J.M.

    1985-09-01

    A test program was conducted by Pacific Northwest Laboratory to determine the gas leak characteristics of metal food pack cans and 2R vessels used to package radioactive material in a D0T 6M specification container. It can be concluded from the tests performed that the inner packaging components (2R vessel, metal product cans) used with a 6M container can be sealed so that they will be gas tight (<10/sup -5/ cc/sec) under elevated temperature and pressure and impact conditions. To maintain gas tight seals under accident conditions, the metal cans must be sealed with a properly adjusted can-sealing machine; the threads of the 2R vessel must be luted with a sealing compound such as a silicone rubber compound; and the metal cans must be protected inside the 2R vessel with spacer plates and impact absorbers. 4 refs., 37 figs.

  16. Decrease in transient receptor potential melastatin 6 mRNA stability caused by rapamycin in renal tubular epithelial cells.

    PubMed

    Ikari, Akira; Sanada, Ayumi; Sawada, Hayato; Okude, Chiaki; Tonegawa, Chie; Sugatani, Junko

    2011-06-01

    Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), is used in treatments for transplantation and cancer. Rapamycin causes hypomagnesemia, although precisely how has not been examined. Here, we investigated the effect of rapamycin on the expression of transient receptor potential melastatin 6 (TRPM6), a Mg2+ channel. Rapamycin and LY-294002, an inhibitor of phosphatidilinositol-3 kinase (PI3K) located upstream of mTOR, inhibited epidermal growth factor (EGF)-induced expression of the TRPM6 protein without affecting TRPM7 expression in rat renal NRK-52E epithelial cells. Both rapamycin and LY-294002 decreased EGF-induced Mg2+ influx. U0126, a MEK inhibitor, inhibited EGF-induced increases in c-Fos, p-ERK, and TRPM6 levels. In contrast, neither rapamycin nor LY-294002 inhibited EGF-induced increases in p-ERK and c-Fos levels. EGF increased p-Akt level, an effect inhibited by LY-294002 and 1L-6-hydroxymethyl-chiro-inositol2-[(R)-2-O-methyl-3-O-octadecylcarbonate] (Akt inhibitor). Akt inhibitor decreased TRPM6 level similar to rapamycin and LY-294002. These results suggest that a PI3K/Akt/mTOR pathway is involved in the regulation of TRPM6 expression. Rapamycin inhibited the EGF-induced increase in TRPM6 mRNA but did not inhibit human TRPM6 promoter activity. In the presence of actinomycin D, a transcriptional inhibitor, rapamycin accelerated the decrease in TRPM6 mRNA. Rapamycin decreased the expression and activity of a luciferase linked with the 3'-untranslated region of human TRPM6 mRNA. These results suggest that TRPM6 expression is up-regulated by a PI3K/Akt/mTOR pathway and rapamycin reduces TRPM6 mRNA stability, resulting in a decrease in the reabsorption of Mg2+. PMID:21073857

  17. Electrocatalytic Reduction of CO2 by Group 6 M(CO)6 Species without "Non-Innocent" Ligands.

    PubMed

    Grice, Kyle A; Saucedo, Cesar

    2016-06-20

    To understand the electrocatalytic CO2 reduction of metal carbonyl complexes without "non-innocent" ligands, the electrochemical responses of group 6 M(CO)6 (M = Cr, Mo, or W) and group 7 M2(CO)10 (M = Mn or Re) complexes were examined under Ar and CO2 at a glassy carbon electrode. All of the complexes showed changes in their cyclic voltammograms under CO2. The group 6 hexacarbonyl species show a significant increase in current under CO2 during metal-based reduction, corresponding to catalytic reduction of CO2. Bulk electrolysis experiments with Mo(CO)6 showed that CO was the primary product. The group 7 dimers showed very little change during metal-based reduction, but return oxidation responses disappeared, indicative of a chemical reaction after exposure to CO2 without catalysis. Addition of H2O, a proton source, to the solutions under CO2 decreased the catalytic current of the group 6 carbonyls and had no effect on the responses of the group 7 carbonyls. The group 6 M(CO)6 species are notable in that that they are effective catalysts without the need for an added "non-innocent" ligand such as 2,2'-bipyridine. PMID:27227447

  18. Grid-based HPC astrophysical applications at INAF Catania.

    NASA Astrophysics Data System (ADS)

    Costa, A.; Calanducci, A.; Becciani, U.; Capuzzo Dolcetta, R.

    The research activity on grid area at INAF Catania has been devoted to two main goals: the integration of a multiprocessor supercomputer (IBM SP4) within INFN-GRID middleware and the developing of a web-portal, Astrocomp-G, for the submission of astrophysical jobs into the grid infrastructure. Most of the actual grid implementation infrastructure is based on common hardware, i.e. i386 architecture machines (Intel Celeron, Pentium III, IV, Amd Duron, Athlon) using Linux RedHat OS. We were the first institute to integrate a totally different machine, an IBM SP with RISC architecture and AIX OS, as a powerful Worker Node inside a grid infrastructure. We identified and ported to AIX OS the grid components dealing with job monitoring and execution and properly tuned the Computing Element to delivery jobs into this special Worker Node. For testing purpose we used MARA, an astrophysical application for the analysis of light curve sequences. Astrocomp-G is a user-friendly front end to our grid site. Users who want to submit the astrophysical applications already available in the portal need to own a valid personal X509 certificate in addiction to a username and password released by the grid portal web master. The personal X509 certificate is a prerequisite for the creation of a short or long-term proxy certificate that allows the grid infrastructure services to identify clearly whether the owner of the job has the permissions to use resources and data. X509 and proxy certificates are part of GSI (Grid Security Infrastructure), a standard security tool adopted by all major grid sites around the world.

  19. NASA Astrophysics EPO Community: Enhancing STEM Instruction

    NASA Astrophysics Data System (ADS)

    Bartolone, L.; Manning, J.; Lawton, B.; Meinke, B. K.; Smith, D. A.; Schultz, G.; NASA Astrophysics EPO community

    2015-11-01

    The NASA Science Mission Directorate (SMD) Astrophysics Education and Public Outreach (EPO) community and Forum work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to enhance Science, Technology, Engineering, and Math (STEM) instruction. In 2010, the Astrophysics EPO community identified online professional development for classroom educators and multiwavelength resources as a common interest and priority for collaborative efforts. The result is NASA's Multiwavelength Universe, a 2-3 week online professional development experience for classroom educators. The course uses a mix of synchronous sessions (live WebEx teleconferences) and asynchronous activities (readings and activities that educators complete on their own on the Moodle, and moderated by course facilitators). The NASA SMD Astrophysics EPO community has proven expertise in providing both professional development and resources to K-12 Educators. These mission- and grant-based EPO programs are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. We present examples of how the NASA Astrophysics EPO community and Forum engage the K-12 education community in these ways, including associated metrics and evaluation findings.

  20. Using the Astrophysics Source Code Library

    NASA Astrophysics Data System (ADS)

    Allen, Alice; Teuben, P. J.; Berriman, G. B.; DuPrie, K.; Hanisch, R. J.; Mink, J. D.; Nemiroff, R. J.; Shamir, L.; Wallin, J. F.

    2013-01-01

    The Astrophysics Source Code Library (ASCL) is a free on-line registry of source codes that are of interest to astrophysicists; with over 500 codes, it is the largest collection of scientist-written astrophysics programs in existence. All ASCL source codes have been used to generate results published in or submitted to a refereed journal and are available either via a download site or from an identified source. An advisory committee formed in 2011 provides input and guides the development and expansion of the ASCL, and since January 2012, all accepted ASCL entries are indexed by ADS. Though software is increasingly important for the advancement of science in astrophysics, these methods are still often hidden from view or difficult to find. The ASCL (ascl.net/) seeks to improve the transparency and reproducibility of research by making these vital methods discoverable, and to provide recognition and incentive to those who write and release programs useful for astrophysics research. This poster provides a description of the ASCL, an update on recent additions, and the changes in the astrophysics community we are starting to see because of the ASCL.

  1. The golden age of multifrequency astrophysics

    NASA Astrophysics Data System (ADS)

    Giovannelli, Franco; Sabau-Graziati, Lola

    In occasion of the Silver Jubilee of the Frascati Workshop about Multifrequency Behaviour of High Energy Cosmic Sources we want to discuss some aspects of the Multifrequency Astrophysics. Multifrequency Astrophysics can be considered as a `new field' of astrophysics born just around the end of 1970-ies - beginning of 1980-ies to which we strongly contributed not only with our own measurements and studies of physical processes spread along the whole electromagnetic spectrum, but mostly with the organization of the Frascati Workshop Series. In this paper we discuss the methodology used in astrophysics for collecting data coming from multifrequency observations of cosmic sources - obtained in different ways - and the relative models developed through theoretical study of physical processes governing their behaviour. Several examples about X-ray binaries, cataclysmic variables, T Tauri stars, relativistic jets from different classes of sources, gamma-ray bursts, and few words about Standard Big Bang Cosmology and experimental proofs fitting the theory will be discussed. We will briefly discuss also the prospects of the multifrequency astrophysics which is now in its golden age without any pretension of completness.

  2. Turbulence and Magnetic Fields in Astrophysics

    NASA Astrophysics Data System (ADS)

    Matthaeus, W. H.

    2004-10-01

    The juxtaposition of ``magnetic fields'' and ``turbulence'' arises in plasma dynamics in various contexts-such as the solar corona, the magnetosphere, space physics in general, cosmic ray propagation, and laboratory plasmas of both fusion and nonfusion types. In astrophysics, the impact of turbulence has arrived relatively recently but is rapidly finding importance. The present volume is a written record of topics presented at a conference, Simulations of Magnetohydrodynamic Turbulence in Astrophysics: Recent Achievements and Perspectives, held at the Institut Henri Poincare, in Paris, in July 2001. The international audience that attended this meeting heard talks on a broad range of astrophysical, space physics, and purely theoretical subjects. A wide range of physical scenarios was discussed, with many different observational data presented. However, true to the conference banner, the emphasis was on the physics of low-frequency plasma turbulence, described by magnetohydrodyamics (MHD), and investigated using numerical simulation.

  3. Review of Astrophysics Experiments on Intense Lasers

    SciTech Connect

    Remington, B A; Drake, R P; Takabe, H; Arnett, D

    2000-01-19

    Astrophysics has traditionally been pursued at astronomical observatories and on theorists' computers. Observations record images from space, and theoretical models are developed to explain the observations. A component often missing has been the ability to test theories and models in an experimental setting where the initial and final states are well characterized. Intense lasers are now being used to recreate aspects of astrophysical phenomena in the laboratory, allowing the creation of experimental testbeds where theory and modeling can be quantitatively tested against data. We describe here several areas of astrophysics--supernovae, supernova remnants, gamma-ray bursts, and giant planets--where laser experiments are under development to test our understanding of these phenomena.

  4. Astrophysical science with a spaceborne photometric telescope

    NASA Technical Reports Server (NTRS)

    Granados, Arno F. (Editor); Borucki, William J. (Editor)

    1994-01-01

    The FRESIP Project (FRequency of Earth-Sized Inner Planets) is currently under study at NASA Ames Research Center. The goal of FRESIP is the measurement of the frequency of Earth-sized extra-solar planets in inner orbits via the photometric signature of a transit event. This will be accomplished with a spaceborne telescope/photometer capable of photometric precision of two parts in 100,000 at a magnitude of m(sub v) = 12.5. To achieve the maximum scientific value from the FRESIP mission, an astrophysical science workshop was held at the SETI Institute in Mountain View, California, November 11-12, 1993. Workshop participants were invited as experts in their field of astrophysical research and discussed the astrophysical science that can be achieved within the context of the FRESIP mission.

  5. Relativistic plasma astrophysics with intense lasers

    NASA Astrophysics Data System (ADS)

    Kuramitsu, Yasuhiro; Chu, Hsu-Hsin; Hau, Lin-Ni; Chen, Shih-Hung; Liu, Yao-Li; Hsieh, Chia-Ying; Sakawa, Youichi; Hideaki, Takabe; Wang, Jyhpyng

    2015-12-01

    Recent progresses of laser technologies enable us to investigate space and astrophysical phenomena in laboratories. In space plasmas the local observations by spacecrafts provide us the microscopic information of the plasma and electric/magnetic fields, however, it is difficult to obtain the global structures of the phenomena. In astrophysical plasmas, in contrast, global images provide us the macroscopic information, although there is no local observation and thus no microscopic information. Laboratory experiments on space and astrophysical phenomena provide us the local and global information simultaneously. We have investigated so far mostly non-relativistic phenomena in the universe with long laser pulses. Now we extend our research from non-relativistic to relativistic regime with an ultra intense laser, the 100 TW laser facility at National Central University. We introduce our facility and model relativistic phenomena in laboratory, focusing on the magnetic field generation and the magnetic reconnection in the universe.

  6. The Astrophysical Multimessenger Observatory Network (AMON)

    NASA Technical Reports Server (NTRS)

    Smith. M. W. E.; Fox, D. B.; Cowen, D. F.; Meszaros, P.; Tesic, G.; Fixelle, J.; Bartos, I.; Sommers, P.; Ashtekar, Abhay; Babu, G. Jogesh; Barthelmy, S. D.; Coutu, S.; DeYoung, T.; Falcone, A. D.; Gao, Shan; Hashemi, B.; Homeier, A.; Marka, S.; Owen, B. J.; Taboada, I.

    2013-01-01

    We summarize the science opportunity, design elements, current and projected partner observatories, and anticipated science returns of the Astrophysical Multimessenger Observatory Network (AMON). AMON will link multiple current and future high-energy, multimessenger, and follow-up observatories together into a single network, enabling near real-time coincidence searches for multimessenger astrophysical transients and their electromagnetic counterparts. Candidate and high-confidence multimessenger transient events will be identified, characterized, and distributed as AMON alerts within the network and to interested external observers, leading to follow-up observations across the electromagnetic spectrum. In this way, AMON aims to evoke the discovery of multimessenger transients from within observatory subthreshold data streams and facilitate the exploitation of these transients for purposes of astronomy and fundamental physics. As a central hub of global multimessenger science, AMON will also enable cross-collaboration analyses of archival datasets in search of rare or exotic astrophysical phenomena.

  7. Underground nuclear astrophysics studies with CASPAR

    NASA Astrophysics Data System (ADS)

    Robertson, Daniel; Couder, Manoel; Greife, Uwe; Strieder, Frank; Wiescher, Michael

    2016-02-01

    The drive of low-energy nuclear astrophysics laboratories is to study the reactions of importance to stellar burning processes and elemental production through stellar nucleosynthesis, over the energy range of astrophysical interest. As laboratory measurements approach the stellar burning window, the rapid drop off of cross-sections is a significant barrier and drives the need to lower background interference. The natural background suppression of underground accelerator facilities enables the extension of current experimental data to lower energies. An example of such reactions of interest are those thought to be sources of neutrons for the s-process, the major production mechanism for elements above the iron peak. The reactions 13C(α,n)16O and 22Ne(α,n)25Mg are the proposed initial focus of the new nuclear astrophysics accelerator laboratory (CASPAR) currently under construction at the Sanford Underground Research Facility, Lead, South Dakota

  8. Astrophysical hints of axion-like particles

    NASA Astrophysics Data System (ADS)

    Roncadelli, M.; Galanti, G.; Tavecchio, F.; Bonnoli, G.

    2015-01-01

    After reviewing three astrophysical hints of the existence of axion-like particles (ALPs), we describe in more detail a new similar hint involving flat spectrum radio quasars (FSRQs). Detection of FSRQs above about 20GeV pose a challenge to very-high-energy (VHE) astrophysics, because at those energies the ultraviolet emission from their broad line region should prevent photons produced by the central engine to leave the source. Although a few astrophysical explanations have been put forward, they are totally ad hoc. We show that a natural explanation instead arises within the conventional models of FSRQs provided that photon-ALP oscillations occur inside the source. Our analysis takes the FSRQ PKR 1222+206 as an example, and it looks tantalizing that basically the same choice of the free model parameters adopted in this case is consistent with those that provide the other three hints of the existence of ALPs.

  9. The Astrophysics Science Division Annual Report 2008

    NASA Technical Reports Server (NTRS)

    Oegerle, William; Reddy, Francis; Tyler, Pat

    2009-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. This report includes the Division's activities during 2008.

  10. Neutrino astrophysics with Hyper-Kamiokande

    NASA Astrophysics Data System (ADS)

    Yano, Takatomi; Hyper-Kamiokande proto Collaboration

    2016-05-01

    Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector. The detector consists of 1 Mt pure water tank with surrounding 99,000 newly developed photo sensors, providing fiducial volume of 0.56 Mt. The energies, positions and directions of charged particles produced by neutrino interactions are detected using its Cherenkov light in water. Our detector will be located at deep underground to reduce the cosmic muon flux and its spallation products, which is a dominant background at the low energy analysis. Hyper-K will play a considerable role in the next neutrino physics frontier, even in the neutrino astrophysics. The detection with large statistics of astrophysical neutrons, i.e., solar neutrino, supernova burst neutrino and supernova relic neutrino, will be remarkable information for both of particle physics and astrophysics.

  11. 22nd Texas Symposium on Relativistic Astrophysics

    SciTech Connect

    Elliott Bloom

    2005-04-01

    The XXII Texas Symposium on Relativistic Astrophysics, jointly organized by the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), the Stanford Linear Accelerator Center, and the Physics Department of Stanford University, was held on December 13-17, 2004. Following the tradition of past Texas Symposia the presentations emphasized recent developments in Cosmology, High Energy Astrophysics and the frontiers between these and Gravitation and Particle Physics. This Symposium was attended by more than 500 colleagues from a spectrum of disciplines mentioned above. There were 9 Plenary Sessions, 3 Parallel Sessions and 2 Poster Sessions held during the five-day program, with 76 oral and 240 poster presentations. These are now documented on CD and in the eConf proceedings archive. Funding of $15,000 received from the DOE under award DE-FG02-05ER41362 was used for expenses related to facility, local transportation and administrative expenses.

  12. Astrophysics Source Code Library: Incite to Cite!

    NASA Astrophysics Data System (ADS)

    DuPrie, K.; Allen, A.; Berriman, B.; Hanisch, R. J.; Mink, J.; Nemiroff, R. J.; Shamir, L.; Shortridge, K.; Taylor, M. B.; Teuben, P.; Wallen, J. F.

    2014-05-01

    The Astrophysics Source Code Library (ASCl,http://ascl.net/) is an on-line registry of over 700 source codes that are of interest to astrophysicists, with more being added regularly. The ASCL actively seeks out codes as well as accepting submissions from the code authors, and all entries are citable and indexed by ADS. All codes have been used to generate results published in or submitted to a refereed journal and are available either via a download site or from an identified source. In addition to being the largest directory of scientist-written astrophysics programs available, the ASCL is also an active participant in the reproducible research movement with presentations at various conferences, numerous blog posts and a journal article. This poster provides a description of the ASCL and the changes that we are starting to see in the astrophysics community as a result of the work we are doing.

  13. Laboratory Astrophysics Division of The AAS (LAD)

    NASA Astrophysics Data System (ADS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-10-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  14. Laboratory Astrophysics Division of the AAS (LAD)

    NASA Technical Reports Server (NTRS)

    Salama, Farid; Drake, R. P.; Federman, S. R.; Haxton, W. C.; Savin, D. W.

    2012-01-01

    The purpose of the Laboratory Astrophysics Division (LAD) is to advance our understanding of the Universe through the promotion of fundamental theoretical and experimental research into the underlying processes that drive the Cosmos. LAD represents all areas of astrophysics and planetary sciences. The first new AAS Division in more than 30 years, the LAD traces its history back to the recommendation from the scientific community via the White Paper from the 2006 NASA-sponsored Laboratory Astrophysics Workshop. This recommendation was endorsed by the Astronomy and Astrophysics Advisory Committee (AAAC), which advises the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the U.S. Department of Energy (DOE) on selected issues within the fields of astronomy and astrophysics that are of mutual interest and concern to the agencies. In January 2007, at the 209th AAS meeting, the AAS Council set up a Steering Committee to formulate Bylaws for a Working Group on Laboratory Astrophysics (WGLA). The AAS Council formally established the WGLA with a five-year mandate in May 2007, at the 210th AAS meeting. From 2008 through 2012, the WGLA annually sponsored Meetings in-a-Meeting at the AAS Summer Meetings. In May 2011, at the 218th AAS meeting, the AAS Council voted to convert the WGLA, at the end of its mandate, into a Division of the AAS and requested draft Bylaws from the Steering Committee. In January 2012, at the 219th AAS Meeting, the AAS Council formally approved the Bylaws and the creation of the LAD. The inaugural gathering and the first business meeting of the LAD were held at the 220th AAS meeting in Anchorage in June 2012. You can learn more about LAD by visiting its website at http://lad.aas.org/ and by subscribing to its mailing list.

  15. Spectral investigation of a group of new cataclysmic variables from the first Byurakan survey with the 6-m telescope

    SciTech Connect

    Kopylov, I.M.; Lipovetskii, V.A.; Somov, N.N.; Somova, T.A.; Stepanyan, D.A.

    1988-09-01

    The paper gives the results of preliminary spectral investigations made with the 6-m telescope for seven stellar objects identified in the First Byurakan Survey (FBS) on the basis of the ultraviolet excess in their spectra. We have classified six of these seven stars as cataclysmic variables. The objects are divided into subclasses: three are dwarf novas, one is a recurrent nova, and two are novalike. One of the stars, FBS 1031 + 590, is, on the basis of all features of the spectrum and the nature of its variability, a polar. Finding charts and samples of spectral scans of the stars are given.

  16. Impact of spin-orbit coupling on the magnetism of Sr3MIrO6 (M = Ni, Co)

    PubMed Central

    Ou, Xuedong; Wu, Hua

    2014-01-01

    Iridates are of current great interest for their entangled spin-orbital state and possibly exotic properties. In this work, using density functional calculations, we have demonstrated that the hexagonal spin-chain materials Sr3MIrO6 (M = Ni, Co) are an iridate system in which the spin-orbit coupling (SOC) tunes the magnetic and electronic properties. The significant SOC alters the orbital state, the exchange pathway, and thus the magnetic structure. This work clarifies the nature and the origin of the intra-chain antiferromagnetism of Sr3MIrO6 and well accounts for the most recent experiments. PMID:24714376

  17. The effect of nuclear reaction rates and convective mixing on the evolution of a 6M{sub ȯ} star

    SciTech Connect

    Halabi, Ghina M.

    2014-05-09

    We present the evolution of a 6M{sub ȯ} star, of solar-like initial metallicity, and investigate the effects of key nuclear reaction rates, as well as the treatment of the convective mixing on its evolution along the Cepheid instability strip. In particular, we study the effect of recent estimates of the {sup 14}N(p,γ){sup 15}O reaction on the formation and extension of the blue loop during core helium burning. We also investigate the effects induced on this blue loop by the adoption of non-standard convective mixing prescriptions, as well as the implications of modifying the Mixing Length Theory.

  18. Scale-covariant theory of gravitation and astrophysical applications

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Adams, P. J.; Hsieh, S.-H.; Tsiang, E.

    1977-01-01

    A scale-covariant theory of gravitation is presented which is characterized by a set of equations that are complete only after a choice of the scale function is made. Special attention is given to gauge conditions and units which allow gravitational phenomena to be described in atomic units. The generalized gravitational-field equations are derived by performing a direct scale transformation, by extending Riemannian geometry to Weyl geometry through the introduction of the notion of cotensors, and from a variation principle. Modified conservation laws are provided, a set of dynamical equations is obtained, and astrophysical consequences are considered. The theory is applied to examine certain homogeneous cosmological solutions, perihelion shifts, light deflections, secular variations of planetary orbital elements, stellar structure equations for a star in quasi-static equilibrium, and the past thermal history of earth. The possible relation of the scale-covariant theory to gauge field theories and their predictions of cosmological constants is discussed.

  19. Astrophysics experiments with radioactive beams at ATLAS

    SciTech Connect

    Back, B. B.; Clark, J. A.; Pardo, R. C.; Rehm, K. E. Savard, G.

    2014-04-15

    Reactions involving short-lived nuclei play an important role in nuclear astrophysics, especially in explosive scenarios which occur in novae, supernovae or X-ray bursts. This article describes the nuclear astrophysics program with radioactive ion beams at the ATLAS accelerator at Argonne National Laboratory. The CARIBU facility as well as recent improvements for the in-flight technique are discussed. New detectors which are important for studies of the rapid proton or the rapid neutron-capture processes are described. At the end we briefly mention plans for future upgrades to enhance the intensity, purity and the range of in-flight and CARIBU beams.

  20. Stellar Astrophysics with the K2 Mission

    NASA Astrophysics Data System (ADS)

    Buzasi, Derek L.

    2016-06-01

    After two years of operation, NASA's K2 spacecraft has established itself as not simply a repurposed Kepler, but as a uniquely capable mission in its own right. While each field of view is observed for only ~80 days, in contrast to the 4+ years achieved by Kepler, the varied locations of the pointings along the ecliptic have made possible a wide range of new astrophysical applications. In this talk, I will discuss recent K2 results in the area of stellar astrophysics, focusing on studies of stellar activity and asteroseismology. I will also present an overview of the different data reduction pipelines available for working with K2 data.

  1. Astrophysical and cosmological constraints to neutrino properties

    NASA Technical Reports Server (NTRS)

    Kolb, Edward W.; Schramm, David N.; Turner, Michael S.

    1989-01-01

    The astrophysical and cosmological constraints on neutrino properties (masses, lifetimes, numbers of flavors, etc.) are reviewed. The freeze out of neutrinos in the early Universe are discussed and then the cosmological limits on masses for stable neutrinos are derived. The freeze out argument coupled with observational limits is then used to constrain decaying neutrinos as well. The limits to neutrino properties which follow from SN1987A are then reviewed. The constraint from the big bang nucleosynthesis on the number of neutrino flavors is also considered. Astrophysical constraints on neutrino-mixing as well as future observations of relevance to neutrino physics are briefly discussed.

  2. Cooperative research in high energy astrophysics

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Details of the activities conducted under the joint effort of the University of Maryland and NASA Goddard Space Flight Center Laboratory for High Energy Astrophysics are detailed for the period July 1989 through April 1994. The research covered a variety of topics including: (1) detection of cosmic rays and studies of the solar modulation of galactic cosmic rays; (2) support work for several x-ray satellites; (3) high resolution gamma-ray spectroscopy of celestial sources; (4)theoretical astrophysics; and (5) active galaxies.

  3. News and Views: Challenges of Relativistic Astrophysics

    NASA Astrophysics Data System (ADS)

    Opher, Reuven

    2013-12-01

    I discuss some of the most outstanding challenges in relativistic astrophysics in the subjects of compact objects (black holes and neutron stars), dark sector (dark matter and dark energy), plasma astrophysics (origin of jets, cosmic rays, and magnetic fields), and the primordial universe (physics at the beginning of the Universe). In these four subjects, I discuss 12 of the most important challenges. These challenges give us insight into new physics that can only be studied in the large scale universe. The near-future possibilities, in observations and theory, for addressing these challenges are also discussed.

  4. Handbook of space astronomy and astrophysics

    NASA Astrophysics Data System (ADS)

    Zombeck, Martin V.

    Tables, graphs, maps, diagrams, and formulas summarizing data and illustrating relationships of interest to space astronomers and astrophysicists are complied in handbook form. General data such as physical and solar-system constants, cosmological parameters, unit conversions, numerical constants, mathematical formulas, and symbols are given in a preliminary section. Individual chapters are devoted to astronomy (A) and astrophysics, radio A, IR A, UV A, X-ray A, gamma-ray A, cosmic rays, earth atmosphere and environment, relativity, atomic physics, electromagnetic radiation, plasma physics, experimental astrophysics, aeronautics and astronautics, mathematics, statistics, radiation safety, and astronomical catalogs.

