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Sample records for studying astrophysical processes

  1. Astrophysical Processes

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  2. Nuclear structure studies for the astrophysical r-process

    CERN Document Server

    Pfeiffer, B; Thielemann, F K; Walters, W B

    2001-01-01

    The production of the heaviest elements in nature occurs via the r-process, i.e. a combination of rapid neutron captures, the inverse photodisintegrations, and slower beta sup - -decays, beta-delayed processes as well as fission and possibly interactions with intense neutrino fluxes. A correct understanding and modeling requires the knowledge of nuclear properties far from stability and a detailed prescription of the astrophysical environment. Experiments at radioactive ion beam facilities have played a pioneering role in exploring the characteristics of nuclear structure in terms of masses and beta-decay properties. Initial examinations paid attention to highly unstable nuclei with magic neutron numbers and their beta-decay properties, related to the location and height of r-process peaks, while recent activities focus on the evolution of shell effects at large distances from the valley of stability. We show in site-independent applications the effect of both types of nuclear properties on r-process abundanc...

  3. Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios

    Directory of Open Access Journals (Sweden)

    Surman R.

    2014-03-01

    Full Text Available In rapid neutron capture, or r-process, nucleosynthesis, heavy elements are built up via a sequence of neutron captures and β decays that involves thousands of nuclei far from stability. Though we understand the basics of how the r process proceeds, its astrophysical site is still not conclusively known. The nuclear network simulations we use to test potential astrophysical scenarios require nuclear physics data (masses, β decay lifetimes, neutron capture rates, fission probabilities for all of the nuclei on the neutron-rich side of the nuclear chart, from the valley of stability to the neutron drip line. Here we discuss recent sensitivity studies that aim to determine which individual pieces of nuclear data are the most crucial for r-process calculations. We consider three types of astrophysical scenarios: a traditional hot r process, a cold r process in which the temperature and density drop rapidly, and a neutron star merger trajectory.

  4. Radiation processes in astrophysics

    CERN Document Server

    Tucker, Wallace H

    1975-01-01

    The purpose of this book is twofold: to provide a brief, simple introduction to the theory of radiation and its application in astrophysics and to serve as a reference manual for researchers. The first part of the book consists of a discussion of the basic formulas and concepts that underlie the classical and quantum descriptions of radiation processes. The rest of the book is concerned with applications. The spirit of the discussion is to present simple derivations that will provide some insight into the basic physics involved and then to state the exact results in a form useful for applications. The reader is referred to the original literature and to reviews for rigorous derivations.The wide range of topics covered is illustrated by the following table of contents: Basic Formulas for Classical Radiation Processes; Basic Formulas for Quantum Radiation Processes; Cyclotron and Synchrotron Radiation; Electron Scattering; Bremsstrahlung and Collision Losses; Radiative Recombination; The Photoelectric Effect; a...

  5. Astrophysical processes on the sun.

    Science.gov (United States)

    Parnell, Clare E

    2012-07-13

    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.

  6. Transport processes in space physics and astrophysics

    CERN Document Server

    Zank, Gary P

    2014-01-01

    Transport Processes in Space Physics and Astrophysics' is aimed at graduate level students to provide the necessary mathematical and physics background to understand the transport of gases, charged particle gases, energetic charged particles, turbulence, and radiation in an astrophysical and space physics context. Subjects emphasized in the work include collisional and collisionless processes in gases (neutral or plasma), analogous processes in turbulence fields and radiation fields, and allows for a simplified treatment of the statistical description of the system. A systematic study that addresses the common tools at a graduate level allows students to progress to a point where they can begin their research in a variety of fields within space physics and astrophysics. This book is for graduate students who expect to complete their research in an area of plasma space physics or plasma astrophysics. By providing a broad synthesis in several areas of transport theory and modeling, the work also benefits resear...

  7. Nuclear Structure Studies at ISOLDE and their Impact on the Astrophysical r-Process

    CERN Document Server

    Kratz, K L; Thielemann, F K; Walters, W B

    2001-01-01

    The focus of the present review is the production of the heaviest elements in nature via the r-process. A correct understanding and modeling requires the knowledge of nuclear properties far from stability and a detailed prescription of the astrophysical environment. Experiments at CERN/ISOLDE have played a pioneering role in exploring the characteristics of nuclear structure in terms of masses and beta-decay properties. Initial examinations paid attention to far unstable nuclei with magic neutron numbers related to r-process peaks, while present activities are centered on the evolution of shell effects with the distance from the valley of stability. We first show in site-independent applications the effect of both types of nuclear properties on r-process abundances. Then, we explore the results of calculations related to two different `realistic' astrophysical sites, (i) the supernova neutrino wind and (ii) neutron star mergers. We close with a list of remaining theoretical and experimental challenges needed ...

  8. Studying Nuclear Astrophysics at NIF

    Energy Technology Data Exchange (ETDEWEB)

    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

  9. Magnetic processes in astrophysics theory, simulations, experiments

    CERN Document Server

    Rüdiger, Günther; Hollerbach, Rainer

    2013-01-01

    In this work the authors draw upon their expertise in geophysical and astrophysical MHD to explore the motion of electrically conducting fluids, the so-called dynamo effect, and describe the similarities and differences between different magnetized objects. They also explain why magnetic fields are crucial to the formation of the stars, and discuss promising experiments currently being designed to investigate some of the relevant physics in the laboratory. This interdisciplinary approach will appeal to a wide audience in physics, astrophysics and geophysics. This second edition covers such add

  10. Coulomb dissociation studies for astrophysical thermonuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Motobayashi, T. [Dept. of Physics, Rikkyo Univ., Toshima, Tokyo (Japan)

    1998-06-01

    The Coulomb dissociation method was applied to several radiative capture processes of astrophysical interest. The method has an advantage of high experimental efficiency, which allow measurements with radioactive nuclear beams. The reactions {sup 13}N(p,{gamma}){sup 14}O and {sup 7}Be(p,{gamma}){sup 8}B are mainly discussed. They are the key reaction in the hot CNO cycle in massive stars and the one closely related to the solar neutrino problem, respectively. (orig.)

  11. Multi-scale Dynamical Processes in Space and Astrophysical Plasmas

    CERN Document Server

    Vörös, Zoltán; IAFA 2011 - International Astrophysics Forum 2011 : Frontiers in Space Environment Research

    2012-01-01

    Magnetized plasmas in the universe exhibit complex dynamical behavior over a huge range of scales. The fundamental mechanisms of energy transport, redistribution and conversion occur at multiple scales. The driving mechanisms often include energy accumulation, free-energy-excited relaxation processes, dissipation and self-organization. The plasma processes associated with energy conversion, transport and self-organization, such as magnetic reconnection, instabilities, linear and nonlinear waves, wave-particle interactions, dynamo processes, turbulence, heating, diffusion and convection represent fundamental physical effects. They demonstrate similar dynamical behavior in near-Earth space, on the Sun, in the heliosphere and in astrophysical environments. 'Multi-scale Dynamical Processes in Space and Astrophysical Plasmas' presents the proceedings of the International Astrophysics Forum Alpbach 2011. The contributions discuss the latest advances in the exploration of dynamical behavior in space plasmas environm...

  12. Alpha resonant scattering for astrophysical reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)

    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.

  13. Probing astrophysically important states in the 26Mg nucleus to study neutron sources for the s process

    Science.gov (United States)

    Talwar, R.; Adachi, T.; Berg, G. P. A.; Bin, L.; Bisterzo, S.; Couder, M.; deBoer, R. J.; Fang, X.; Fujita, H.; Fujita, Y.; Görres, J.; Hatanaka, K.; Itoh, T.; Kadoya, T.; Long, A.; Miki, K.; Patel, D.; Pignatari, M.; Shimbara, Y.; Tamii, A.; Wiescher, M.; Yamamoto, T.; Yosoi, M.

    2016-05-01

    Background: The 22Ne(α ,n )25Mg reaction is the dominant neutron source for the slow neutron capture process (s process) in massive stars, and contributes, together with 13C (α ,n )16O, to the production of neutrons for the s process in asymptotic giant branch (AGB) stars. However, the reaction is endothermic and competes directly with 22Ne(α ,γ )26Mg radiative capture. The uncertainties for both reactions are large owing to the uncertainty in the level structure of 26Mg near the α and neutron separation energies. These uncertainties affect the s -process nucleosynthesis calculations in theoretical stellar models. Purpose: Indirect studies in the past have been successful in determining the energies and the γ -ray and neutron widths of the 26Mg states in the energy region of interest. But, the high Coulomb barrier hinders a direct measurement of the resonance strengths, which are determined by the α widths for these states. The goal of the present experiments is to identify the critical resonance states and to precisely measure the α widths by α -transfer techniques. Methods: The α -inelastic scattering and α -transfer measurements were performed on a solid 26Mg target and a 22Ne gas target, respectively, using the Grand Raiden Spectrometer at the Research Center for Nuclear Physics in Osaka, Japan. The (α ,α') measurements were performed at 0 .45∘ , 4 .1∘ , 8 .6∘ , and 11 .1∘ and the (6Li,d ) measurements at 0∘ and 10∘. The scattered α particles and deuterons were detected by the focal plane detection system consisting of multiwire drift chambers and plastic scintillators. The focal plane energy calibration allowed the study of 26Mg levels from Ex = 7.69-12.06 MeV in the (α ,α') measurement and Ex = 7.36-11.32 MeV in the (6Li,d ) measurement. Results: Six levels (Ex = 10717, 10822, 10951, 11085, 11167, and 11317 keV) were observed above the α threshold in the region of interest (10.61-11.32 MeV). The α widths were calculated for these

  14. Reaction Studies for Explosive Nuclear Astrophysics

    Science.gov (United States)

    Woods, Philip J.

    The paper describes experimental approaches to measuring key nuclear astrophysical reactions involving radioactive isotopes. Specifically the paper considers the utilisation of (d, n) and (d, p) transfer reactions to probe the strengths of key resonances in the hydrogen burning/proton capture reactions 30P(p, γ) and 26Al(p, γ). The use of a radioactive target and silicon strip detector set-ups to study the key 26Al(n, p) and (n, α) destruction reactions relevant to explosive burning conditions in core collapse supernovae is also reported.

  15. Studies of High Energy Particle Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Nitz, David F [Michigan Technological University; Fick, Brian E [Michigan Technological University

    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.

  16. High Energy Studies of Astrophysical Dust

    Science.gov (United States)

    Corrales, Lia Racquel

    Astrophysical dust---any condensed matter ranging from tens of atoms to micron sized grains---accounts for about one third of the heavy elements produced in stars and disseminated into space. These tiny pollutants are responsible for producing the mottled appearance in the spray of light we call the "Milky Way." However these seemingly inert particles play a strong role in the physics of the interstellar medium, aiding star and planet formation, and perhaps helping to guide galaxy evolution. Most dust grains are transparent to X-ray light, leaving a signature of atomic absorption, but also scattering the light over small angles. Bright X-ray objects serendipitously situated behind large columns of dust and gas provide a unique opportunity to study the dust along the line of sight. I focus primarily on X-ray scattering through dust, which produces a diffuse halo image around a central point source. Such objects have been observed around X-ray bright Galactic binaries and extragalactic objects that happen to shine through the plane of the Milky Way. I use the Chandra X-ray Observatory, a space-based laboratory operated by NASA, which has imaging resolution ideal for studying X-ray scattering halos. I examine several bright X-ray objects with dust-free sight lines to test their viability as templates and develop a parametric model for the Chandra HETG point spread function (PSF). The PSF describes the instrument's imaging response to a point source, an understanding of which is necessary for properly measuring the surface brightness of X-ray scattering halos. I use an HETG observation of Cygnus X-3, one of the brightest objects available in the Chandra archive, to derive a dust grain size distribution. There exist degenerate solutions for the dust scattering halo, but with the aid of Bayesian analytics I am able to apply prior knowledge about the Cyg X-3 sight line to measure the relative abundance of dust in intervening Milky Way spiral arms. I also demonstrate how

  17. The Link between Rare-Earth Peak Formation and the Astrophysical Site of the R Process

    Science.gov (United States)

    Mumpower, Matthew R.; McLaughlin, Gail C.; Surman, Rebecca; Steiner, Andrew W.

    2016-12-01

    The primary astrophysical source of the rare-earth elements is the rapid neutron capture process (r process). The rare-earth peak that is seen in the solar r-process residuals has been proposed to originate as a pile-up of nuclei during the end of the r process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare-earth region, that includes self-consistently adjusting β-decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare-earth peak. We demonstrate our method with two types of astrophysical scenario, one corresponding to conditions typical of hot winds from core-collapse supernovae and stellar-mass accretion disks, and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical condition, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare-earth peak. For each scenario, we find that the change in the mass surface has qualitatively different features, thus future measurements can shed light on the type of environment in which the r process occurred.

  18. Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process

    Science.gov (United States)

    Lederer, C.; Giubrone, G.; Massimi, C.; Žugec, P.; Barbagallo, M.; Colonna, N.; Domingo-Pardo, C.; Guerrero, C.; Gunsing, F.; Käppeler, F.; Tain, J. L.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Duran, I.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Gurusamy, P.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Korschinek, G.; Krtička, M.; Kroll, J.; Langer, C.; Leeb, H.; Leong, L. S.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Roman, F.; Rubbia, C.; Sarmento, R.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T. J.

    2014-06-01

    Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at the neutron time-of-flight facility n_TOF at CERN focussing on the Fe/Ni mass region. Recent results and future developments in the neutron time-of-flight technique are discussed.

  19. Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process

    CERN Document Server

    Lederer, C; Massimi, C; Žugec, P; Barbagallo, M; Colonna, N; Domingo-Pardo, C; Guerrero, C; Gunsing, F; Käppeler, F; Tain, J L; Altstadt, S; Andrzejewski, J; Audouin, L; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krtička, M; Kroll, J; Langer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J

    2014-01-01

    Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at the neutron time-of-flight facility n\\_TOF at CERN focussing on the Fe/Ni mass region. Recent results and future developments in the neutron time-of-flight technique are discussed.

  20. Recent Astrophysical Studies with Exotic Beams at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Bardayan, Daniel W [ORNL

    2006-02-01

    The availability of exotic beams has produced great opportunities for advances in our understanding of the nucleosynthesis occurring in stellar burning and stellar explosions such as novae, X-ray bursts, and supernovae. In these extreme environments, synthesized radioactive nuclei can undergo subsequent nuclear processing before they decay, and thus to understand these events, we must understand reaction rates involving radioactive nuclei. At the ORNL Holi led Radioactive Ion Beam Facility (HRIBF), we have made several recent measurements using proton-rich beams such as 18F and 7Be and neutron-rich beams such as 82Ge and 84Se that help clarify the structure of astrophysically-important nuclei. We are also poised to begin studies with doubly-magic 132Sn. The experimental methods and results are discussed.