  5. Gamma-Ray Astrophysics: New Insight Into the Universe

    NASA Technical Reports Server (NTRS)

    Fichtel, Carl E.; Trombka, Jacob I.

    1997-01-01

    During the 15 years that have passed since the first edition of this book was published, there has been a major increase in our knowledge of gamma-ray astronomy. Much of this advance arises from the extensive results that have been forthcoming from the Compton Gamma-Ray Observatory. There has been the discovery of a new class of gamma-ray objects, namely high-energy gamma- ray-emitting blazars, a special class of Active Galactic Nuclei, whose basic high-energy properties now seem to be understood. A much improved picture of our galaxy now exists in the frequency range of gamma rays. The question of whether cosmic rays are galactic or metagalactic now seems settled with certainty. Significant new information exists on the gamma-ray properties of neutron star pulsars, Seyfert galaxies, and gamma-ray bursts. Substantial new insight has been obtained on solar phenomena through gamma-ray observations. Hence, this seemed to be an appropriate time to write a new edition of this book to add the important scientific implications of these many new findings. The special importance of gamma-ray astrophysics had long been recognized by many physicists and astronomers, and theorists had pursued many aspects of the subject well before the experimental results began to become available. The slower development of the experimental side was not because of a lack of incentive, but due to the substantial experimental difficulties that had to be overcome. Thus, as the gamma-ray results became available in much greater number and detail, it was possible to build upon the theoretical work that already existed and to make substantial progress in the study of many of the phenomena involved. Consequently, a much better understanding of many of the astrophysical phenomena mentioned here and others is now possible. Our principal aims in writing this book are the same as they were for the first edition: to provide a text which describes the significance of gamma-ray astrophysics and to assemble

  6. Minicourses in Astrophysics, Modular Approach, Vol. II.

    ERIC Educational Resources Information Center

    Illinois Univ., Chicago.

    This is the second of a two-volume minicourse in astrophysics. It contains chapters on the following topics: stellar nuclear energy sources and nucleosynthesis; stellar evolution; stellar structure and its determination; and pulsars. Each chapter gives much technical discussion, mathematical treatment, diagrams, and examples. References are…

  7. The Dawn of Gravitational-Wave Astrophysics

    NASA Astrophysics Data System (ADS)

    Kalogera, Vassiliki; LIGO - Virgo Collaborations

    2016-06-01

    With the detection of GW150914 and its identification as the binary merger of two heavy black holes LIGO has launched the era of gravitational-wave astrophysics. I will review what this implies for our understanding of binary compact object formation and how we can use it to constrain current models.

  8. Chemical Processes in Astrophysical Radiation Fields

    SciTech Connect

    Stancil, P.C.; Dalgarno, A.

    1997-12-31

    The effects of stimulated photon emission on chemical processes in a radiation field are considered and their influence on the chemistry of the early universe and other astrophysical environments is investigated. Spontaneous and stimulated radiative attachment rate coefficients for H(-), Li(-) and C(-) are presented.

  9. Recent Status of Astrophysical S17

    NASA Astrophysics Data System (ADS)

    Motobayashi, T.

    2002-12-01

    The present status of the astrophysical S factor for the 7Be(p, γ)8B reaction is reviewed. Because of its importance for the solar neutrino problem, the reaction has been extensively studied. Three independent methods, the direct capture, the Coulomb dissociation and the ANC method, give almost consistent results within 10-20% accuracy.

  10. Nonlinear astrophysical fluid dynamics: the video.

    NASA Astrophysics Data System (ADS)

    Norman, M. L.

    A videotape has been assembled containing animations shown by speakers at the Nonlinear Astrophysical Fluid Dynamics Conference. This videotape forms a useful supplement to the conference proceedings. The videotape is available from the National Center for Supercomputing Applications for the cost of materials (6 for 1/2″tapes; 12.50 for 3/4″tapes) and shipping.

  11. A recoil separator for nuclear astrophysics SECAR

    NASA Astrophysics Data System (ADS)

    Berg, G. P. A.; Bardayan, D. W.; Blackmon, J. C.; Chipps, K. A.; Couder, M.; Greife, U.; Hager, U.; Montes, F.; Rehm, K. E.; Schatz, H.; Smith, M. S.; Wiescher, M.; Wrede, C.; Zeller, A.

    2016-06-01

    A recoil separator SECAR has been designed to study radiative capture reactions relevant for the astrophysical rp-process in inverse kinematics for the Facility for Rare Isotope Beams (FRIB). We describe the design, layout, and ion optics of the recoil separator and present the status of the project.

  12. Nuclear astrophysics and the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Spitaleri, C.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A. M.; Pizzone, R. G.

    2016-04-01

    In this review, we discuss the new recent results of the Trojan Horse Method that is used to determine reaction rates for nuclear processes in several astrophysical scenarios. The theory behind this technique is shortly presented. This is followed by an overview of some new experiments that have been carried out using this indirect approach.

  13. Advancing Underground Nuclear Astrophysics with CASPAR

    NASA Astrophysics Data System (ADS)

    Robertson, Daniel; Couder, Manoel; Greife, Uwe; Strieder, Frank; Wells, Doug; Wiescher, Michael

    2015-04-01

    The advancement of experimental nuclear astrophysics techniques and the requirement of astrophysical network models for further nuclear data over greater energy ranges, has led to the requirement for the better understanding of nuclear reactions in stellar burning regimes. For those reactions of importance to stellar burning processes and elemental production through stellar nucleosynthesis, the energy range of astrophysical interest is always problematic to probe. As reaction measurements approach the burning window of interest, the rapid drop off in cross-section hampers laboratory investigation. The natural background suppression of underground accelerator facilities enables the extension of current experimental data to lower energies. An example of such reactions of interest are those thought to be sources of neutrons for the s-process, the major production mechanism for elements above the iron peak. The reactions 13 C(α,n)16 O and 22 Ne(α,n)25 Mg are the proposed initial focus of the new nuclear astrophysics accelerator laboratory (CASPAR) currently under construction at the Sanford Underground Research Facility, Lead, SD. With thanks to funding provided by South Dakota Science and Technology Authority and the NSF under Grant Number PHY-1419765.

  14. Gamma ray spectroscopy in astrophysics. [conferences

    NASA Technical Reports Server (NTRS)

    Cline, T. L. (Editor); Ramaty, R. (Editor)

    1978-01-01

    Experimental and theoretical aspects of gamma ray spectroscopy in high energy astrophysics are discussed. Line spectra from solar, stellar, planetary, and cosmic gamma rays are examined as well as HEAO investigations, the prospects of a gamma ray observatory, and follow-on X-ray experiments in space.

  15. Overview of the NASA astrophysics data system

    NASA Technical Reports Server (NTRS)

    Pomphrey, Rick B.

    1991-01-01

    Overview of the NASA Astrophysics Data Systems (ADS) is presented in the form of view graphs. The following subject areas are covered: The problem; the ADS project; architectural approach; elements of the solution; status of the effort; and the future plans.

  16. Neutrino mixing and oscillations in astrophysical environments

    SciTech Connect

    Balantekin, A. B.

    2014-05-02

    A brief review of the current status of neutrino mixing and oscillations in astrophysical environments, with particular emphasis on the Sun and core-collapse supernovae, is given. Implications of the existence of sterile states which mix with the active neutrinos are discussed.

  17. Nuclear Data on Unstable Nuclei for Astrophysics

    NASA Astrophysics Data System (ADS)

    Smith, Michael; Bardayan, Daniel; Blackmon, Jeffery; Nesaraja, Caroline; Lingerfelt, Eric; Scott, Jason; Hix, W. Raphael; Chae, Kyungyuk; Ma, Zhanwen; Guidry, Michael; Kozub, Raymond; Sharp, Jacob; Meyer, Richard

    2004-10-01

    The sequence of nuclear reactions occurring in supernova explosions is believed to involve thousands of neutron-rich nuclei, and a knowledge of the properties of these nuclei is essential to calculating the element synthesis in these cataclysmic events. Similarly, information on proton-rich nuclei is needed to understand nova explosions occurring on the surfaces of white dwarf stars and X-ray bursts occurring on the surfaces of neutron stars. Recent measurements with radioactive beams at ORNL's Holifield Radioactive Ion Beam Facility (HRIBF) and elsewhere have prompted the evaluation of a number of reactions involving unstable nuclei needed for stellar explosion studies. Recent evaluation efforts will be presented. To ensure that the latest relevant experimental and theoretical nuclear physics results are rapidly incorporated into astrophysical models, we have created a new computational infrastructure for nuclear astrophysics data. Available on-line at www.nucastrodata.org, a simple point-and-click interface guides users to convert evaluated nuclear reaction and structure information as input into thermonuclear reaction rates in a variety of output formats. It also enables users to combine a new reaction rate with an existing library, as well as to create, merge, store, document, and share custom libraries. Future capabilities will include tools to carry out data evaluations and to calculate and visualize the synthesis of elements in astrophysical environments. The site www.nucastrodata.org also features a comprehensive set of links (over 60 so far) to nuclear datasets around the world which are important for nuclear astrophysics studies.

  18. New Directions in Black Hole Astrophysics

    NASA Astrophysics Data System (ADS)

    Reynolds, C. S.

    2002-12-01

    The astrophysics of accreting black holes has been a scientific focus of most major future X-ray missions. In this presentation, I will describe how our science goals and expectations have been effected by new data from Chandra and XMM-Newton as well as new theoretical work. I will argue on the basis of XMM-Newton data that black hole spin does not manifest itself through subtle effects but may have dramatic astrophysical consequences. If this is correct, the exotic astrophysics of black hole spin, including astrophysical realizations of the Penrose and Blandford-Znajek processes, will be a principal focus of Constellation-X, XEUS and MAXIM. On the other hand, data from the late stages of the RXTE/ASCA missions as well as XMM-Newton suggest that the simple technique of relativistic X-ray iron line reverberation mapping, which was originally touted as a good method for studying the inner accretion disk, may be hard to realize. Finally, I will discuss recent theoretical/simulation work on the appearance of a MHD turbulent accretion disk around a black hole. Such simulations may be a good framework to understand future timing observations of Galactic Black Hole Candidates and their quasi-periodic oscillations. They also suggest a quantitative way of measuring the space-time geometry around supermassive black holes in AGN.

  19. Nonlinear, relativistic Langmuir waves in astrophysical magnetospheres

    NASA Technical Reports Server (NTRS)

    Chian, Abraham C.-L.

    1987-01-01

    Large amplitude, electrostatic plasma waves are relevant to physical processes occurring in the astrophysical magnetospheres wherein charged particles are accelerated to relativistic energies by strong waves emitted by pulsars, quasars, or radio galaxies. The nonlinear, relativistic theory of traveling Langmuir waves in a cold plasma is reviewed. The cases of streaming electron plasma, electronic plasma, and two-streams are discussed.

  20. Astrophysical applications of gravitational microlensing

    NASA Astrophysics Data System (ADS)

    Dong, Subo

    The first few topics are on searching and characterizing extrasolar planets by means of high-magnification microlensing events. The detection efficiency analysis of the A max ~ 3000 event OGLE-2004-BLG-343 is presented. Due to human error, intensive monitoring did not begin until 43 minutes after peak, at which point the magnification had fallen to A ~ 1200. It is shown that, had a similar event been well sampled over the peak, it would have been sensitive to almost all Neptune-mass planets over a factor of 5 in projected separation and even would have had some sensitivity to Earth-mass planets. New algorithms optimized for fast evaluation of binary-lens models with finite-sources effects have been developed. These algorithms have enabled efficient and thorough parameter-space searches in modeling planetary high- magnification events. The detection of the cool, Jovian-mass planet MOA-2007- BLG-400Lb, discovered from an A max = 628 event with severe finite-source effects, is reported. Detailed analysis yields a fairly precise planet/star mass ratio of q = ([Special characters omitted.] ) × 10^-3 , while the planet/ star projected separation is subject to a strong close/wide degeneracy. Photometric and astrometric measurements from Hubble Space Telescope, as well as constraints from higher order effects extracted from the ground-based light curve (microlens parallax, planetary orbital motion and finite-source effects) are used to constrain the nature of planetary event OGLE-2005-BLG-071Lb. Our primary analysis leads to the conclusion that the host is an M = 0.46 ± 0.04 [Special characters omitted.] M dwarf and that the planet has mass M p = 3.8 ± 0.4 M Jupiter , which is likely to be the most massive planet yet discovered that is hosted by an M dwarf. Next a spaced-based microlens parallax is determined for the first time using Spitzer and ground-based observations for binary-lens event OGLE-2005-SMC-001. The parallax measurement yields a projected velocity v

  1. The Astrophysics Simulation Collaboratory portal: A framework foreffective distributed research

    SciTech Connect

    Bondarescu, Ruxandra; Allen, Gabrielle; Daues, Gregory; Kelly,Ian; Russell, Michael; Seidel, Edward; Shalf, John; Tobias, Malcolm

    2003-03-03

    We describe the motivation, architecture, and implementation of the Astrophysics Simulation Collaboratory (ASC) portal. The ASC project provides a web-based problem solving framework for the astrophysics community that harnesses the capabilities of emerging computational grids.

  2. Seismic telescope for astrophysical research from space (STARS) triply reflecting telescope: a space instrument for astrophysics.

    PubMed

    Badiali, M; Amoretti, M

    1997-12-01

    We describe the characteristics of the wide-field, triply reflecting telescope adopted for the European Space Agency project STARS (seismic telescope for astrophysical research from space), operating in the visible and UV range. PMID:18264439

  3. Witnessing magnetic twist with high-resolution observation from the 1.6-m New Solar Telescope.

    PubMed

    Wang, Haimin; Cao, Wenda; Liu, Chang; Xu, Yan; Liu, Rui; Zeng, Zhicheng; Chae, Jongchul; Ji, Haisheng

    2015-01-01

    Magnetic flux ropes are highly twisted, current-carrying magnetic fields. They are crucial for the instability of plasma involved in solar eruptions, which may lead to adverse space weather effects. Here we present observations of a flaring using the highest resolution chromospheric images from the 1.6-m New Solar Telescope at Big Bear Solar Observatory, supplemented by a magnetic field extrapolation model. A set of loops initially appear to peel off from an overall inverse S-shaped flux bundle, and then develop into a multi-stranded twisted flux rope, producing a two-ribbon flare. We show evidence that the flux rope is embedded in sheared arcades and becomes unstable following the enhancement of its twists. The subsequent motion of the flux rope is confined due to the strong strapping effect of the overlying field. These results provide a first opportunity to witness the detailed structure and evolution of flux ropes in the low solar atmosphere. PMID:25919706

  4. Quantitative Measurements of the Daytime Near Infrared Sky Brightness at the AEOS 3.6 m Telescope

    NASA Astrophysics Data System (ADS)

    Hart, M.; Jefferies, S.; Hope, D.; Nagy, J.; Williams, S.

    2014-09-01

    We report daytime sky brightness measurements recorded in the near infrared from the 3.6 m AEOS telescope. Measurements were made at various positions in the sky and separation angles from the sun. The detector was an InGaAs focal plane array in a FLIR SC6000 camera, with images taken through a 50 nm wide filter centered at 1250 nm as well as without any optical filter. The brightness measurements have been calibrated by reference to observations of a photometric standard star in the same bands. We discuss how these new results are motivated by the selection of optimal techniques for high-resolution imaging of satellites from the AEOS telescope.

  5. A growth mechanism of porous film formed on Al in 0.6 M oxalic acid electrolyte.

    PubMed

    Han, Seong Ho; Kim, Hyoung Chan

    2012-04-01

    Understanding of mechanism of porous film formation is of fundamental importance for anodizing in general because, the onset of pore initiation terminates the barrier film growth process over the macroscopic metal surface. Several mechanisms have been proposed to explain pore formation. They include direct injection of aluminum ions into electrolyte and a field-assisted dissolution mechanism. High-resolution scanning electron microscopy of anodized surfaces and direct TEM of ion beam thinned films and ultrarmicrotomed film sections have been employed to gain further insight into the mechanism of initial porous film growth in 0.6 M oxalic acid. From detailed examination of the behavior of the xenon-tagged layer in the film during pore initiation and development in oxalic acid, the film structure of the barrier layer is found to be unstable during pore initiation and the instability of the film structure is possibly related to the field-assisted structure modification process. PMID:22849190

  6. Design and Fabrication of a Supporting Structure for 3.6m Long Nb3Sn Racetrack Coils

    SciTech Connect

    Ambrosio, G.; Anerella, M.; Barzi, E.; Caspi, Shlomo; Cheng, Daniel; Dietderich, Daniel; Gourlay, Steve; Hafalia, A. Ray; Hannaford, Charles; Lietzke, Alan; Nobrega, A.R.; Sabbi, GianLuca; Schmalzle, J.; Wanderer, R. J; Zlobin, A.V.; Ferracin, P.

    2007-06-01

    As part of the LHC Accelerator Research Program (LARP), three US national laboratories (BNL, FNAL, and LBNL) are currently engaged in the development of superconducting magnets for the LHC Interaction Regions (IR) beyond the current design. As a first step towards the development of long Nb{sub 3}Sn quadrupole magnets, a 3.6 m long structure, based on the LBNL Subscale Common-Coil Magnet design, will be fabricated, assembled, and tested with aluminum-plate 'dummy coils'. The structure features an aluminum shell pre-tensioned over iron yokes using pressurized bladders and locking keys (bladder and key technology). Pre-load homogeneity and mechanical responses are monitored with pressure sensitive films and strain gauges mounted on the aluminum shell and the dummy coils. The details of the design and fabrication are presented and discussed, and the expected mechanical behavior is analyzed with finite element models.

  7. Witnessing magnetic twist with high-resolution observation from the 1.6-m New Solar Telescope

    PubMed Central

    Wang, Haimin; Cao, Wenda; Liu, Chang; Xu, Yan; Liu, Rui; Zeng, Zhicheng; Chae, Jongchul; Ji, Haisheng

    2015-01-01

    Magnetic flux ropes are highly twisted, current-carrying magnetic fields. They are crucial for the instability of plasma involved in solar eruptions, which may lead to adverse space weather effects. Here we present observations of a flaring using the highest resolution chromospheric images from the 1.6-m New Solar Telescope at Big Bear Solar Observatory, supplemented by a magnetic field extrapolation model. A set of loops initially appear to peel off from an overall inverse S-shaped flux bundle, and then develop into a multi-stranded twisted flux rope, producing a two-ribbon flare. We show evidence that the flux rope is embedded in sheared arcades and becomes unstable following the enhancement of its twists. The subsequent motion of the flux rope is confined due to the strong strapping effect of the overlying field. These results provide a first opportunity to witness the detailed structure and evolution of flux ropes in the low solar atmosphere. PMID:25919706

  8. A multidisciplinary study of planetary, solar and astrophysical radio emissions

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Calvert, W.; Fielder, R.; Goertz, C.; Grabbe, C.; Kurth, W.; Mutel, R.; Sheerin, J.; Mellott, M.; Spangler, S.

    1986-01-01

    Combination of the related fields of planetary, solar, and astrophysical radio emissions was attempted in order to more fully understand the radio emission processes. Topics addressed include: remote sensing of astrophysical plasma turbulence; Alfven waves; astrophysical shock waves; surface waves; very long base interferometry results; very large array observations; solar magnetic flux; and magnetohydrodynamic waves as a tool for solar corona diagnostics.

  9. Astrophysical Magnetic Fields and Topics in Galaxy Formation

    NASA Technical Reports Server (NTRS)

    Field, George B.

    1997-01-01

    The grant was used to support theoretical research on a variety of astro-physical topics falling broadly into those described by the proposal: galaxy formation, astrophysical magnetic fields, magnetized accretion disks in AGN, new physics, and other astrophysical problems. Work accomplished; references are to work authored by project personel.

  10. Nuclear astrophysics. Proceedings. Caltech Centennial Year Nuclear Astrophysics Symposium in Honor of William A. Fowler's 80th Birthday

    NASA Astrophysics Data System (ADS)

    Schramm, D. N.; Woosley, S. E.

    1993-05-01

    Contents: 1. The early universe. 2. Laboratory nuclear astrophysics. 3. Stellar evolution and supernovae. 4. Neutrino astrophysics. 5. Heavy-element nucleosynthesis, galactic chemical evolution. 6. Nucleosynthesis, isotopic anomalies, and gamma rays.

  11. 78 FR 20356 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... following topics: --Astrophysics Division Update --Report from Astrophysics Roadmap Team --James Webb...

  12. 76 FR 66998 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting... Space Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory... following topic: --Astrophysics Division Update --Results from Acting Astrophysics Division...

  13. Astrophysical phenomena related to supermassive black holes

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2006-12-01

    The thesis contains the results of my recent projects in astrophysical research. All projects aim at pushing the limits of our knowledge about the interaction between a galaxy, the fundamental building block of today's universe, and a supermassive black hole (SMBH) at its center. Over the past years a lot of observational evidence has been gathered for the current understanding, that at least a major part of the galaxies with a stellar bulge contain central SMBHs. The typical extragalactic approach consists of searching for the spectroscopic pattern of Keplerian rotation, produced by stars and gas, when orbiting a central dark mass (Kormendy & Richstone 1995). It suggests that a significant fraction of large galaxies host in their very nucleus a SMBH of millions to billions of solar masses (Kormendy & Gebhardt 2001). In the closest case, the center of our Milky Way, the most central stars, which can be imaged, were shown to move on orbits with circulation times of a few decades only, evidencing a mass and compactness of the dark counter part of the Keplerian motion, which can only be explained by a SMBH (Eckart & Genzel 1996; Ghez et al. 2000; Schödel et al. 2002). Having acknowledged the widespread existence of SMBHs the obvious next step is investigating the interaction with their environment. Although the basic property of a SMBH, which is concentrating a huge amount of mass in a ludicrously small volume defined by the Schwarzschild radius, only creates a deep gravitational trough, its existence evokes much more phenomena than simply attracting the surrounding matter. It can trigger or exacerbate star formation via tidal forces (Morris 1993). It shapes the distribution of its surrounding matter to accretion discs, which themselves release gravitational potential energy as radiation, possibly due to magnetic friction (Blandford 1995). The radiation efficiency of such active galactic nuclei (AGN) can become roughly 100 times more efficient than atomic nuclear

  14. NASA Astrophysics Funds Strategic Technology Development

    NASA Astrophysics Data System (ADS)

    Seery, Bernard D.; Ganel, Opher; Pham, Bruce

    2016-01-01

    The COR and PCOS Program Offices (POs) reside at the NASA Goddard Space Flight Center (GSFC), serving as the NASA Astrophysics Division's implementation arm for matters relating to the two programs. One aspect of the PO's activities is managing the COR and PCOS Strategic Astrophysics Technology (SAT) program, helping mature technologies to enable and enhance future astrophysics missions. For example, the SAT program is expected to fund key technology developments needed to close gaps identified by Science and Technology Definition Teams (STDTs) planned to study several large mission concept studies in preparation for the 2020 Decadal Survey.The POs are guided by the National Research Council's "New Worlds, New Horizons in Astronomy and Astrophysics" Decadal Survey report, NASA's Astrophysics Implementation Plan, and the visionary Astrophysics Roadmap, "Enduring Quests, Daring Visions." Strategic goals include dark energy, gravitational waves, and X-ray observatories. Future missions pursuing these goals include, e.g., US participation in ESA's Euclid, Athena, and L3 missions; Inflation probe; and a large UV/Optical/IR (LUVOIR) telescope.To date, 65 COR and 71 PCOS SAT proposals have been received, of which 15 COR and 22 PCOS projects were funded. Notable successes include maturation of a new far-IR detector, later adopted by the SOFIA HAWC instrument; maturation of the H4RG near-IR detector, adopted by WFIRST; development of an antenna-coupled transition-edge superconducting bolometer, a technology deployed by BICEP2/BICEP3/Keck to measure polarization in the CMB signal; advanced UV reflective coatings implemented on the optics of GOLD and ICON, two heliophysics Explorers; and finally, the REXIS instrument on OSIRIS-REx is incorporating CCDs with directly deposited optical blocking filters developed by another SAT-funded project.We discuss our technology development process, with community input and strategic prioritization informing calls for SAT proposals and

  15. A method for comparing non-nested models with application to astrophysical searches for new physics

    NASA Astrophysics Data System (ADS)

    Algeri, Sara; Conrad, Jan; van Dyk, David A.

    2016-05-01

    Searches for unknown physics and decisions between competing astrophysical models to explain data both rely on statistical hypothesis testing. The usual approach in searches for new physical phenomena is based on the statistical likelihood ratio test and its asymptotic properties. In the common situation, when neither of the two models under comparison is a special case of the other i.e. when the hypotheses are non-nested, this test is not applicable. In astrophysics, this problem occurs when two models that reside in different parameter spaces are to be compared. An important example is the recently reported excess emission in astrophysical γ-rays and the question whether its origin is known astrophysics or dark matter. We develop and study a new, simple, generally applicable, frequentist method and validate its statistical properties using a suite of simulations studies. We exemplify it on realistic simulated data of the Fermi-Large Area Telescope γ-ray satellite, where non-nested hypotheses testing appears in the search for particle dark matter.

  16. Exploring Astrophysical Magnetohydrodynamics in the Laboratory

    NASA Astrophysics Data System (ADS)

    Manuel, Mario

    2014-10-01

    Plasma evolution in many astrophysical systems is dominated by magnetohydrodynamics. Specifically of interest to this talk are collimated outflows from accretion systems. Away from the central object, the Euler equations can represent the plasma dynamics well and may be scaled to a laboratory system. We have performed experiments to investigate the effects of a background magnetic field on an otherwise hydrodynamically collimated plasma. Laser-irradiated, cone targets produce hydrodynamically collimated plasma jets and a pulse-powered solenoid provides a constant background magnetic field. The application of this field is shown to completely disrupt the original flow and a new magnetically-collimated, hollow envelope is produced. Results from these experiments and potential implications for their astrophysical analogs will be discussed.

  17. Gamma-ray astrophysics with AGILE

    NASA Astrophysics Data System (ADS)

    Tavani, M.

    2003-09-01

    Gamma-ray astrophysics above 30 MeV will soon be revitalized by a new generation of high-energy detectors in space. We discuss here the AGILE Mission that will be dedicated to gamma-ray astrophysics above 30 MeV during the period 2005-2006. The main characteristics of AGILE are: (1) excellent imaging and monitoring capabilities both in the γ-ray (30 MeV - 30 GeV) and hard X-ray (10-40 keV) energy ranges (reaching an arcminute source positioning), (2) very good timing (improving by three orders of magnitude the instrumental deadtime for γ-ray detection compared to previous instruments), and (3) excellent imaging and triggering capability for Gamma-Ray Bursts. The AGILE scientific program will emphasize a quick response to gamma-ray transients and multiwavelength studies of gamma-ray sources.

  18. Astrophysical payload accommodation on the space station

    NASA Technical Reports Server (NTRS)

    Woods, B. P.

    1985-01-01

    Surveys of potential space station astrophysics payload requirements and existing point mount design concepts were performed to identify potential design approaches for accommodating astrophysics instruments from space station. Most existing instrument pointing systems were designed for operation from the space shuttle and it is unlikely that they will sustain their performance requirements when exposed to the space station disturbance environment. The technology exists or is becoming available so that precision pointing can be provided from the space station manned core. Development of a disturbance insensitive pointing mount is the key to providing a generic system for space station. It is recommended that the MSFC Suspended Experiment Mount concept be investigated for use as part of a generic pointing mount for space station. Availability of a shirtsleeve module for instrument change out, maintenance and repair is desirable from the user's point of view. Addition of a shirtsleeve module on space station would require a major program commitment.

  19. Vision Forward for NASA's Astrophysics Education Program

    NASA Astrophysics Data System (ADS)

    Hasan, Hashima; Sheth, Kartik J.

    2016-01-01

    NASA has recently re-structured its Science Education program with the competitive selection of twenty-seven programs. Of these, ~60% are relevant to Astrophysics, and three have primarily Astrophysics content. A brief overview of the rationale for re-structuring will be presented. We have taken a strategic approach, building on our science-discipline based legacy and looking at new approaches given Stakeholder priorities. We plan to achieve our education goals with the selection of organizations that utilize NASA data, products, or processes to meet NASA's education objectives; and by enabling our scientists and engineers with education professionals, tools, and processes to better meet user needs. Highlights of the selected programs will be presented, and how they enable the vision going forward of achieving the goal of enabling NASA scientists and engineers to engage more effectively with learners of all ages.

  20. NASA's Astrophysics Education and Public Outreach Portfolio

    NASA Astrophysics Data System (ADS)

    Hasan, Hashima; Smith, D. A.

    2013-01-01

    NASA’s Astrophysics Education and Public Outreach (E/PO) portfolio can be classified into four entities - Astrophysics Science Education and Public Outreach Forum (SEPOF), Program Offices, flight missions, smaller competed opportunities - through which different aspects of the E/PO program is conducted. These work together to produce a unified program, which reaches diverse audiences in the areas of K-12 formal education, higher education, informal education and public outreach. An overview of the portfolio will be presented, together with information on how astronomers can engage in NASA E/PO activities and take the excitement of science conducted by NASA flight missions into their local communities. Recent highlights will be presented as examples of the wide reach of NASA E/PO and its role in inspiring students to undertake scientific careers and enhancing public understanding of science and technology.

  1. Astrophysical data analysis with information field theory

    SciTech Connect

    Enßlin, Torsten

    2014-12-05

    Non-parametric imaging and data analysis in astrophysics and cosmology can be addressed by information field theory (IFT), a means of Bayesian, data based inference on spatially distributed signal fields. IFT is a statistical field theory, which permits the construction of optimal signal recovery algorithms. It exploits spatial correlations of the signal fields even for nonlinear and non-Gaussian signal inference problems. The alleviation of a perception threshold for recovering signals of unknown correlation structure by using IFT will be discussed in particular as well as a novel improvement on instrumental self-calibration schemes. IFT can be applied to many areas. Here, applications in in cosmology (cosmic microwave background, large-scale structure) and astrophysics (galactic magnetism, radio interferometry) are presented.

  2. Getting Astrophysical Information from LISA Data

    NASA Technical Reports Server (NTRS)

    Stebbins, R. T.; Bender, P. L.; Folkner, W. M.

    1997-01-01

    Gravitational wave signals from a large number of astrophysical sources will be present in the LISA data. Information about as many sources as possible must be estimated from time series of strain measurements. Several types of signals are expected to be present: simple periodic signals from relatively stable binary systems, chirped signals from coalescing binary systems, complex waveforms from highly relativistic binary systems, stochastic backgrounds from galactic and extragalactic binary systems and possibly stochastic backgrounds from the early Universe. The orbital motion of the LISA antenna will modulate the phase and amplitude of all these signals, except the isotropic backgrounds and thereby give information on the directions of sources. Here we describe a candidate process for disentangling the gravitational wave signals and estimating the relevant astrophysical parameters from one year of LISA data. Nearly all of the sources will be identified by searching with templates based on source parameters and directions.

  3. Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics

    SciTech Connect

    Klein, R I; Stone, J M

    2007-11-20

    We describe numerical methods for solving the equations of radiation magnetohydrodynamics (MHD) for astrophysical fluid flow. Such methods are essential for the investigation of the time-dependent and multidimensional dynamics of a variety of astrophysical systems, although our particular interest is motivated by problems in star formation. Over the past few years, the authors have been members of two parallel code development efforts, and this review reflects that organization. In particular, we discuss numerical methods for MHD as implemented in the Athena code, and numerical methods for radiation hydrodynamics as implemented in the Orion code. We discuss the challenges introduced by the use of adaptive mesh refinement in both codes, as well as the most promising directions for future developments.

  4. Laboratory Astrophysics: Enabling Scientific Discovery and Understanding

    NASA Technical Reports Server (NTRS)

    Kirby, K.

    2006-01-01

    NASA's Science Strategic Roadmap for Universe Exploration lays out a series of science objectives on a grand scale and discusses the various missions, over a wide range of wavelengths, which will enable discovery. Astronomical spectroscopy is arguably the most powerful tool we have for exploring the Universe. Experimental and theoretical studies in Laboratory Astrophysics convert "hard-won data into scientific understanding". However, the development of instruments with increasingly high spectroscopic resolution demands atomic and molecular data of unprecedented accuracy and completeness. How to meet these needs, in a time of severe budgetary constraints, poses a significant challenge both to NASA, the astronomical observers and model-builders, and the laboratory astrophysics community. I will discuss these issues, together with some recent examples of productive astronomy/lab astro collaborations.

  5. Numerical MHD codes for modeling astrophysical flows

    NASA Astrophysics Data System (ADS)

    Koldoba, A. V.; Ustyugova, G. V.; Lii, P. S.; Comins, M. L.; Dyda, S.; Romanova, M. M.; Lovelace, R. V. E.

    2016-05-01

    We describe a Godunov-type magnetohydrodynamic (MHD) code based on the Miyoshi and Kusano (2005) solver which can be used to solve various astrophysical hydrodynamic and MHD problems. The energy equation is in the form of entropy conservation. The code has been implemented on several different coordinate systems: 2.5D axisymmetric cylindrical coordinates, 2D Cartesian coordinates, 2D plane polar coordinates, and fully 3D cylindrical coordinates. Viscosity and diffusivity are implemented in the code to control the accretion rate in the disk and the rate of penetration of the disk matter through the magnetic field lines. The code has been utilized for the numerical investigations of a number of different astrophysical problems, several examples of which are shown.

  6. Optimizing Laboratory Experiments for Dynamic Astrophysical Phenomena

    SciTech Connect

    Ryutov, D; Remington, B

    2005-09-13

    To make a laboratory experiment an efficient tool for the studying the dynamical astrophysical phenomena, it is desirable to perform them in such a way as to observe the scaling invariance with respect to the astrophysical system under study. Several examples are presented of such scalings in the area of magnetohydrodynamic phenomena, where a number of scaled experiments have been performed. A difficult issue of the effect of fine-scale dissipative structures on the global scale dissipation-free flow is discussed. The second part of the paper is concerned with much less developed area of the scalings relevant to the interaction of an ultra-intense laser pulse with a pre-formed plasma. The use of the symmetry arguments in such experiments is also considered.

  7. Research in cosmic and gamma ray astrophysics

    NASA Technical Reports Server (NTRS)

    Stone, Edward C.; Mewaldt, Richard A.; Prince, Thomas A.

    1992-01-01

    Discussed here is research in cosmic ray and gamma ray astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology. The primary activities discussed involve the development of new instrumentation and techniques for future space flight. In many cases these instrumentation developments were tested in balloon flight instruments designed to conduct new investigations in cosmic ray and gamma ray astrophysics. The results of these investigations are briefly summarized. Specific topics include a quantitative investigation of the solar modulation of cosmic ray protons and helium nuclei, a study of cosmic ray positron and electron spectra in interplanetary and interstellar space, the solar modulation of cosmic rays, an investigation of techniques for the measurement and interpretation of cosmic ray isotopic abundances, and a balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen.

  8. Nuclear Astrophysics with the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Spitaleri, Claudio

    2015-04-01

    In stars nuclear reactions take place at physical conditions that make very hard their measurements in terrestrial laboratories. Indeed in astrophysical environments nuclear reactions between charged nuclei occur at energies much lower than the Coulomb barrier and the corresponding cross section values lie in the nano or picobarn regime, that makes their experimental determination extremely difficult. This is due to the very small barrier Coulomb penetration factor, which produces an exponential fall off of the cross section as a function of energy. Additionally, the presence of the electron screening needs to be properly taken into account when dealing with cross section measurements at low-energies. The Trojan Horse Method (THM) represents an independent experimental technique, allowing one to measure astrophysical S(E)-factor bared from both Coulomb penetration and electron screening effects. The main advantages and the most recent results are here shown and discussed.

  9. New developments for high-energy astrophysics

    NASA Astrophysics Data System (ADS)

    Paul, J.

    2000-03-01

    Unlike nearly all branches of physics, founded on the elaboration and analysis of experiments, astronomy is, above all, a science of observation, based mainly on the detection and study of the electromagnetic radiation emitted by celestial bodies. If one excepts devices operating in the radio bands, nearly all instruments used in astrophysics are based on the detection of photons. This review intends to highlight recent developments in high-energy astronomy and astrophysics studies from ground and space observations (from the X-ray band up to high-energy γ-rays and neutrinos). Particular attention will be given not only to recent technologies of photodetection now at work in the field of high-energy astronomy and to emerging photodetection studies in progress for future missions, but also to advanced imaging techniques used in the high-energy domain, which beyond any doubt, constitutes the most arduous of new astronomical disciplines.

  10. Gravitational Wave Astrophysics: Opening the New Frontier

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2011-01-01

    The gravitational wave window onto the universe is expected to open in 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources such as masses, spins, luminosity distances, and orbital parameters through dense, obscured regions across cosmic time. This article explores gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum. Keywords: Gravitational wave astrophysics; gravitational radiation; gravitational wave detectors; black holes.

  11. Broadening Undergraduate Research Skills With A New Astrophysics Laboratory Class

    NASA Astrophysics Data System (ADS)

    Smecker-Hane, Tammy A.; Barth, A. J.

    2009-05-01

    To broaden the research skills of undergraduate students at the University of California, Irvine, we created a new required laboratory class called Observational Astrophysics, designed to be taken by junior and senior physics majors specializing in astrophysics. Students spend the first two weeks learning the basics of observational astronomy (coordinate systems, telescopes, CCDs, etc.) and completing homework assignments. Students spend the next eight weeks performing three lab experiments that involve: 1) CCD imaging of Jupiter with an 8-inch Meade telescope, doing astrometry of the their four brightest moons, and fitting the moons' distance versus time to derive the moons' orbital period, semimajor axis and inclination and Jupiter's mass, 2) CCD imaging of star cluster with a 24-inch telescope, doing profile-fitting photometry with DAOPHOT and doing main-sequence fitting of their observed color-magnitude diagram with stellar evolutionary models to derive the cluster's distance, reddening, and age, and 3) reducing longslit spectra of an x-ray binary previously taken with the Keck 10-meter telescope, deriving the radial velocity curve from cross-correlating the spectra with stellar templates, and deriving a lower limit on the mass of the black hole. In this paper, we discuss the course, report on the student reactions, and summarize some of the important things we learned in creating the class. Students enjoy the class. Although they find it difficult, they highly value the experience because they realize they are learning crucial research skills that will greatly help them when go on to do summer research, attend graduate school or work to industry. We are open to sharing our lab manual and data with others who wish to augment their university's curriculum.

  12. Photoionized astrophysical plasmas in the laboratory

    SciTech Connect

    Hill, Edward; Rose, Steven

    2010-10-15

    The time-dependent collisional-radiative code ALICE [E. G. Hill and S. J. Rose, High Energy Density Phys. 5, 302 (2009)] is used to model the spectrum from a laboratory photoionized silicon plasma [S. Fujioka et al., Nat. Phys. 5, 821 (2009)]. The results show a good agreement with the laboratory spectrum and lend support to the accompanying analytical discussion of photoionized laboratory spectra, their parametrization, and relevance to astrophysics.

  13. Astrophysics. Volume 2 - Interstellar matter and galaxies

    NASA Astrophysics Data System (ADS)

    Bowers, Richard L.; Deeming, Terry

    The astrophysics of interstellar matter, galaxies, and cosmology is presented in an intermediate-level college textbook. Chapters are devoted to interstellar matter, interstellar dust grains, gaseous nebulae, hydrodynamics, the virial theorem, star formation, supersonic flow and shock waves, diffuse supernova remnants, the expanding universe, galaxies, dynamics of stellar systems, axially symmetric galaxies, spiral structure, and galactic evolution. Diagrams, graphs, photographs, and problems are provided.

  14. Opacity project - Astrophysical and fusion applications

    NASA Technical Reports Server (NTRS)

    Pradhan, A. K.

    1987-01-01

    An overview is presented of a project to calculate large quantities of accurate atomic data for radiative processes of importance in the precise determination of opacities in stellar atmospheres, and for astrophysical and laboratory applications in general. Work is in progress on the oscillator strengths, photoionization cross sections, damping constants, etc., for all atoms and ions in hydrogen through neon isoelectronic sequences going up to iron.

  15. Fully covariant cosmology and its astrophysical implications

    NASA Technical Reports Server (NTRS)

    Wesson, Paul S.; Liu, Hongya

    1995-01-01

    We present a cosmological model with good physical properties which is invariant not only under changes of the space and time coordinates but also under changes of an extra (Kaluza-Klein) coordinate related to rest mass. In frames where the latter is chosen to be constant we recover standard cosmology. In frames where it is chosen to be variable we obtain new astrophysical effects and gain insight into the nature of the big bang.

  16. Large Format Detector Arrays for Astrophysics

    NASA Technical Reports Server (NTRS)

    Moseley, Harvey

    2006-01-01

    Improvements in detector design and advances in fabrication techniques has resulted in devices which can reach fundamental sensitivity limits in many cases. Many pressing astrophysical questions require large arrays of such sensitive detectors. I will describe the state of far infrared through millimeter detector development at NASA/GSFC, the design and production of large format arrays, and the initial deployment of these powerful new tools.

  17. ASTROPHYSICS: Astronomers Spot Their First Carbon Bomb.

    PubMed

    Irion, R

    2000-11-17

    Carbon on the surface of an ultradense star detonated in a 3-hour thermonuclear explosion, according to a report at a meeting here last week of the American Astronomical Society's High Energy Astrophysics Division. If confirmed, the burst would be the first known cosmic explosion fueled solely by carbon rather than hydrogen or helium and could verify or revise models of carbon combustion. PMID:17787227

  18. Impact of THM reaction rates for astrophysics

    NASA Astrophysics Data System (ADS)

    Lamia, L.; Spitaleri, C.; Tognelli, E.; Degl'Innocenti, S.; Pizzone, R. G.; Moroni, P. G. Prada; Puglia, S. M. R.; Romano, S.; Sergi, M. L.

    2015-10-01

    Burning reaction S(E)-factor determinations are among the key ingredients for stellar models when one has to deal with energy generation evaluation and the genesis of the elements at stellar conditions. To by pass the still present uncertainties in extrapolating low-energies values, S(E)-factor measurements for charged-particle induced reactions involving light elements have been made available by devote Trojan Horse Method (THM) experiments. The recent results are here discussed together with their impact in astrophysics.

  19. Global Astrophysical Telescope System - telescope No. 2

    NASA Astrophysics Data System (ADS)

    Kamiński, Krzysztof; Baranowski, Roman; Fagas, Monika; Borczyk, Wojciech; Dimitrov, Wojciech; Polińska, Magdalena

    2014-02-01

    We present the new, second spectroscopic telescope of Poznań Astronomical Observatory. The telescope allows automatic simultaneous spectroscopic and photometric observations and is scheduled to begin operation from Arizona in autumn 2013. Together with the telescope located in Borowiec, Poland, it will constitute a perfect instrument for nearly continuous spectroscopic observations of variable stars. With both instruments operational, the Global Astrophysical Telescope System will be established.

  20. Cooperative Research in High Energy Astrophysics

    NASA Technical Reports Server (NTRS)

    Trasco, John D.

    1997-01-01

    A joint agreement between NASA/Goddard and The University of Maryland currently supports cooperative research in Satellite Based Studies of Photons and Charged Particles in the following areas: 1) Detection of cosmic rays and studies of the solar modulation of galactic cosmic rays; 2) Research with several past and upcoming X-ray satellites; 3) High resolution gamma-ray spectroscopy of celestial sources; 4) Theoretical astrophysics.

  1. A model for astrophysical spallation reactions

    NASA Technical Reports Server (NTRS)

    Schmitt, W. F.; Ayres, C. L.; Merker, M.; Shen, B. S. P.

    1974-01-01

    A Monte-Carlo model (RENO) for spallation reactions is described which can treat both the spallations induced by a free nucleon and those induced by a complex nucleus. It differs from other such models in that it employs a discrete-nucleon representation of the nucleus and allows clusters of nucleons to form and to participate in the reaction. The RENO model is particularly suited for spallations involving the relatively light nuclei of astrophysical and cosmic-ray interest.

  2. Perovskite LaPbMSbO{sub 6} (M=Co, Ni): Structural distortion, magnetic and dielectric properties

    SciTech Connect

    Bai, Yijia; Han, Lin; Liu, Xiaojuan; Deng, Xiaolong; Wu, Xiaojie; Yao, Chuangang; Liang, Qingshuang; Meng, Junling; Meng, Jian

    2014-09-15

    The B-site ordered double perovskite oxides LaPbMSbO{sub 6} (M=Co, Ni) have been synthesized via the modified Sol–Gel precursor two-step route. Rietveld refinements reveal strong abnormal structural distortion and BO{sub 6} octahedral deformation appearing along the ab plane. Owing to the cooperative Jahn–Teller effect of Co{sup 2+} and Pb{sup 2+} ions, the Co-related compound exhibits almost complete Co{sup 2+}–Sb{sup 5+} order. For magnetic properties, spin-canted antiferromagnetic state with high extent of magnetic frustration is confirmed. The Ni-related compound presents heavier magnetic frustration for introducing tiny disorder on site occupation accompanied with valence state and further enhancing the complexity of magnetic competition. Dielectric measurements present a considerable temperature dependent dielectric relaxation with great dc-like loss feature in the LaPbCoSbO{sub 6}. For LaPbNiSbO{sub 6}, however, the permittivity with low dielectric loss is shown to be insensitive to either temperature or frequency. The corresponding electronic active energy manifests that the weakly bounded 3d-electron is prone to hop in a more distorted Co–Sb sublattice. - Graphical abstract: XRD Rietveld refinement result of LaPbCoSbO{sub 6} presented a large BO{sub 6} octahedral distortion along the ab plane. Based upon the variations from Co–O–Sb bond angles, a fierce competition from many extended magnetic coupling routes (M–O–O–M) would induce a considerably large magnetic frustration and electron hopping restriction. - Highlights: • Highly ordered LaPbMSbO{sub 6} (M=Co, Ni) were synthesized. • Abnormal structural distortion appeared in the ab plane. • Strong magnetic frustration was confirmed via M{sup 2+}–O–O–M{sup 2+} route. • Dielectric measurements presented a large difference between Co and Ni samples. • 3d-electronic structure determines lattice distortion and physical properties.

  3. Astrophysics for Early Elementary Students and Teachers

    NASA Astrophysics Data System (ADS)

    Kang, R.

    2004-12-01

    How can very young students be taught astrophysics? What can we offer to teachers of K-4 students? Whether you deal directly with youngsters in classrooms, work with your School of Education to develop science inquiry training, or offer occasional general outreach, we discuss activities your program can adopt from the University of Oregon's Electronic Universe outreach program. This collaboration through NASA's Oregon Space Grant plus citizen amateur astronomers has been successfully delivering astrophysics to students in all grades throughout Oregon for over a decade. Students in grades K-4 are generally very enthusiastic learners who have a lot of interest in content and technology about space. Unfortunately typical curricula, state learning requirements, and typical training of their teachers is usually very simplistic and often contains erroneous and outdated materials. We'll work through a series of explorations designed for elementary level that use digital data and virtual reality simulations in conjunction with kinesthetic activities to connect observations such as brightness, shadows, motions, shapes, and colors to basic physical characteristics and properties. This is the starting place where we can grab already curious students and inspire teachers, particularly new teachers, to use space science content to develop science inquiry based curricula. Young students and their teachers can handle astrophysics if the topics are presented in familiar terms and with use of sufficient first hand modeling. Don't be afraid to start them early on these topics, this could dispel myths, generate future interest, and promote careers in science.

  4. Goddard's Astrophysics Science Division Annual Report 2013

    NASA Technical Reports Server (NTRS)

    Weaver, Kimberly A. (Editor); Reddy, Francis J. (Editor); Tyler, Patricia A. (Editor)

    2014-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for two orbiting astrophysics missions Fermi Gamma-ray Space Telescope and Swift as well as the Science Support Center for Fermi. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contrast imaging techniques to search for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and support the astronomical community, and enable future missions by conceiving new concepts and inventing new technologies.

  5. Goddard's Astrophysics Science Division Annual Report 2011

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Reddy, Francis; Tyler, Pat

    2012-01-01

    The Astrophysics Science Division(ASD) at Goddard Space Flight Center(GSFC)is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radiowavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contract imaging techniques to serch for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, and provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and suppport the astronomical community, and enable future missions by conceiving new conepts and inventing new technologies.

  6. Molecular hydrogen and thermal phases in astrophysics

    SciTech Connect

    Lepp, S.H.

    1984-01-01

    The general theme of this thesis is to stress the importance of hydrogen molecules (H/sub 2/) in astrophysics and to illustrate the connection of atomic and molecular physics with radiative, thermal, and dynamical processes in space. Detailed models of the thermal structure and spectral emission of interstellar gas in a variety of astrophysical environments were constructed: x-ray sources in molecular clouds; quasars; and the early universe. The thesis consists of four research papers. In the first, new dissociation rates for H/sub 2/ at low (astrophysical) densities are calculated. The second paper analyzes the thermal structure and characteristic spectral emission of a molecular cloud with an embedded x-ray source. The third paper, extends these results, and x-ray illuminated gas in interstellar space and quasars is studied. It is possible that broad emission line clouds in quasars could have warm (T < 2000 K) molecular cores. In the last paper, the author computes the trace abundance of H/sub 2/, HD, and LiH produced following the recombination epoch in a homogeneous Big Bang model and in the collapse of primordial gas clouds.

  7. Inverse Bremsstrahlung in Shocked Astrophysical Plasmas

    NASA Technical Reports Server (NTRS)

    Baring, Matthew G.; Jones, Frank C.; Ellison, Donald C.

    2000-01-01

    There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical contexts. This follows a long hiatus in the application of suprathermal ion bremsstrahlung to astrophysical models since the early 1970s. The potential importance of inverse bremsstrahlung relative to normal bremsstrahlung, i.e. where ions are at rest, hinges upon the underlying velocity distributions of the interacting species. In this paper, we identify the conditions under which the inverse bremsstrahlung emissivity is significant relative to that for normal bremsstrahlung in shocked astrophysical plasmas. We determine that, since both observational and theoretical evidence favors electron temperatures almost comparable to, and certainly not very deficient relative to proton temperatures in shocked plasmas, these environments generally render inverse bremsstrahlung at best a minor contributor to the overall emission. Hence inverse bremsstrahlung can be safely neglected in most models invoking shock acceleration in discrete sources such as supernova remnants. However, on scales approximately > 100 pc distant from these sources, Coulomb collisional losses can deplete the cosmic ray electrons, rendering inverse bremsstrahlung, and perhaps bremsstrahlung from knock-on electrons, possibly detectable.

  8. Current Perspectives in High Energy Astrophysics

    NASA Technical Reports Server (NTRS)

    Ormes, Jonathan F. (Editor)

    1996-01-01

    High energy astrophysics is a space-age discipline that has taken a quantum leap forward in the 1990s. The observables are photons and particles that are unable to penetrate the atmosphere and can only be observed from space or very high altitude balloons. The lectures presented as chapters of this book are based on the results from the Compton Gamma-Ray Observatory (CGRO) and Advanced Satellite for Cosmology and Astrophysics (ASCA) missions to which the Laboratory for High Energy Astrophysics at NASA's Goddard Space Flight Center made significant hardware contributions. These missions study emissions from very hot plasmas, nuclear processes, and high energy particle interactions in space. Results to be discussed include gamma-ray beaming from active galactic nuclei (AGN), gamma-ray emission from pulsars, radioactive elements in the interstellar medium, X-ray emission from clusters of galaxies, and the progress being made to unravel the gamma-ray burst mystery. The recently launched X-ray Timing Explorer (XTE) and prospects for upcoming Astro-E and Advanced X-ray Astronomy Satellite (AXAF) missions are also discussed.

  9. General-relativistic astrophysics. [gravitational wave astronomy

    NASA Technical Reports Server (NTRS)

    Thorne, K. S.

    1978-01-01

    The overall relevance of general relativity to astrophysics is considered, and some of the knowledge about the ways in which general relativity should influence astrophysical systems is reviewed. Attention is focused primarily on finite-sized astrophysical systems, such as stars, globular clusters, galactic nuclei, and primordial black holes. Stages in the evolution of such systems and tools for studying the effects of relativistic gravity in these systems are examined. Gravitational-wave astronomy is discussed in detail, with emphasis placed on estimates of the strongest gravitational waves that bathe earth, present obstacles and future prospects for detection of the predicted waves, the theory of small perturbations of relativistic stars and black holes, and the gravitational waves such objects generate. Characteristics of waves produced by black-hole events in general, pregalactic black-hole events, black-hole events in galactic nuclei and quasars, black-hole events in globular clusters, the collapse of normal stars to form black holes or neutron stars, and corequakes in neutron stars are analyzed. The state of the art in gravitational-wave detection and characteristics of various types of detector are described.

  10. Simple analytic model for astrophysical S factors

    SciTech Connect

    Yakovlev, D. G.; Beard, M.; Gasques, L. R.; Wiescher, M.

    2010-10-15

    We propose a physically transparent analytic model of astrophysical S factors as a function of a center-of-mass energy E of colliding nuclei (below and above the Coulomb barrier) for nonresonant fusion reactions. For any given reaction, the S(E) model contains four parameters [two of which approximate the barrier potential, U(r)]. They are easily interpolated along many reactions involving isotopes of the same elements; they give accurate practical expressions for S(E) with only several input parameters for many reactions. The model reproduces the suppression of S(E) at low energies (of astrophysical importance) due to the shape of the low-r wing of U(r). The model can be used to reconstruct U(r) from computed or measured S(E). For illustration, we parametrize our recent calculations of S(E) (using the Sao Paulo potential and the barrier penetration formalism) for 946 reactions involving stable and unstable isotopes of C, O, Ne, and Mg (with nine parameters for all reactions involving many isotopes of the same elements, e.g., C+O). In addition, we analyze astrophysically important {sup 12}C+{sup 12}C reaction, compare theoretical models with experimental data, and discuss the problem of interpolating reliably known S(E) values to low energies (E < or approx. 2-3 MeV).

  11. Gravitational microlensing I: A unique astrophysical tool

    NASA Astrophysics Data System (ADS)

    Rahvar, Sohrab

    2015-04-01

    In this paper, we review the astrophysical application of gravitational microlensing. After introducing the history of gravitational lensing, we present the key equations and concept of microlensing. The most frequent microlensing events are single-lens events and historically it has been used for searching dark matter in the form of compact astrophysical halo objects in the Galactic halo. We discuss about the degeneracy problem in the parameters of lens and perturbation effects that can partially break the degeneracy between the lens parameters. The rest of paper is about the astrophysical applications of microlensing. One of the important applications is in the stellar physics by probing the surface of source stars in the high magnification microlensing events. The astrometric and polarimetric observations will be complimentary for probing the atmosphere and stellar spots on the surface of source stars. Finally we discuss about the future projects as space-based telescopes for parallax and astrometry observations of microlensing events. With this project, we would expect to produce a complete stellar and remnant mass function and study the structure of Galaxy in term of distribution of stars along our line of sight towards the center of galaxy.