  1. Studies of astrophysically interesting nucleus 23Al

    Science.gov (United States)

    Saastamoinen, A.; Trache, L.; Banu, A.; Bentley, M. A.; Davinson, T.; Eronen, T.; Hardy, J. C.; Iacob, V. E.; Jenkins, D.; Jokinen, A.; McCleskey, M.; Roeder, B.; Tabacaru, G.; Tribble, R. E.; Woods, P. J.; Äystö, J.; Igisol/Mars Groups

    2010-01-01

    We have studied the β-delayed proton decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton branching of the IAS in 23Mg and to determine the absolute proton branchings by combining our results to the latest βγ-decay data. We have made also a high precision mass measurement of the ground state of 23Al to establish more accurate proton separation energy of 23Al. Here the description of the used techniques along with preliminary results of the experiments are given.

  2. The new worlds observer: The astrophysics strategic mission concept study

    Directory of Open Access Journals (Sweden)

    Cash W.

    2011-07-01

    Full Text Available We present some results of the Astrophysics Strategic Mission Concept Study for the New Worlds Observer (NWO. We show that the use of starshades is the most effective and affordable path to mapping and understanding our neighboring planetary systems, to opening the search for life outside our solar system, while serving the needs of the greater astronomy community. A starshade-based mission can be implemented immediately with a near term program of technology demonstration.

  3. NATO Advanced Study Institute on Optics in Astrophysics

    CERN Document Server

    Foy, Renaud

    2005-01-01

    Astrophysics is facing challenging aims such as deep cosmology at redshift higher than 10 to constrain cosmology models, or the detection of exoplanets, and possibly terrestrial exoplanets, and several others. It requires unprecedented ambitious R&D programs, which have definitely to rely on a tight cooperation between astrophysics and optics communities. The book addresses most of the most critical interdisciplinary domains where they interact, or where they will do. A first need is to collect more light, i.e. telescopes still larger than the current 8-10 meter class ones. Decametric, and even hectometric, optical (from UV to IR wavelengths) telescopes are being studied. Whereas up to now the light collecting surface of new telescopes was approximately 4 times that of the previous generation, now this factor is growing to 10 to 100. This quantum leap urges to implement new methods or technologies developed in the optics community, both in academic labs and in the industry. Given the astrophysical goals a...

  4. Astrophysical site(s of r-process elements in galactic chemodynamical evolution model

    Directory of Open Access Journals (Sweden)

    Hirai Yutaka

    2016-01-01

    Full Text Available Astrophysical site(s of rapid neutron-capture process (r-process is (are not identified yet. Although core-collapse supernovae have been regarded as one of the possible candidates of the astrophysical site of r-process, nucleosynthesis studies suggest that serious difficulties in core-collapse supernovae to produce heavy elements with mass number of ≳110. Recent studies show that neutron star mergers (NSMs can synthesize these elements due to their neutron rich environment. Some chemical evolution studies of the Milky Way halo, however, hardly reproduce the observed star-to-star scatters of the abundance ratios of r-process elements (e.g., Eu in extremely metal-poor stars. This is because of their low rate (∼ 10−4 yr−1 for a Milky Way size galaxy and long merger time (≳ 100 Myr. This problem might be solved if the stars in the Galactic halo are consisted of the stars formed in dwarf galaxies where the star formation efficiencies were very low. In this study, we carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code. We construct detailed chemo-dynamical evolution model for the Local Group dwarf spheroidal galaxies (dSphs assuming that the NSMs are the major source of r-process elements. Our models successfully reproduce the observed dispersion in [Eu/Fe] as a function of [Fe/H] if we set merger time of NSMs, ≲ 300 Myr with the Galactic NSM rate of ∼ 10−4 yr−1. In addition, our results are consistent with the observed metallicity distribution of dSphs. In the early phase (≲1 Gyr of galaxy evolution is constant due to low star formation efficiency of dSphs. This study supports the idea that NSMs are the major site of r-process nucleosynthesis.

  5. Experiments with neutron beams for the astrophysical s process

    Science.gov (United States)

    Lederer, C.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Korschinek, G.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Leeb, H.; Leong, L. S.; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Roman, F.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiβ, C.; Wright, T.; Žugec, P.

    2016-01-01

    Neutron capture cross sections are the key nuclear physics input to study the slow neutron capture process, which is responsible for forming about half of the elemental abundances above Fe. Stellar neutron capture cross section can be measured by the time-of-flight technique, or by activation. Both techniques will be discussed and recent experiments in the Fe/Ni mass region will be presented.

  6. The Rare Earth Peak and the Astrophysical Location of the r Process

    Science.gov (United States)

    Mumpower, M. R.; McLaughlin, G. C.; Surman, R.; Steiner, A. W.

    The question of astrophysical site(s) for the rapid neutron capture or r process of nucleosynthesis remains one of the most challenging open problems in all of physics. Neutron star mergers and core collapse supernovae are the leading candidates, but conclusions regarding both are limited by our knowledge of nuclear physics far from stability. Current and future radioactive beam facilities will aid in this endeavor by providing a plethora of new nuclear data information to be used in theoretical simulations. We present a new theoretical framework which, if used in combination with future measurements, will give strong clues to the astrophysical site of the r process.

  7. Self-Organized Criticality in Astrophysics The Statistics of Nonlinear Processes in the Universe

    CERN Document Server

    Aschwanden, Markus

    2011-01-01

    The concept of ‘self-organized criticality’ (SOC) has been applied to a variety of problems, ranging from population growth and traffic jams to earthquakes, landslides and forest fires. The technique is now being applied to a wide range of phenomena in astrophysics, such as planetary magnetospheres, solar flares, cataclysmic variable stars, accretion disks, black holes and gamma-ray bursts, and also to phenomena in galactic physics and cosmology. Self-organized Criticality in Astrophysics introduces the concept of SOC and shows that, due to its universality and ubiquity, it is a law of nature. The theoretical framework and specific physical models are described, together with a range of applications in various aspects of astrophyics. The mathematical techniques, including the statistics of random processes, time series analysis, time scale and waiting time distributions, are presented and the results are applied to specific observations of astrophysical phenomena.

  8. Essential astrophysics

    CERN Document Server

    Lang, Kenneth R

    2013-01-01

    Essential Astrophysics is a book to learn or teach from, as well as a fundamental reference volume for anyone interested in astronomy and astrophysics. It presents astrophysics from basic principles without requiring any previous study of astronomy or astrophysics. It serves as a comprehensive introductory text, which takes the student through the field of astrophysics in lecture-sized chapters of basic physical principles applied to the cosmos. This one-semester overview will be enjoyed by undergraduate students with an interest in the physical sciences, such as astronomy, chemistry, engineering or physics, as well as by any curious student interested in learning about our celestial science. The mathematics required for understanding the text is on the level of simple algebra, for that is all that is needed to describe the fundamental principles. The text is of sufficient breadth and depth to prepare the interested student for more advanced specialized courses in the future. Astronomical examples are provide...

  9. Perspectives on Gravity-Induced Radiative Processes in Astrophysics

    Directory of Open Access Journals (Sweden)

    Giorgio Papini

    2015-04-01

    Full Text Available Single-vertex Feynman diagrams represent the dominant contribution to physical processes, but are frequently forbidden kinematically. This is changed when the particles involved propagate in a gravitational background and acquire an effective mass. Procedures are introduced that allow the calculation of lowest order diagrams, their corresponding transition probabilities, emission powers and spectra to all orders in the metric deviation, for particles of any spin propagating in gravitational fields described by any metric. Physical properties of the “space-time medium” are also discussed. It is shown in particular that a small dissipation term in the particle wave equations can trigger a strong back-reaction that introduces resonances in the radiative process and affects the resulting gravitational background.

  10. Emission processes and dynamics of hot gases in astrophysics

    Science.gov (United States)

    Chevalier, Roger A.; Sarazin, Craig L.

    1991-01-01

    A detailed model was developed for Kepler's supernova remnant (SNR). Observations of the SNR revealed a strong interaction with the surrounding circumstellar medium, which was studied through both analytical and numerical calculations. Effects were studied of electron thermal conduction on the structure of radiative interstellar shock waves. An explanation is sought for the observed line emission from metal rich ejecta in SNR, incorporating atomic data. Light echoes around SN 1987A was also studied. Analysis of infrared and scattered circumstellar light echoes was accomplished with early observations to set limits on the mass of circumstellar dust. Work was completed on the emission from heavy element gas ejected in the supernova explosion of massive stars. It was assumed that a radioactive energy source was present and calculated the detailed heating and ionization of the gas. The evolution was studied of SNR in the very high pressure environment of a starburst galaxy.

  11. Studying astrophysical reactions with low-energy RI beams at CRIB

    Directory of Open Access Journals (Sweden)

    Yamaguchi H.

    2016-01-01

    Full Text Available Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI beams at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study (CNS, the University of Tokyo. A typical measurement performed at CRIB is the elastic resonant scattering with the inverse kinematics. One recent experiment was on the α resonant scattering with 7Li and 7Be beams. This study is related to the astrophysical 7Li/7Be(α,γ reactions, important at hot p-p chain and νp-process in supernovae. There have also been measurements based on other experimental methods. The first THM measurement using an RI beam has been performed at CRIB, to study the 18F(p, α15O reaction at astrophysical energies via the three body reaction 2H(18F, α15On. The 18F(p, α 15O reaction rate is crucial to understand the 511-keV γ-ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time.

  12. Studying astrophysical reactions with low-energy RI beams at CRIB

    Science.gov (United States)

    Yamaguchi, H.; Kahl, D.; Hayakawa, S.; Sakaguchi, Y.; Wakabayashi, Y.; Hashimoto, T.; Cherubini, S.; Gulino, M.; Spitaleri, C.; Rapisarda, G. G.; La Cognata, M.; Lamia, L.; Romano, S.; Kubono, S.; Iwasa, N.; Teranishi, T.; Kawabata, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kato, S.; Komatsubara, T.; Coc, A.; De Sereville, N.; Hammache, F.; Kiss, G.; Bishop, S.

    2016-05-01

    Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study (CNS), the University of Tokyo. A typical measurement performed at CRIB is the elastic resonant scattering with the inverse kinematics. One recent experiment was on the α resonant scattering with 7Li and 7Be beams. This study is related to the astrophysical 7Li/7Be(α,γ) reactions, important at hot p-p chain and νp-process in supernovae. There have also been measurements based on other experimental methods. The first THM measurement using an RI beam has been performed at CRIB, to study the 18F(p, α)15O reaction at astrophysical energies via the three body reaction 2H(18F, α15O)n. The 18F(p, α) 15O reaction rate is crucial to understand the 511-keV γ-ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time.

  13. High-Energy-Density, Laboratory-Astrophysics Studies of Jets and Bow Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Foster, J M; Wilde, B H; Rosen, P A; Perry, T S; Khokhlov, A M; Coker, R F; Frank, A; Keiter, P A; Blue, B E; Drake, R P; Knauer, J P; Williams, R R

    2005-01-24

    Large-scale directional outflows of supersonic plasma, also known as ''jets'', are ubiquitous phenomena in astrophysics [1]. The interaction of such jets with surrounding matter often results in spectacular bow shocks, and intense radiation from radio to gamma-ray wavelengths. The traditional approach to understanding such phenomena is through theoretical analysis and numerical simulations. However, such numerical simulations have limited resolution, often assume axial symmetry, do not include all relevant physical processes, and fail to scale correctly in Reynolds number and perhaps other key dimensionless parameters. Additionally, they are frequently not tested by comparison with laboratory experiments. Recent advances in high-energy-density physics using large inertial-confinement-fusion devices now allow controlled laboratory experiments on macroscopic volumes of plasma of direct relevance relevant to astrophysics [2]. In this Letter we report the first results of experiments designed to study the evolution of supersonic plasma jets and the bow shocks they drive into a surrounding medium. Our experiments reveal both regular and highly complex flow patterns in the bow shock, thus opening a new window--complementary to computer simulations--into understanding the nature of three-dimensional astrophysical jets.

  14. Nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Nuclear astrophysics at ISAC with DRAGON: Initial studies

    Energy Technology Data Exchange (ETDEWEB)

    Olin, Art; Bishop, Shawn; Buchmann, Lothar; Chatterjee, Mohan L.; Chen, Alan; D' Auria, John M.; Engel, Sabine; Gigliott, Dario; Greife, Uwe; Hunter, Don; Hussein, Ahmed; Hutcheon, Dave; Jewett, Cybele; King, Jim; Kubono, Shigeru; Lamey, Michael; Laird, Alison M.; Lewis, Rachel; Liu, Wenjie; Michimasa, Shin' ichiro; Ottewell, Dave; Parker, Peter; Rogers, Joel; Strieder, Frank; Wrede, Chris

    2003-06-30

    The new DRAGON recoil separator facility, designed and built to measure directly the rates of radiative proton and alpha capture reactions important for nuclear astrophysics, is now in operation at the TRIUMF-ISAC radioactive beams facility in Vancouver, Canada. Experiments have been conducted for the first time on the {sup 21}Na(p,{gamma}){sup 22}Mg reaction. The evolution of nova explosions, and particularly their {sup 22}Na abundance, depends sensitively on this reaction rate. Commissioning studies using the well-known stable beam reactions {sup 21}Ne(p,{gamma}){sup 22}Na, {sup 20}Ne(p,{gamma}){sup 21}Na, and {sup 24}Mg(p,{gamma}){sup 25}Al have shown that the recoil separator performs within its design specifications both in suppression power and acceptance. The first radioactive beam studies were done using a beam of 5 x 10{sup 821}Na atoms/s. Yield measurements recording simultaneously singles and coincident heavy-ion and gamma signals were performed, scanning in energy over the known resonance reported previously in {sup 22}Mg at E{sub cm} = 212 keV, and in addition, over a strong resonance observed at E{sub cm} {approx}822 keV.

  17. Magnetic Reconnection, a Key Self-Organization Process in Laboratory and Astrophysical Plasmas : Recent Research Progress(Nonequilibrium Dynamics in Astrophysics and Materials Science)

    OpenAIRE

    MASAAKI, YAMADA; Center of Magnetic Self-Organization, Princeton Plasmas Physics Laboratory, Princeton University

    2012-01-01

    Magnetic reconnection is a phenomenon of nature in which magnetic field lines change their topology and convert magnetic energy to plasma particles by acceleration and heating. The process can stretch out over time or occur quite suddenly. It is one of the most fundamental processes at work in laboratory and astrophysical plasmas. Magnetic reconnection occurs everywhere: In solar flares; coronal mass ejections; the earth's magnetosphere; in the star forming galaxies; and in plasma fusion devi...

  18. Current progress of nuclear astrophysics study and BRNBF at CIAE

    CERN Document Server

    LiuWeiPing; Bai Xi Xiang; Wang You Bao; Lian Gang; Zeng Sheng; Yan Sheng Quan; Wang Bao Xiang; Zhao Zhi Xiang; Zhang Tian Jue; Tang Hong Qing; Yang Bing Fan; Guan Xia Ling; Cui Bao Qun

    2003-01-01

    A secondary beam line (GIRAFFE) at the Beijing tandem accelerator lab was constructed for yielding low energy secondary beams. The current progress on the study of nuclear astrophysics and nuclear structure is presented. Up to now, we have carried out measurement of sup 7 Be(d,n) sup 8 B, sup 1 sup 1 C(d,n) sup 1 sup 2 N, sup 8 Li(d,n) sup 9 Be and sup 6 He(p,n) sup 6 Li reactions. The proposed Beijing radioactive nuclear beam facility and its current R and D progress are briefly introduced. This facility is based on the exist HI-13 tandem accelerator. A proton cyclotron will be built to provide 100 MeV 200 mu A proton beam, together with an isotope separator on line system and a super-conducting heavy ion LINAC. By this facility, intensity of order of 10 sup 9 pps radioactive nuclear beams for mass up to A=120 will be produced.