  12. The Astrophysics Science Division Annual Report 2009

    NASA Technical Reports Server (NTRS)

    Oegerle, William (Editor); Reddy, Francis (Editor); Tyler, Pat (Editor)

    2010-01-01

    The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum - from gamma rays to radio wavelengths - as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions - WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contrast imaging techniques to search for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and support the astronomical community, and enable future missions by conceiving new concepts and inventing new technologies.

  13. The Astrophysics Source Code Library: An Update

    NASA Astrophysics Data System (ADS)

    Allen, Alice; Nemiroff, R. J.; Shamir, L.; Teuben, P. J.

    2012-01-01

    The Astrophysics Source Code Library (ASCL), founded in 1999, takes an active approach to sharing astrophysical source code. ASCL's editor seeks out both new and old peer-reviewed papers that describe methods or experiments that involve the development or use of source code, and adds entries for the found codes to the library. This approach ensures that source codes are added without requiring authors to actively submit them, resulting in a comprehensive listing that covers a significant number of the astrophysics source codes used in peer-reviewed studies. The ASCL moved to a new location in 2010, and has over 300 codes in it and continues to grow. In 2011, the ASCL (http://asterisk.apod.com/viewforum.php?f=35) has on average added 19 new codes per month; we encourage scientists to submit their codes for inclusion. An advisory committee has been established to provide input and guide the development and expansion of its new site, and a marketing plan has been developed and is being executed. All ASCL source codes have been used to generate results published in or submitted to a refereed journal and are freely available either via a download site or from an identified source. This presentation covers the history of the ASCL and examines the current state and benefits of the ASCL, the means of and requirements for including codes, and outlines its future plans.

  14. [Petrological Analysis of Astrophysical Dust Analog Evolution

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  15. Development and tests of interferometry facility in 6-m diameter radiometer thermal vacuum chamber in Tsukuba Space Center

    NASA Astrophysics Data System (ADS)

    Suganuma, Masahiro; Katayama, Haruyoshi; Naitoh, Masataka; Imai, Tadashi; Miyamoto, Masashi; Maruyama, Kenta; Kaneda, Hidehiro; Tange, Yoshio; Nakagawa, Takao

    2010-07-01

    We present a test of optical metrology for 800-mm spaceborne optics in the 6-m radiometer thermal vacuum chamber at JAXA's Tsukuba Space Center of JAXA. Under the framework of the JAXA's large-optics study program for astronomy and Earth observations, we developed a test bench for interferometric metrology of large optics with an auto-collimation method in the chamber. The optical system was aligned in a horizontal light-axis configuration within the facility limit to handle a 3.5-m aperture telescope like SPICA. A high-speed interferometer was contained in an aluminum and titanmade pressure vessel, which was mounted on the five-axis stage. We tested the 800-mm lightweight C/SiC optics using a 900-mm diameter flat mirror. Alignment changes in tilts of about ten arcseconds were observed as pressure went down from 1 atm to vacuum. After we re-aligned the interferometer and flat mirror, the wavefronts through the optics under vacuum were observed to increase in astigmatism aberration by 0.07λRMS at λ=633nm from under atmosphere, which might be caused by a deformation in the test optics or flat mirror.

  16. Unprecedented Fine Structure of a Solar Flare Revealed by the 1.6~m New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Jing, Ju; Xu, Yan; Cao, Wenda; Liu, Chang; Gary, Dale E.; Wang, Haimin

    2016-05-01

    Solar flares signify the sudden release of magnetic energy and are sources of so called space weather. The fine structures (below 500 km) of flares are rarely observed and are accessible to only a few instruments world-wide. Here we present observation of a solar flare using exceptionally high resolution images from the 1.6~m New Solar Telescope (NST) equipped with high order adaptive optics at Big Bear Solar Observatory (BBSO). The observation reveals the process of the flare in unprecedented detail, including the flare ribbon propagating across the sunspots, coronal rain (made of condensing plasma) streaming down along the post-flare loops, and the chromosphere's response to the impact of coronal rain, showing fine-scale brightenings at the footpoints of the falling plasma. Taking advantage of the resolving power of the NST, we measure the cross-sectional widths of flare ribbons, post-flare loops and footpoint brighenings, which generally lie in the range of 80-200 km, well below the resolution of most current instruments used for flare studies. Confining the scale of such fine structure provides an essential piece of information in modeling the energy transport mechanism of flares, which is an important issue in solar and plasma physics.

  17. Assembly and Test of a Support Structure for 3.6 m Long Nb3Sn Racetrack Coils

    SciTech Connect

    Ambrosio, G.; Anerella, M.; Caspi, S.; Cheng, D.W.; Felice, H.; Hafalia, A.R.; Hannaford, C.R.; Lietzke, A.F.; Lizarazo, J.; Muratore, J.; Sabbi, G.L.; Schmalzle, J.; Thomas, R.; Wanderer, P.J.; Ferracin, P.

    2008-06-01

    The LHC Accelerator Research Program (LARP) is currently developing 4 m long Nb{sub 3}Sn quadrupole magnets for a possible upgrade of the LHC Interaction Regions (IR). In order to provide a reliable test bed for the fabrication and test of long Nb{sub 3}Sn coils, LARP has started the development of the long racetrack magnet LRS01. The magnet is composed of two 3.6 m long racetrack coils contained in a support structure based on an aluminum shell pre-tensioned with water-pressurized bladders and interference keys. For the phase-one test of the assembly procedure and loading operation, the structure was pre-stressed at room temperature and cooled down to 77 K with instrumented, solid aluminum 'dummy coils'. Mechanical behavior and stress homogeneity were monitored with strain gauges mounted on the shell and the dummy coils. The dummy coils were replaced with reacted and impregnated Nb{sub 3}Sn coils in a second assembly procedure, followed by cool-down to 4.5 K and powered magnet test. This paper report on the assembly and loading procedures of the support structure as well as the comparison between strain gauge data and 3D model predictions.

  18. Unprecedented Fine Structure of a Solar Flare Revealed by the 1.6 m New Solar Telescope.

    PubMed

    Jing, Ju; Xu, Yan; Cao, Wenda; Liu, Chang; Gary, Dale; Wang, Haimin

    2016-01-01

    Solar flares signify the sudden release of magnetic energy and are sources of so called space weather. The fine structures (below 500 km) of flares are rarely observed and are accessible to only a few instruments world-wide. Here we present observation of a solar flare using exceptionally high resolution images from the 1.6 m New Solar Telescope (NST) equipped with high order adaptive optics at Big Bear Solar Observatory (BBSO). The observation reveals the process of the flare in unprecedented detail, including the flare ribbon propagating across the sunspots, coronal rain (made of condensing plasma) streaming down along the post-flare loops, and the chromosphere's response to the impact of coronal rain, showing fine-scale brightenings at the footpoints of the falling plasma. Taking advantage of the resolving power of the NST, we measure the cross-sectional widths of flare ribbons, post-flare loops and footpoint brighenings, which generally lie in the range of 80-200 km, well below the resolution of most current instruments used for flare studies. Confining the scale of such fine structure provides an essential piece of information in modeling the energy transport mechanism of flares, which is an important issue in solar and plasma physics. PMID:27071459

  19. Ultra high tip speed (670.6 m/sec) fan stage with composite rotor: Aerodynamic and mechanical design

    NASA Technical Reports Server (NTRS)

    Halle, J. E.; Burger, G. D.; Dundas, R. E.

    1977-01-01

    A highly loaded, single-stage compressor having a tip speed of 670.6 m/sec was designed for the purpose of investigating very high tip speeds and high aerodynamic loadings to obtain high stage pressure ratios at acceptable levels of efficiency. The design pressure ratio is 2.8 at an adiabatic efficiency of 84.4%. Corrected design flow is 83.4 kg/sec; corrected design speed is 15,200 rpm; and rotor inlet tip diameter is 0.853 m. The rotor uses multiple-circular-arc airfoils from 0 to 15% span, precompression airfoils assuming single, strong oblique shocks from 21 to 43% span, and precompression airfoils assuming multiple oblique shocks from 52% span to the tip. Because of the high tip speeds, the rotor blades are designed to be fabricated of composite materials. Two composite materials were investigated: Courtaulds HTS graphite fiber in a Kerimid 601 polyimide matrix and the same fibers in a PMR polyimide matrix. In addition to providing a description of the aerodynamic and mechanical design of the 670.0 m/sec fan, discussion is presented of the results of structural tests of blades fabricated with both types of matrices.

  20. Goddard's Astrophysics Science Divsion Annual Report 2014

    NASA Technical Reports Server (NTRS)

    Weaver, Kimberly (Editor); Reddy, Francis (Editor); Tyler, Pat (Editor)

    2015-01-01

    The Astrophysics Science Division (ASD, Code 660) is one of the world's largest and most diverse astronomical organizations. Space flight missions are conceived, built and launched to observe the entire range of the electromagnetic spectrum, from gamma rays to centimeter waves. In addition, experiments are flown to gather data on high-energy cosmic rays, and plans are being made to detect gravitational radiation from space-borne missions. To enable these missions, we have vigorous programs of instrument and detector development. Division scientists also carry out preparatory theoretical work and subsequent data analysis and modeling. In addition to space flight missions, we have a vibrant suborbital program with numerous sounding rocket and balloon payloads in development or operation. The ASD is organized into five labs: the Astroparticle Physics Lab, the X-ray Astrophysics Lab, the Gravitational Astrophysics Lab, the Observational Cosmology Lab, and the Exoplanets and Stellar Astrophysics Lab. The High Energy Astrophysics Science Archive Research Center (HEASARC) is an Office at the Division level. Approximately 400 scientists and engineers work in ASD. Of these, 80 are civil servant scientists, while the rest are resident university-based scientists, contractors, postdoctoral fellows, graduate students, and administrative staff. We currently operate the Swift Explorer mission and the Fermi Gamma-ray Space Telescope. In addition, we provide data archiving and operational support for the XMM mission (jointly with ESA) and the Suzaku mission (with JAXA). We are also a partner with Caltech on the NuSTAR mission. The Hubble Space Telescope Project is headquartered at Goddard, and ASD provides Project Scientists to oversee operations at the Space Telescope Science Institute. Projects in development include the Neutron Interior Composition Explorer (NICER) mission, an X-ray timing experiment for the International Space Station; the Transiting Exoplanet Sky Survey (TESS

  1. Nuclear Astrophysics Animations from the Nuclear Astrophysics Group at Clemson University

    DOE Data Explorer

    Meyer, Bradley; The, Lih-Sin

    The nuclear astrophysics group at Clemson University in South Carolina develops on-line tools and computer programs for astronomy, nuclear physics, and nuclear astrophysics. They have also done short animations that illustrate results from research with some of their tools. The animations are organized into three sections. The r-Process Movies demonstrate r-Process network calculations from the paper "Neutrino Capture and the R-Process" Meyer, McLaughlin, and Fuller, Phys. Rev. C, 58, 3696-3710 (1998). The Alpha-Rich Freezeout Movies are related to the reference: Standard alpha-rich freezeout calculation from The, Clayton, Jin, and Meyer 1998, Astrophysical Journal, "Reaction Rates Governing the Synthesis of 44Ti" At the current writing, the category for Low Metallicity s-Process Movies has only one item called n, p, 13C, 14N, 54Fe, and 88Sr Time evolution in convective zone.

  2. Specialized Science

    PubMed Central

    Fang, Ferric C.

    2014-01-01

    As the body of scientific knowledge in a discipline increases, there is pressure for specialization. Fields spawn subfields that then become entities in themselves that promote further specialization. The process by which scientists join specialized groups has remarkable similarities to the guild system of the middle ages. The advantages of specialization of science include efficiency, the establishment of normative standards, and the potential for greater rigor in experimental research. However, specialization also carries risks of monopoly, monotony, and isolation. The current tendency to judge scientific work by the impact factor of the journal in which it is published may have roots in overspecialization, as scientists are less able to critically evaluate work outside their field than before. Scientists in particular define themselves through group identity and adopt practices that conform to the expectations and dynamics of such groups. As part of our continuing analysis of issues confronting contemporary science, we analyze the emergence and consequences of specialization in science, with a particular emphasis on microbiology, a field highly vulnerable to balkanization along microbial phylogenetic boundaries, and suggest that specialization carries significant costs. We propose measures to mitigate the detrimental effects of scientific specialism. PMID:24421049

  3. Special Needs.

    ERIC Educational Resources Information Center

    Braswell, Ray, Ed.

    This document contains the following papers on special needs instruction and technology: (1) "Hawaii Special Education Teacher Induction" (Kalena Oliva and Quinn Avery); (2) "The Impact of Group v Individual Use of Hypermedia-Based Instruction" (Lewis R. Johnson, Louis P. Semrau, and Gail E. Fitzgerald); (3) "Assistive Technology Meets…

  4. Double Perovskite Anode Materials Sr2MMoO6 (M = Co, Ni) for Solid-Oxide Fuel Cells

    SciTech Connect

    Huang, Y.; Liang, G; Croft, M; Lehtimaki, M; Karppinen, M; Goodenough, J

    2009-01-01

    Double-perovskites Sr2MMoO6 (M = Co, Ni) have been investigated as anode materials for a solid oxide fuel cell. At room temperature, both Sr2CoMoO6 and Sr2NiMoO6 are tetragonal (I4/m). X-ray absorption spectroscopy confirmed the presence of Co2+/Mo6+ and Ni2+/Mo6+ pairs in the oxygen-stoichiometric compounds. The samples contain a limited concentration of oxygen vacancies in the reducing atmospheres at an anode. Reoxidation is facile below 600 C; they become antiferromagnetic at low temperatures TN = 37 and 80 K for M = Co and Ni, respectively. As an anode with a 300 em thick La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte and SrFe0.2Co0.8O3-d as a cathode, Sr2CoMoO6 exhibited maximum power densities of 735 mW/cm2 in H2 and 527 mW/cm2 in wet CH4 at 800 C; Sr2NiMoO6 shows a notable power output only in dry CH4. The high performance of Sr2CoMoO6 in wet CH4 may be due to its catalytic effect on steam reforming of methane, but some degradation of the structure that occurred in CH4 obscures identification of the catalytic reaction processes at the surface. However, the stronger octahedral-site preference of Ni2+ versus Co2+ can account for the lower performance of the M = Ni anode.

  5. Expression of interleukin 6 receptors and interleukin 6 mRNA by bovine leukaemia virus-induced tumour cells.

    PubMed

    Droogmans, L; Cludts, I; Cleuter, Y; Kerkhofs, P; Adam, E; Willems, L; Kettmann, R; Burny, A

    1994-11-01

    Bovine leukaemia virus (BLV) is the aetiologic agent of bovine leucosis. The virus induces malignancies of the B-cell lineage (leukaemia/lymphoma). The role played by interleukin 6 (IL-6) in the BLV-induced leukemogenesis process was evaluated. Six cell lines derived from BLV-induced tumours were tested for the expression of IL-6 receptors. Two cell lines (LB155 and YR2) display 250-300 receptor per cell (kd = 1.7 10(-10) M and 1.4 10(-10) M, respectively) whereas the other four (LB159, LB167, YR1 and M51) do not display detectable amounts of receptors. Very low (if any) expression of IL-6 receptors has been found in the case of the B lymphocytes of animals in persistent lymphocytosis (PL). Despite the presence of IL-6 receptors on the surface of LB155 and YR2 cells, no influence of exogenous IL-6 on their growth has been observed. Northern analyses indicated the presence of IL-6 transcripts only in the case of mRNA isolated from LB155 cells. Since this cell line also expresses receptors for the cytokine, an autocrine loop may exist in these cells. Experiments in which bovine and bovine epithelial cell lines were transfected with a plasmid containing the bovine IL-6 promoter controlling the expression of the reporter cat gene failed to indicate any influence of the viral transactivator p34tax on the activity of this promoter. We conclude that IL-6 receptors and IL-6 mRNA can be found in some BLV-induced tumours, but this does not correlate with viral expression in BLV-induced leukaemia/lymphoma. PMID:7893972

  6. KMTNET: A Network of 1.6 m Wide-Field Optical Telescopes Installed at Three Southern Observatories

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Lee; Lee, Chung-Uk; Park, Byeong-Gon; Kim, Dong-Jin; Cha, Sang-Mok; Lee, Yongseok; Han, Cheongho; Chun, Moo-Young; Yuk, Insoo

    2016-02-01

    The Korea Microlensing Telescope Network (KMTNet) is a wide-field photometric system installed by the Korea Astronomy and Space Science Institute (KASI). Here, we present the overall technical specifications of the KMTNet observation system, test observation results, data transfer and image processing procedure, and finally, the KMTNet science programs. The system consists of three 1.6 m wide-field optical telescopes equipped with mosaic CCD cameras of 18k by 18k pixels. Each telescope provides a 2.0 by 2.0 square degree field of view. We have finished installing all three telescopes and cameras sequentially at the Cerro-Tololo Inter-American Observatory (CTIO) in Chile, the South African Astronomical Observatory (SAAO) in South Africa, and the Siding Spring Observatory (SSO) in Australia. This network of telescopes, which is spread over three different continents at a similar latitude of about -30 degrees, enables 24-hour continuous monitoring of targets observable in the Southern Hemisphere. The test observations showed good image quality that meets the seeing requirement of less than 1.0 arcsec in I-band. All of the observation data are transferred to the KMTNet data center at KASI via the international network communication and are processed with the KMTNet data pipeline. The primary scientific goal of the KMTNet is to discover numerous extrasolar planets toward the Galactic bulge by using the gravitational microlensing technique, especially earth-mass planets in the habitable zone. During the non-bulge season, the system is used for wide-field photometric survey science on supernovae, asteroids, and external galaxies.

  7. KMTNet: a network of 1.6-m wide field optical telescopes installed at three southern observatories

    NASA Astrophysics Data System (ADS)

    Lee, Chung-Uk; Kim, Seung-Lee; Cha, Sang-Mok; Lee, Yongseok; Kim, Dong-Jin; Park, Byeong-Gon; Lee, Dong-Joo; Koo, Jae-Rim; Hong, Kyeongsoo; Lee, Jae Woo; Ryu, Yoon-Hyun; Lim, Beomdu; Lim, Jin-Sun; Gho, Seung-Won; Kim, Min-Jun

    2015-08-01

    Korea Astronomy and Space Science Institute (KASI) have installed three identical 1.6-m telescopes, called Korea Microlensing Telescope Network (KMTNet), which cover 2 x 2 degree field of view with the plate scale of 0.4 arcsec/pixel at three observatories - CTIO, SSO and SAAO in southern hemisphere. The uniqueness of the system is the uninterupted 24-hour monitoring with a wide field optics in southern hemisphere. The telescope adopts prime focus using a parabolic mirror and four spherical flattening lenses. The structural design and driving systems are modified from the degin of 2MASS telescope. The one piece filter-shutter assembly has a sliding shutter and four 310-mm square filters. Each observation system produces a 680MB size image file at site and the images are transfered to KASI data center using the Global Ring Network for Advanced Application Development (GLORIAD) network with the band width of 50Mbps in average. The main science goal of the KMTNet is to discover Earth like extra solar planet using the microlensing technique during bulge season, and 50% of the total observation time is allocated for the science program solely. The other telescope times are allocated for pre-selected seven science programs during non-bulge season. From the test observation, we verify that the most important two requirements are satisfied: 10 arcsec in RMS for the pointing accuracy and 1 arcsec of delivered image quality in I-band. In this presentation, we introduce finally installed system at each observatory and its observational performance obtained from the test observation.

  8. Superdiffusive transport in laboratory and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Zimbardo, G.; Amato, E.; Bovet, A.; Effenberger, F.; Fasoli, A.; Fichtner, H.; Furno, I.; Gustafson, K.; Ricci, P.; Perri, S.

    2015-12-01

    > In the last few years it has been demonstrated, both by data analysis and by numerical simulations, that the transport of energetic particles in the presence of magnetic turbulence can be superdiffusive rather than normal diffusive (Gaussian). The term `superdiffusive' refers to the mean square displacement of particle positions growing superlinearly with time, as compared to the normal linear growth. The so-called anomalous transport, which in general comprises both subdiffusion and superdiffusion, has gained growing attention during the last two decades in many fields including laboratory plasma physics, and recently in astrophysics and space physics. Here we show a number of examples, both from laboratory and from astrophysical plasmas, where superdiffusive transport has been identified, with a focus on what could be the main influence of superdiffusion on fundamental processes like diffusive shock acceleration and heliospheric energetic particle propagation. For laboratory plasmas, superdiffusion appears to be due to the presence of electrostatic turbulence which creates long-range correlations and convoluted structures in perpendicular transport: this corresponds to a similar phenomenon in the propagation of solar energetic particles (SEPs) which leads to SEP dropouts. For the propagation of energetic particles accelerated at interplanetary shocks in the solar wind, parallel superdiffusion seems to be prevailing; this is based on a pitch-angle scattering process different from that envisaged by quasi-linear theory, and this emphasizes the importance of nonlinear interactions and trapping effects. In the case of supernova remnant shocks, parallel superdiffusion is possible at quasi-parallel shocks, as occurring in the interplanetary space, and perpendicular superdiffusion is possible at quasi-perpendicular shocks, as corresponding to Richardson diffusion: therefore, cosmic ray acceleration at supernova remnant shocks should be formulated in terms of

  9. Numerical methods for supersonic astrophysical jets

    NASA Astrophysics Data System (ADS)

    Ha, Youngsoo

    2003-09-01

    The Euler equations of gas dynamics are used for the simulation of general astrophysical fluid flows including high Mach number astrophysical jets with radiative cooling. To accurately compute supersonic jet solutions with sharp resolution of shock waves, three modern numerical methods for gas dynamics were used: (1)a second-order Godunov method in LeVeque's software package CLAWPACK, (2)the Nessyahu-Tadmor-Kurganov (NTK) central hyperbolic scheme, and (3)the WENO-LF (Weighted Essentially Non-Oscillatory Lax-Friedrichs) scheme. Then simulations of supersonic astrophysical jets were compared, first without and then with radiative cooling. CLAWPACK consists of routines for solving time-dependent nonlinear hyperbolic conservation laws based on higher order Godunov methods and approximate Riemann problem solutions; the NTK scheme solves conservation laws using a modified Lax-Friedrichs central difference method without appealing to Riemann problem solutions; and the WENO-LF finite difference scheme is based on the Essentially Non-Oscillatory (ENO) idea by using Lax- Friedrichs flux splitting. The ENO method constructs a solution using the smoothness of the interpolating polynomial on given stencils; on the other hand, the WENO scheme uses a convex combination of the interpolate functions on all candidate stencils. The third-order and fifth-order WENO-LF methods were used to simulate the high Mach number jets. Appropriate numerical methods for incorporating radiative cooling in these numerical methods are also discussed. Interactions of supersonic jets with their environments (jet-“blob” interactions) are shown after modifying the codes to handle high Mach numbers and radiative cooling.

  10. High energy particles and quanta in astrophysics

    NASA Technical Reports Server (NTRS)

    Mcdonald, F. B. (Editor); Fichtel, C. E.

    1974-01-01

    The various subdisciplines of high-energy astrophysics are surveyed in a series of articles which attempt to give an overall view of the subject as a whole by emphasizing the basic physics common to all fields in which high-energy particles and quanta play a role. Successive chapters cover cosmic ray experimental observations, the abundances of nuclei in the cosmic radiation, cosmic electrons, solar modulation, solar particles (observation, relationship to the sun acceleration, interplanetary medium), radio astronomy, galactic X-ray sources, the cosmic X-ray background, and gamma ray astronomy. Individual items are announced in this issue.

  11. Emission lines from hot astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Raymond, John C.

    The spectral lines which dominate the X-ray emission of hot, optically thin astrophysical plasmas reflect the elemental abundances, temperature distribution, and other physical parameters of the emitting gas. The accuracy and level of detail with which these parameters can be inferred are limited by the measurement uncertainties and uncertainties in atomic rates used to compute the model spectrum. This paper discusses the relative importance and the likely uncertainties in the various atomic rates and the likely uncertainties in the overall ionization balance and spectral line emissivities predicted by the computer codes currently used to fit X-ray spectral data.

  12. Alpha resonant scattering for astrophysical reaction studies

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-05-01

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of 7Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the 7Be(α,γ) reaction, and proposed a new cluster band in 11C.

  13. Nonlinear evolution of astrophysical Alfven waves

    SciTech Connect

    Spangler, S.R.

    1984-11-01

    Nonlinear Alfven waves were studied using the derivative nonlinear Schrodinger equation as a model. The evolution of initial conditions, such as envelope solitons, amplitude-modulated waves, and band-limited noise was investigated. The last two furnish models for naturally occurring Alfven waves in an astrophysical plasma. A collapse instability in which a wave packet becomes more intense and of smaller spatial extent was analyzed. It is argued that this instability leads to enhanced plasma heating. In studies in which the waves are amplified by an electron beam, the instability tends to modestly inhibit wave growth. (ESA)

  14. Gravitational Wave Astrophysics: Opening the New Frontier

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2011-01-01

    The gravitational wave window onto the universe is expected to open in approximately 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters through dense, obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum.

  15. ASTROPHYSICS: Neutron Stars Imply Relativity's a Drag.

    PubMed

    Schilling, G

    2000-09-01

    A new finding, based on x-rays from distant neutron stars, could be the first clear evidence of a weird relativistic effect called frame dragging, in which a heavy chunk of spinning matter wrenches the space-time around it like an eggbeater. Using data from NASA's Rossi X-ray Timing Explorer, three astronomers in Amsterdam found circumstantial evidence for frame dragging in the flickering of three neutron stars in binary systems. They announced their results in the 1 September issue of The Astrophysical Journal. PMID:17839511

  16. Gamma ray astronomy and black hole astrophysics

    NASA Technical Reports Server (NTRS)

    Liang, Edison P.

    1990-01-01

    The study of soft gamma emissions from black-hole candidates is identified as an important element in understanding black-hole phenomena ranging from stellar-mass black holes to AGNs. The spectra of Cyg X-1 and observations of the Galactic Center are emphasized, since thermal origins and MeV gamma-ray bumps are evident and suggest a thermal-pair cloud picture. MeV gamma-ray observations are suggested for studying black hole astrophysics such as the theorized escaping pair wind, the anticorrelation between the MeV gamma bump and the soft continuum, and the relationship between source compactness and temperature.

  17. Astrophysical constraints on scalar field models

    SciTech Connect

    Bertolami, O.; Paramos, J.

    2005-01-15

    We use stellar structure dynamics arguments to extract bounds on the relevant parameters of two scalar field models: the putative scalar field mediator of a fifth force with a Yukawa potential and the new variable mass particle models. We also analyze the impact of a constant solar inbound acceleration, such as the one reported by the Pioneer anomaly, on stellar astrophysics. We consider the polytropic gas model to estimate the effect of these models on the hydrostatic equilibrium equation and fundamental quantities such as the central temperature. The current bound on the solar luminosity is used to constrain the relevant parameters of each model.

  18. Astrophysics Source Code Library -- Now even better!

    NASA Astrophysics Data System (ADS)

    Allen, Alice; Schmidt, Judy; Berriman, Bruce; DuPrie, Kimberly; Hanisch, Robert J.; Mink, Jessica D.; Nemiroff, Robert J.; Shamir, Lior; Shortridge, Keith; Taylor, Mark B.; Teuben, Peter J.; Wallin, John F.

    2015-01-01

    The Astrophysics Source Code Library (ASCL, ascl.net) is a free online registry of codes used in astronomy research. Indexed by ADS, it now contains nearly 1,000 codes and with recent major changes, is better than ever! The resource has a new infrastructure that offers greater flexibility and functionality for users, including an easier submission process, better browsing, one-click author search, and an RSS feeder for news. The new database structure is easier to maintain and offers new possibilities for collaboration. Come see what we've done!

  19. Recent Discoveries in Nuclear Line Astrophysics

    NASA Astrophysics Data System (ADS)

    Boggs, Steven E.

    2016-06-01

    Nuclear gamma-ray lines provide a unique probe of supernovae and nuclear astrophysics. The potential for significant contributions to the understanding supernovae, as well as the large potential for new discoveries, has long been recognized. I will review several major discoveries in the past few years from the NuSTAR and INTEGRAL missions, including observations of SN 1987A, Cas A, and SN 2014J. In addition, I will look forward to the next generation of gamma-ray line instruments currently under development, including wide-field Compton telescopes and focusing lens telescopes.

  20. Gravitational Wave Astrophysics: Opening the New Frontier

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2011-01-01

    The gravitational wave window onto the universe is expected to open in approx. 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters, through dense, obscured regions across cosmic time. This article explores gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum.

  1. Nonlinear evolution of astrophysical Alfven waves

    NASA Technical Reports Server (NTRS)

    Spangler, S. R.

    1984-01-01

    Nonlinear Alfven waves were studied using the derivative nonlinear Schrodinger equation as a model. The evolution of initial conditions, such as envelope solitons, amplitude-modulated waves, and band-limited noise was investigated. The last two furnish models for naturally occurring Alfven waves in an astrophysical plasma. A collapse instability in which a wave packet becomes more intense and of smaller spatial extent was analyzed. It is argued that this instability leads to enhanced plasma heating. In studies in which the waves are amplified by an electron beam, the instability tends to modestly inhibit wave growth.

  2. Alpha resonant scattering for astrophysical reaction studies

    SciTech Connect

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  3. Nuclear data on unstable nuclei for astrophysics

    NASA Astrophysics Data System (ADS)

    Smith, Michael S.; Meyer, Richard A.; Bardayan, Daniel W.; Blackmon, Jeffery C.; Chae, Kyungyuk; Guidry, Michael W.; Hix, W. Raphael; Kozub, R. L.; Lingerfelt, Eric J.; Ma, Zhanwen; Scott, Jason P.

    2004-12-01

    Recent measurements with radioactive beams at ORNL's Holifield Radioactive Ion Beam Facility (HRIBF) have prompted the evaluation of a number of reactions involving unstable nuclei needed for stellar explosion studies. We discuss these evaluations, as well as the development of a new computational infrastructure to enable the rapid incorporation of the latest nuclear physics results in astrophysics models. This infrastructure includes programs that simplify the generation of reaction rates, manage rate databases, and visualize reaction rates, all hosted at a new website http://www.nucastrodata.org.

  4. Recent Nuclear Astrophysics Data Activities at ORNL

    NASA Astrophysics Data System (ADS)

    Smith, Michael S.; Bardayan, Daniel W.; Blackmon, Jeffery C.; Meyer, Richard A.; Chae, Kyungyuk; Guidry, Michael W.; Hix, W. Raphael; Lingerfelt, Eric J.; Ma, Zhanwen; Scott, Jason P.; Kozub, Raymond L.

    2005-12-01

    Recent measurements with radioactive beams at ORNL's Holifield Radioactive Ion Beam Facility (HRIBF) have prompted the evaluation of a number of reactions involving unstable nuclei needed for stellar explosion studies. We discuss these evaluations, as well as the development of a new computational infrastructure to enable the rapid incorporation of the latest nuclear physics results in astrophysics models. This infrastructure includes programs that simplify the generation of reaction rates, manage rate databases, and visualize reaction rates, all hosted at a new website .

  5. Astrotech 21: A technology program for future astrophysics missions

    NASA Technical Reports Server (NTRS)

    Cutts, James A.; Newton, George P.

    1991-01-01

    The Astrotech 21 technology program is being formulated to enable a program of advanced astrophysical observatories in the first decade of the 21st century. This paper describes the objectives of Astrotech 21 and the process that NASA is using to plan and implement it. It also describes the future astrophysical mission concepts that have been defined for the twenty-first century and discusses some of the requirements that they will impose on information systems for space astrophysics.

  6. SPACE PHYSICS: Developing resources for astrophysics at A-level: the TRUMP Astrophysics project

    NASA Astrophysics Data System (ADS)

    Swinbank, Elizabeth

    1997-01-01

    After outlining the astrophysical options now available in A-level physics syllabuses, this paper notes some of the particular challenges facing A-level teachers and students who chose these options and describes a project designed to support them. The paper highlights some key features of the project that could readily be incorporated into other areas of physics curriculum development.

  7. Special Delivery.

    ERIC Educational Resources Information Center

    Zimmer, Phil

    1986-01-01

    Specialized publications such as "Opera News,""Gourmet," and "Forbes" can bring an institution's story to targeted audiences. The experiences of Chautauqua Institution are described. Some of the benefits of marketing articles to these publications are discussed. (MLW)

  8. Special Libraries

    ERIC Educational Resources Information Center

    Lavendel, Giuliana

    1977-01-01

    Discusses problems involved in maintaining special scientific or engineering libraries, including budget problems, remote storage locations, rental computer retrieval systems, protecting trade secrets, and establishing a magnetic tape library. (MLH)

  9. Nuclear Data for Astrophysics Research: A New Online Paradigm

    SciTech Connect

    Smith, Michael Scott

    2011-01-01

    Our knowledge of a wide range of astrophysical processes depends crucially on nuclear physics data. While new nuclear information is being generated at an ever-increasing rate, the methods to process this information into astrophysical simulations have changed little over the decades and cannot keep pace. Working online, 'cloud computing', may be the methodology breakthrough needed to ensure that the latest nuclear data quickly gets into astrophysics codes. The successes of the first utilization of cloud computing for nuclear astrophysics will be described. The advantages of cloud computing for the broader nuclear data community are also discussed.

  10. Central limit theorems under special relativity

    PubMed Central

    McKeague, Ian W.

    2015-01-01

    Several relativistic extensions of the Maxwell–Boltzmann distribution have been proposed, but they do not explain observed lognormal tail-behavior in the flux distribution of various astrophysical sources. Motivated by this question, extensions of classical central limit theorems are developed under the conditions of special relativity. The results are related to CLTs on locally compact Lie groups developed by Wehn, Stroock and Varadhan, but in this special case the asymptotic distribution has an explicit form that is readily seen to exhibit lognormal tail behavior. PMID:25798020

  11. Nuclear astrophysics at the east drip line

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Teranishi, T.; Notani, M.; Yamaguchi, H.; Saito, A.; He, J. J.; Wakabayashi, Y.; Fujikawa, H.; Amadio, G.; Baba, H.; Fukuchi, T.; Shimoura, S.; Michimasa, S.; Nishimura, S.; Nishimura, M.; Gono, Y.; Odahara, A.; Kato, S.; Moon, J. Y.; Lee, J. H.; Kwon, Y. K.; Lee, C. S.; Hahn, K. I.; Fülöp, Zs.; Guimar Aes, V.; Lichtenthaler, R.

    2006-03-01

    In the first half of the paper, the nuclear astrophysics activities in Japan, especially in experimental studies are briefly overviewed. A variety of beams have been developed and used for nuclear astrophysics experiments in Japan. The activities include the RI beam facilities at low energies by the in-flight method at the Center for Nuclear Study (CNS), University of Tokyo and by the ISOL-based method at the JAERI tandem facility, and the RI beam facility at intermediate energies at RIKEN. Other activities include a study of the 12C(α,γ)16O reaction exclusively at the tandem accelerator at the Kyushu University, and studies at the neutron facility at Tokyo Institute of Technology and at the photon facility at AIST (Sanso-ken). Research opportunities in the future at RIBF, J-PARC, and SPRING8 are also discussed. A discussion on the research activities at CNS has been specifically extended in the latter half, including various possibilities in collaboration at the RI beam factory at RIKEN.

  12. ZAPP: The Z Astrophysical Plasma Properties collaboration

    SciTech Connect

    Rochau, G. A.; Bailey, J. E.; Falcon, R. E.; Loisel, G. P.; Nagayama, T.; Mancini, R. C.; Hall, I.; Winget, D. E.; Montgomery, M. H.; Liedahl, D. A.

    2014-05-15

    The Z Facility at Sandia National Laboratories [Matzen et al., Phys. Plasmas 12, 055503 (2005)] provides MJ-class x-ray sources that can emit powers >0.3 PW. This capability enables benchmark experiments of fundamental material properties in radiation-heated matter at conditions previously unattainable in the laboratory. Experiments on Z can produce uniform, long-lived, and large plasmas with volumes up to 20 cc, temperatures from 1–200 eV, and electron densities from 10{sup 17–23} cc{sup −1}. These unique characteristics and the ability to radiatively heat multiple experiments in a single shot have led to a new effort called the Z Astrophysical Plasma Properties (ZAPP) collaboration. The focus of the ZAPP collaboration is to reproduce the radiation and material characteristics of astrophysical plasmas as closely as possible in the laboratory and use detailed spectral measurements to strengthen models for atoms in plasmas. Specific issues under investigation include the LTE opacity of iron at stellar-interior conditions, photoionization around active galactic nuclei, the efficiency of resonant Auger destruction in black-hole accretion disks, and H-Balmer line shapes in white dwarf photospheres.

  13. Astrophysical Model Selection in Gravitational Wave Astronomy

    NASA Technical Reports Server (NTRS)

    Adams, Matthew R.; Cornish, Neil J.; Littenberg, Tyson B.

    2012-01-01

    Theoretical studies in gravitational wave astronomy have mostly focused on the information that can be extracted from individual detections, such as the mass of a binary system and its location in space. Here we consider how the information from multiple detections can be used to constrain astrophysical population models. This seemingly simple problem is made challenging by the high dimensionality and high degree of correlation in the parameter spaces that describe the signals, and by the complexity of the astrophysical models, which can also depend on a large number of parameters, some of which might not be directly constrained by the observations. We present a method for constraining population models using a hierarchical Bayesian modeling approach which simultaneously infers the source parameters and population model and provides the joint probability distributions for both. We illustrate this approach by considering the constraints that can be placed on population models for galactic white dwarf binaries using a future space-based gravitational wave detector. We find that a mission that is able to resolve approximately 5000 of the shortest period binaries will be able to constrain the population model parameters, including the chirp mass distribution and a characteristic galaxy disk radius to within a few percent. This compares favorably to existing bounds, where electromagnetic observations of stars in the galaxy constrain disk radii to within 20%.

  14. Communicating the Science from NASA's Astrophysics Missions

    NASA Astrophysics Data System (ADS)

    Hasan, Hashima; Smith, Denise A.

    2015-01-01

    Communicating science from NASA's Astrophysics missions has multiple objectives, which leads to a multi-faceted approach. While a timely dissemination of knowledge to the scientific community follows the time-honored process of publication in peer reviewed journals, NASA delivers newsworthy research result to the public through news releases, its websites and social media. Knowledge in greater depth is infused into the educational system by the creation of educational material and teacher workshops that engage students and educators in cutting-edge NASA Astrophysics discoveries. Yet another avenue for the general public to learn about the science and technology through NASA missions is through exhibits at museums, science centers, libraries and other public venues. Examples of the variety of ways NASA conveys the excitement of its scientific discoveries to students, educators and the general public will be discussed in this talk. A brief overview of NASA's participation in the International Year of Light will also be given, as well as of the celebration of the twenty-fifth year of the launch of the Hubble Space Telescope.

  15. Ultraviolet and Visible Emission Mechanisms in Astrophysics

    NASA Technical Reports Server (NTRS)

    Stancil, Phillip C.; Schultz, David R.

    2003-01-01

    The project involved the study of ultraviolet (UV) and visible emission mechanisms in astrophysical and atmospheric environments. In many situations, the emission is a direct consequence of a charge transferring collision of an ion with a neutral with capture of an electron to an excited state of the product ion. The process is also important in establishing the ionization and thermal balance of an astrophysical plasma. As little of the necessary collision data are available, the main thrust of the project was the calculation of total and state-selective charge transfer cross sections and rate coefficients for a very large number of collision systems. The data was computed using modern explicit techniques including the molecular-orbital close-coupling (MOCC), classical trajectory Monte Carlo (CTMC), and continuum distorted wave (CDW) methods. Estimates were also made in some instances using the multichannel Landau-Zener (MCLZ) and classical over-the-barrier (COB) models. Much of the data which has been computed has been formatted for inclusion in a charge transfer database on the World Wide Web (cfadc.phy.ornl.gov/astro/ps/data/). A considerable amount of data has been generated during the lifetime of the grant. Some of it has not been analyzed, but it will be as soon as possible, the data placed on our website, and papers ultimately written.

  16. Bubble chambers for experiments in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Raut, R.; Rehm, K. E.; Robinson, A.; Sonnenschein, A.; Rusev, G.; Tonchev, A. P.; Ugalde, C.

    2015-05-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with γ-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross-sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross-sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross-sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the γ-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed.

  17. Astrophysically Triggered Searches for Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Marka, Zsuzsa

    2010-02-01

    Many expected sources of gravitational waves are observable in more traditional channels, via gamma rays, X-rays, optical, radio, or neutrino emission. Some of these channels are already being used in searches for gravitational waves with the LIGO-GEO600-Virgo interferometer network, and others are currently being incorporated into new or planned searches. Astrophysical targets include gamma-ray bursts, soft-gamma repeaters, supernovae, and glitching pulsars. The observation of electromagnetic or neutrino emission simultaneously with gravitational waves could be crucial for the first direct detection of gravitational waves. Information on the progenitor, such as trigger time, direction and expected frequency range, can enhance our ability to identify gravitational wave signatures with amplitude close to the noise floor of the detector. Furthermore, combining gravitational waves with electromagnetic and neutrino observations will enable the extraction of scientific insight that was hidden from us before. We will discuss the status for astrophysically triggered searches with the LIGO-GEO600-Virgo network and the science goals and outlook for the second and third generation gravitational wave detector era. )

  18. X-ray monitoring for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Pina, L.; Burrows, D.; Cash, W.; Cerna, D.; Gorenstein, P.; Hudec, R.; Inneman, A.; Jakubek, J.; Marsikova, V.; Sieger, L.; Tichy, V.

    2014-09-01

    This work addresses the issue of X-ray monitoring for astrophysical applications. The proposed wide-field optical system has not been used in space yet. The proposed novel approach is based on the use of 1D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV. The proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is the only solution in cases the intensity of impinging X-ray radiation is below the sensitivity of the detector, e.g. while monitoring astrophysical objects in space, or phenomena in the Earth's atmosphere. The optical system could be used in a student rocket experiment at University of Colorado. Ideal opportunity is to extend the CubeSat of Pennsylvania State University with the hard X-ray telescope demonstrator consisting of an optical module and Timepix detector.

  19. Nuclear and High-Energy Astrophysics

    NASA Astrophysics Data System (ADS)

    Weber, Fridolin

    2003-10-01

    There has never been a more exciting time in the overlapping areas of nuclear physics, particle physics and relativistic astrophysics than today. Orbiting observatories such as the Hubble Space Telescope, Rossi X-ray Timing Explorer (RXTE), Chandra X-ray satellite, and the X-ray Multi Mirror Mission (XMM) have extended our vision tremendously, allowing us to see vistas with an unprecedented clarity and angular resolution that previously were only imagined, enabling astrophysicists for the first time ever to perform detailed studies of large samples of galactic and extragalactic objects. On the Earth, radio telescopes (e.g., Arecibo, Green Bank, Parkes, VLA) and instruments using adaptive optics and other revolutionary techniques have exceeded previous expectations of what can be accomplished from the ground. The gravitational wave detectors LIGO, LISA VIRGO, and Geo-600 are opening up a window for the detection of gravitational waves emitted from compact stellar objects such as neutron stars and black holes. Together with new experimental forefront facilities like ISAC, ORLAND and RIA, these detectors provide direct, quantitative physical insight into nucleosynthesis, supernova dynamics, accreting compact objects, cosmic-ray acceleration, and pairproduction in high energy sources which reinforce the urgent need for a strong and continuous feedback from nuclear and particle theory and theoretical astrophysics. In my lectures, I shall concentrate on three selected topics, which range from the behavior of superdense stellar matter, to general relativistic stellar models, to strange quark stars and possible signals of quark matter in neutron stars.

  20. Art as a Vehicle for Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Kilburn, Micha

    2013-04-01

    One aim of the The Joint Institute for Nuclear Astrophysics (JINA) is to teach K-12 students concepts and ideas related to nuclear astrophysics. For students who have not yet seen the periodic table, this can be daunting, and we often begin with astronomy concepts. The field of astronomy naturally lends itself to an art connection through its beautiful images. Our Art 2 Science programming adopts a hands-on approach by teaching astronomy through student created art projects. This approach engages the students, through tactile means, visually and spatially. For younger students, we also include physics based craft projects that facilitate the assimilation of problem solving skills. The arts can be useful for aural and kinetic learners as well. Our program also includes singing and dancing to songs with lyrics that teach physics and astronomy concepts. The Art 2 Science programming has been successfully used in after-school programs at schools, community centers, and art studios. We have even expanded the program into a popular week long summer camp. I will discuss our methods, projects, specific goals, and survey results for JINA's Art 2 Science programs.

  1. NASA's Laboratory Astrophysics Workshop: Opening Remarks

    NASA Technical Reports Server (NTRS)

    Hasan, Hashima

    2002-01-01

    The Astronomy and Physics Division at NASA Headquarters has an active and vibrant program in Laboratory Astrophysics. The objective of the program is to provide the spectroscopic data required by observers to analyze data from NASA space astronomy missions. The program also supports theoretical investigations to provide those spectroscopic parameters that cannot be obtained in the laboratory; simulate space environment to understand formation of certain molecules, dust grains and ices; and production of critically compiled databases of spectroscopic parameters. NASA annually solicits proposals, and utilizes the peer review process to select meritorious investigations for funding. As the mission of NASA evolves, new missions are launched, and old ones are terminated, the Laboratory Astrophysics program needs to evolve accordingly. Consequently, it is advantageous for NASA and the astronomical community to periodically conduct a dialog to assess the status of the program. This Workshop provides a forum for producers and users of laboratory data to get together and understand each others needs and limitations. A multi-wavelength approach enables a cross fertilization of ideas across wavelength bands.

  2. Highlights of the NASA Particle Astrophysics Program

    NASA Astrophysics Data System (ADS)

    Jones, William Vernon

    2014-10-01

    The NASA Particle Astrophysics Program covers Origin of the Elements, Nearest Sources of Cosmic Rays, How Cosmic Particle Accelerators Work, The Nature of Dark Matter, and Neutrino Astrophysics. Progress in each of these topics has come from sophisticated instrumentation flown on long duration balloon (LDB) flights around Antarctica over the past two decades. New opportunities including Super Pressure Balloons (SPB) and International Space Station (ISS) platforms are emerging for the next major step. Stable altitudes and long durations enabled by SPB flights ensure ultra-long duration balloon (ULDB) missions that can open doors to new science opportunities. The Alpha Magnetic Spectrometer (AMS) has been operating on the ISS since May 2011. The CALorimetric Electron Telescope (CALET) and Cosmic Ray Energetics And Mass (CREAM) experiments are being developed for launch to the Japanese Experiment Module Exposed Facility (JEM-EF) in 2014. And, the Extreme Universe Space Observatory (EUSO) is planned for launch to the ISS JEM-EF after 2017. Collectively, these four complementary ISS missions covering a large portion of the cosmic ray energy spectrum serve as a cosmic ray observatory.

  3. Astrophysical Plasmas: Codes, Models, and Observations

    NASA Astrophysics Data System (ADS)

    Canto, Jorge; Rodriguez, Luis F.

    2000-05-01

    The conference Astrophysical Plasmas: Codes, Models, and Observations was aimed at discussing the most recent advances, arid some of the avenues for future work, in the field of cosmical plasmas. It was held (hiring the week of October 25th to 29th 1999, at the Centro Nacional de las Artes (CNA) in Mexico City, Mexico it modern and impressive center of theaters and schools devoted to the performing arts. This was an excellent setting, for reviewing the present status of observational (both on earth and in space) arid theoretical research. as well as some of the recent advances of laboratory research that are relevant, to astrophysics. The demography of the meeting was impressive: 128 participants from 12 countries in 4 continents, a large fraction of them, 29% were women and most of them were young persons (either recent Ph.Ds. or graduate students). This created it very lively and friendly atmosphere that made it easy to move from the ionization of the Universe and high-redshift absorbers, to Active Galactic Nucleotides (AGN)s and X-rays from galaxies, to the gas in the Magellanic Clouds and our Galaxy, to the evolution of H II regions and Planetary Nebulae (PNe), and to the details of plasmas in the Solar System and the lab. All these topics were well covered with 23 invited talks, 43 contributed talks. and 22 posters. Most of them are contained in these proceedings, in the same order of the presentations.

  4. Collisional Behaviors of Astrophysical Collisionless Plasmas

    NASA Astrophysics Data System (ADS)

    Bret, A.

    2015-12-01

    In collisional fluids, a number of key processes rely on the frequency of binary collisions. Collisions seem necessary to generate a shock wave when two fluids collide fast enough, to fulfill the Rankine-Hugoniot (RH) relations, to establish an equation of state or a Maxwellian distribution. Yet, these seemingly collisional features are routinely either observed or assumed, in relation with collisionless astrophysical plasmas. This article will review our current answers to the following questions: How do colliding collisionless plasmas end-up generating a shock as if they were fluids? To which extent are the RH relations fulfilled in this case? Do collisionless shocks propagate like fluid ones? Can we use an equation of state to describe collisionless plasmas, like MHD codes for astrophysics do? Why are Maxwellian distributions ubiquitous in particle-in-cell simulations of collisionless shocks? Time and length scales defining the border between the collisional and the collisionless behavior will be given when relevant. In general, when the time and length scales involved in the collisionless processes responsible for the fluid-like behavior may be neglected, the system may be treated like a fluid.

  5. The Center for Astrophysics in Antarctica

    NASA Technical Reports Server (NTRS)

    Pernic, Robert J.; Harper, D. AL, Jr.; Bausch, Judith A.

    1995-01-01

    Nowhere on Earth are the infrared skies clearer, darker, or more stable than on the high Antarctic Plateau. At some wavelengths, Antarctic telescopes may be more than one to two orders of magnitude more efficient than at other sites. However, exploiting these advantages requires first addressing the formidable practical difficulties of working in the remote and frigid polar environment. This was the motivation for the Center for Astrophysical Research in Antarctica (CARA), one of twenty-five National Science Foundation Science and Technology Centers. At its inception, the Center organized its research into four projects. Three - AST/RO, COBRA, and SPIREX - address key problems in star formation, evolution of galaxies, and the distribution of matter in the early universe. They feature surveys which can be conducted effectively with moderate-size telescopes operated in a highly automated mode. They also explore the potential of the Antarctic Plateau for a broad range of astrophysical research over a spectral range extending from the near-infrared to millimeter wavelengths. A fourth, ATP, was created to obtain quantitative data on the qualities of the South Pole site and to plan for future scientific projects. During the next five years, AST/RO, COBRA, and SPIREX will become operational, and the Center will begin to build a second generation of telescopes which can address a broader range of problems and accommodate a larger community of users.

  6. Astrophysical Boundary Layers: A New Picture

    NASA Astrophysics Data System (ADS)

    Belyaev, Mikhail; Rafikov, Roman R.; Mclellan Stone, James

    2016-04-01

    Accretion is a ubiquitous process in astrophysics. In cases when the magnetic field is not too strong and a disk is formed, accretion can proceed through the mid plane all the way to the surface of the central compact object. Unless that compact object is a black hole, a boundary layer will be formed where the accretion disk touches its surfaces. The boundary layer is both dynamically and observationally significant as up to half of the accretion energy is dissipated there.Using a combination of analytical theory and computer simulations we show that angular momentum transport and accretion in the boundary layer is mediated by waves. This breaks with the standard astrophysical paradigm of an anomalous turbulent viscosity that drives accretion. However, wave-mediated angular momentum transport is a natural consequence of "sonic instability." The sonic instability, which we describe analytically and observe in our simulations, is a close cousin of the Papaloizou-Pringle instability. However, it is very vigorous in the boundary layer due to the immense radial velocity shear present at the equator.Our results are applicable to accreting neutron stars, white dwarfs, protostars, and protoplanets.

  7. NASA Laboratory Astrophysics Workshop 2006 Introductory Remarks

    NASA Technical Reports Server (NTRS)

    Hasan, Hashima

    2006-01-01

    NASA Laboratory Astrophysics Workshop 2006, is the fourth in a series of workshops held at four year intervals, to assess the laboratory needs of NASA's astrophysics missions - past, current and future. Investigators who need laboratory data to interpret their observations from space missions, theorists and modelers, experimentalists who produce the data, and scientists who compile databases have an opportunity to exchange ideas and understand each other's needs and limitations. The multi-wavelength character of these workshops allows cross-fertilization of ideas, raises awareness in the scientific community of the rapid advances in other fields, and the challenges it faces in prioritizing its laboratory needs in a tight budget environment. Currently, we are in the golden age of Space Astronomy, with three of NASA s Great Observatories, Hubble Space Telescope (HST), Chandra X-Ray Observatory (CXO), and Spitzer Space Telescope (SST), in operation and providing astronomers and opportunity to perform synergistic observations. In addition, the Far Ultraviolet Spectroscopic Explorer (FUSE), XMM-Newton, HETE-2, Galaxy Evolution Explorer (GALEX), INTEGRAL and Wilkinson Microwave Anisotropy Probe (WMAP), are operating in an extended phase, while Swift and Suzaku are in their prime phase of operations. The wealth of data from these missions is stretching the Laboratory Astrophysics program to its limits. Missions in the future, which also need such data include the James Webb Space Telescope (JWST), Space Interferometry Mission (SIM), Constellation-X (Con-X), Herschel, and Planck. The interpretation of spectroscopic data from these missions requires knowledge of atomic and molecular parameters such as transition probabilities, f-values, oscillator strengths, excitation cross sections, collision strengths, which have either to be measured in the laboratory by simulating space plasma and interactions therein, or by theoretical calculations and modeling. Once the laboratory

  8. Magnetic Reconnection in Extreme Astrophysical Environments

    NASA Astrophysics Data System (ADS)

    Uzdensky, Dmitri

    Magnetic reconnection is a fundamental plasma physics process of breaking ideal-MHD's frozen-in constraints on magnetic field connectivity and of dramatic rearranging of the magnetic topol-ogy, which often leads to a violent release of the free magnetic energy. Reconnection has long been acknowledged to be of great importance in laboratory plasma physics (magnetic fusion) and in space and solar physics (responsible for solar flares and magnetospheric substorms). In addition, its importance in Astrophysics has been increasingly recognized in recent years. However, due to a great diversity of astrophysical environments, the fundamental physics of astrophysical magnetic reconnection can be quite different from that of the traditional recon-nection encountered in the solar system. In particular, environments like the solar corona and the magnetosphere are characterized by relatively low energy densities, where the plasma is ad-equately described as a mixture of electrons and ions whose numbers are conserved and where the dissipated magnetic energy basically stays with the plasma. In contrast, in many high-energy astrophysical phenomena the energy density is so large that photons play as important a role as electrons and ions and, in particular, radiation pressure and radiative cooling become dominant. In this talk I focus on the most extreme case of high-energy-density astrophysical reconnec-tion — reconnection of magnetar-strength (1014 - 1015 Gauss) magnetic fields, important for giant flares in soft-gamma repeaters (SGRs), and for rapid magnetic energy release in either the central engines or in the relativistic jets of Gamma Ray Bursts (GRBs). I outline the key relevant physical processes and present a new theoretical picture of magnetic reconnection in these environments. The corresponding magnetic energy density is so enormous that, when suddenly released, it inevitably heats the plasma to relativistic temperatures, resulting in co-pious production of electron

  9. A multiphysics and multiscale software environment for modeling astrophysical systems

    NASA Astrophysics Data System (ADS)

    Portegies Zwart, Simon; McMillan, Steve; Harfst, Stefan; Groen, Derek; Fujii, Michiko; Nualláin, Breanndán Ó.; Glebbeek, Evert; Heggie, Douglas; Lombardi, James; Hut, Piet; Angelou, Vangelis; Banerjee, Sambaran; Belkus, Houria; Fragos, Tassos; Fregeau, John; Gaburov, Evghenii; Izzard, Rob; Jurić, Mario; Justham, Stephen; Sottoriva, Andrea; Teuben, Peter; van Bever, Joris; Yaron, Ofer; Zemp, Marcel

    2009-05-01

    We present MUSE, a software framework for combining existing computational tools for different astrophysical domains into a single multiphysics, multiscale application. MUSE facilitates the coupling of existing codes written in different languages by providing inter-language tools and by specifying an interface between each module and the framework that represents a balance between generality and computational efficiency. This approach allows scientists to use combinations of codes to solve highly coupled problems without the need to write new codes for other domains or significantly alter their existing codes. MUSE currently incorporates the domains of stellar dynamics, stellar evolution and stellar hydrodynamics for studying generalized stellar systems. We have now reached a "Noah's Ark" milestone, with (at least) two available numerical solvers for each domain. MUSE can treat multiscale and multiphysics systems in which the time- and size-scales are well separated, like simulating the evolution of planetary systems, small stellar associations, dense stellar clusters, galaxies and galactic nuclei. In this paper we describe three examples calculated using MUSE: the merger of two galaxies, the merger of two evolving stars, and a hybrid N-body simulation. In addition, we demonstrate an implementation of MUSE on a distributed computer which may also include special-purpose hardware, such as GRAPEs or GPUs, to accelerate computations. The current MUSE code base is publicly available as open source at http://muse.li.