  19. Falling through spacetime: Four studies in neutrino astrophysics

    Science.gov (United States)

    Kishimoto, Chad T.

    2009-06-01

    For a significant fraction of the history of the universe, neutrinos freely fall through spacetime. While they only weakly interact with matter, neutrinos have a significant impact in astrophysics. Experimental neutrino physics and observational cosmology are amidst an interesting era, where precision measurements in both fields have significantly improved scientific understanding of the standard model of particle physics and of the universe. Experiments in neutrino physics have not only discerned that neutrinos are massive particles, but have also measured their relative masses (but not their absolute masses) and the quantum mechanical mixing matrix that is a consequence of these differing mass scales. Meanwhile, precision cosmological observations have determined the energy content of the universe, which in turn has presented a self-consistent story of the history and evolution of the universe and its contents. The topics discussed in this dissertation are based upon an interplay between these two fields, at times pushing the envelope, but always focused upon the basic physical processes that affect massive neutrinos in an expanding universe. A hearty, pedagogical introduction is presented to highlight the relevant neutrino physics described in this work and an overview of cosmology, strongly biased toward the early universe, the paradigm in which much of the work in this dissertation is based. Sterile neutrinos in different regimes of mass and mixing with active neutrinos are proposed as well as asymmetries between the number density of active neutrinos and antineutrinos in the early universe. The consequences of these two propositions are discussed in terms of observables such as primordial light element abundances and the observables related to a sterile neutrino dark matter candidate. Neutrino emission from high-entropy electron-positron plasmas are introduced, and the effects of this large flux of neutrinos and antineutrinos on hot hydrogen burning are

  20. Laboratory study of methyl isocyanate ices under astrophysical conditions

    Science.gov (United States)

    Maté, B.; Molpeceres, G.; Timón, V.; Tanarro, I.; Escribano, R.; Guillemin, J. C.; Cernicharo, J.; Herrero, V. J.

    2017-10-01

    Methyl isocyanate has been recently detected in comet 67P/Churyumov-Gerasimenko (67P/CG) and in the interstellar medium. New physicochemical studies on this species are now necessary as tools for subsequent studies in astrophysics. In this work, infrared spectra of solid CH3NCO have been obtained at temperatures of relevance for astronomical environments. The spectra are dominated by a strong, characteristic multiplet feature at 2350-2250 cm-1, which can be attributed to the asymmetric stretching of the NCO group. A phase transition from amorphous to crystalline methyl isocyanate is observed at ˜90 K. The band strengths for the absorptions of CH3NCO in ice at 20 K have been measured. Deuterated methyl isocyanate is used to help with the spectral assignment. No X-ray structure has been reported for crystalline CH3NCO. Here we advance a tentative theoretical structure, based on density functional theory (DFT) calculations, derived taking the crystal of isocyanic acid as a starting point. A harmonic theoretical spectrum is then calculated for the proposed structure and compared with the experimental data. A mixed ice of H2O and CH3NCO was formed by simultaneous deposition of water and methyl isocyanate at 20 K. The absence of new spectral features indicates that methyl isocyanate and water do not react appreciably at 20 K, but form a stable mixture. The high CH3NCO/H2O ratio reported for comet 67P/CG, and the characteristic structure of the 2350-2250 cm-1 band, makes it a very good candidate for future astronomical searches.

  1. Plasma astrophysics

    CERN Document Server

    Kaplan, S A; ter Haar, D

    2013-01-01

    Plasma Astrophysics is a translation from the Russian language; the topics discussed are based on lectures given by V.N. Tsytovich at several universities. The book describes the physics of the various phenomena and their mathematical formulation connected with plasma astrophysics. This book also explains the theory of the interaction of fast particles plasma, their radiation activities, as well as the plasma behavior when exposed to a very strong magnetic field. The text describes the nature of collective plasma processes and of plasma turbulence. One author explains the method of elementary

  2. Astrophysical Concepts

    CERN Document Server

    Harwit, Martin

    2006-01-01

    This classic text, aimed at senior undergraduates and beginning graduate students in physics and astronomy, presents a wide range of astrophysical concepts in sufficient depth to give the reader a quantitative understanding of the subject. Emphasizing physical concepts, the book outlines cosmic events but does not portray them in detail: it provides a series of astrophysical sketches. For this fourth edition, nearly every part of the text has been reconsidered and rewritten, new sections have been added to cover recent developments, and others have been extensively revised and brought up to date. The book begins with an outline of the scope of modern astrophysics and enumerates some of the outstanding problems faced in the field today. The basic physics needed to tackle these questions are developed in the next few chapters using specific astronomical processes as examples. The second half of the book enlarges on these topics and shows how we can obtain quantitative insight into the structure and evolution of...

  3. Photonuclear reactions in astrophysical p-process: Theoretical calculations and experiment simulation based on ELI-NP

    Directory of Open Access Journals (Sweden)

    Xu Yi

    2017-01-01

    Full Text Available The astrophysical p-process is an important way of nucleosynthesis to produce the stable and proton-rich nuclei beyond Fe which can not be reached by the s- and r-processes. In the present study, the astrophysical reaction rates of (γ,n, (γ,p, and (γ,α reactions are computed within the modern reaction code TALYS for about 3000 stable and proton-rich nuclei with 12 < Z < 110. The nuclear structure ingredients involved in the calculation are determined from experimental data whenever available and, if not, from global microscopic nuclear models. In particular, both of the Wood-Saxon potential and the double folding potential with density dependent M3Y (DDM3Y effective interaction are used for the calculations. It is found that the photonuclear reaction rates are very sensitive to the nuclear potential, and the better determination of nuclear potential would be important to reduce the uncertainties of reaction rates. Meanwhile, the Extreme Light Infrastructure-Nuclear Physics (ELI-NP facility is being developed, which will provide the great opportunity to experimentally study the photonuclear reactions in p-process. Simulations of the experimental setup for the measurements of the photonuclear reactions 96Ru(γ,p and 96Ru(γ,α are performed. It is shown that the experiments of photonuclear reactions in p-process based on ELI-NP are quite promising.

  4. Photonuclear reactions in astrophysical p-process: Theoretical calculations and experiment simulation based on ELI-NP

    Science.gov (United States)

    Xu, Yi; Luo, Wen; Balabanski, Dimiter; Goriely, Stephane; Matei, Catalin; Tesileanu, Ovidiu

    2017-09-01

    The astrophysical p-process is an important way of nucleosynthesis to produce the stable and proton-rich nuclei beyond Fe which can not be reached by the s- and r-processes. In the present study, the astrophysical reaction rates of (γ,n), (γ,p), and (γ,α) reactions are computed within the modern reaction code TALYS for about 3000 stable and proton-rich nuclei with 12 structure ingredients involved in the calculation are determined from experimental data whenever available and, if not, from global microscopic nuclear models. In particular, both of the Wood-Saxon potential and the double folding potential with density dependent M3Y (DDM3Y) effective interaction are used for the calculations. It is found that the photonuclear reaction rates are very sensitive to the nuclear potential, and the better determination of nuclear potential would be important to reduce the uncertainties of reaction rates. Meanwhile, the Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility is being developed, which will provide the great opportunity to experimentally study the photonuclear reactions in p-process. Simulations of the experimental setup for the measurements of the photonuclear reactions 96Ru(γ,p) and 96Ru(γ,α) are performed. It is shown that the experiments of photonuclear reactions in p-process based on ELI-NP are quite promising.

  5. Collaborative Astrophysical Research in Aire

    Science.gov (United States)

    Zhou, Jianfeng

    The AIRE (Astrophysical Integrated Research Environment) consists of three main parts: a Data Archive Center (DAC) which collects and manages public astrophysical data; a web-based Data Processing Center (DPC) which enables astrophysicists to process the data in a central server at any place and anytime; and a Collaborative Astrophysical Research Project System (CARPS) with which astrophysicists in different fields can pursue a collaborative reserch efficiently. Two research examples QPO study of RXTE data and wavelet analysis of large amount of galaxies are shown here.

  6. Radiative Processes in Astrophysical Gases: From the Intergalactic and Interstellar Medium to Exoplanetary Atmospheres

    Science.gov (United States)

    Oklopi'c, Antonija

    2017-05-01

    This thesis presents theoretical investigations in three areas of astrophysics, all related to radiative processes and interactions between stellar radiation and gaseous media in the Universe, ranging from the intergalactic and interstellar medium to planetary atmospheres. Part I of the thesis consists of two independent investigations in which we study the effects of stellar feedback in high-redshift environments. The topic of Chapter 2 is the intergalactic medium (IGM) in the epoch just after the formation of the first stars in the Universe, but before the cosmic reionization was completed. This epoch is of great interest for the ongoing and future experiments aimed at observing the neutral IGM via the redshifted 21 cm line of hydrogen. We study the effects of resonant scattering of Lyman-α photons produced by early stars on the structure of temperature fluctuations in the IGM. In Chapter 3, we use cosmological hydrodynamic simulations of galaxy evolution to study the effects of stellar feedback on the clumpy structure of star-forming galaxies at i>zproject. Part II of the thesis is devoted to the effects of Raman scattering of stellar radiation in the atmospheres of extrasolar planets. Spectral signatures of Raman scattering imprinted in the geometric albedo spectrum of a gaseous planet carry information about the properties of the planet's atmosphere--its composition, temperature, and the radiation-penetration depth. In Chapter 5, we present the results of radiative transfer calculations including the treatment of Raman scattering for different types of planetary atmospheres and analyze the feasibility of detecting the spectral signatures of Raman scattering in nearby exoplanets. The structure and the intensity of Raman spectral features depends on both the atmospheric properties and the shape of the stellar spectrum irradiating the atmosphere. In Chapter 6, we analyze the diversity of Raman features in the geometric albedo spectra of planets hosted by

  7. Pioneering mass measurements in the rare-earth region for the astrophysical r-process

    Science.gov (United States)

    Kelly, James M.; Vilen, Markus; Brodeur, Maxime; Kankainen, Anu; Igisol Team

    2017-09-01

    The astrophysical r-process generates around half of the elements heavier than iron, yet precisely where or how this occurs remains a topic of intense inquiry. Understanding the formation of one of its hallmarks, the rare-earth abundance peak, could shed light on the astrophysical sites because this feature is very sensitive to underlying nuclear properties, particularly to nuclear binding energies which have so far been largely derived from theoretical mass models. We have performed precise atomic mass measurements of 12 neutron-rich rare-earth isotopes using the JYFLTRAP double Penning trap mass spectrometer. The atomic masses of 158Nd, 160Pm, 162Sm, and 164-166Gd have been experimentally determined for the first time, and the precisions for 156Nd, 158Pm, 162,163Eu, 163Gd, and 164Tb have been significantly improved. The 163Gd measurement also indicates the presence of a previously suspected isomeric state. Trends in two-neutron separation energies are compared to theoretical mass model predictions, and the effects of these new mass measurements on r-process abundance calculations will be examined.

  8. A Laboratory Astrophysical Jet to Study Canonical Flux Tubes

    Energy Technology Data Exchange (ETDEWEB)

    You, Setthivoine [Univ. of Washington, Seattle, WA (United States)

    2017-12-20

    Understanding the interaction between plasma flows and magnetic fields remains a fundamental problem in plasma physics, with important applications to astrophysics, fusion energy, and advanced space propulsion. For example, flows are of primary importance in astrophysical jets even if it is not fully understood how jets become so long without becoming unstable. Theories for the origin of magnetic fields in the cosmos rely on flowing charged fluids that should generate magnetic fields, yet this remains to be demonstrated experimentally. Fusion energy reactors can be made smaller with flows that improve stability and confinement. Advanced space propulsion could be more efficient with collimated and stable plasma flows through magnetic nozzles but must eventually detach from the nozzle. In all these cases, there appears to be a spontaneous emergence of flowing and/or magnetic structures, suggesting a form of self-organization in plasmas. Beyond satisfying simple intellectual curiosity, understanding plasma self-organization could enable the development of methods to control plasma structures for fusion energy, space propulsion, and other applications. The research project has therefore built a theory and an experiment to investigate the interaction between magnetic fields and plasma flows. The theory is called canonical field theory for short, and the experiment is called Mochi after a rice cake filled with surprising, yet delicious fillings.

  9. Alpha induced reaction cross section measurements on {sup 162}Er for the astrophysical γ process

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, G.G., E-mail: ggkiss@atomki.mta.hu [Institute for Nuclear Research (MTA ATOMKI), H-4001 Debrecen (Hungary); Szücs, T. [Institute for Nuclear Research (MTA ATOMKI), H-4001 Debrecen (Hungary); Rauscher, T. [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Department of Physics, University of Basel, 4052 Basel (Switzerland); Török, Zs.; Fülöp, Zs.; Gyürky, Gy. [Institute for Nuclear Research (MTA ATOMKI), H-4001 Debrecen (Hungary); Halász, Z. [Institute for Nuclear Research (MTA ATOMKI), H-4001 Debrecen (Hungary); University of Debrecen, Department of Theoretical Physics, H-4001 Debrecen (Hungary); Somorjai, E. [Institute for Nuclear Research (MTA ATOMKI), H-4001 Debrecen (Hungary)

    2014-07-30

    The cross sections of the {sup 162}Er(α,γ){sup 166}Yb and {sup 162}Er(α,n){sup 165}Yb reactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from E{sub c.m.}=16.09 MeV down to E{sub c.m.}=11.21 MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48 MeV at 3 GK stellar temperature). The {sup 162}Er(α,n){sup 165}Yb reaction was studied above the reaction threshold between E{sub c.m.}=12.19 and 16.09 MeV. The fact that the {sup 162}Er(α,γ){sup 166}Yb cross sections were measured below the (α,n) threshold at first time in this mass region opens the opportunity to study directly the α-widths required for the determination of astrophysical reaction rates. The data clearly show that compound nucleus formation in this reaction proceeds differently than previously predicted.

  10. alpha-nucleus optical potential measurements for the astrophysical p-process

    CERN Document Server

    Fülöp, Z; Somorjai, E; Máté, Z; Zolnai, L; Galaviz, D; Babilon, M; Hillier, R; Mohr, P J; Zilges, A

    2003-01-01

    The heavy, proton-rich nuclei (p-nuclei) are produced by the so called astrophysical p-process during the explosive nucleosynthesis of massive stars. The (gamma,alpha) reaction rates show a strong dependence on the chosen alpha-nucleus potential, which makes them of special interest. Using this technique, the alpha-nucleus potentials of two proton rich nuclei ( sup 1 sup 4 sup 4 Sm and sup 9 sup 2 Mo) have been determined in the ATOMKI in the recent years [1,2]. These potentials have been used to calculate the (alpha,gamma) reaction cross sections, and their inverse (gamma,alpha) reaction rates can be calculated using detailed balance. (R.P.)