  10. Website for the Astrochemistry Laboratory, Astrophysics Branch, Space Sciences Division

    NASA Technical Reports Server (NTRS)

    Sandford, Scott; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The Astrochemistry Laboratory in the Astrophysics Branch (SSA) of the Space Sciences Division at NASA's Ames Research Center specializes in the study of extraterrestrial materials and their analogs. The staff has pioneered laboratory studies of space environments including interstellar, cometary, and planetary ices, simulations of the so-called 'Unidentified' Infrared Emission Bands and Diffuse Interstellar Bands using PAHs (Polycyclic Aromatic Hydrocarbons) and PAH-related materials, and has extensive experience with low-temperature spectroscopy and astronomical observation. Important discoveries made by the Astrochemistry Group include: (1) The recognition that polycyclic aromatic hydrocarbons and their ions are common in space; (2) The identification of a major fraction of the known molecular species frozen in interstellar/pre-cometary ices; (3) The recognition that a significant fraction of the carbon in the interstellar medium is carried by both microdiamonds and organic materials; (4) The expansion of the types of molecules expected to be synthesized in interstellar/pre-cometary ices. These could be delivered to the early Earth (or other body) and influence the origin or early evolution of life.

  11. FOREWORD: Nuclear Physics in Astrophysics V

    NASA Astrophysics Data System (ADS)

    Auerbach, Naftali; Hass, Michael; Paul, Michael

    2012-02-01

    The fifth edition of the bi-annual 'Nuclear Physics in Astrophysics (NPA)' conference series was held in Eilat, Israel on April 3-8, 2011. This Conference is also designated as the 24th Nuclear Physics Divisional Conference of the EPS. The main purpose of this conference, as that of the four previous ones in this series, is to deal with those aspects of nuclear physics that are directly related to astrophysics. The concept of such a meeting was conceived by the Nuclear Physics Board of the European Physical Society in 1998. At that time, the idea of such a conference was quite new and it was decided that this meeting would be sponsored by the EPS. The first meeting, in January 2001, was planned and organized in Eilat, Israel. Due to international circumstances the conference was moved to Debrecen, Hungary. Subsequent conferences were held in Debrecen again, in Dresden, Germany, and in Frascati, Italy (moved from Gran Sasso due to the tragic earthquake that hit the L'Aquila region). After 10 years the conference finally returned to Eilat, the originally envisioned site. Eilat is a resort town located on the shore of the Gulf of Eilat, which connects Israel to the Red Sea and further south to the Indian Ocean. It commands spectacular views of the desert and mountains, offering unique touristic attractions. The local scientific backdrop of the conference is the fact that the Israeli scientific scene exhibits a wide variety of research activities in many areas of nuclear physics and astrophysics. A new accelerator, SARAF at Soreq Nuclear Research Center is presently undergoing final acceptance tests. SARAF will serve as a platform for production of radioactive ion beams and nuclear-astrophysics research in Israel. The meeting in Eilat was organized by four Israeli scientific institutions, Hebrew University, Soreq Nuclear Research Center, Tel Aviv University and the Weizmann Institute of Science. The welcome reception and lectures were held at the King Solomon hotel and

  12. Infrared Spectroscopy of Astrophysical Gas, Grains, and Ices with the Stratospheric Observatory for Infrared Astronomy (sofia)

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Becklin, E. E.

    2009-06-01

    The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) will be a premier facility for studying the physics and chemistry of the stellar evolution process for many decades. SOFIA spectroscopic science applications will be discussed, with special emphasis on investigations related to infrared spectroscopy of astrophysical gas, grains, and ices. Examples will be given of spectroscopic studies of the interstellar medium, protostars, obscured sources in molecular cloud cores, circumstellar disks around young stellar objects, remnants of nova and supernova explosions, and winds of evolved stellar systems.

  13. Effective field theory approach to tidal dynamics of spinning astrophysical systems

    NASA Astrophysics Data System (ADS)

    Endlich, Solomon; Penco, Riccardo

    2016-03-01

    We develop a description of tidal effects in astrophysical systems using effective field theory techniques. While our approach is equally capable of describing objects in the Newtonian regime (e.g. moons, rocky planets, main sequence stars, etc.) as well as relativistic objects (e.g. neutron stars and black holes), in this paper we focus special attention on the Newtonian regime. In this limit, we recover the dynamical equations for the "weak friction model" with additional corrections due to tidal and rotational deformations.

  14. Search for Coincidences in Time and Arrival Direction of Auger Data with Astrophysical Transients

    SciTech Connect

    Anchordoqui, Luis; Collaboration, for the Pierre Auger

    2007-06-01

    The data collected by the Pierre Auger Observatory are analyzed to search for coincidences between the arrival directions of high-energy cosmic rays and the positions in the sky of astrophysical transients. Special attention is directed towards gamma ray observations recorded by NASA's Swift mission, which have an angular resolution similar to that of the Auger surface detectors. In particular, we check our data for evidence of a signal associated with the giant flare that came from the soft gamma repeater 1806-20 on December 27, 2004.

  15. BOOK REVIEW: Astrophysics (Advanced Physics Readers)

    NASA Astrophysics Data System (ADS)

    Kibble, Bob

    2000-07-01

    Here is a handy and attractive reader to support students on post-16 courses. It covers the astrophysics, astronomy and cosmology that are demanded at A-level and offers anyone interested in these fields an interesting and engaging reference book. The author and the production team deserve credit for producing such an attractive book. The content, in ten chapters, covers what one would expect at this level but it is how it is presented that struck me as the book's most powerful asset. Each chapter ends with a summary of key ideas. Line drawings are clear and convey enough information to make them more than illustrations - they are as valuable as the text in conveying information. Full colour is used throughout to enhance illustrations and tables and to lift key sections of the text. A number of colour photographs complement the material and serve to maintain interest and remind readers that astrophysics is about real observable phenomena. Included towards the end is a set of tables offering information on physical and astronomical data, mathematical techniques and constellation names and abbreviations. This last table puzzled me as to its value. There is a helpful bibliography which includes society contacts and a website related to the text. Perhaps my one regret is that there is no section where students are encouraged to actually do some real astronomy. Astrophysics is in danger of becoming an armchair and calculator interest. There are practical projects that students could undertake either for school assessment or for personal interest. Simple astrophotography to capture star trails, observe star colours and estimate apparent magnitudes is an example, as is a simple double-star search. There are dozens more. However, the author's style is friendly and collaborative. He befriends the reader as they journey together through the ideas. There are progress questions at the end of each chapter. Their style tends to be rather closed and they emphasize factual recall

  16. Novel laboratory simulations of astrophysical jets

    NASA Astrophysics Data System (ADS)

    Brady, Parrish Clawson

    This thesis was motivated by the promise that some physical aspects of astrophysical jets and collimation processes can be scaled to laboratory parameters through hydrodynamic scaling laws. The simulation of astrophysical jet phenomena with laser-produced plasmas was attractive because the laser- target interaction can inject energetic, repeatable plasma into an external environment. Novel laboratory simulations of astrophysical jets involved constructing and using the YOGA laser, giving a 1064 nm, 8 ns pulse laser with energies up to 3.7 + 0.2 J . Laser-produced plasmas were characterized using Schlieren, interferometry and ICCD photography for their use in simulating jet and magnetosphere physics. The evolution of the laser-produced plasma in various conditions was compared with self-similar solutions and HYADES computer simulations. Millimeter-scale magnetized collimated outflows were produced by a centimeter scale cylindrically symmetric electrode configuration triggered by a laser-produced plasma. A cavity with a flared nozzle surrounded the center electrode and the electrode ablation created supersonic uncollimated flows. This flow became collimated when the center electrode changed from an anodeto a cathode. The plasma jets were in axially directed permanent magnetic fields with strengths up to 5000 Gauss. The collimated magnetized jets were 0.1-0. 3 cm wide, up to 2.0 cm long, and had velocities of ~4.0 × 10 6 cm/s. The dynamics of the evolution of the jet were compared qualitatively and quantitatively with fluxtube simulations from Bellan's formulation [6] giving a calculated estimate of ~2.6 × 10 6 cm/s for jet evolution velocity and evidence for jet rotation. The density measured with interferometry was 1.9 ± 0.2 × 10 17 cm -3 compared with 2.1 × 10 16 cm -3 calculated with Bellan's pressure balance formulation. Kinks in the jet column were produced consistent with the Kruskal-Shafranov condition which allowed stable and symmetric jets to form with

  17. Interface between astrophysical datasets and distributed database management systems (DAVID)

    NASA Technical Reports Server (NTRS)

    Iyengar, S. S.

    1988-01-01

    This is a status report on the progress of the DAVID (Distributed Access View Integrated Database Management System) project being carried out at Louisiana State University, Baton Rouge, Louisiana. The objective is to implement an interface between Astrophysical datasets and DAVID. Discussed are design details and implementation specifics between DAVID and astrophysical datasets.

  18. Measuring Stellar Temperatures: An Astrophysical Laboratory for Undergraduate Students

    ERIC Educational Resources Information Center

    Cenadelli, D.; Zeni, M.

    2008-01-01

    While astrophysics is a fascinating subject, it hardly lends itself to laboratory experiences accessible to undergraduate students. In this paper, we describe a feasible astrophysical laboratory experience in which the students are guided to take several stellar spectra, using a telescope, a spectrograph and a CCD camera, and perform a full data…

  19. Nuclear Astrophysics from View Point of Few-Body Problems

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spitaleri, C.; Bertulani, C.; Mukhamedzhanov, A. M.

    2013-08-01

    Few-body systems provide very useful tools to solve different problems for nuclear astrophysics. This is the case of indirect techniques, developed to overcome some of the limits of direct measurements at astrophysical energies. Here the Coulomb dissociation, the asymptotic normalization coefficient and the Trojan Horse method are discussed.

  20. Safety analysis report for packaging: the ORNL DOT specification 6M - tritium trap package. [Tritium absorbed as solid uranium tritide in depleted uranium trap

    SciTech Connect

    DeVore, J.R.

    1984-04-01

    The ORNL DOT Specification 6M--Tritium Trap Package was fabricated at the Oak Ridge National Laboratory (ORNL) for the transport of Type B quantities of tritium as solid uranium tritide. The package was evaluated on the basis of tests performed by the Dow Chemical Company, Rocky Flats Division, on the DOT-6M container, a drop test performed by the ORNL Operations Division, and International Atomic Energy Agency (IAEA) approvals on a similar tritium transport container. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of Type B quantities of tritium. 4 references, 8 figures.

  1. Double layers and circuits in astrophysics

    NASA Technical Reports Server (NTRS)

    Alfven, H.

    1986-01-01

    A simple circuit is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the Sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object. It is suggested that X-ray and gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). The way the most used textbooks in astrophysics treat concepts like double layers, critical velocity, pinch effects and circuits was studied. It is found that students using these textbooks remain essentially ignorant of even the existence of these, although some of the phenomena were discovered 50 yr ago.

  2. Studies of High Energy Particle Astrophysics

    SciTech Connect

    Nitz, David F; Fick, Brian E

    2014-07-30

    This report covers the progress of the Michigan Technological University particle astrophysics group during the period April 15th, 2011 through April 30th, 2014. The principal investigator is Professor David Nitz. Professor Brian Fick is the Co-PI. The focus of the group is the study of the highest energy cosmic rays using the Pierre Auger Observatory. The major goals of the Pierre Auger Observatory are to discover and understand the source or sources of cosmic rays with energies exceeding 10**19 eV, to identify the particle type(s), and to investigate the interactions of those cosmic particles both in space and in the Earth's atmosphere. The Pierre Auger Observatory in Argentina was completed in June 2008 with 1660 surface detector stations and 24 fluorescence telescopes arranged in 4 stations. It has a collecting area of 3,000 square km, yielding an aperture of 7,000 km**2 sr.

  3. Export Controls on Astrophysical Simulation Codes

    NASA Astrophysics Data System (ADS)

    Whalen, Daniel

    2015-01-01

    Amidst concerns about nuclear proliferation, the US government has established guidelines on what types of astrophysical simulation codes can be run and disseminated on open systems. I will review the basic export controls that have been enacted by the federal government to slow the pace of software acquisition by potential adversaries who seek to develop weapons of mass destruction. The good news is that it is relatively simple to avoid ITAR issues with the Department of Energy if one remembers a few simple rules. I will discuss in particular what types of algorithm development can get researchers into trouble if they are not aware of the regulations and how to avoid these pitfalls while doing world class science.

  4. Improving general relativistic astrophysics workflows with ADIOS

    NASA Astrophysics Data System (ADS)

    Bode, Tanja; Slawinska, Magdalena; Logan, Jeremy; Clark, Michael; Kinsey, Matthew; Wolf, Matthew; Klasky, Scott; Laguna, Pablo

    2013-04-01

    There are many challenges in analyzing and visualizing data from current cutting-edge general relativistic astrophysics simulations. Many of the associated tasks are time-consuming, with large performance degradation due to the magnitude and complexity of the data. The Adaptable IO System (ADIOS) is a componentization of the IO layer that has demonstrated remarkable IO performance improvements on applications running on leadership class machines while also offering new in-memory ``staging'' operations for transforming data in situ. We have incorporated ADIOS staging technologies into our Maya numerical relativity code based on Cactus infrastructure and Carpet mesh refinement. We present results that demonstrate how ADIOS yields significant gains on IO performance while utilizing leveraged investments in ADIOS plugins for visualization tools such as VisIt.

  5. Information technologies for astrophysics circa 2001

    NASA Astrophysics Data System (ADS)

    Denning, Peter J.

    1990-05-01

    It is easy to extrapolate current trends to see where technologies relating to information systems in astrophysics and other disciplines will be by the end of the decade. These technologies include mineaturization, multiprocessing, software technology, networking, databases, graphics, pattern computation, and interdisciplinary studies. It is easy to see what limits our current paradigms place on our thinking about technologies that will allow us to understand the laws governing very large systems about which we have large datasets. Three limiting paradigms are saving all the bits collected by instruments or generated by supercomputers; obtaining technology for information compression, storage and retrieval off the shelf; and the linear mode of innovation. We must extend these paradigms to meet our goals for information technology at the end of the decade.

  6. Nuclear astrophysics with radioactive ions at FAIR

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Altstadt, S.; Göbel, K.; Heftrich, T.; Heil, M.; Koloczek, A.; Langer, C.; Plag, R.; Pohl, M.; Sonnabend, K.; Weigand, M.; Adachi, T.; Aksouh, F.; Al-Khalili, J.; AlGarawi, M.; AlGhamdi, S.; Alkhazov, G.; Alkhomashi, N.; Alvarez-Pol, H.; Alvarez-Rodriguez, R.; Andreev, V.; Andrei, B.; Atar, L.; Aumann, T.; Avdeichikov, V.; Bacri, C.; Bagchi, S.; Barbieri, C.; Beceiro, S.; Beck, C.; Beinrucker, C.; Belier, G.; Bemmerer, D.; Bendel, M.; Benlliure, J.; Benzoni, G.; Berjillos, R.; Bertini, D.; Bertulani, C.; Bishop, S.; Blasi, N.; Bloch, T.; Blumenfeld, Y.; Bonaccorso, A.; Boretzky, K.; Botvina, A.; Boudard, A.; Boutachkov, P.; Boztosun, I.; Bracco, A.; Brambilla, S.; Briz Monago, J.; Caamano, M.; Caesar, C.; Camera, F.; Casarejos, E.; Catford, W.; Cederkall, J.; Cederwall, B.; Chartier, M.; Chatillon, A.; Cherciu, M.; Chulkov, L.; Coleman-Smith, P.; Cortina-Gil, D.; Crespi, F.; Crespo, R.; Cresswell, J.; Csatlós, M.; Déchery, F.; Davids, B.; Davinson, T.; Derya, V.; Detistov, P.; Diaz Fernandez, P.; DiJulio, D.; Dmitry, S.; Doré, D.; Dueñas, J.; Dupont, E.; Egelhof, P.; Egorova, I.; Elekes, Z.; Enders, J.; Endres, J.; Ershov, S.; Ershova, O.; Fernandez-Dominguez, B.; Fetisov, A.; Fiori, E.; Fomichev, A.; Fonseca, M.; Fraile, L.; Freer, M.; Friese, J.; Borge, M. G.; Galaviz Redondo, D.; Gannon, S.; Garg, U.; Gasparic, I.; Gasques, L.; Gastineau, B.; Geissel, H.; Gernhäuser, R.; Ghosh, T.; Gilbert, M.; Glorius, J.; Golubev, P.; Gorshkov, A.; Gourishetty, A.; Grigorenko, L.; Gulyas, J.; Haiduc, M.; Hammache, F.; Harakeh, M.; Hass, M.; Heine, M.; Hennig, A.; Henriques, A.; Herzberg, R.; Holl, M.; Ignatov, A.; Ignatyuk, A.; Ilieva, S.; Ivanov, M.; Iwasa, N.; Jakobsson, B.; Johansson, H.; Jonson, B.; Joshi, P.; Junghans, A.; Jurado, B.; Körner, G.; Kalantar, N.; Kanungo, R.; Kelic-Heil, A.; Kezzar, K.; Khan, E.; Khanzadeev, A.; Kiselev, O.; Kogimtzis, M.; Körper, D.; Kräckmann, S.; Kröll, T.; Krücken, R.; Krasznahorkay, A.; Kratz, J.; Kresan, D.; Krings, T.; Krumbholz, A.; Krupko, S.; Kulessa, R.; Kumar, S.; Kurz, N.; Kuzmin, E.; Labiche, M.; Langanke, K.; Lazarus, I.; Le Bleis, T.; Lederer, C.; Lemasson, A.; Lemmon, R.; Liberati, V.; Litvinov, Y.; Löher, B.; Lopez Herraiz, J.; Münzenberg, G.; Machado, J.; Maev, E.; Mahata, K.; Mancusi, D.; Marganiec, J.; Martinez Perez, M.; Marusov, V.; Mengoni, D.; Million, B.; Morcelle, V.; Moreno, O.; Movsesyan, A.; Nacher, E.; Najafi, M.; Nakamura, T.; Naqvi, F.; Nikolski, E.; Nilsson, T.; Nociforo, C.; Nolan, P.; Novatsky, B.; Nyman, G.; Ornelas, A.; Palit, R.; Pandit, S.; Panin, V.; Paradela, C.; Parkar, V.; Paschalis, S.; Pawłowski, P.; Perea, A.; Pereira, J.; Petrache, C.; Petri, M.; Pickstone, S.; Pietralla, N.; Pietri, S.; Pivovarov, Y.; Potlog, P.; Prokofiev, A.; Rastrepina, G.; Rauscher, T.; Ribeiro, G.; Ricciardi, M.; Richter, A.; Rigollet, C.; Riisager, K.; Rios, A.; Ritter, C.; Rodriguez Frutos, T.; Rodriguez Vignote, J.; Röder, M.; Romig, C.; Rossi, D.; Roussel-Chomaz, P.; Rout, P.; Roy, S.; Söderström, P.; Saha Sarkar, M.; Sakuta, S.; Salsac, M.; Sampson, J.; Sanchez, J.; Rio Saez, del; Sanchez Rosado, J.; Sanjari, S.; Sarriguren, P.; Sauerwein, A.; Savran, D.; Scheidenberger, C.; Scheit, H.; Schmidt, S.; Schmitt, C.; Schnorrenberger, L.; Schrock, P.; Schwengner, R.; Seddon, D.; Sherrill, B.; Shrivastava, A.; Sidorchuk, S.; Silva, J.; Simon, H.; Simpson, E.; Singh, P.; Slobodan, D.; Sohler, D.; Spieker, M.; Stach, D.; Stan, E.; Stanoiu, M.; Stepantsov, S.; Stevenson, P.; Strieder, F.; Stuhl, L.; Suda, T.; Sümmerer, K.; Streicher, B.; Taieb, J.; Takechi, M.; Tanihata, I.; Taylor, J.; Tengblad, O.; Ter-Akopian, G.; Terashima, S.; Teubig, P.; Thies, R.; Thoennessen, M.; Thomas, T.; Thornhill, J.; Thungstrom, G.; Timar, J.; Togano, Y.; Tomohiro, U.; Tornyi, T.; Tostevin, J.; Townsley, C.; Trautmann, W.; Trivedi, T.; Typel, S.; Uberseder, E.; Udias, J.; Uesaka, T.; Uvarov, L.; Vajta, Z.; Velho, P.; Vikhrov, V.; Volknandt, M.; Volkov, V.; von Neumann-Cosel, P.; von Schmid, M.; Wagner, A.; Wamers, F.; Weick, H.; Wells, D.; Westerberg, L.; Wieland, O.; Wiescher, M.; Wimmer, C.; Wimmer, K.; Winfield, J. S.; Winkel, M.; Woods, P.; Wyss, R.; Yakorev, D.; Yavor, M.; Zamora Cardona, J.; Zartova, I.; Zerguerras, T.; Zgura, M.; Zhdanov, A.; Zhukov, M.; Zieblinski, M.; Zilges, A.; Zuber, K.

    2016-01-01

    The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.

  7. Vortical mechanism for generation of astrophysical jets

    NASA Astrophysics Data System (ADS)

    Abrahamyan, M. G.

    2008-04-01

    A vortical mechanism for generation of astrophysical jets is proposed based on exact solutions of the hydrodynamic equations with a generalized Rankine vortex. It is shown that the development of a Rankine vortex in the polar layer of a rotating gravitating body creates longitudinal fluxes of matter that converge toward the vortex trunk, providing an exponential growth in the angular rotation velocity of the trunk and a pressure drop on its axis. The increased rotational velocity of the vortex trunk and the on-axis pressure drop cease when the discontinuity in the azimuthal velocity at the surface of the trunk reaches the sound speed. During this time, ever deeper layers of the gravitating body are brought into the vortical motion, while the longitudinal velocity of the flow along the vortex trunk builds up, producing jet outflows of mass from its surface. The resulting vortices are essentially dissipationless.

  8. Okayama astrophysical observatory wide field camera

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Kenshi; Shimizu, Yasuhiro; Okita, Kiichi; Kuroda, Daisuke; Koyano, Hisashi; Tsutsui, Hironori; Toda, Hiroyuki; Izumiura, Hideyuki; Yoshida, Michitoshi; Ohta, Kouji; Kawai, Nobuyuki; Yamamuro, Tomoyasu

    2014-08-01

    Okayama Astrophysical Observatory Wide Field Camera: OAOWFC is a near-infrared (0.9-2.5 μm) survey telescope, whose aperture is 0.91m. It works at Y, J, H, and Ks bands. The optics are consisted of forward Cassegrain and quasi Schmidt which yield the image circle of Φ 52 mm or Φ 1.3 deg at the focal plane. The overall F-ratio is F/2.51 which is one of the fastest among near infrared imagers in the world. A HAWAII-1 detector array placed at the focal plane cuts the central 0.48 deg. x 0.48 deg. with a pixel scale of 1.67 arcsec/pix. It will be used to survey the Galactic plane for variability and search for transients such as Gamma-ray burst afterglows optical counterpart of gravitational wave sources.

  9. Decay of high-energy astrophysical neutrinos.

    PubMed

    Beacom, John F; Bell, Nicole F; Hooper, Dan; Pakvasa, Sandip; Weiler, Thomas J

    2003-05-01

    Existing limits on the nonradiative decay of one neutrino to another plus a massless particle (e.g., a singlet Majoron) are very weak. The best limits on the lifetime to mass ratio come from solar neutrino observations and are tau/m greater, similar 10(-4) s/eV for the relevant mass eigenstate(s). For lifetimes even several orders of magnitude longer, high-energy neutrinos from distant astrophysical sources would decay. This would strongly alter the flavor ratios from the phi(nu(e)):phi(nu(mu)):phi(nu(tau))=1:1:1 expected from oscillations alone and should be readily visible in the near future in detectors such as IceCube. PMID:12785996

  10. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role polycyclic aromatic compounds (PAC) in the interstellar medium (ISM). Twenty years ago, the notion of an abundant population of large, carbon rich molecules in the ISM was considered preposterous. Today, the unmistakable spectroscopic signatures of PAC - shockingly large molecules by previous interstellar chemistry standards - are recognized throughout the Universe. In this paper, we will examine the interstellar PAC model and its importance to astrophysics, including: (1) the evidence which led to inception of the model; (2) the ensuing laboratory and theoretical studies of the fundamental spectroscopic properties of PAC by which the model has been refined and extended; and (3) a few examples of how the model is being exploited to derive insight into the nature of the interstellar PAC population.

  11. A Hydrodynamical Mechanism for Generating Astrophysical Jets

    NASA Astrophysics Data System (ADS)

    Hernández, X.; Rendón, P. L.; Rodríguez-Mota, R. G.; Capella, A.

    2014-04-01

    Whenever in a classical accretion disk the thin disk approximation fails interior to a certain radius, a transition from Keplerian to radial infalling trajectories should occur. We show that this transition is actually expected to occur interior to a certain critical radius, provided surface density profiles are steeper than Sigma(R) ~ R(-1/2) , and further, that it probably corresponds to the observationally inferred phenomena of thick hot walls internally limiting the extent of many stellar accretion disks. Infalling trajectories will lead to the convergent focusing and concentration of matter towards the very central regions, most of which will simply be swallowed by the central object. We show through a perturbative hydrodynamical analysis, that this will naturally develop a well collimated pair of polar jets. A first analytic treatment of the problem described is given, proving the feasibility of purely hydrodynamical mechanisms for astrophysical jet generation.

  12. New Prospects in High Energy Astrophysics

    SciTech Connect

    Blandford, Roger; /KIPAC, Menlo Park

    2011-11-15

    Recent discoveries using TeV, X-ray and radio telescopes as well as Ultra High Energy Cosmic Ray arrays are leading to new insights into longstanding puzzles in high energy astrophysics. Many of these insights come from combining observations throughout the electromagnetic and other spectra as well as evidence assembled from different types of source to propose general principles. Issues discussed in this general overview include methods of accelerating relativistic particles, and amplifying magnetic field, the dynamics of relativistic outflows and the nature of the prime movers that power them. Observational approaches to distinguishing hadronic, leptonic and electromagnetic outflows and emission mechanisms are discussed along with probes of the velocity field and the confinement mechanisms. Observations with GLAST promise to be very prescriptive for addressing these problems.

  13. Theoretically Palatable Flavor Combinations of Astrophysical Neutrinos.

    PubMed

    Bustamante, Mauricio; Beacom, John F; Winter, Walter

    2015-10-16

    The flavor composition of high-energy astrophysical neutrinos can reveal the physics governing their production, propagation, and interaction. The IceCube Collaboration has published the first experimental determination of the ratio of the flux in each flavor to the total. We present, as a theoretical counterpart, new results for the allowed ranges of flavor ratios at Earth for arbitrary flavor ratios in the sources. Our results will allow IceCube to more quickly identify when their data imply standard physics, a general class of new physics with arbitrary (incoherent) combinations of mass eigenstates, or new physics that goes beyond that, e.g., with terms that dominate the Hamiltonian at high energy. PMID:26550861

  14. Astrophysical black holes in screened modified gravity

    SciTech Connect

    Davis, Anne-Christine; Jha, Rahul; Muir, Jessica; Gregory, Ruth E-mail: r.a.w.gregory@durham.ac.uk E-mail: jlmuir@umich.edu

    2014-08-01

    Chameleon, environmentally dependent dilaton, and symmetron gravity are three models of modified gravity in which the effects of the additional scalar degree of freedom are screened in dense environments. They have been extensively studied in laboratory, cosmological, and astrophysical contexts. In this paper, we present a preliminary investigation into whether additional constraints can be provided by studying these scalar fields around black holes. By looking at the properties of a static, spherically symmetric black hole, we find that the presence of a non-uniform matter distribution induces a non-constant scalar profile in chameleon and dilaton, but not necessarily symmetron gravity. An order of magnitude estimate shows that the effects of these profiles on in-falling test particles will be sub-leading compared to gravitational waves and hence observationally challenging to detect.

  15. Astrophysics of Reference Frame Tie Objects

    NASA Technical Reports Server (NTRS)

    Johnston, Kenneth J.; Boboltz, David; Fey, Alan Lee; Gaume, Ralph A.; Zacharias, Norbert

    2004-01-01

    The Astrophysics of Reference Frame Tie Objects Key Science program will investigate the underlying physics of SIM grid objects. Extragalactic objects in the SIM grid will be used to tie the SIM reference frame to the quasi-inertial reference frame defined by extragalactic objects and to remove any residual frame rotation with respect to the extragalactic frame. The current realization of the extragalactic frame is the International Celestial Reference Frame (ICRF). The ICRF is defined by the radio positions of 212 extragalactic objects and is the IAU sanctioned fundamental astronomical reference frame. This key project will advance our knowledge of the physics of the objects which will make up the SIM grid, such as quasars and chromospherically active stars, and relates directly to the stability of the SIM reference frame. The following questions concerning the physics of reference frame tie objects will be investigated.

  16. Fundamental Interactions, Nuclear Masses, Astrophysics, and QCD

    NASA Astrophysics Data System (ADS)

    Gagliardi, C. A.

    2008-01-01

    During his long and varied career, Robert Tribble has made important contributions in many areas of nuclear physics. He has set new limits on the existence of second-class currents, lepton-flavor violation, and right-handed interactions. He optimized the use of the (4He,8He) reaction to determine nuclear masses and study charge-dependent effects in nuclei. He has developed a new indirect procedure to determine astrophysical reaction rates and applied it to study important nuclear reactions that occur in our sun, in massive stars, and in novae. He has explored anti-quark distributions in nucleons and nuclei, and the polarization of gluons in the nucleon. A brief overview of Bob Tribble's many accomplishments is presented.

  17. Nuclear Astrophysics at IFIN-HH

    NASA Astrophysics Data System (ADS)

    Livius, Trache

    2016-04-01

    I will present the possibilities and some results of doing nuclear astrophysics research in IFIN-HH Bucharest-Magurele. There are basically two lines of experimental activities: (1) direct measurements with beams from the local accelerators, in particular with the new 3 MV Tandetron accelerator. This facility turns out to be competitive for reactions induced by a-particles and light ions. Extra capabilities are given by the ultra-low background laboratory we have in a salt mine about 2.5 hrs. driving north of Bucharest; (2) indirect measurements done with beams at international facilities, in particular at those providing Rare Ion Beams. Completely new and unique opportunities will be provided by ELI-NP, under construction in our institute.

  18. Strange quark matter fragmentation in astrophysical events

    NASA Astrophysics Data System (ADS)

    Paulucci, L.; Horvath, J. E.

    2014-06-01

    The conjecture of Bodmer-Witten-Terazawa suggesting a form of quark matter (Strange Quark Matter) as the ground state of hadronic interactions has been studied in laboratory and astrophysical contexts by a large number of authors. If strange stars exist, some violent events involving these compact objects, such as mergers and even their formation process, might eject some strange matter into the interstellar medium that could be detected as a trace signal in the cosmic ray flux. To evaluate this possibility, it is necessary to understand how this matter in bulk would fragment in the form of strangelets (small lumps of strange quark matter in which finite effects become important). We calculate the mass distribution outcome using the statistical multifragmentation model and point out several caveats affecting it. In particular, the possibility that strangelets fragmentation will render a tiny fraction of contamination in the cosmic ray flux is discussed.

  19. A laser application to nuclear astrophysics

    SciTech Connect

    Barbui, M.; Hagel, K.; Schmidt, K.; Zheng, H.; Burch, R.; Barbarino, M.; Natowitz, J. B.; Bang, W.; Dyer, G.; Quevedo, H. J.; Gaul, E.; Bernstein, A. C.; Donovan, M.; Bonasera, A.; Kimura, S.; Mazzocco, M.; Consoli, F.; De Angelis, R.; Andreoli, P.; Ditmire, T.

    2014-05-09

    In the last decade, the availability in high-intensity laser beams capable of producing plasmas with ion energies large enough to induce nuclear reactions has opened new research paths in nuclear physics. We studied the reactions {sup 3}He(d,p){sup 4}He and d(d,n){sup 3}He at temperatures of few keV in a plasma, generated by the interaction of intense ultrafast laser pulses with molecular deuterium or deuterated-methane clusters mixed with {sup 3}He atoms. The yield of 14.7 MeV protons from the {sup 3}He(d,p){sup 4}He reaction was used to extract the astrophysical S factor. Results of the experiment performed at the Center for High Energy Density Science at The University of Texas at Austin will be presented.

  20. Hydrodynamic instability in warped astrophysical discs

    NASA Astrophysics Data System (ADS)

    Ogilvie, Gordon I.; Latter, Henrik N.

    2013-08-01

    Warped astrophysical discs are usually treated as laminar viscous flows, which have anomalous properties when the disc is nearly Keplerian and the viscosity is small: fast horizontal shearing motions and large torques are generated, which cause the warp to evolve rapidly, in some cases at a rate that is inversely proportional to the viscosity. However, these flows are often subject to a linear hydrodynamic instability, which may produce small-scale turbulence and modify the large-scale dynamics of the disc. We use a warped shearing sheet to compute the oscillatory laminar flows in a warped disc and to analyse their linear stability by the Floquet method. We find widespread hydrodynamic instability deriving from the parametric resonance of inertial waves. Even very small, unobservable warps in nearly Keplerian discs of low viscosity can be expected to generate hydrodynamic turbulence, or at least wave activity, by this mechanism.

  1. Effective Field Theory in Nuclear Astrophysics

    NASA Astrophysics Data System (ADS)

    Chen, Jiunn-Wei

    2001-04-01

    I will discuss some basic ideas of effective field theory and its application to two nucleon systems. The theory allows a perturbative treatment of strongly interacting, bound state problems such that the calculations can be systematically improved and reliable error estimation performed. Also, the field theory formalism naturally allows manifest incorporation of symmetry properties such as gauge symmetry and Lorentz symmetry. Emphasis will be placed on some high precision calculations to low energy astrophysical problems: neutron radiative capture onto proton which is relevant to big-bang nucleosynthesis; neutrino deuteron inelastic scattering employed in the solar neutrino detection by Sudbury Neutrino Observatory (SNO) and the proton-proton solar fusion process which is an important process to fuel the sun. The last two classes of processes share the same two-body operator which is proposed to be measured at ORLAND and could serve to calibrate SNO and the solar fusion rate.

  2. Information technologies for astrophysics circa 2001

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1991-01-01

    It is easy to extrapolate current trends to see where technologies relating to information systems in astrophysics and other disciplines will be by the end of the decade. These technologies include miniaturization, multiprocessing, software technology, networking, databases, graphics, pattern computation, and interdisciplinary studies. It is less easy to see what limits our current paradigms place on our thinking about technologies that will allow us to understand the laws governing very large systems about which we have large data sets. Three limiting paradigms are as follows: saving all the bits collected by instruments or generated by supercomputers; obtaining technology for information compression, storage, and retrieval off the shelf; and the linear model of innovation. We must extend these paradigms to meet our goals for information technology at the end of the decade.

  3. Information technologies for astrophysics circa 2001

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1990-01-01

    It is easy to extrapolate current trends to see where technologies relating to information systems in astrophysics and other disciplines will be by the end of the decade. These technologies include mineaturization, multiprocessing, software technology, networking, databases, graphics, pattern computation, and interdisciplinary studies. It is easy to see what limits our current paradigms place on our thinking about technologies that will allow us to understand the laws governing very large systems about which we have large datasets. Three limiting paradigms are saving all the bits collected by instruments or generated by supercomputers; obtaining technology for information compression, storage and retrieval off the shelf; and the linear mode of innovation. We must extend these paradigms to meet our goals for information technology at the end of the decade.

  4. A New Astrophysical Setting for Chondrule Formation

    NASA Astrophysics Data System (ADS)

    Krot, Alexander N.; Meibom, Anders; Russell, Sara S.; O'D. Alexander, Conel M.; Jeffries, Timothy E.; Keil, Klaus

    2001-03-01

    Chondrules in the metal-rich meteorites Hammadah al Hamra 237 and QUE 94411 have recorded highly energetic thermal events that resulted in complete vaporization of a dusty region of the solar nebula (dust/gas ratio of about 10 to 50 times solar). These chondrules formed under oxidizing conditions before condensation of iron-nickel metal, at temperatures greater than or equal to 1500 K, and were isolated from the cooling gas before condensation of moderately volatile elements such as manganese, sodium, potassium, and sulfur. This astrophysical environment is fundamentally different from conventional models for chondrule formation by localized, brief, repetitive heating events that resulted in incomplete melting of solid precursors initially residing at ambient temperatures below approximately 650 K.

  5. Proton-Rich Nuclei in Nuclear Astrophysics

    SciTech Connect

    Rehm, K. E.

    2007-11-30

    The stable isotopes which we observe on Earth are to a large extent, produced in nature via a 'detour' through unstable nuclei. The reaction path leading through proton-rich nuclei is the so-called rapid proton capture process, where, starting from carbon, nitrogen and oxygen through successive capture or protons and alphas, followed by beta decays, nuclei up to the mass 100 region can be produced. In order to understand the reaction paths and the conditions at various astrophysical sites (e.g. Novae and X-ray bursts) cross sections, masses and half-lives of unstable nuclei have to be measured. In this contribution recent results involving proton-rich nuclei are discussed.

  6. Proton-rich nuclei in nuclear astrophysics.

    SciTech Connect

    Rehm, K. E.; Physics

    2007-01-01

    The stable isotopes which we observe on Earth are to a large extent, produced in nature via a 'detour' through unstable nuclei. The reaction path leading through proton-rich nuclei is the so-called rapid proton capture process, where, starting from carbon, nitrogen and oxygen through successive capture or protons and alphas, followed by beta decays, nuclei up to the mass 100 region can be produced. In order to understand the reaction paths and the conditions at various astrophysical sites (e.g. Novae and X-ray bursts) cross sections, masses and half-lives of unstable nuclei have to be measured. In this contribution recent results involving proton-rich nuclei are discussed.

  7. Protection of the Guillermo Haro Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Carrasco, E.; Carraminana, A. P.

    The Guillermo Haro Astrophysical Observatory, with a 2m telescope, is one of only two professional observatories in Mexico. The observatory, run by the InstitutoNacional de Astrofisica, Optica y Electronica (INAOE), is located in the north of Mexico, in Cananea, Sonora. Since 1995 the observatory has faced the potential threat of pollution by an open cast mine to be opened at 3kms from the observatory. In the absence of national or regional laws enforcing protection to astronomical sites in Mexico, considerable effort has been needed to guarantee the conditions of the site. We present the studies carried out to ensure the protection of the Guillermo Haro Observatory from pollution due to dust, light and vibrations.

  8. Java 3D Interactive Visualization for Astrophysics

    NASA Astrophysics Data System (ADS)

    Chae, K.; Edirisinghe, D.; Lingerfelt, E. J.; Guidry, M. W.

    2003-05-01

    We are developing a series of interactive 3D visualization tools that employ the Java 3D API. We have applied this approach initially to a simple 3-dimensional galaxy collision model (restricted 3-body approximation), with quite satisfactory results. Running either as an applet under Web browser control, or as a Java standalone application, this program permits real-time zooming, panning, and 3-dimensional rotation of the galaxy collision simulation under user mouse and keyboard control. We shall also discuss applications of this technology to 3-dimensional visualization for other problems of astrophysical interest such as neutron star mergers and the time evolution of element/energy production networks in X-ray bursts. *Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.

  9. New equation of state for astrophysical simulations

    SciTech Connect

    Shen, G.; Horowitz, C. J.; Teige, S.

    2011-03-15

    We generate a new complete equation of state (EOS) of nuclear matter for a wide range of temperatures, densities, and proton fractions ready for use in astrophysical simulations of supernovae and neutron star mergers. Our previous two papers tabulated the EOS at over 180 000 grid points in the temperature range T=0-80 MeV, the density range n{sub B}=10{sup -8}-1.6 fm{sup -3}, and the proton fraction range Y{sub P}=0-0.56. In this paper we combine these data points using a suitable interpolation scheme to generate a single EOS table on a finer grid. This table is thermodynamically consistent and conserves entropy during adiabatic compression tests. We present various thermodynamic quantities and the composition of matter in the new EOS, along with several comparisons with existing EOS tables. Our EOS table is available for download.

  10. Astrophysical constraints on Planck scale dissipative phenomena.

    PubMed

    Liberati, Stefano; Maccione, Luca

    2014-04-18

    The emergence of a classical spacetime from any quantum gravity model is still a subtle and only partially understood issue. If indeed spacetime is arising as some sort of large scale condensate of more fundamental objects, then it is natural to expect that matter, being a collective excitation of the spacetime constituents, will present modified kinematics at sufficiently high energies. We consider here the phenomenology of the dissipative effects necessarily arising in such a picture. Adopting dissipative hydrodynamics as a general framework for the description of the energy exchange between collective excitations and the spacetime fundamental degrees of freedom, we discuss how rates of energy loss for elementary particles can be derived from dispersion relations and used to provide strong constraints on the base of current astrophysical observations of high-energy particles. PMID:24785026

  11. Rossby Wave Instability in Astrophysical Disks

    NASA Astrophysics Data System (ADS)

    Lovelace, Richard; Li, Hui

    2014-10-01

    A brief review is given of the Rossby wave instability in astrophysical disks. In non-self-gravitating discs, around for example a newly forming stars, the instability can be triggered by an axisymmetric bump at some radius r0 in the disk surface mass-density. It gives rise to exponentially growing non-axisymmetric perturbation (proportional to Exp[im ϕ], m = 1,2,...) in the vicinity of r0 consisting of anticyclonic vortices. These vortices are regions of high pressure and consequently act to trap dust particles which in turn can facilitate planetesimal growth in protoplanetary disks. The Rossby vortices in the disks around stars and black holes may cause the observed quasi-periodic modulations of the disk's thermal emission. Stirling Colgate's long standing interest in all types of vortices - particularly tornados - had an important part in stimulating the research on the Rossby wave instability.

  12. Prospects of High Energy Laboratory Astrophysics

    SciTech Connect

    Ng, J.S.T.; Chen, P.; /SLAC

    2006-09-21

    Ultra high energy cosmic rays (UHECR) have been observed but their sources and production mechanisms are yet to be understood. We envision a laboratory astrophysics program that will contribute to the understanding of cosmic accelerators with efforts to: (1) test and calibrate UHECR observational techniques, and (2) elucidate the underlying physics of cosmic acceleration through laboratory experiments and computer simulations. Innovative experiments belonging to the first category have already been done at the SLAC FFTB. Results on air fluorescence yields from the FLASH experiment are reviewed. Proposed future accelerator facilities can provided unprecedented high-energy-densities in a regime relevant to cosmic acceleration studies and accessible in a terrestrial environment for the first time. We review recent simulation studies of nonlinear plasma dynamics that could give rise to cosmic acceleration, and discuss prospects for experimental investigation of the underlying mechanisms.

  13. Cosmology, astrophysics and elementary particle physics

    NASA Astrophysics Data System (ADS)

    Tayler, R. J.

    1980-03-01

    The physics of the early universe are studied and the role of new particles such as heavy leptons, neutrinos and quarks and possible relationship of the net baryon number of the universe to unified models of elementary particle physics are discussed. Consideration is given to the role of neutrinos in stellar evolution, particularly in the explosion of supernovae and in the cooling of neutron stars. Black holes are discussed in connection with Hawking's discovery that low-mass black holes can emit a thermal distribution of particles which could be of cosmological or astrophysical importance. Finally, the evidence that the laws of physics are unchanging is examined, and it is concluded that there is no clear case in favor of change.

  14. Nonequilibrium route to nanodiamond with astrophysical implications.

    PubMed

    Marks, N A; Lattemann, M; McKenzie, D R

    2012-02-17

    Nanometer-sized diamond grains are commonly found in primitive chondritic meteorites, but their origin is puzzling. Using evidence from atomistic simulation, we establish a mechanism by which nanodiamonds form abundantly in space in a two-stage process involving condensation of vapor to form carbon onions followed by transformation to nanodiamond in an energetic impact. This nonequilibrium process is consistent with common environments in space and invokes the fewest assumptions of any proposed model. Accordingly, our model can explain nanodiamond formation in both presolar and solar environments. The model provides an attractive framework for understanding noble gas incorporation and explains all key features of meteoritic nanodiamond, including size, shape, and polytype. By understanding the creation of nanodiamonds, new opportunities arise for their exploitation as a powerful astrophysical probe. PMID:22401225

  15. Nonequilibrium Route to Nanodiamond with Astrophysical Implications

    NASA Astrophysics Data System (ADS)

    Marks, N. A.; Lattemann, M.; McKenzie, D. R.

    2012-02-01

    Nanometer-sized diamond grains are commonly found in primitive chondritic meteorites, but their origin is puzzling. Using evidence from atomistic simulation, we establish a mechanism by which nanodiamonds form abundantly in space in a two-stage process involving condensation of vapor to form carbon onions followed by transformation to nanodiamond in an energetic impact. This nonequilibrium process is consistent with common environments in space and invokes the fewest assumptions of any proposed model. Accordingly, our model can explain nanodiamond formation in both presolar and solar environments. The model provides an attractive framework for understanding noble gas incorporation and explains all key features of meteoritic nanodiamond, including size, shape, and polytype. By understanding the creation of nanodiamonds, new opportunities arise for their exploitation as a powerful astrophysical probe.

  16. Letter from the Board of Directors of Astronomy & Astrophysics

    NASA Astrophysics Data System (ADS)

    Meynet, Georges

    2005-07-01

    1. New A&A memberships and scientific editorial structure for the Letters section At its meeting in Tartu, Estonia on 8 May 2004, the A&A Board of Directors decided to grant observer status on the Board to Brazil, Chile, and Portugal (Sandqvist 2004, A&A, 426, E15). Then on 6-7 May 2005, at its meeting in La Laguna, Spain, the Board of Directors admitted these three countries to full membership in A&A, starting 1 January 2006. The Letters Editor, Dr. P. Schneider, will complete his terms of service on 31 January 2006. A&A is indebted to him for his thoughtful and competent editing over the past several years. As a consequence of his departure, the Board has decided to restructure the manner in which the Letters will be handled as of 1 January 2006. The Associate Editor-in-Chief, Dr. M. Walmsley, will also become Editor-in-Chief for the Letters, and he will forward the Letters to the appropriate topical Associate Editor to organize the reviewing process. Likewise, the Editor-in-Chief, Dr. C. Bertout, will become the Associate Letters-Editor-in-Chief. This change will permit a more specialized treatment of Letters in the future and also allow Letters to benefit from language editing. Hence, after 1 January 2006, manuscripts for Letters should be submitted via the A&A Manuscript Management System (MMS) that is already in place for Main Journal submissions. Letters submitted before that will be handled by the current Letters Editor even after 1 January 2006. 2. New Associate Editor positions Considering both the increased workload on the Associate Editors due to the above change and the continuing specialization of sub-fields in astronomy, the Board decided to open two new positions for Associate Editors, one specialized in Cosmology with a particular interest in theoretical aspects and the other in Observational Stellar Physics. Applications are invited for these two new positions. The Associate Editors are expected to have a broad knowledge of astronomy and

  17. Investigating High Field Gravity using Astrophysical Techniques

    SciTech Connect

    Bloom, Elliott D.; /SLAC

    2008-02-01

    The purpose of these lectures is to introduce particle physicists to astrophysical techniques. These techniques can help us understand certain phenomena important to particle physics that are currently impossible to address using standard particle physics experimental techniques. As the subject matter is vast, compromises are necessary in order to convey the central ideas to the reader. Many general references are included for those who want to learn more. The paragraphs below elaborate on the structure of these lectures. I hope this discussion will clarify my motivation and make the lectures easier to follow. The lectures begin with a brief review of more theoretical ideas. First, elements of general relativity are reviewed, concentrating on those aspects that are needed to understand compact stellar objects (white dwarf stars, neutron stars, and black holes). I then review the equations of state of these objects, concentrating on the simplest standard models from astrophysics. After these mathematical preliminaries, Sec. 2(c) discusses 'The End State of Stars'. Most of this section also uses the simplest standard models. However, as these lectures are for particle physicists, I also discuss some of the more recent approaches to the equation of state of very dense compact objects. These particle-physics-motivated equations of state can dramatically change how we view the formation of black holes. Section 3 focuses on the properties of the objects that we want to characterize and measure. X-ray binary systems and Active Galactic Nuclei (AGN) are stressed because the lectures center on understanding very dense stellar objects, black hole candidates (BHCs), and their accompanying high gravitational fields. The use of x-ray timing and gamma-ray experiments is also introduced in this section. Sections 4 and 5 review information from x-ray and gamma-ray experiments. These sections also discuss the current state of the art in x-ray and gamma-ray satellite experiments and

  18. Atomic Data in X-Ray Astrophysics

    NASA Technical Reports Server (NTRS)

    Brickhouse, N. S.

    2000-01-01

    With the launches of the Chandra X-ray Observatory (CXO) and the X-ray Multimirror Mission (XMM) and the upcoming launch of the Japanese mission ASTRO-E, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources will provide not only invaluable calibration data, but will also give us benchmarks for the atomic data under collisional equilibrium conditions. Analysis of the Chandra X-ray Observatory data, and data from other telescopes taken simultaneously, for these stars is ongoing as part of the Emission Line Project. Goals of the Emission Line Project are: (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. The Astrophysical Plasma Emission Database will be described in some detail, as it is introducing standardization and flexibility into X-ray spectral modeling. Spectral models of X-ray astrophysical plasmas can be generally classified as dominated by either collisional ionization or by X-ray photoionization. While the atomic data needs for spectral models under these two types of ionization are significantly different, there axe overlapping data needs, as I will describe. Early results from the Emission Line Project benchmarks are providing an invaluable starting place, but continuing work to improve the accuracy and completeness of atomic data is needed. Additionally, we consider the possibility that some sources will require that both collisional ionization and photoionization be taken into account, or that time-dependent ionization be considered. Thus plasma spectral models of general use need to be computed over a wide range of physical conditions.

  19. Neutron capture measurements for nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Reifarth, Rene

    2005-04-01

    Almost all of the heavy elements are produced via neutron capture reactions in a multitude of stellar production sites. The predictive power of the underlying stellar models is currently limited because they contain poorly constrained physics components such as convection, rotation or magnetic fields. Neutron captures measurements on heavy radioactive isotopes provide a unique opportunity to largely improve these physics components, and thereby address important questions of nuclear astrophysics. Such species are branch-points in the otherwise uniquely defined path of subsequent n-captures along the s-process path in the valley of stability. These branch points reveal themselves through unmistakable signatures recovered from pre-solar meteoritic grains that originate in individual element producing stars. Measurements on radioactive isotopes for neutron energies in the keV region represent a stringent challenge for further improvements of experimental techniques. This holds true for the neutron sources, the detection systems and the technology to handle radioactive material. Though the activation method or accelerator mass spectroscopy of the reaction products could be applied in a limited number of cases, Experimental facilities like DANCE at LANL, USA and n-TOF at CERN, Switzerland are addressing the need for such measurements on the basis of the more universal method of detecting the prompt capture gamma-rays, which is required for the application of neutron time-of-flight (TOF) techniques. With a strongly optimized neutron facility at the Rare Isotope Accelerator (RIA) isotopes with half-lives down to tens of days could be investigated, while present facilities require half-lives of a few hundred days. Recent neutron capture experiments on radioactive isotopes with relevance for nuclear astrophysics and possibilities for future experimental setups will be discussed during the talk.

  20. Laboratory Astrophysics on High Power Lasers and Pulsed Power Facilities

    SciTech Connect

    Remington, B A

    2002-02-05

    Over the past decade a new genre of laboratory astrophysics has emerged, made possible by the new high energy density (HED) experimental facilities, such as large lasers, z-pinch generators, and high current particle accelerators. (Remington, 1999; 2000; Drake, 1998; Takabe, 2001) On these facilities, macroscopic collections of matter can be created in astrophysically relevant conditions, and its collective properties measured. Examples of processes and issues that can be experimentally addressed include compressible hydrodynamic mixing, strong shock phenomena, radiative shocks, radiation flow, high Mach-number jets, complex opacities, photoionized plasmas, equations of state of highly compressed matter, and relativistic plasmas. These processes are relevant to a wide range of astrophysical phenomena, such as supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. These phenomena will be discussed in the context of laboratory astrophysics experiments possible on existing and future HED facilities.

  1. Special Advocate.

    ERIC Educational Resources Information Center

    Vander Weele, Maribeth

    1992-01-01

    Thomas Hehir, special education chief of Chicago Public Schools, is evangelist of integrating children with disabilities into regular classrooms. By completely reorganizing department viewed as political patronage dumping ground, Hehir has made remarkable progress in handling large number of children awaiting evaluation and placement in special…

  2. Special Relativity

    NASA Astrophysics Data System (ADS)

    Sartori, L.; Murdin, P.

    2000-11-01

    The special theory of relativity (SR), developed by ALBERT EINSTEIN in 1905, represents a revolutionary change in the human conception of the nature of space and time. According to SR, space and time are not absolute but must be viewed as components of a single entity, SPACE-TIME. This idea has numerous important implications, both conceptual and practical....