  11. Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

    CERN Document Server

    Caciolli, A; Di Leva, A; Formicola, A; Aliotta, M; Anders, M; Bellini, A; Bemmerer, D; Broggini, C; Campeggio, M; Corvisiero, P; Depalo, R; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Marta, M; Menegazzo, R; Napolitani, E; Prati, P; Rigato, V; Roca, V; Rolfs, C; Alvarez, C Rossi; Somorjai, E; Salvo, C; Straniero, O; Strieder, F; Szücs, T; Terrasi, F; Trautvetter, H P; Trezzi, D

    2012-01-01

    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.

  12. astrophysical significance

    Directory of Open Access Journals (Sweden)

    Dartois E.

    2014-02-01

    Full Text Available Clathrate hydrates, ice inclusion compounds, are of major importance for the Earth’s permafrost regions and may control the stability of gases in many astrophysical bodies such as the planets, comets and possibly interstellar grains. Their physical behavior may provide a trapping mechanism to modify the absolute and relative composition of icy bodies that could be the source of late-time injection of gaseous species in planetary atmospheres or hot cores. In this study, we provide and discuss laboratory-recorded infrared signatures of clathrate hydrates in the near to mid-infrared and the implications for space-based astrophysical tele-detection in order to constrain their possible presence.

  13. High energy astrophysics. An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Courvoisier, Thierry J.L. [Geneva Univ., Versoix (Switzerland). ISDC, Data Centre for Astrophysics

    2013-07-01

    Based on observational examples this book reveals and explains high-energy astrophysical processes. Presents the theory of astrophysical processes in a didactic approach by deriving equations step by step. With several attractive astronomical pictures. High-energy astrophysics has unveiled a Universe very different from that only known from optical observations. It has revealed many types of objects in which typical variability timescales are as short as years, months, days, and hours (in quasars, X-ray binaries, and other objects), and even down to milli-seconds in gamma ray bursts. The sources of energy that are encountered are only very seldom nuclear fusion, and most of the time gravitation, a paradox when one thinks that gravitation is, by many orders of magnitude, the weakest of the fundamental interactions. The understanding of these objects' physical conditions and the processes revealed by high-energy astrophysics in the last decades is nowadays part of astrophysicists' culture, even of those active in other domains of astronomy. This book evolved from lectures given to master and PhD students at the University of Geneva since the early 1990s. It aims at providing astronomers and physicists intending to be active in high-energy astrophysics a broad basis on which they should be able to build the more specific knowledge they will need. While in the first part of the book the physical processes are described and derived in detail, the second part studies astrophysical objects in which high-energy astrophysics plays a crucial role. This two-pronged approach will help students recognise physical processes by their observational signatures in contexts that may differ widely from those presented here.

  14. Nanostructured surfaces for nuclear astrophysics studies in laser-plasmas

    Science.gov (United States)

    Altana, Carmen; Amarù, Vincenzo; Castro, Giuseppe; Frassetto, Marco; Lanzalone, Gaetano; Malferrari, Luciana; Mascali, David; Muoio, Annamaria; Odorici, Fabrizio; Tudisco, Salvo

    2018-01-01

    The future availability of high-intensity laser facilities capable of delivering tens of petawatts of power (e.g. ELI-NP) into small volumes of matter at high repetition rates will give the unique opportunity to investigate nuclear reactions and fundamental interactions process under extreme plasma conditions [1]. In this context, use of targets with nanostructured surfaces is giving promising indications to reproduce plasma conditions suitable for measurements of thermonuclear reactions rates, in the domain of nanosecond laser pulses.

  15. Astrophysical Hydrodynamics An Introduction

    CERN Document Server

    Shore, Steven N

    2007-01-01

    This latest edition of the proven and comprehensive treatment on the topic -- from the bestselling author of ""Tapestry of Modern Astrophysics"" -- has been updated and revised to reflect the newest research results. Suitable for AS0000 and AS0200 courses, as well as advanced astrophysics and astronomy lectures, this is an indispensable theoretical backup for studies on celestial body formation and astrophysics. Includes exercises with solutions.

  16. Low-energy nuclear astrophysics studies at the Multicharged Ion Research Facility

    Science.gov (United States)

    Febbraro, Michael; Pain, Steven; Bannister, Mark; Deboer, Richard; Chipps, Kelly; Havener, Charles; Peters, Willan; Ummel, Chad; Smith, Michael; Temanson, Eli; Toomey, Rebecca; Walter, David

    2017-09-01

    As low-energy nuclear astrophysics progresses toward measuring reaction cross sections in the stellar burning regimes, a worldwide effort is underway to continue these measurements at underground laboratories to achieve the requisite ultra-low-background environment. These facilities are crucial for providing the required low-background environments to perform such measurements of astrophysical importance. While advances have been made in the use of accelerators underground, of equal importance is the detectors, high-current targets, and techniques required to perform such measurements. With these goals in mind, a newly established astrophysics beamline has been built at the Multicharged Ion Research Facility (MIRF) located at Oak Ridge National Laboratory. The unique capabilities of MIRF will be demonstrated through two recent low-energy above-ground measurements of the dominant s-process neutron source 13C(α,n)16O and associated beam-induced background source 13C(d,n)14N. This material is based upon work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics. Research sponsored by the LDRD Program of ORNL, managed by UT-Battelle, LLC, for the U.S. DOE.

  17. Experimental studies of keV energy neutron-induced reactions relevant to astrophysics and nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Shima, T.; Kii, T.; Kikuchi, T.; Okazaki, F.; Kobayashi, T.; Baba, T.; Nagai, Y. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Igashira, M.

    1997-03-01

    Nuclear reactions induced by keV energy neutrons provide a plenty of informations for studies of both astrophysics and nuclear physics. In this paper we will show our experimental studies of neutron- induced reactions of light nuclei in the keV energy region by means of a pulsed keV neutron beam and high-sensitivity detectors. Also we will discuss astrophysical and nuclear-physical consequences by using the obtained results. (author)

  18. Study of the {sup 3}He(α,γ){sup 7}Be and {sup 3}H(α,γ){sup 7}Li reactions at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, H.; Ghasemi, R. [Arak University, Arak (Iran, Islamic Republic of)

    2014-06-15

    We have studied the important astrophysical {sup 3}He(α,γ){sup 7}Be and {sup 3}H(α,γ){sup 7}Li reactions in the framework of a potential model. {sup 3}He(α,γ){sup 7}Be and {sup 3}H(α,γ){sup 7}Li processes are key reactions in both big bang nucleosynthesis and the p-p chain of hydrogen-burning in stars. The stellar {sup 3}He(α,γ){sup 7}Be and {sup 3}H(α,γ){sup 7}Li reactions were analyzed at low energies on the basis of a direct radiative capture mechanism. The astrophysical S-factors near zero energy were calculated without using the effective expansion of the S-factor or the asymptotic wave functions. In this paper, {sup 3}He(α,γ){sup 7}Be and {sup 3}H(α,γ){sup 7}Li radiative capture reactions at very low energies are taken as a case study. Using the M3Y potential, we have calculated the astrophysical S-factors for the E1 transition. In comparison with other theoretical methods and available experimental data, excellent agreement is achieved for the astrophysical S-factors of these processes.

  19. A space Fresnel imager concept assessment study led by CNES for astrophysical applications

    Science.gov (United States)

    Hinglais, Emmanuel

    2011-06-01

    In 2009, the Centre National d'Etudes Spatiales (CNES) carried out an assessment study on a "Fresnel telescope" concept based on a two-spacecraftformation flying configuration. This concept uses a binary Fresnel zone plate, and the principle of diffraction focusing, which allows high resolution optical imaging for astrophysics. In addition to CNES, the Laboratoire d'Astrophysique de Toulouse Tarbes (LATT) was deeply involved at two levels: through Research & Technology (R&T) studies to simulate and validate on a test bench the Fresnel concept performance, and through active participation in the CNES team for the optical aspects and to define the astrophysical fields of Fresnel-based space missions. The study was conducted within the technical limitations that resulted from a compromise between the R&T state of the art and the potential scientific domains of interest. The main technical limitations are linked to the size of the primary Fresnel array and to its usable spectral bandwidth. In this framework, the study covers ambitious architectures, correlating the technology readiness of the main critical components with the time-scale and programmatic horizons. The possible scientific topics arise from this range of missions. In this paper, I present a mission launched by a Soyuz, dedicated to astrophysics in the Ultra Violet (UV) band: 120 to 300 nm using a 4-m Fresnel array. It could be competitive in the next fifteen years, whereas a 10-m aperture mission in different bands; UV, visible or Infra Red (IR) (up to 6 μm) could be achievable in the future. Larger missions, using a primary array larger than 20 m, request technologies not yet available but that will probably be based on new inflatable structures with membranes, as already tested in the USA for other ends.

  20. Astrophysics Decoding the cosmos

    CERN Document Server

    Irwin, Judith A

    2007-01-01

    Astrophysics: Decoding the Cosmos is an accessible introduction to the key principles and theories underlying astrophysics. This text takes a close look at the radiation and particles that we receive from astronomical objects, providing a thorough understanding of what this tells us, drawing the information together using examples to illustrate the process of astrophysics. Chapters dedicated to objects showing complex processes are written in an accessible manner and pull relevant background information together to put the subject firmly into context. The intention of the author is that the book will be a 'tool chest' for undergraduate astronomers wanting to know the how of astrophysics. Students will gain a thorough grasp of the key principles, ensuring that this often-difficult subject becomes more accessible.

  1. Relativistic astrophysics

    CERN Document Server

    Demianski, Marek

    2013-01-01

    Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity

  2. Laboratory high-energy astrophysics on lasers

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, W.H.; Liedahl, D.A.; Walling, R.S.; Foord, M.E.; Osterheld, A.L.; Wilson, B.G.

    1994-12-01

    The tremendous range of temperatures and densities spanned by astrophysical plasmas has significant overlap with conditions attainable using high-power laser facilities. These facilities provide an opportunity to create, control, and characterize plasmas in the laboratory that mirror conditions in some of the most important cosmological systems. Moreover, laboratory experiments can enhance astrophysical understanding by focusing on and isolating important physical processes, without necessarily reproducing the exact conditions of the integral system. Basic study of radiative properties, transport phenomena, thermodynamic response and hydrodynamic evolution in plasmas under properly scaled conditions leads both directly and indirectly to improved models of complex astrophysical systems. In this paper, we will discuss opportunities for current and planned highpower lasers to contribute to the study of high-energy astrophysics.

  3. Formal results regarding metric space techniques for the study of astrophysical maps

    Science.gov (United States)

    Adams, Fred C.; Wiseman, Jennifer J.

    1994-01-01

    We extend a newly developed formal system for the description of astrophyscial maps. In this formalism, we consider the difference between maps to be the distance between elements of a pseudometric space (the space of all such maps). This Ansatz allows us to measure quantitatively the difference between any two maps and to order the space of all maps. For each physical characteristic of interest, this technique assigns an 'output' function to each map; the difference between the maps is then determined from the difference between their corresponding output functions. In this present study, we show that the results of this procedure are invariant under a class of transformations of the maps and the domains of the maps. In addition, we study the propagation of errors (observational uncertainties) through this formalism. We show that the uncertainties in the output functions can be controlled provided that the signal to noise ratios in the original astrophysical maps are sufficiently high. The results of this paper thus increase the effectiveness of this formal system for the description, classification, and analysis of astrophysical maps.

  4. Underground nuclear astrophysics: why and how

    CERN Document Server

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

    2016-01-01

    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. Astrophysics teaching at Assam University, Silchar

    Science.gov (United States)

    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.

  6. The efficient photodesorption of nitric oxide (NO) ices. A laboratory astrophysics study

    Science.gov (United States)

    Dupuy, R.; Féraud, G.; Bertin, M.; Michaut, X.; Putaud, T.; Jeseck, P.; Philippe, L.; Romanzin, C.; Baglin, V.; Cimino, R.; Fillion, J.-H.

    2017-10-01

    The study and quantification of UV photon-induced desorption of frozen molecules furthers our understanding of the chemical evolution of cold interstellar regions. Nitric oxide (NO) is an important intermediate species in both gas-phase and solid-phase chemical networks. In this work, we present quantitative measurements of the photodesorption of a pure NO ice. We used the tunable monochromatic synchrotron light of the DESIRS beamline of the SOLEIL facility near Paris to irradiate NO ices in the 6-13.6 eV range and measured desorption by quadrupole mass spectrometry. We find that NO photodesorption is very efficient, its yield being around 10-2 molecule per incident photon for UV fields relevant to the diffuse and dense interstellar medium. We discuss the extrapolation of our results to an astrophysical context and we compare photodesorption of NO to previously studied molecules.

  7. Nuclear Astrophysics

    Science.gov (United States)

    Drago, Alessandro

    2005-04-01

    The activity of the Italian nuclear physicists community in the field of Nuclear Astrophysics is reported. The researches here described have been performed within the project "Fisica teorica del nucleo e dei sistemi a multi corpi", supported by the Ministero dell'Istruzione, dell'Università e della Ricerca.

  8. Astrophysics today

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Nuclear Astrophysics

    CERN Document Server

    Langanke, K

    1999-01-01

    The manuscript reviews progress achieved in recent years in various aspects of nuclear astrophysics, including stellar nucleosynthesis, nuclear aspects of supernova collapse and explosion, neutrino-induced reactions and their possible role in the supernova mechanism and nucleosynthesis, explosive hydrogen burning in binary systems, and finally the observation of gamma-rays from supernova remnants.

  10. Relativistic astrophysics

    CERN Document Server

    Price, R H

    1993-01-01

    Work reported in the workshop on relativistic astrophysics spanned a wide varicy of topics. Two specific areas seemed of particular interest. Much attention was focussed on gravitational wave sources, especially on the waveforms they produce, and progress was reported in theoretical and observational aspects of accretion disks.

  11. Trojan Horse method and radioactive ion beams: study of $^{18}$F(p,$\\alpha$)$^{15}$O reaction at astrophysical energies

    CERN Document Server

    Gulino, M; Rapisarda, G G; Kubono, S; Lamia, L; La Cognata, M; Yamaguchi, H; Hayakawa, S; Wakabayashi, Y; Iwasa, N; Kato, S; Komatsubara, H; Teranishi, T; Coc, A; De Séréville, N; Hammache, F; Spitaleri, C

    2012-01-01

    The Trojan Horse Method was applied for the first time to a Radioactive Ion Beam induced reaction to study the reaction $^{18}$F(p,$\\alpha$)$^{15}$O via the three body reaction $^{18}$F(d,$\\alpha$ $^{15}$O)n at the low energies relevant for astrophysics. The abundance of $^{18}$F in Nova explosions is an important issue for the understanding of this astrophysical phenomenon. For this reason it is necessary to study the nuclear reactions that produce or destroy $^{18}$F in Novae. $^{18}$F(p,$\\alpha$)$^{15}$O is one of the main $^{18}$F destruction channels. Preliminary results are presented in this paper.

  12. Bio-inspired computational heuristics to study Lane-Emden systems arising in astrophysics model.

    Science.gov (United States)

    Ahmad, Iftikhar; Raja, Muhammad Asif Zahoor; Bilal, Muhammad; Ashraf, Farooq

    2016-01-01

    This study reports novel hybrid computational methods for the solutions of nonlinear singular Lane-Emden type differential equation arising in astrophysics models by exploiting the strength of unsupervised neural network models and stochastic optimization techniques. In the scheme the neural network, sub-part of large field called soft computing, is exploited for modelling of the equation in an unsupervised manner. The proposed approximated solutions of higher order ordinary differential equation are calculated with the weights of neural networks trained with genetic algorithm, and pattern search hybrid with sequential quadratic programming for rapid local convergence. The results of proposed solvers for solving the nonlinear singular systems are in good agreements with the standard solutions. Accuracy and convergence the design schemes are demonstrated by the results of statistical performance measures based on the sufficient large number of independent runs.

  13. Processing of N2O ice by fast ions: implications on nitrogen chemistry in cold astrophysical environments

    Science.gov (United States)

    Almeida, G. C.; Pilling, S.; de Barros, A. L. F.; da Costa, C. A. P.; Pereira, R. C.; da Silveira, E. F.

    2017-10-01

    Nitrous oxide, N2O, is found in the interstellar medium associated with dense molecular clouds and its abundance is explained by active chemistry occurring on N2 rich ice surfaces of dust grains. Such regions are being constantly exposed to ionizing radiation that triggers chemical processes which change molecular abundances with time. Due to its non-zero dipole moment, N2O can be used as an important tracer for the abundance of N2 in such regions as well as for characterization of nitrogen content of ices in outer bodies of Solar system. In this work, we experimentally investigate the resistance of frozen N2O molecules against radiation in attempt to estimate their half-life in astrophysical environments. All the radiolysis products, such as NO2 and NO, were identified by Fourier transform infrared spectroscopy. The infrared absorbance as a function of fluence is modified by ice compaction and by radiolysis, the compaction being dominant at the beginning of the ice processing. The N2O destruction cross-section as well the formation cross-sections of the products NxOy (x = 1-2 and y = 1-5) oxides and ozone (O3) by 1.5 MeV 14N+ ion beam are determined. The characterization of radiation resistance of N2O in cold astrophysical environments is relevant since it yields limits for the nitrogen abundance where the N2O molecule is used to indirectly derive its concentration. The half-life of solid N2O molecules dissociated by medium-mass cosmic rays at Pluto's orbit and at the interstellar medium is estimated.

  14. Observational astrophysics

    CERN Document Server

    Léna, Pierre; Lebrun, François; Mignard, François; Pelat, Didier

    2012-01-01

    This is the updated, widely revised, restructured and expanded third edition of Léna et al.'s successful work Observational Astrophysics. It presents a synthesis on tools and methods of observational astrophysics of the early 21st century. Written specifically for astrophysicists and graduate students, this textbook focuses on fundamental and sometimes practical limitations on the ultimate performance that an astronomical system may reach, rather than presenting particular systems in detail. In little more than a decade there has been extraordinary progress in imaging and detection technologies, in the fields of adaptive optics, optical interferometry, in the sub-millimetre waveband, observation of neutrinos, discovery of exoplanets, to name but a few examples. The work deals with ground-based and space-based astronomy and their respective fields. And it also presents the ambitious concepts behind space missions aimed for the next decades. Avoiding particulars, it covers the whole of the electromagnetic spec...

  15. Cognitive Astrophysics

    Science.gov (United States)

    Madore, Barry F.

    2012-09-01

    Cognitive Astrophysics works at the cusp between Cognitive Science and Astrophysics, drawing upon lessons learned in the Philosophy of Science, Linguistics and Artificial Intelligence. We will introduce and illustrate the concept of ``Downward Causation,'' common in philosophical discussions, but either unknown to or disdained by most physicists. A clear example operating on cosmological scales involving the origin of large-scale structure will be given. We will also make the case that on scales exceeding most laboratory experiments, self-gravitating matter can be considered to be in a ``fifth state'', characterized primarily by its negative specific heat, as first recognized by Lynden-Bell and Lynden-Bell (1977, MNRAS, 181, 405). Such systems increase their temperature as they lose energy. Numerous examples will be given and discussed.

  16. Cosmochemical evidence for astrophysical processes during the formation of our solar system.

    Science.gov (United States)

    MacPherson, Glenn J; Boss, Alan

    2011-11-29

    Through the laboratory study of ancient solar system materials such as meteorites and comet dust, we can recognize evidence for the same star-formation processes in our own solar system as those that we can observe now through telescopes in nearby star-forming regions. High temperature grains formed in the innermost region of the solar system ended up much farther out in the solar system, not only the asteroid belt but even in the comet accretion region, suggesting a huge and efficient process of mass transport. Bi-polar outflows, turbulent diffusion, and marginal gravitational instability are the likely mechanisms for this transport. The presence of short-lived radionuclides in the early solar system, especially (60)Fe, (26)Al, and (41)Ca, requires a nearby supernova shortly before our solar system was formed, suggesting that the Sun was formed in a massive star-forming region similar to Orion or Carina. Solar system formation may have been "triggered" by ionizing radiation originating from massive O and B stars at the center of an expanding HII bubble, one of which may have later provided the supernova source for the short-lived radionuclides. Alternatively, a supernova shock wave may have simultaneously triggered the collapse and injected the short-lived radionuclides. Because the Sun formed in a region where many other stars were forming more or less contemporaneously, the bi-polar outflows from all such stars enriched the local region in interstellar silicate and oxide dust. This may explain several observed anomalies in the meteorite record: a near absence of detectable (no extreme isotopic properties) presolar silicate grains and a dichotomy in the isotope record between (26)Al and nucleosynthetic (nonradiogenic) anomalies.

  17. Theoretical astrophysics an introduction

    CERN Document Server

    Bartelmann, Matthias

    2013-01-01

    A concise yet comprehensive introduction to the central theoretical concepts of modern astrophysics, presenting hydrodynamics, radiation, and stellar dynamics all in one textbook. Adopting a modular structure, the author illustrates a small number of fundamental physical methods and principles, which are sufficient to describe and understand a wide range of seemingly very diverse astrophysical phenomena and processes. For example, the formulae that define the macroscopic behavior of stellar systems are all derived in the same way from the microscopic distribution function. This function it

  18. Houdini for Astrophysical Visualization

    Science.gov (United States)

    Naiman, J. P.; Borkiewicz, Kalina; Christensen, A. J.

    2017-05-01

    The rapid growth in scale and complexity of both computational and observational astrophysics over the past decade necessitates efficient and intuitive methods for examining and visualizing large data sets. Here, we discuss some newly developed tools used to import and manipulate astrophysical data into the three-dimensional visual effects software, Houdini. This software is widely used by visual effects artists, but a recently implemented Python API now allows astronomers to more easily use Houdini as a visualization tool. This paper includes a description of features, workflow, and various example visualizations. The project website, www.ytini.com, is aimed at a scientific audience and contains Houdini tutorials and links to the Python script Bitbucket repository to simplify the process of importing and rendering astrophysical data.

  19. Compressive Sampling for Efficient Astrophysical Signals Digitizing: From Compressibility Study to Data Recovery

    Science.gov (United States)

    Gargouri, Yosra; Petit, Hervé; Loumeau, Patrick; Cecconi, Baptiste; Desgreys, Patricia

    2016-03-01

    The design of a new digital radio receiver for radio astronomical observations in outer space is challenged with energy and bandwidth constraints. This paper proposes a new solution to reduce the number of samples acquired under the Shannon-Nyquist limit while retaining the relevant information of the signal. For this, it proposes to exploit the sparsity of the signal by using a compressive sampling process (also called Compressed Sensing (CS)) at the Analog-to-Digital Converter (ADC) to reduce the amount of data acquired and the energy consumption. As an example of an astrophysical signal, we have analyzed a real Jovian signal within a bandwidth of 40MHz. We have demonstrated that its best sparsity is in the frequency domain with a sparsity level of at least 10% and we have chosen, through a literature review, the Non-Uniform Sampler (NUS) as the receiver architecture. A method for evaluating the reconstruction of the Jovian signal is implemented to assess the impact of CS compression on the relevant information and to calibrate the detection threshold. Through extensive numerical simulations, and by using Orthogonal Matching Pursuit (OMP) as the reconstruction algorithm, we have shown that the Jovian signal could be sensed by taking only 20% of samples at random, while still recovering the relevant information.

  20. Black-hole astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others

    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.

  1. Astrophysical cosmology

    Science.gov (United States)

    Bardeen, J. M.

    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.

  2. Study of the pd reaction in the astrophysical energy region using the Hall accelerator

    Science.gov (United States)

    Bystritsky, V. M.; Gerasimov, V. V.; Krylov, A. R.; Parzhitskii, S. S.; Dudkin, G. N.; Kaminskii, V. L.; Nechaev, B. A.; Padalko, V. N.; Petrov, A. V.; Mesyats, G. A.; Filipowicz, M.; Wozniak, J.; Bystritskii, Vit. M.

    2008-10-01

    The pd reaction at ultra-low proton deuteron collision energies has been studied using the Hall pulsed ion accelerator and the solid target of heavy water D2O. The experiment on measurement of the astrophysical Spd factor and the pd reaction cross-section was carried out at average pd collision energies 8.28, 9.49, and 10.10 keV. The 5.5-MeV γ rays from the pd reaction were detected by detectors based on plastic scintillators and NaI(Tl) crystals. Parameters of the accelerated hydrogen ion flux were measured and monitored with diagnostic equipment consisting of an energy analyzer, plasma optical radiation detectors, the Rogovsky belt, and collimated Faraday cups. The results obtained agree within the errors with the data of the pd experiments carried out by the LUNA collaboration at the Gran Sasso Laboratory with a target filled with gaseous deuterium. The reported experiment was carried out at the Hall ion accelerator of the Research Institute of Nuclear Physics, Tomsk Polytechnic University.

  3. Astrophysics of the Interstellar Medium

    CERN Document Server

    Maciel, Walter J

    2013-01-01

    The space between the stars includes a large variety of objects, where physical processes occur that are fundamental for the structure and evolution of galaxies. This book gives the reader some basic knowledge of these processes and at the same time, presents estimates of the main quantities relevant to the study of the interstellar medium. The book could be used as an introductory course on the interstellar medium  by science students or by readers interested in astrophysics with an adequate physics and mathematics background.

  4. New prototype of acousto-optical radio-wave spectrometer with parallel frequency processing for astrophysical applications

    Science.gov (United States)

    Shcherbakov, Alexandre S.; Chavez Dagostino, Miguel; Arellanes, Adan O.; Aguirre Lopez, Arturo

    2016-09-01

    We develop a multi-band spectrometer with a few spatially parallel optical arms for the combined processing of their data flow. Such multi-band capability has various applications in astrophysical scenarios at different scales: from objects in the distant universe to planetary atmospheres in the Solar system. Each optical arm exhibits original performances to provide parallel multi-band observations with different scales simultaneously. Similar possibility is based on designing each optical arm individually via exploiting different materials for acousto-optical cells operating within various regimes, frequency ranges and light wavelengths from independent light sources. Individual beam shapers provide both the needed incident light polarization and the required apodization to increase the dynamic range of a system. After parallel acousto-optical processing, data flows are united by the joint CCD matrix on the stage of the combined electronic data processing. At the moment, the prototype combines still three bands, i.e. includes three spatial optical arms. The first low-frequency arm operates at the central frequencies 60-80 MHz with frequency bandwidth 40 MHz. The second arm is oriented to middle-frequencies 350-500 MHz with frequency bandwidth 200-300 MHz. The third arm is intended for ultra-high-frequency radio-wave signals about 1.0-1.5 GHz with frequency bandwidth <300 MHz. To-day, this spectrometer has the following preliminary performances. The first arm exhibits frequency resolution 20 KHz; while the second and third arms give the resolution 150-200 KHz. The numbers of resolvable spots are 1500- 2000 depending on the regime of operation. The fourth optical arm at the frequency range 3.5 GHz is currently under construction.

  5. The X-Ray Surveyor Mission Concept Study: Forging the Path to NASA Astrophysics 2020 Decadal Survey Prioritization

    Science.gov (United States)

    Gaskin, Jessica; Ozel, Feryal; Vikhlinin, Alexey

    2016-01-01

    The X-Ray Surveyor mission concept is unique among those being studied for prioritization in the NASA Astrophysics 2020 Decadal Survey. The X-Ray Surveyor mission will explore the high-energy Universe; providing essential and complimentary observations to the Astronomy Community. The NASA Astrophysics Roadmap (Enduring Quests, Daring Visions) describes the need for an X-Ray Observatory that is capable of addressing topics such as the origin and growth of the first supermassive black holes, galaxy evolution and growth of the cosmic structure, and the origin and evolution of the stars that make up our Universe. To address these scientifically compelling topics and more, an Observatory that exhibits leaps in capability over that of previous X-Ray Observatories in needed. This paper describes the current status of the X-Ray Surveyor Mission Concept Study and the path forward, which includes scientific investigations, technology development, and community participation.

  6. Astrophysical disks Collective and Stochastic Phenomena

    CERN Document Server

    Fridman, Alexei M; Kovalenko, Ilya G

    2006-01-01

    The book deals with collective and stochastic processes in astrophysical discs involving theory, observations, and the results of modelling. Among others, it examines the spiral-vortex structure in galactic and accretion disks , stochastic and ordered structures in the developed turbulence. It also describes sources of turbulence in the accretion disks, internal structure of disk in the vicinity of a black hole, numerical modelling of Be envelopes in binaries, gaseous disks in spiral galaxies with shock waves formation, observation of accretion disks in a binary system and mass distribution of luminous matter in disk galaxies. The editors adaptly brought together collective and stochastic phenomena in the modern field of astrophysical discs, their formation, structure, and evolution involving the methodology to deal with, the results of observation and modelling, thereby advancing the study in this important branch of astrophysics and benefiting Professional Researchers, Lecturers, and Graduate Students.

  7. Astrophysics: An Integrative Course

    Science.gov (United States)

    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…

  8. Recent Progresses in Ab-Initio Studies of Low-Energy Few-Nucleon Reactions of Astrophysical Interest

    Science.gov (United States)

    Marcucci, Laura E.

    2017-03-01

    We review the most recent theoretical studies of nuclear reactions of astrophysical interest involving few-nucleon systems. In particular, we focus on the radiative capture of protons by deuterons in the energy range of interest for Big Bang Nucleosynthesis. Related to this, we will discuss also the most recent calculation of tritium β -decay. Two frameworks will be considered, the conventional and the chiral effective field theory approach.

  9. What does Astrophysics want to know about (Astrophysical) Reconnection?

    Science.gov (United States)

    Rosner, R.

    2005-12-01

    Magnetic reconnection is commonly invoked as a plasma energization and particle acceleration process in astrophysics, but the levels of detail regarding the underlying physics that are required are generally far demanding than what is typically encountered in laboratory or space plasma physics. Naively, one would therefore expect it to be far easier to answer questions regarding reconnection in the astrophysical context as opposed to the laboratory or space plasma physics contexts. My talk will focus on why this naive expectation is not correct, and will discuss the specifics of such astrophysics-motivated questions, as well as some possible answers.