  3. Special Reports.

    ERIC Educational Resources Information Center

    Wiant, Sarah K.; Lynch, Clifford; Nevins, Kate; Juergens, Bonnie

    1998-01-01

    Contains three special reports: developments in copyright law, 1997 (World Intellectual Property Organization (WIPO) legislation, Ashcroft Bill, No Electronic Theft Act, database protection, Conference on Fair Use (CONFU), judicial decisions, principles for licensing electronic resources, and Uniform Commercial Code Article 2B); Internet2 and the…

  4. Specialized Mediation.

    ERIC Educational Resources Information Center

    Hammond, Carol; And Others

    1992-01-01

    Six articles discuss librarians as mediators in special circumstances. Highlights include the reference librarian and the information paraprofessional; effective reference mediation for nontraditional public library users, including mentally impaired patrons and illiterate adults; the academic librarian's role in the education process; and…

  5. 75 FR 2893 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... and Space Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA... the room. The agenda for the meeting includes the following topics: --Astrophysics Division...

  6. 77 FR 62536 - Meeting of Astrophysics Subcommittee of the NASA Advisory Council Science Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-15

    ... SPACE ADMINISTRATION Meeting of Astrophysics Subcommittee of the NASA Advisory Council Science Committee... Space Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory... topics: --Astrophysics Division Update --Proposed Data Centers Study --Strategic Implementation for...

  7. 76 FR 35481 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... meeting includes the following topics: --Astrophysics Division Update. --Research and Analysis...

  8. 77 FR 38090 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-26

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee (APS) of the NASA Advisory Council... the following topics: --Astrophysics Division Update --James Webb Space Telescope Update...

  9. 76 FR 5405 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... meeting includes the following topics: --Astrophysics Division Update --Update from the James Webb...

  10. 75 FR 33837 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... and Space Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA... of the room. The agenda for the meeting includes the following topics: --Astrophysics Division...

  11. 75 FR 51116 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... the meeting includes the following topics: --Astrophysics Division Update --2010 Astronomy...

  12. 75 FR 13597 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-22

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... and Space Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA... following topics: --Astrophysics Division Update. --Kepler Data Release Policy. It is imperative that...

  13. 77 FR 4370 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-27

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... meeting includes the following topics: --Astrophysics Division Update --Update on Balloons Return...

  14. 76 FR 14106 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... SPACE ADMINISTRATION NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY... Administration (NASA) announces a meeting of the Astrophysics Subcommittee of the NASA Advisory Council (NAC... meeting includes the following topic: --Astrophysics Division Update. It is imperative that the meeting...

  15. Texas Symposium on Relativistic Astrophysics, 11th, Austin, TX, December 12-17, 1982, Proceedings

    NASA Technical Reports Server (NTRS)

    Evans, D. S. (Editor)

    1984-01-01

    Various papers on relativistic astrophysics are presented. The general subjects addressed include: particle physics and astrophysics, general relativity, large-scale structure, big bang cosmology, new-generation telescopes, pulsars, supernovae, high-energy astrophysics, and active galaxies.

  16. Higher Education Resources from the NASA SMD Astrophysics Forum

    NASA Astrophysics Data System (ADS)

    Meinke, Bonnie K.; Schultz, Gregory R.; Manning, James; Smith, Denise A.; Bianchi, Luciana; Blair, William P.; Fraknoi, Andrew

    2014-06-01

    The NASA Astrophysics Science Education and Public Outreach Forum (SEPOF) coordinates the work of individual NASA Science Mission Directorate (SMD) Astrophysics EPO projects and their teams into a coherent, effective, efficient, and sustainable effort. The Astrophysics Forum assists scientists and educators with becoming involved in SMD E/PO and makes SMD E/PO resources and expertise accessible to the science and education communities. Here we describe how the Astrophysics Forum and the Astrophysics E/PO community have focused efforts to support and engage the higher education community on enhancing awareness of the resources available to them. To ensure Astrophysics higher education efforts are grounded in audience needs, we held informal conversations with instructors of introductory astronomy courses, convened sessions with higher education faculty and E/PO professionals at conferences, and examined existing literature and findings of the SMD Higher Education Working Group. To address the expressed needs, the Astrophysics Forum collaborated with the Astrophysics E/PO community, researchers, and Astronomy 101 instructors to place individual science discoveries and learning resources into context for higher education audiences. Among these resources are two Resource Guides on the topics of cosmology and exoplanets. These fields are ripe with scientific developments that college instructors have told us they find challenging to stay current. Each guide includes a wide variety of sources and is available through the ASP website: http://www.astrosociety.org/education/astronomy-resource-guides/ To complement the resource guides, we are developing a series of slide sets to help Astronomy 101 instructors incorporate new discoveries from individual SMD Astrophysics missions in their classrooms. The “Astro 101 slide sets” are 5-7 slide presentations on a new development or discovery from a NASA SMD Astrophysics mission relevant to an Astronomy 101 topic. We intend for

  17. Astrophysical phenomena related to supermassive black holes

    NASA Astrophysics Data System (ADS)

    Pott, Jörg-Uwe

    2006-12-01

    The thesis contains the results of my recent projects in astrophysical research. All projects aim at pushing the limits of our knowledge about the interaction between a galaxy, the fundamental building block of today's universe, and a supermassive black hole (SMBH) at its center. Over the past years a lot of observational evidence has been gathered for the current understanding, that at least a major part of the galaxies with a stellar bulge contain central SMBHs. The typical extragalactic approach consists of searching for the spectroscopic pattern of Keplerian rotation, produced by stars and gas, when orbiting a central dark mass (Kormendy & Richstone 1995). It suggests that a significant fraction of large galaxies host in their very nucleus a SMBH of millions to billions of solar masses (Kormendy & Gebhardt 2001). In the closest case, the center of our Milky Way, the most central stars, which can be imaged, were shown to move on orbits with circulation times of a few decades only, evidencing a mass and compactness of the dark counter part of the Keplerian motion, which can only be explained by a SMBH (Eckart & Genzel 1996; Ghez et al. 2000; Schödel et al. 2002). Having acknowledged the widespread existence of SMBHs the obvious next step is investigating the interaction with their environment. Although the basic property of a SMBH, which is concentrating a huge amount of mass in a ludicrously small volume defined by the Schwarzschild radius, only creates a deep gravitational trough, its existence evokes much more phenomena than simply attracting the surrounding matter. It can trigger or exacerbate star formation via tidal forces (Morris 1993). It shapes the distribution of its surrounding matter to accretion discs, which themselves release gravitational potential energy as radiation, possibly due to magnetic friction (Blandford 1995). The radiation efficiency of such active galactic nuclei (AGN) can become roughly 100 times more efficient than atomic nuclear

  18. 2nd Iberian Nuclear Astrophysics Meeting on Compact Stars

    NASA Astrophysics Data System (ADS)

    Perez-Garcia, M. Angeles; Pons, Jose; Albertus, C.

    2012-02-01

    experts from the computational simulation of core-collapse supernovae and the effect of hadron-quark phase transitions developed specialized review talks. Prospects in future observations or a more dilute classification of magnetars were also discussed. The importance of the equation of state, three-body forces, finite nuclei, phenomenological fermionic interaction models, and the microphysics inputs of different many-body approaches to some very important quantities as the symmetry energy were reviewed and discussed from either the non-relativistic to the relativistic framework. The importance of the crust with the existence of a crystallized structure and vortex-crust pinning were some of the important subjects discussed in the context of cooling and field dynamics. Finally, some condensed matter and optics talks presented us the rich insight that Cold Atom Physics can give us on low-density interactions and the new and very intense laser Petawatt beams can test matter under strong external fields, respectively. We would to thank the Faculty of Science and University of Salamanca for hosting the meeting. We also thank for partial financial support the European ERC Network COMPSTAR, The Physics of Neutron Stars under reference 3803 and the Spanish Ministerio de Ciencia e Innovación (MICINN) with project FIS2011-14759 and the local institutions of Instituto de Física Fundamental y Matemáticas (IUFFYM) and Universidad de Salamanca, Spain. Of course we thank those who have contributed to make this meeting a nice occasion to gather and start to develop fruitful collaborations. To them go our grateful acknowledgments. December 2011, Salamanca,Spain M Ángeles Pérez-García, J A Miralles, J Pons, C Albertus, F Atrio Organizing Committee of II Iberian Nuclear Astrophysics Meeting SPONSOR OR FUNDING ACKNOWLEDGMENTS European ERC Network COMPSTAR, The Physics of Neutron Stars under meeting ref. 3803 COMPSTAR logo Spanish Ministerio de Ciencia e Innovación (MICINN) with

  19. Special Rules for Special Ed.

    ERIC Educational Resources Information Center

    Weatherly, Julie J.

    2000-01-01

    School districts are on safer legal ground if they recommend appropriate educational services for each special-needs child, convene parents and school personnel for Individual Education Plan meetings, make placement decisions based on individualized, thorough evaluations; document alternative options; develop behavior-management programs, and use…

  20. EDITORIAL: Astrophysics by all means - but by what means?

    NASA Astrophysics Data System (ADS)

    Kibble, Bob

    1997-01-01

    The October total lunar eclipse offered me no more company than two foxes out on a night excursion across Caterham Common. It was 4am, however, so company was an optimistic hope. The deep pink/red umbral phase was indeed breathtaking, as indeed was teaching physics the following day after only 90 minutes sleep. Two weeks later it was altogether a different story. I lost count of the people who kept me company on Waterloo Bridge for the duration of the partial solar eclipse. With telescope and safe projection all set up I met Americans on holiday, families out for the day, Greek students from King's College and a host of casual passers-by. It was a happy and interactive event. I had quite a crowd at one point and the broad pavement was blocked. There was much talk of Cornwall 1999 and the 'big one'. I have shared these scenes with you because for me they encapture the emerging renaissance of astronomy within the public domain. Was it a coincidence that the same month saw an entire night devoted to Star Trek on the TV, not to mention National Astronomy week. Translated into the curriculum, this movement has given birth to Earth and Beyond at Key Stages 1 to 4, to a revitalized GCSE astronomy course and to cosmology and astrophysics modules at A-level. This special issue provides readers with some engaging reading to support their interest in space and physics. From the personal account of three professionals who reflect on life after astrophysics to the latest curriculum package to emerge from the Trump team I hope you will find material here to enrich your own perspectives and your teaching. This is the third astronomy-related special that I have been associated with and there will no doubt be more. As 1999 approaches and we in the UK gear ourselves for those few minutes of totality, an equally significant event will be underway in schools and colleges. The post-Dearing physics syllabuses will be in operation, eclipsing the current, outdated, uninspiring, subject

  1. Tracheal overexpression of IL-1β, IRAK-1 and TRAF-6 mRNA in obese-asthmatic male Wistar rats

    PubMed Central

    Aslani, Mohammad Reza; Keyhanmanesh, Rana; Khamaneh, Amir Mehdi; Abbasi, Mehran Mesgari; Fallahi, Maryam; Alipour, Mohammad Reza

    2016-01-01

    Objective(s): Human and animal studies have shown a close relationship between obesity and asthma severity. Here, we examined the effects of diet-induced obesity (DIO) on the expression levels of IL-1β, IRAK-1 and TRAF-6 mRNA in male Wistar rats tracheal after sensitization with ovalbumin (OVA). Materials and Methods: Twenty male Wistar rats divided to four groups, included, control group with normal diet (C+ND), OVA-sensitized group with normal diet (S+ND), control group with high-fat diet (C+HFD), and OVA-sensitized group with high-fat diet (S+HFD). All animals fed for 8 weeks with standard pelts or high-fat diet, and then were sensitized and challenged with OVA or saline for another 4 weeks with designed regimens. At the end of study, trachea isolated and examined for expression levels of IL-1β, IRAK-1 and TRAF-6 mRNA with RT-PCR method. Results: Diet-induced obesity groups developed increased weight, obesity indexes and lipid profiles (P<0.05 to P<0.001). The expression levels of IL-1β mRNA in OVA-sensitization groups (S+ND and S+HFD) showed a significantly increased when compared with control group. Also in S+HFD group, expression level of TRAF-6 mRNA was higher than other groups (P<0.001). IRAK-1 expression level was high in S+HFD compared with control group.IL-1β and TRAF-6 mRNA correlated positively with obesity indexes. Conclusion: The results showed that DIO causes overexpression of IL-1β, IRAK-1 and TRAF-6 mRNA in an experimental model of asthma. Our results suggested that in obese-asthmatic conditions locally production and activation of pro-inflammatory agents can be increased. These findings showed that possible mechanism for obesity-asthma relationships. PMID:27279977

  2. Special Relativity

    NASA Astrophysics Data System (ADS)

    Woodhouse, Nicholas M. J.

    This course on special relativity emphasizes the coordinate-free and tensorial approach to Einstein's theory. The author encourages the reader to look at problems from a four-dimensional point of view, so preparing them for further study in relativistic physics, gravitation and cosmology. The book will be especially appealing to students with a mathematical bent and those who like brevity and clarity of reasoning.

  3. NASA Announces 2009 Astronomy and Astrophysics Fellows

    NASA Astrophysics Data System (ADS)

    2009-02-01

    WASHINGTON -- NASA has selected fellows in three areas of astronomy and astrophysics for its Einstein, Hubble, and Sagan Fellowships. The recipients of this year's post-doctoral fellowships will conduct independent research at institutions around the country. "The new fellows are among the best and brightest young astronomers in the world," said Jon Morse, director of the Astrophysics Division in NASA's Science Mission Directorate in Washington. "They already have contributed significantly to studies of how the universe works, the origin of our cosmos and whether we are alone in the cosmos. The fellowships will serve as a springboard for scientific leadership in the years to come, and as an inspiration for the next generation of students and early career researchers." Each fellowship provides support to the awardees for three years. The fellows may pursue their research at any host university or research center of their choosing in the United States. The new fellows will begin their programs in the fall of 2009. "I cannot tell you how much I am looking forward to spending the next few years conducting research in the U.S., thanks to the fellowships," said Karin Oberg, a graduate student in Leiden, The Netherlands. Oberg will study the evolution of water and ices during star formation when she starts her fellowship at the Smithsonian Astrophysical Observatory in Cambridge, Mass. People Who Read This Also Read... Milky Way's Super-efficient Particle Accelerators Caught in The Act Cosmic Heavyweights in Free-for-all Galaxies Coming of Age in Cosmic Blobs Cassiopeia A Comes Alive Across Time and Space A diverse group of 32 young scientists will work on a wide variety of projects, such as understanding supernova hydrodynamics, radio transients, neutron stars, galaxy clusters and the intercluster medium, supermassive black holes, their mergers and the associated gravitational waves, dark energy, dark matter and the reionization process. Other research topics include

  4. Astrophysical Probes of Dark Matter Interactions

    NASA Astrophysics Data System (ADS)

    Reece, Matthew

    The majority of matter in the universe is dark matter, made up of some particle beyond those in the Standard Model of particle physics. So far we have very little information about what dark matter is and how it interacts, except through gravity. Constraints from halo shapes and the Bullet Cluster give upper bounds on the self-interaction strength of dark matter, but these bounds are very weak: roughly the same size as nuclear physics cross sections, which are very large by the standards of particle physics. Given how little we know about dark matter, it is important to search for it in as broad a context as possible. Existing direct and indirect detection analyses are typically motivated by simple particle physics models like WIMP dark matter. This research will aim to widen the scope of searches for dark matter by considering a more complete range of particle physics models, working out their implications for astrophysical data, and interpreting existing data in terms of these new models. New models of dark matter can affect searches in a variety of ways. Signals may show up in conventional indirect detection searches, e.g. in gamma rays detected by Fermi-LAT or in antiprotons detected by AMS-02. The new particle physics content of the models could be reflected in surprising spectral shapes or other features of such signals, or in gamma rays with a different profile on the sky than expected in typical models. The PI has worked, for example, on a model in which signals may arise from a dark disk, which is just one of many possibilities. Signals of new dark matter models might also arise in more subtle ways. Structure in the dark sector could influence the development of structure in the visible sector, indirectly. For instance, a dark matter disk or other dark structures could alter the orbits of stars in the galaxy and may be detectable through detailed studies of the kinematics of stellar populations. Dark accretion disks could exist around astrophysical objects

  5. Long-Term Space Astrophysics Program

    NASA Technical Reports Server (NTRS)

    Nowark, Michael A.

    2001-01-01

    This is the final report for our Long-Term Space Astrophysics Program (NRA 94-OSS-12) grant NAG 5-3225. The proposal is entitled 'Spectral and Temporal Properties of Black Hole Candidates', and began funding in May 1995, and ran through 31 Aug 2000. The project summary from the original proposal was as follows: 'We will study the spectral and temporal properties of black hole candidates (BHC) by using data from archival sources (e.g., EXOSAT, Ginga, ROSAT) and proposed follow-up observations with modern instruments (e.g., ASCA, XTE). Our spectral studies will focus on identifying the basic characteristics and luminosities of the emission components in the various 'states' of BHC. We hope to understand and quantify the global energetics of these states. Our temporal studies will focus on expanding and classifying our knowledge of BHC variability properties in each state. We will explore the nature of quasi-periodic oscillations in BHC. We will combine our spectral and temporal studies by analyzing time lags and variability coherence between energy channels. In addition, we will investigate ways of correlating observed variability behavior with specific emission components.' We have accomplished many of these goals laid out within the original proposal. As originally proposed, we have utilized both archival and proprietary satellite data. In terms of archival data, we have utilized data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), ROSAT, and the Rossi X-ray Timing Explorer (RXTE). We also obtained proprietary data from ASCA, RXTE, and the Extreme Ultraviolet Explorer (EUVE). In terms of sources, we have examined a wide variety of both galactic black hole candidates and extra-galactic black holes. For the galactic black holes we have observed and analyzed both the low/hard state and the high/soft state. We have performed both spectral and timing analyses on all of these objects. In addition, we have also examined a number of neutron stars or

  6. Current progress of nuclear astrophysics experiments at CIAE

    SciTech Connect

    Liu Weiping; Li Zhihong; Su Jun; Bai Xixiang; Wang Youbao; Lian Gang; Guo Bing; Zeng Sheng; Yan Shengquan; Wang Baoxiang; Shu Nengchuan; Chen Yongshou

    2006-07-12

    This paper described current progress of nuclear astrophysical studies using the unstable ion beam facility GIRAFFE. We measured the angular distributions for some low energy reactions, such as 11C(d,n)12N, 8Li(d,p)9Li and 17F(d,n)18Ne in inverse kinematics, and indirectly derived the astrophysical S-factors or reaction rates of 11C(p,{gamma})12N, 8Li(n,{gamma})9Li, 8B(p,{gamma})9C at astrophysically relevant energies.

  7. An Android application for receiving notifications of astrophysical transient events

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Bond, I. A.; Sweatman, W. L.

    2014-10-01

    We describe an application written for the Android platform for receiving real-time notifications of astrophysical transient events. The key feature of our application is the use of message oriented middleware as a message broker, with the messages in VOEvent format. We describe the design features and implementation details of our application. In particular, it was necessary to implement support for the Simple Text Oriented Messaging Protocol (STOMP) to allow communication with the broker. Our application is designed around VOEvent alerts from the Microlensing Observations in Astrophysics (MOA) project, but could easily be adapted for other surveys that issue VOEvent notices of astrophysical transients.

  8. The Million-Body Problem: Particle Simulations in Astrophysics

    ScienceCinema

    Rasio, Fred [Northwestern University

    2009-09-01

    Computer simulations using particles play a key role in astrophysics. They are widely used to study problems across the entire range of astrophysical scales, from the dynamics of stars, gaseous nebulae, and galaxies, to the formation of the largest-scale structures in the universe. The 'particles' can be anything from elementary particles to macroscopic fluid elements, entire stars, or even entire galaxies. Using particle simulations as a common thread, this talk will present an overview of computational astrophysics research currently done in our theory group at Northwestern. Topics will include stellar collisions and the gravothermal catastrophe in dense star clusters.

  9. Astrophysical outflows simulated by laser-driven plasma jets

    NASA Astrophysics Data System (ADS)

    Michaut, C.; Gregory, C. D.; Loupias, B.; Falize, E.; Ravasio, A.; Dizière, A.; Vinci, T.; Koenig, M.; Bouquet, S.

    2011-02-01

    Within the framework of laboratory astrophysics, we form a qualified multidisciplinary group in radiative hydrodynamics. Since 10 years, we have developed laboratory experiments as radiative shocks and plasma jets in connection to astrophysics. Such laboratory experiments provide a unique opportunity to validate models and numerical schemes introduced in radiative hydrodynamics codes. Here we summarize our experimental researches about plasma jets. Laboratory astrophysical experiments have been performed using LULI2000 (France), VULCAN (UK) and GEKKO XII (Japan) intense lasers. The goal of these experiments is to investigate some of the complex features of jets from Young Stellar Objects (YSO), and in particular its interaction with the interstellar medium (ISM).

  10. Cooperative Research in High Energy Astrophysics between JHU and GSFC

    NASA Technical Reports Server (NTRS)

    Vishniac, Ethan

    2004-01-01

    This grant was awarded to establish and support cooperative research programs between the Center of Astrophysical Sciences (CAS) at the Johns Hopkins University and the Laboratory for High Energy Astrophysics (LHEA) at the NASA/Goddard Space Flight Center (GSFC). The goals o f the program are to facilitate, encourage and initiate: (1) sharing of resources, knowledge and expertise in the general astrophysics, and relevant databases; (2) new collaborations and projects between the two institutions and its scientists, (3) training and mentoring of JHU students and junior researchers by way of connecting them with appropriate researchers and experts at the LHEA.

  11. Astronomy education and the Astrophysics Source Code Library

    NASA Astrophysics Data System (ADS)

    Allen, Alice; Nemiroff, Robert J.

    2016-01-01

    The Astrophysics Source Code Library (ASCL) is an online registry of source codes used in refereed astrophysics research. It currently lists nearly 1,200 codes and covers all aspects of computational astrophysics. How can this resource be of use to educators and to the graduate students they mentor? The ASCL serves as a discovery tool for codes that can be used for one's own research. Graduate students can also investigate existing codes to see how common astronomical problems are approached numerically in practice, and use these codes as benchmarks for their own solutions to these problems. Further, they can deepen their knowledge of software practices and techniques through examination of others' codes.

  12. Recent Nuclear Astrophysics Data Activities in the US

    SciTech Connect

    Bardayan, D.W.; Blackmon, J.C.; Browne, E.; Firestone, R.B.; Hale, G.M.; Hoffman, R.D.; Ma, Z.; McLane, V.; Norman, E.B.; Shu, N.; Smith, D.L.; Smith, M.S.; Van Wormer, L.A.; Woosley, S.E.; Wu, S.-C.

    1999-08-30

    Measurements in nuclear physics laboratories form the empirical foundation for new, realistic, sophisticated theoretical models of a wide variety of astrophysical systems. The predictive power of these models has, in many instances, a strong dependence on the input nuclear data, and more extensive and accurate nuclear data is required for these models than ever before. Progress in astrophysics can be aided by providing scientists with more usable, accurate, and significant amounts of nuclear data in a timely fashion in formats that can be easily incorporated into their models. A number of recent data compilations, evaluations, calculations, and disseminations that address nuclear astrophysics data needs will be described.

  13. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2001-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  14. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2009-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  15. Nuclear astrophysics in the laboratory and in the universe

    SciTech Connect

    Champagne, A. E. Iliadis, C.; Longland, R.

    2014-04-15

    Nuclear processes drive stellar evolution and so nuclear physics, stellar models and observations together allow us to describe the inner workings of stars and their life stories. This Information on nuclear reaction rates and nuclear properties are critical ingredients in addressing most questions in astrophysics and often the nuclear database is incomplete or lacking the needed precision. Direct measurements of astrophysically-interesting reactions are necessary and the experimental focus is on improving both sensitivity and precision. In the following, we review recent results and approaches taken at the Laboratory for Experimental Nuclear Astrophysics (LENA, http://research.physics.unc.edu/project/nuclearastro/Welcome.html )

  16. Spaced-based Cosmic Ray Astrophysics

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Suk

    2016-03-01

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

  17. Double layers and circuits in astrophysics

    NASA Technical Reports Server (NTRS)

    Alfven, Hannes

    1986-01-01

    As the rate of energy release in a double layer with voltage delta V is P approx I delta V, a double layer must be treated as a part of a circuit which delivers the current I. As neither double layer nor circuit can be derived from magnetofluid models of a plasma, such models are useless for treating energy transfer by means of double layers. They must be replaced by particle models and circuit theory. A simple circuit is suggested which is applied to the energizing of auroral particles, to solar flares, and to intergalactic double radio sources. Application to the heliospheric current systems leads to the prediction of two double layers on the Sun's axis which may give radiations detectable from Earth. Double layers in space should be classified as a new type of celestial object (one example is the double radio sources). It is tentatively suggested in X-ray and Gamma-ray bursts may be due to exploding double layers (although annihilation is an alternative energy source). A study of how a number of the most used textbooks in astrophysics treat important concepts like double layers, critical velocity, pinch effects and circuits is made.

  18. Rapid Distortion Theory in astrophysical turbulence

    NASA Astrophysics Data System (ADS)

    Safonov, Sergey; Petrosyan, Arakel

    2016-04-01

    In this report, we study statistical properties of astrophysical turbulent plasma flows using Rapid Distortion Theory (RDT). The core assumption is that the turbulence responds to the external distortion so fast, that inertial and viscous forces result in a negligible change in velocity distribution. Thus it is assumed that the response to the external effect takes place in the time interval much smaller than turbulence decay time. This allows to linearize equations and to derive equations for second moments of turbulence. We apply RDT to incompressible turbulent MHD flows distorted with external magnetic field and linear velocity shear in cases of rotating and non-rotating plasma. It is shown that even with a strong nonlinearity many properties of turbulence can be qualitatively studied using a linear theory. A closed system of linear equations for velocity and magnetic field fluctuations is derived. Development of initially isotropic turbulence and transition to anisotropy are studied. Equations for fluid, current and cross helicity are derived. Differences in cases of rotating and non-rotating flows are discussed. Changes introduced by considering Hall effect are discussed.

  19. AstroDance: Teaching Astrophysics Through Dance?

    NASA Astrophysics Data System (ADS)

    Noel-Storr, Jacob; Campanelli, M.; Bochner, J.; Warfield, T.; Bischof, H.; Zlochower, Y.; Nordhaus, J.; Watkins, G.; NSF CRPA AstroDance Team

    2014-01-01

    Through a collaboration involving scientists, artists and educators, members of the Center for Computational Relativity and Gravitation and the National Technical Institute for the Deaf at the Rochester Institute of Technology we developed a unique project for Communicating Research to Public Audiences. The project used dance and multi-media theater techniques to expose a broad audience, about half of which is comprised of deaf and hard-of-hearing individuals, to an aesthetic, educational performance representing the concepts of gravitational physics in astrophysical settings. Since deaf and hard-of-hearing people rely heavily on visual communication for learning and gaining access to information, dance and multi-media theater provide a kinesthetic and visual experience that is fully accessible to them, as well as hearing audience members, and help facilitate their learning and development of non-linguistic representations of concepts. Here we present the results of our research into the learning outcomes for the diverse audiences of this project in terms of both knowledge and attitudes towards science.

  20. Saturn's Rings: An Accessible Astrophysical Disk

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.; Cassini Imaging Team

    2007-12-01

    Saturn's ring system is an astrophysical disk that is neither light-years away nor billions of years in the past. We can visit this disk at close range and observe a number of phenomena that also operate in disks of other kinds. As a result, we see small-scale processes that shape ring texture, connect those processes to the bodies and structures that cause them, and watch closely as the disk changes with time. Recent observations include: 1) "self-gravity wakes” (see Julian and Toomre 1966) dominating the texture of some ring regions; 2) km-sized "propeller-shaped” features caused by small (100-meter) moonlets embedded in the disk; 3) irregular edge shapes in the gaps opened up by larger ( 10 km) moons, which may hold clues to angular momentum transport; 4) resonant spiral density waves excited by more distant large moons, which serve as in situ probes of local disk density and viscosity; 5) waves whose form changes with time, due to the varying orbits of the moons Janus and Epimetheus. The latest results from the Cassini mission will be presented.