  10. Accretion Processes in Astrophysics

    Science.gov (United States)

    González Martínez-País, Ignacio; Shahbaz, Tariq; Casares Velázquez, Jorge

    2014-03-01

    List of contributors; List of participants; Preface; Acknowledgments; Abbreviations; 1. Accretion disks Henk Spruit; 2. The evolution of binary systems Philipp Podsiadlowski; 3. Accretion onto white dwarfs Brian Warner; 4. Accretion in X-ray binary systems Robert I. Hynes; 5. X-ray binary populations in galaxies Giuseppina Fabbiano; 6. Observational characteristics of accretion onto black holes I Chris Done; 7. Observational characteristics of accretion onto black holes II Rob Fender; 8. Computing black hole accretion John F. Hawley; Appendix: Piazzi Smyth, the Cape of Good Hope, Tenerife and the siting of large telescopes Brian Warner.

  11. SOPHIA: Simulations Of Photo Hadronic Interactions in Astrophysics

    Science.gov (United States)

    Reimer, A.; Engel, Ralph; Rachen, J. P.; Protheroe, R. J.; Stanev, Todor

    2014-12-01

    SOPHIA (Simulations Of Photo Hadronic Interactions in Astrophysics) solves problems connected to photohadronic processes in astrophysical environments and can also be used for radiation and background studies at high energy colliders such as LEP2 and HERA, as well as for simulations of photon induced air showers. SOPHIA implements well established phenomenological models, symmetries of hadronic interactions in a way that describes correctly the available exclusive and inclusive photohadronic cross section data obtained at fixed target and collider experiments.

  12. Nuclear astrophysics with radioactive beams

    CERN Document Server

    Schatz, H

    2002-01-01

    Nuclei far from stability play an important role in our understanding of astrophysical scenarios with extreme temperature and density conditions. Among these are nova explosions, accreting neutron stars, supernovae, and the site of the r-process. I will give a brief review of the important open astrophysical questions in these scenarios and discuss the radioactive beam experiments at ISOL-type and at fragmentation-type facilities that are needed to answer them.

  13. Trends in Nuclear Astrophysics

    OpenAIRE

    Schatz, Hendrik

    2016-01-01

    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.

  14. High Time Resolution Astrophysics

    CERN Document Server

    Phelan, Don; Shearer, Andrew

    2008-01-01

    High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

  15. Astrophysics a new approach

    CERN Document Server

    Kundt, Wolfgang

    2005-01-01

    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 wary 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 in astrophysical research. The author compares mainstream interpretations with new and even controversial ones he wishes to emphasize. The...

  16. Nuclear astrophysics

    Science.gov (United States)

    Penionzhkevich, Yu. E.

    2010-08-01

    The International Year of Astronomy 2009 (IYA2009) was declared by the 62nd General Assembly of the United Nations and was also endorsed by UNESCO. Investigations in the realms of particle and nuclear physicsmake a large contribution in the development of our ideas of the properties of the Universe. The present article discusses some problems of the evolution of the Universe, nucleosyntheses, and cosmochronology from the point of view of nuclear and particle physics. Processes occurring in the Universe are compared with the mechanisms of the production and decay of nuclei, as well as with the mechanisms of their interaction at high energies. Examples that demonstrate the potential of nuclearphysics methods for studying cosmic objects and the properties of the Universe are given. The results that come from investigations into nuclear reactions induced by beams of radioactive nuclei and which make it possible to take a fresh look at the nucleosynthesis scenario in the range at light nuclei are presented.

  17. Microphysics of Astrophysical Flames

    Science.gov (United States)

    Dursi, L. J.; Zingale, M.; Caceres, A.; Calder, A. C.; Timmes, F. X.; Truran, J. W.; Rosner, R.; Lamb, D. Q.; Brown, E.; Ricker, P.; Fryxell, B.; Olson, K.; Riley, K.; Siegel, A.; Vladimirova, N.

    2003-03-01

    Type Ia supernovae are thought to begin with a deflagration phase, where burning occurs as a subsonic flame which accelerates and possibly undergoes a transition to a supersonic detonation. Both the acceleration and possible transition will depend on the microphysics of astrophysical flames, and their interaction with a turbulent flow in degenerate material. Here we present recent progress in studying the interactions of astrophysical flames and curvature and strain at the FLASH center; in particular, we discuss quantitative measurements of the effects of strain on burning rate of these flames, and implications for instability growth and quenching. This work was supported by the DOE ASCI/Alliances program at the University of Chicago under grant No. B341495 and the Scientific through Advanced Computing (SciDAC) program of the DOE, grant number DE-FC02-01ER41176 to the Supernova Science Center/UCSC.

  18. First application of the Trojan Horse Method with a Radioactive Ion Beam: study of the $^{18}$F($p,{\\alpha}$)$^{15}$O}} reaction at astrophysical energies

    CERN Document Server

    Cherubini, S; Spitaleri, C; Rapisarda, G G; La Cognata, M; Lamia, L; Pizzone, R G; Romano, S; Kubono, S; Yamaguchi, H; Hayakawa, S; Wakabayashi, Y; Iwasa, N; Kato, S; Komatsubara, T; Teranishi, T; Coc, A; de Séréville, N; Hammache, F; Kiss, G; Bishop, S; Binh, D N

    2015-01-01

    Measurement of nuclear cross sections at astrophysical energies involving unstable species is one of the most challenging tasks in experimental nuclear physics. The use of indirect methods is often unavoidable in this scenario. In this paper the Trojan Horse Method is applied for the first time to a radioactive ion beam induced reaction studying the $^{18}$F($p,{\\alpha}$)$^{15}$O process at low energies relevant to astrophysics via the three body reaction $^{2}$H($^{18}$F,${\\alpha}^{15}$O)n. The knowledge of the $^{18}$F($p, {\\alpha}$)$^{15}$O reaction rate is crucial to understand the nova explosion phenomena. The cross section of this reaction is characterized by the presence of several resonances in $^{19}$Ne and possibly interference effects among them. The results reported in Literature are not satisfactory and new investigations of the $^{18}$F($p,{\\alpha}$)$^{15}$O reaction cross section will be useful. In the present work the spin-parity assignments of relevant levels have been discussed and the astro...

  19. Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

    Science.gov (United States)

    Gatu Johnson, M.; Zylstra, A. B.; Bacher, A.; Brune, C. R.; Casey, D. T.; Forrest, C.; Herrmann, H. W.; Hohenberger, M.; Sayre, D. B.; Bionta, R. M.; Bourgade, J.-L.; Caggiano, J. A.; Cerjan, C.; Craxton, R. S.; Dearborn, D.; Farrell, M.; Frenje, J. A.; Garcia, E. M.; Glebov, V. Yu.; Hale, G.; Hartouni, E. P.; Hatarik, R.; Hohensee, M.; Holunga, D. M.; Hoppe, M.; Janezic, R.; Khan, S. F.; Kilkenny, J. D.; Kim, Y. H.; Knauer, J. P.; Kohut, T. R.; Lahmann, B.; Landoas, O.; Li, C. K.; Marshall, F. J.; Masse, L.; McEvoy, A.; McKenty, P.; McNabb, D. P.; Nikroo, A.; Parham, T. G.; Paris, M.; Petrasso, R. D.; Pino, J.; Radha, P. B.; Remington, B.; Rinderknecht, H. G.; Robey, H.; Rosenberg, M. J.; Rosse, B.; Rubery, M.; Sangster, T. C.; Sanchez, J.; Schmitt, M.; Schoff, M.; Séguin, F. H.; Seka, W.; Sio, H.; Stoeckl, C.; Tipton, R. E.

    2017-04-01

    This paper describes the development of a platform to study astrophysically relevant nuclear reactions using inertial-confinement fusion implosions on the OMEGA and National Ignition Facility laser facilities, with a particular focus on optimizing the implosions to study charged-particle-producing reactions. Primary requirements on the platform are high yield, for high statistics in the fusion product measurements, combined with low areal density, to allow the charged fusion products to escape. This is optimally achieved with direct-drive exploding pusher implosions using thin-glass-shell capsules. Mitigation strategies to eliminate a possible target sheath potential which would accelerate the emitted ions are discussed. The potential impact of kinetic effects on the implosions is also considered. The platform is initially employed to study the complementary T(t,2n)α, T(3He,np)α and 3He(3He,2p)α reactions. Proof-of-principle results from the first experiments demonstrating the ability to accurately measure the energy and yields of charged particles are presented. Lessons learned from these experiments will be used in studies of other reactions. The goals are to explore thermonuclear reaction rates and fundamental nuclear physics in stellar-like plasma environments, and to push this new frontier of nuclear astrophysics into unique regimes not reachable through existing platforms, with thermal ion velocity distributions, plasma screening, and low reactant energies.

  20. Advances IN Explosive Nuclear Astrophysics

    Science.gov (United States)

    Lotay, Gavin

    2016-09-01

    Breathtaking results from the Planck satellite mission and Hubble space telescope have highlighted the key role modern Astronomy is playing for our understanding of Big Bang Cosmology. However, not so widely publicized is the similar wealth of observational data now available on explosive stellar phenomena, such as X-ray bursts, novae and Supernovae. These astronomical events are responsible for the synthesis of almost all the chemical elements we find on Earth and observe in our Galaxy, as well as energy generation throughout the cosmos. Regrettably, understanding the latest collection of observational data is severely hindered by the current, large uncertainties in the underlying nuclear physics processes that drive such stellar scenarios. In order to resolve this issue, it is becoming increasingly clear that there is a need to explore the unknown properties and reactions of nuclei away from the line of stability. Consequently, state-of-the-art radioactive beam facilities have become terrestrial laboratories for the reproduction of explosive astrophysical events. In this talk, both direct and indirect methods for studying key astrophysical reactions using radioactive beams will be discussed.

  1. FLARE STARS—A FAVORABLE OBJECT FOR STUDYING MECHANISMS OF NONTHERMAL ASTROPHYSICAL PHENOMENA

    Energy Technology Data Exchange (ETDEWEB)

    Oks, E. [Physics Department, 206 Allison Lab., Auburn University, Auburn, AL 36849 (United States); Gershberg, R. E. [Crimean Astrophysical Observatory, Nauchny, Bakhchisaray region, Crimea, 298409 (Russian Federation)

    2016-03-01

    We present a spectroscopic method for diagnosing a low-frequency electrostatic plasma turbulence (LEPT) in plasmas of flare stars. This method had been previously developed by one of us and successfully applied to diagnosing the LEPT in solar flares. In distinction to our previous applications of the method, here we use the latest advances in the theory of the Stark broadening of hydrogen spectral lines. By analyzing observed emission Balmer lines, we show that it is very likely that the LEPT was developed in several flares of AD Leo, as well as in one flare of EV Lac. We found the LEPT (though of different field strengths) both in the explosive/impulsive phase and at the phase of the maximum, as well as at the gradual phase of the stellar flares. While for solar flares our method allows diagnosing the LEPT only in the most powerful flares, for the flare stars it seems that the method allows revealing the LEPT practically in every flare. It should be important to obtain new and better spectrograms of stellar flares, allowing their analysis by the method outlined in the present paper. This can be the most favorable way to the detailed understanding of the nature of nonthermal astrophysical phenomena.

  2. Microphysics in Astrophysical Plasmas

    Science.gov (United States)

    Schwartz, Steven J.; Zweibel, Ellen G.; Goldman, Martin

    Although macroscale features dominate astrophysical images and energetics, the physics is controlled through microscale transport processes (conduction, diffusion) that mediate the flow of mass, momentum, energy, and charge. These microphysical processes manifest themselves in key (all) boundary layers and also operate within the body of the plasma. Crucially, most plasmas of interest are rarefied to the extent that classical particle collision length- and time-scales are long. Collective plasma kinetic phenomena then serve to scatter or otherwise modify the particle distribution functions and in so-doing govern the transport at the microscale level. Thus collisionless plasmas are capable of supporting thin shocks, current sheets which may be prone to magnetic reconnection, and the dissipation of turbulence cascades at kinetic scales. This paper lays the foundation for the accompanying collection that explores the current state of knowledge in this subject. The richness of plasma kinetic phenomena brings with it a rich diversity of microphysics that does not always, if ever, simply mimic classical collision-dominated transport. This can couple the macro- and microscale physics in profound ways, and in ways which thus depend on the astrophysical context.

  3. Astrophysical techniques

    CERN Document Server

    Kitchin, CR

    2013-01-01

    DetectorsOptical DetectionRadio and Microwave DetectionX-Ray and Gamma-Ray DetectionCosmic Ray DetectorsNeutrino DetectorsGravitational Radiation Dark Matter and Dark Energy Detection ImagingThe Inverse ProblemPhotographyElectronic ImagingScanningInterferometrySpeckle InterferometryOccultationsRadarElectronic ImagesPhotometryPhotometryPhotometersSpectroscopySpectroscopy SpectroscopesOther TechniquesAstrometryPolarimetrySolar StudiesMagnetometryComputers and The Internet.

  4. Spectroscopic study of the radionuclide 21Na for the astrophysical 17F(α ,p )20Ne reaction rate

    Science.gov (United States)

    Cha, S. M.; Chae, K. Y.; Ahn, S.; Bardayan, D. W.; Chipps, K. A.; Cizewski, J. A.; Howard, M. E.; Kozub, R. L.; Kwak, K.; Manning, B.; Matos, M.; O'Malley, P. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Ratkiewicz, A.; Smith, M. S.; Strauss, S.

    2017-08-01

    The 24Mg(p ,α )21Na reaction was measured at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory to study the spectroscopy of the radionuclide 21Na. A 31-MeV proton beam from the 25 MV tandem accelerator bombarded isotopically enriched 24Mg targets. Recoiling 4He particles were identified by an annular silicon strip detector array. Two energy levels at Ex=6.594 and 7.132 MeV were observed for the first time. By comparing the experimentally obtained angular distributions and distorted wave Born approximation calculations, the spins and parities of 21Na energy levels were constrained. The astrophysically-important 17F(α ,p )20Ne reaction rate was also calculated for the first time using resonance parameters for 12 energy levels.

  5. Nuclear astrophysics lessons from INTEGRAL.

    Science.gov (United States)

    Diehl, Roland

    2013-02-01

    Measurements of high-energy photons from cosmic sources of nuclear radiation through ESA's INTEGRAL mission have advanced our knowledge: new data with high spectral resolution showed that characteristic gamma-ray lines from radioactive decays occur throughout the Galaxy in its interstellar medium. Although the number of detected sources and often the significance of the astrophysical results remain modest, conclusions derived from this unique astronomical window of radiation originating from nuclear processes are important, complementing the widely-employed atomic-line based spectroscopy. We review the results and insights obtained in the past decade from gamma-ray line measurements of cosmic sources in the context of their astrophysical questions.

  6. High Energy Density Laboratory Astrophysics

    CERN Document Server

    Lebedev, Sergey V

    2007-01-01

    During the past decade, research teams around the world have developed astrophysics-relevant research utilizing high energy-density facilities such as intense lasers and z-pinches. Every two years, at the International conference on High Energy Density Laboratory Astrophysics, scientists interested in this emerging field discuss the progress in topics covering: - Stellar evolution, stellar envelopes, opacities, radiation transport - Planetary Interiors, high-pressure EOS, dense plasma atomic physics - Supernovae, gamma-ray bursts, exploding systems, strong shocks, turbulent mixing - Supernova remnants, shock processing, radiative shocks - Astrophysical jets, high-Mach-number flows, magnetized radiative jets, magnetic reconnection - Compact object accretion disks, x-ray photoionized plasmas - Ultrastrong fields, particle acceleration, collisionless shocks. These proceedings cover many of the invited and contributed papers presented at the 6th International Conference on High Energy Density Laboratory Astrophys...

  7. A pair spectrometer for nuclear astrophysics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Guerro, L.; Saltarelli, A.; Tabassam, U. [University of Camerino, Division of Physics, School of Science and Technology, Camerino (Italy); INFN, Sezione di Perugia, Perugia (Italy); Di Leva, A. [INFN, Napoli (Italy); University of Naples ' ' Federico II' ' , Physics Department, Naples (Italy); Gialanella, L.; De Cesare, N.; D' Onofrio, A.; Terrasi, F. [Second University of Naples, Department of Mathematics and Physics, Caserta (Italy); INFN, Napoli (Italy); Schuermann, D.; Romoli, M. [INFN, Napoli (Italy); Busso, M. [INFN, Sezione di Perugia, Perugia (Italy); University of Perugia, Department of Physics, Perugia (Italy)

    2014-11-15

    Non-radiative transitions in nuclear capture reactions between light nuclei play a relevant role in stellar nuclear astrophysics, where nuclear processes occur at typical energies from tens to hundreds of keV. At higher energies, instead, the E0 contributions may be shadowed by more intense transitions. The experimental study of E0 transitions requires a specific detection setup, able to uniquely identify events where an electron-positron pair is produced. A compact ΔE-E charged-particle spectrometer based on two silicon detectors has been designed to be installed in the jet gas target chamber of the recoil mass separator ERNA (European Recoil separator for Nuclear Astrophysics) at the CIRCE laboratory of Caserta, Italy. The detector design, its performances and the first foreseen applications are described. (orig.)

  8. NASA Astrophysics Funds Strategic Technology Development

    Science.gov (United States)

    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

  9. New sup 22 Ne(. alpha. ,n) sup 25 Mg-resonances at very low energies relevant for the astrophysical s-process

    Energy Technology Data Exchange (ETDEWEB)

    Drotleff, H.W.; Denker, A.; Hammer, J.W.; Knee, H.; Kuechler, S.; Streit, D. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Strahlenphysik); Rolfs, C.; Trautvetter, H.P. (Bochum Univ. (Germany, F.R.). Inst. fuer Experimentalphysik 3)

    1991-03-01

    The {sup 22}Ne({alpha}, n){sup 25}Mg reaction is thought to be one of the main neutron sources for the astrophysical s-process. Thus cross section data for this reaction have been obtained from near the threshold (E{sub {alpha}}{approx equal}570 keV) up to E{sub {alpha}}=2100 keV using the 4 MV DYNAMITRON accelertor at Stuttgart, the windowless gastarget system RHINOCEROS and a 4 {pi} neutron detector. Two new resonances have been observed E{sub {alpha}}=623+-6 and 838+-6 keV, which dominate the reaction rate at T{sub 9}<0.3. Possible background reactions are discussed. (orig.).

  10. Particle Physics & Astrophysics (PPA)

    Data.gov (United States)

    Federal Laboratory Consortium — Scientists at SLAC's Particle Physics and Astrophysics develop and utilize unique instruments from underground to outer space to explore the ultimate laws of nature...

  11. Transient Astrophysics Probe

    Science.gov (United States)

    Camp, Jordan

    2017-08-01

    Transient Astrophysics Probe (TAP), selected by NASA for a funded Concept Study, is a wide-field high-energy transient mission proposed for flight starting in the late 2020s. TAP’s main science goals, called out as Frontier Discovery areas in the 2010 Decadal Survey, are time-domain astrophysics and counterparts of gravitational wave (GW) detections. The mission instruments include unique imaging soft X-ray optics that allow ~500 deg2 FoV in each of four separate modules; a high sensitivity, 1 deg2 FoV soft X-ray telescope based on single crystal silicon optics; a passively cooled, 1 deg2 FoV Infrared telescope with bandpass 0.6-3 micron; and a set of ~8 small NaI gamma-ray detectors. TAP will observe many events per year of X-ray transients related to compact objects, including tidal disruptions of stars, supernova shock breakouts, neutron star bursts and superbursts, and high redshift Gamma-Ray Bursts. Perhaps most exciting is TAP’s capability to observe X-ray and IR counterparts of GWs involving stellar mass black holes detected by LIGO/Virgo, and possibly X-ray counterparts of GWs from supermassive black holes, detected by LISA and Pulsar Timing Arrays.

  12. Titles of Scientific Letters and Research Papers in Astrophysics: A Comparative Study of Some Linguistic Aspects and Their Relationship with Collaboration Issues

    Science.gov (United States)

    Méndez, David I.; Alcaraz, M. Ángeles

    2017-01-01

    In this study we compare the titles of scientific letters and those of research papers published in the field of astrophysics in order to identify the possible differences and/or similarities between both genres in terms of several linguistic and extra-linguistic variables (length, lexical density, number of prepositions, number of compound…

  13. Traversable braneworld wormholes supported by astrophysical observations

    Science.gov (United States)

    Wang, Deng; Meng, Xin-He

    2018-02-01

    In this study, we investigate the characteristics and properties of a traversable wormhole constrained by the current astrophysical observations in the framework of modified theories of gravity (MOG). As a concrete case, we study traversable wormhole space-time configurations in the Dvali-Gabadadze-Porrati (DGP) braneworld scenario, which are supported by the effects of the gravity leakage of extra dimensions. We find that the wormhole space-time structure will open in terms of the 2 σ confidence level when we utilize the joint constraints supernovae (SNe) Ia + observational Hubble parameter data (OHD) + Planck + gravitational wave (GW) and z wormholes can be divided into four classes during the evolutionary processes of the universe based on various energy conditions; (ii) we can offer a strict restriction to the local wormhole space-time structure by using the current astrophysical observations; and (iii) we can clearly identify a physical gravitational resource for the wormholes supported by astrophysical observations, namely the dark energy components of the universe or equivalent space-time curvature effects from MOG. Moreover, we find that the strong energy condition is always violated at low redshifts.

  14. Determining the 13C(α, n)16O absolute cross section through the concurrent application of ANC and THM and astrophysical consequences for the s-process in AGB-LMSs.

    Science.gov (United States)

    Trippella, Oscar; La Cognata, Marco

    2018-01-01

    The 13C(α, n)16O reaction is considered to be the most important neutron source for the s-process main component in low-mass asymptotic giant branch stars. No direct experimental data exist at very low energies and measurements performed through direct techniques show inconsistent results, mostly in their absolute values. In this context, we reversed the usual normalization procedure combining two indirect approaches, the asymptotic normalization coefficient and the Trojan Horse Method, to unambiguously determine the absolute value of the 13C(α, n)16O astrophysical S(E)-factor in the most relevant energy-region for astrophysics. Adopting the new reaction rate for the n-source in the NEWTON s-process nucleosynthesis code, astrophysical calculations show only limited variations, less than 1%, for those nuclei whose production is considered to be totally due to slow neutron captures.

  15. NASA's Physics of the Cosmos and Cosmic Origins programs manage Strategic Astrophysics Technology (SAT) development

    Science.gov (United States)

    Pham, Thai; Thronson, Harley; Seery, Bernard; Ganel, Opher

    2016-07-01

    The strategic astrophysics missions of the coming decades will help answer the questions "How did our universe begin and evolve?" "How did galaxies, stars, and planets come to be?" and "Are we alone?" Enabling these missions requires advances in key technologies far beyond the current state of the art. NASA's Physics of the Cosmos2 (PCOS), Cosmic Origins3 (COR), and Exoplanet Exploration Program4 (ExEP) Program Offices manage technology maturation projects funded through the Strategic Astrophysics Technology (SAT) program to accomplish such advances. The PCOS and COR Program Offices, residing at the NASA Goddard Space Flight Center (GSFC), were established in 2011, and serve as the implementation arm for the Astrophysics Division at NASA Headquarters. We present an overview of the Programs' technology development activities and the current technology investment portfolio of 23 technology advancements. We discuss the process for addressing community-provided technology gaps and Technology Management Board (TMB)-vetted prioritization and investment recommendations that inform the SAT program. The process improves the transparency and relevance of our technology investments, provides the community a voice in the process, and promotes targeted external technology investments by defining needs and identifying customers. The Programs' priorities are driven by strategic direction from the Astrophysics Division, which is informed by the National Research Council's (NRC) "New Worlds, New Horizons in Astronomy and Astrophysics" (NWNH) 2010 Decadal Survey report [1], the Astrophysics Implementation Plan (AIP) [2] as updated, and the Astrophysics Roadmap "Enduring Quests, Daring Visions" [3]. These priorities include technology development for missions to study dark energy, gravitational waves, X-ray and inflation probe science, and large far-infrared (IR) and ultraviolet (UV)/optical/IR telescopes to conduct imaging and spectroscopy studies. The SAT program is the

  16. Galaxy Evolution Studies with the SPace IR Telescope for Cosmology and Astrophysics (SPICA): The Power of IR Spectroscopy

    Science.gov (United States)

    Spinoglio, L.; Alonso-Herrero, A.; Armus, L.; Baes, M.; Bernard-Salas, J.; Bianchi, S.; Bocchio, M.; Bolatto, A.; Bradford, C.; Braine, J.; Carrera, F. J.; Ciesla, L.; Clements, D. L.; Dannerbauer, H.; Doi, Y.; Efstathiou, A.; Egami, E.; Fernández-Ontiveros, J. A.; Ferrara, A.; Fischer, J.; Franceschini, A.; Gallerani, S.; Giard, M.; González-Alfonso, E.; Gruppioni, C.; Guillard, P.; Hatziminaoglou, E.; Imanishi, M.; Ishihara, D.; Isobe, N.; Kaneda, H.; Kawada, M.; Kohno, K.; Kwon, J.; Madden, S.; Malkan, M. A.; Marassi, S.; Matsuhara, H.; Matsuura, M.; Miniutti, G.; Nagamine, K.; Nagao, T.; Najarro, F.; Nakagawa, T.; Onaka, T.; Oyabu, S.; Pallottini, A.; Piro, L.; Pozzi, F.; Rodighiero, G.; Roelfsema, P.; Sakon, I.; Santini, P.; Schaerer, D.; Schneider, R.; Scott, D.; Serjeant, S.; Shibai, H.; Smith, J.-D. T.; Sobacchi, E.; Sturm, E.; Suzuki, T.; Vallini, L.; van der Tak, F.; Vignali, C.; Yamada, T.; Wada, T.; Wang, L.

    2017-11-01

    IR spectroscopy in the range 12-230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA's large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z 6.

  17. Stellar Astrophysics with Arcus

    Science.gov (United States)

    Brickhouse, Nancy S.; Huenemoerder, David P.; Wolk, Scott; Schulz, Norbert; Foster, Adam; Brenneman, Laura; Poppenhaeger, Katja; Arcus Team

    2018-01-01

    The Arcus mission is now in Phase A of the NASA Medium-Class Explorer competition. We present here the Arcus science case for stellar astrophysics. With spectral resolving power of at least 2500 and effective area greater than 400 cm^2, Arcus will measure new diagnostic lines, e.g. for H- and He-like ions of oxygen and other elements. Weak dielectronic recombination lines will provide sensitive measurements of temperature to test stellar coronal heating models. Arcus will also resolve the coronal and accretion line components in young accreting stars, allowing detailed studies of accretion shocks and their post-shock behavior. Arcus can resolve line shapes and variability in hot star winds to study inhomogeneities and dynamics of wind structure. Such profiles will provide an independent measure of mass loss rates, for which theoretical and observational discrepancies can reach an order of magnitude. Arcus will also study exoplanet atmospheres through X-ray absorption, determing their extent and composition.

  18. Current Perspectives in High Energy Astrophysics

    Science.gov (United States)

    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.

  19. Astronomy and astrophysics

    National Research Council Canada - National Science Library

    National Research Council Staff

    1988-01-01

    ... for the Decades 1995 to 2015 Astronomy and Astrophysics Task Group on Astronomy and Astrophysics Space Science Board Commission on Physical Sciences, Mathematics, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1988 Copyrightoriginal retained, the be not from cannot book, paper original however, for version formatting, author...

  20. Theoretical Particle Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Kamionkowski, Marc [Johns Hopkins Univ., Baltimore, MD (United States)

    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.

  1. Applications of the Trojan Horse method in nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Spitaleri, Claudio, E-mail: spitaleri@lns.infn.it [Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy and Laboratori Nazionali del Sud-INFN, Catania (Italy)

    2015-02-24

    The study of the energy production in stars and related nucleosyntesis processes requires increasingly precise knowledge of the nuclear reaction cross section and reaction rates at interaction energy. In order to overcome the experimental difficulties, arising from small cross-sections involved in charge particle induced reactions at astrophysical energies, and from the presence of electron screening, it was necessary to introduce indirect methods. Trough these methods it is possible to measure cross sections at very small energies and retrieve information on electron screening effect when ultra-low energy direct measurements are available. The Trojan Horse Method (THM) represents the indirect technique to determine the bare nucleus astrophysical S-factor for reactions between charged particles at astrophysical energies. The basic theory of the THM is discussed in the case of non-resonant.

  2. Experimental astrophysics with high power lasers and Z pinches

    Energy Technology Data Exchange (ETDEWEB)

    Remington, B A; Drake, R P; Ryutov, D D

    2004-12-10

    With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

  3. 77 FR 62536 - Meeting of Astrophysics Subcommittee of the NASA Advisory Council Science Committee

    Science.gov (United States)

    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 the...

  4. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  5. Astrophysics in a nutshell

    CERN Document Server

    Maoz, Dan

    2007-01-01

    A concise but thorough introduction to the observational data and theoretical concepts underlying modern astronomy, Astrophysics in a Nutshell is designed for advanced undergraduate science majors taking a one-semester course. This well-balanced and up-to-date textbook covers the essentials of modern astrophysics--from stars to cosmology--emphasizing the common, familiar physical principles that govern astronomical phenomena, and the interplay between theory and observation. In addition to traditional topics such as stellar remnants, galaxies, and the interstellar medium, Astrophysics in a N

  6. An invitation to astrophysics

    CERN Document Server

    Padmanabhan, Thanu

    2006-01-01

    This unique book provides a clear and lucid description of several aspects of astrophysics and cosmology in a language understandable to a physicist or beginner in astrophysics. It presents the key topics in all branches of astrophysics and cosmology in a simple and concise language. The emphasis is on currently active research areas and exciting new frontiers rather than on more pedantic topics. Many complicated results are introduced with simple, novel derivations which strengthen the conceptual understanding of the subject. The book also contains over one hundred exercises which will help s

  7. The astrophysical r-process and its dependence on properties of nuclei far from stability beta strength functions and neutron capture rates

    CERN Document Server

    Klapdor-Kleingrothaus, H V; Metzinger, J; Oda, T; Thielemann, F K

    1981-01-01

    It is shown that the astrophysical r-process and the question of its site are very sensitive to 'standard' nuclear physics parameters like the beta decay properties and neutron capture rates. Since for these quantities in almost all r-process calculations up to now, and also in all estimates of the production rates of chronometric pairs, only very rough assumptions have been made, it is attempted to present procedures which put the calculation of these quantities for nuclei far from stability on a reliable physical basis. This is done by a microscopic description of the beta strength function and by using a statistical model based on a 'next to first principles' optical potential including effects of deformation for the neutron capture rates. The beta -decay rates for approximately 6000 nuclei between the beta -stability line and the neutron drip line are calculated. The heavy element synthesis by explosive He burning then is calculated using these beta -rates and using realistic star models treating the supe...

  8. New Approach to Concept Feasibility and Design Studies for Astrophysics Missions

    Science.gov (United States)

    Deutsch, M. J.; McLaughlin, W.; Nichols, J.

    1998-01-01

    JPL has assembled a team of multidisciplinary experts with corporate knowledge of space mission and instrument development. The advanced Concept Design Team, known as Team X, provides interactive design trades including cost as a design parameter, and advanced visualization for pre-Phase A Studies.

  9. Code Validation With Laser Astrophysics Experiments

    Science.gov (United States)

    Calder, A. C.; Fryxell, B.; Rosner, R.; Dursi, L. J.; Ricker, P. M.; Timmes, F. X.; Zingale, M.; Kane, J. O.; Remington, B. A.; Drake, R. P.; Olson, K.; MacNeice, P.; Tufo, H. M.

    2001-05-01

    An essential part of numerical modeling is validating simulation codes with laboratory experiments that capture many of the physical processes of interest. Validation is difficult in astrophysics because the problems of interest typically encompass complex physics and involve conditions that are difficult to reproduce in a terrestrial laboratory. Laboratory astrophysics with intense lasers serves as an invaluable validation tool by providing the chance to experimentally probe environments similar to those in which complex astrophysical phenomena occur. We describe the process of validating FLASH, an adaptive mesh astrophysical simulation code for compressible, reactive flows. We present the results of validation simulations, principally simulations of laser experiments involving shock propagation through multi-layer targets performed at the Omega laser facility at the University of Rochester. This work was supported by the DOE ASCI/Alliances program at the University of Chicago under grant No. B341495.

  10. Astrophysical payloads for picosatellites

    Science.gov (United States)

    Hudec, R.

    2017-07-01

    The recent progress in cubesatellite technology allows to consider scientific applications of these minsatellites including astrophysical research. Miniature X-ray and UV-payloads may serve as an example.

  11. Astrophysics Program Overview; Briefing

    National Research Council Canada - National Science Library

    1998-01-01

    This is an overview briefing of the NAS Astrophysics programs. These program should lead the opening scientific frontiers and disseminate new knowledge, as the Hubble Space Telescope and Compton Gamma Ray Observatory are currently doing...

  12. Theoretical physics and astrophysics

    CERN Document Server

    Ginzburg, Vitalii Lazarevich

    1979-01-01

    The aim of this book is to present, on the one hand various topics in theoretical physics in depth - especially topics related to electrodynamics - and on the other hand to show how these topics find applications in various aspects of astrophysics. The first text on theoretical physics and astrophysical applications, it covers many recent advances including those in X-ray, &ggr;-ray and radio-astronomy, with comprehensive coverage of the literature

  13. Collisionless plasmas in astrophysics

    CERN Document Server

    Belmont, Gerard; Mottez, Fabrice; Pantellini, Filippo; Pelletier, Guy

    2013-01-01

    Collisionless Plasmas in Astrophysics examines the unique properties of media without collisions in plasma physics. Experts in this field, the authors present the first book to concentrate on collisionless conditions in plasmas, whether close or not to thermal equilibrium. Filling a void in scientific literature, Collisionless Plasmas in Astrophysics explains the possibilities of modeling such plasmas, using a fluid or a kinetic framework. It also addresses common misconceptions that even professionals may possess, on phenomena such as "collisionless (Landau) damping". Abundant illustrations

  14. Precision mass measurements on neutron-rich Zn isotopes and their consequences on the astrophysical r-process

    Energy Technology Data Exchange (ETDEWEB)

    Baruah, Sudarshan

    2008-07-15

    The rapid neutron-capture or the r-process is responsible for the origin of about half of the neutron-rich atomic nuclei in the universe heavier than iron. For the calculation of the abundances of those nuclei, atomic masses are required as one of the input parameters with very high precision. In the present work, the masses of the neutron rich Zn isotopes (A=71 to 81) lying in the r-process path have been measured in the ISOLTRAP experiment at ISOLDE/CERN. The mass of {sup 81}Zn has been measured directly for the rst time. The half-lives of the nuclides ranged from 46.5 h ({sup 72}Zn) down to 290 ms ({sup 81}Zn). In case of all the nuclides, the relative mass uncertainty ({delta}m=m) achieved was in the order of 10{sup -8} corresponding to a 100-fold improvement in precision over previous measurements. (orig.)

  15. Spinning Unmagnetized Plasma for Laboratory Studies of Astrophysical Accretion Disks & Dynamos

    Science.gov (United States)

    Collins, Cami

    2015-11-01

    A technique for creating a large, fast-flowing, unmagnetized plasma has been demonstrated experimentally. This marks an important first step towards laboratory studies of phenomenon such as magnetic field generation through self-excited dynamos, or the magnetorotational instability (MRI), the mechanism of interest for its role in the efficient outward transport of angular momentum in accretion disks. In the Plasma Couette Experiment (PCX), a sufficiently hot, steady-state plasma is confined in a cylindrical, axisymmetric multicusp magnetic field, with Tetorque using toroidally localized, biased hot cathodes in the magnetized edge region. Measurements show that momentum couples viscously from the magnetized edge to the unmagnetized core, and the core rotates when collisional ion viscosity overcomes the drag due to ion-neutral collisions. Torque can be applied at the inner or outer boundaries, resulting in controlled, differential rotation. Maximum speeds are observed (He ~ 12 km/s, Ne ~ 4 km/s, Ar ~ 3.2 km/s, Xe ~ 1.4 km/s), consistent with a critical ionization velocity limit reported to occur in partially ionized plasmas. PCX has achieved magnetic Reynolds numbers of Rm ~ 65 and magnetic Prandtl numbers of Pm ~ 0.2-10, which are approaching regimes shown to excite the MRI in a global Hall-MHD stability analysis. Ion-neutral collisions effectively add a body force that undesirably changes the flow profile shape. Recent upgrades have increased the ionization fraction with an additional 6 kW of microwave heating power and stronger magnets that reduce loss area and increase plasma volume by 150%. In addition, an alternative scheme using volume-applied JxB force will maintain the shear profile and destabilize the MRI at more easily achievable plasma parameters.

  16. Constraint of the 13C(α,n) Cross Section Toward Astrophysical Energies for the Main s-Process

    Science.gov (United States)

    Toomey, Rebecca; Febbraro, Michael T.; Pain, Steven D.; Peters, William A.; Cizewski, Jolie A.; Havener, Charles C.; Bannister, Mark E.; Chipps, Kelly A.; Walter, David G.; Ummel, Chad C.; Sims, Harrison

    2017-09-01

    The slow neutron capture process (s-process) typically occurs in relatively low neutron flux environments, such as AGB stars, and is a key mechanism in heavy-element synthesis. The dominant source of neutrons for the main s-process is the 13C(α,n) reaction, which proceeds at stellar temperatures ( 0.1 GK, 200 keV), via reactions well below the Coulomb barrier. Direct measurements of the reaction rate in the Gamow window ( 140- 230 keV) is difficult, complicated by the low yields and high beam currents required. Current measurements have constrained the cross section down to approximately 320 keV - still well above stellar conditions- with significant statistical uncertainties. These uncertainties, and the influence of a near-threshold 1 /2+ state at 6.4 MeV, means that extrapolation of the data into the Gamow window is unreliable. These measurements typically use high-efficiency moderated neutron counter detectors, meaning energy information of the incident neutrons is lost. A quasi-spectroscopic approach has been used to measure the 13C(α,n) reaction rate at energies between 300-350 keV with the aim of reducing uncertainties in current measurements. Work supported in part by U.S. D.O.E., the National Science Foundation and the LDRD Program of ORNL, managed by UT-Battelle, LLC.

  17. Scaling Extreme Astrophysical Phenomena to the Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Follow-up of GW150914 and multi-messenger studies of transient astrophysical sources with the ANTARES neutrino telescope

    Directory of Open Access Journals (Sweden)

    Coleiro Alexis

    2017-01-01

    Full Text Available By constantly monitoring at least one complete hemisphere of the sky, neutrino telescopes are well designed to detect neutrinos emitted by transient astrophysical sources. In particular, the ANTARES telescope is currently the largest high-energy neutrino detector in the Northern Hemisphere. Searches for ANTARES neutrino candidates coincident with multi-wavelength and multi-messenger transient phenomena are performed by triggering optical, X-ray and radio observations immediately after the detection of an interesting ANTARES event and also by looking for neutrino emission spatially and temporally coincident with transient astrophysical events detected across the electromagnetic spectrum or with new messengers as gravitational-wave signals. The latest results of the multi-messenger analyses performed with ANTARES will be presented in this contribution. In particular, we will focus on the neutrino follow-up performed after the detection of the first gravitation-wave event, GW150914.

  19. Life origination and development hydrate theory (LOH-Theory) in the context of biological, physicochemical, astrophysical, and paleontological studies

    Science.gov (United States)

    Ostrovskii, V. E.; Kadyshevich, E. A.

    2014-04-01

    Till now, we formulated and developed the Life Origination Hydrate Theory (LOH-Theory) and Mitosis and Replication Hydrate Theory (MRHTheory) as the instruments for understanding the physical and chemical mechanisms applied by Nature for the living matter origination and propagation. This work is aimed at coordination of these theories with the paleontological and astrophysical knowledges and hypotheses of the Earth and Solar System remote histories.

  20. Focusing Telescopes in Nuclear Astrophysics

    CERN Document Server

    Ballmoos, Peter von

    2007-01-01

    This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference

  1. Astrophysics in a nutshell

    CERN Document Server

    Maoz, Dan

    2016-01-01

    Winner of the American Astronomical Society's Chambliss Award, Astrophysics in a Nutshell has become the text of choice in astrophysics courses for science majors at top universities in North America and beyond. In this expanded and fully updated second edition, the book gets even better, with a new chapter on extrasolar planets; a greatly expanded chapter on the interstellar medium; fully updated facts and figures on all subjects, from the observed properties of white dwarfs to the latest results from precision cosmology; and additional instructive problem sets. Throughout, the text features the same focused, concise style and emphasis on physics intuition that have made the book a favorite of students and teachers.

  2. Astrophysics with Microarcsecond Accuracy Astrometry

    Science.gov (United States)

    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.

  3. FOREWORD: Nuclear Physics in Astrophysics V

    Science.gov (United States)

    Auerbach, Naftali; Hass, Michael; Paul, Michael

    2012-02-01

    of neutrinos, such as double-beta decay and neutrino mixing were well represented at the conference. One of the central problems in modern cosmology and astrophysics is the search for dark matter. Several talks dealt with this subject and with methods to detect dark matter. Another intriguing and rather novel subject that was discussed at the meeting was time variation of fundamental physical constants. Two speakers have examined the sensitivity of Big-Bang Nucleosynthesis to the variation of the values of the fundamental constants. The role of some specific nuclei (such as Ni 56) in cosmology was pointed out. Many of the presentations at the conference described experimental studies of reactions relevant to nucleosynthesis at various stages of cosmic evolution. As reflected in the conference, these activities are widespread, encompassing many laboratories. Rare Isotope Beam (RIB) facilities are in the forefront of these studies. To understand the various processes of nucleosynthesis one has to have a good theory of nuclei far from the stability line. A number of presentations dealt with the description of such exotic nuclei. It is clear from the presentations that the future of experimental nuclear astrophysics looks promising as existing experimental facilities are being upgraded and new facilities are being built. X-Ray and Gamma-Ray Bursts and cosmic explosions were the subject of several talks. A discussion of various experiments attempting to measure time-reversal violation was the subject of one lecture. The solution of the puzzle as to why the universe is asymmetric with respect to matter-antimatter requires knowledge of the limit of time-reversal conservation. The late John Bahcall was a great astrophysicist and a supporter of the conference series 'Nuclear physics in Astrophysics'. On the last day of the conference, following a talk by Neta Bahcall from Princeton University on dark matter in the Universe, a short commemoration for John was held. Detailed

  4. The Trojan Horse method for nuclear astrophysics: Recent results on resonance reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cognata, M. La; Pizzone, R. G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Spitaleri, C.; Cherubini, S.; Romano, S. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy and Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Gulino, M.; Tumino, A. [Kore University, Enna, Italy and Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Lamia, L. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy)

    2014-05-09

    Nuclear astrophysics aims to measure nuclear-reaction cross sections of astrophysical interest to be included into models to study stellar evolution and nucleosynthesis. Low energies, < 1 MeV or even < 10 keV, are requested for this is the window where these processes are more effective. Two effects have prevented to achieve a satisfactory knowledge of the relevant nuclear processes, namely, the Coulomb barrier exponentially suppressing the cross section and the presence of atomic electrons. These difficulties have triggered theoretical and experimental investigations to extend our knowledge down to astrophysical energies. For instance, indirect techniques such as the Trojan Horse Method have been devised yielding new cutting-edge results. In particular, I will focus on the application of this indirect method to resonance reactions. Resonances might dramatically enhance the astrophysical S(E)-factor so, when they occur right at astrophysical energies, their measurement is crucial to pin down the astrophysical scenario. Unknown or unpredicted resonances might introduce large systematic errors in nucleosynthesis models. These considerations apply to low-energy resonances and to sub-threshold resonances as well, as they may produce sizable modifications of the S-factor due to, for instance, destructive interference with another resonance.

  5. Ab Initio Quantum Chemical Studies of Reactions in Astrophysical Ices. 1. Aminolysis, Hydrolysis, and Polymerization in H 2CO/NH 3/H 2O Ices

    Science.gov (United States)

    Woon, David E.

    1999-12-01

    Laboratory studies of astrophysical ices by W. A. Schutte, L. J. Allamandola, and S. A. Sandford (1993, Science259, 1143-1145; 1993, Icarus104, 118-137) indicate that ices containing formaldehyde (H 2CO) and at least a trace of ammonia (NH 3) will undergo reactions as the samples are heated from 10 K with no additional irradiation. A residue composed of higher-boiling-point organic species persists to 190 K and beyond. Spectral changes indicate that reactions begin to occur as low as 40 K. The present study employed theoretical electronic structure methods to investigate possible microscopic mechanisms that would account for various aspects of the experimental phenomena. Reaction components were characterized in clusters composed of reactants with up to two explicit catalytically active waters present and then embedded in a continuum polarization field to incorporate the bulk solvation effects of ice. Direct dimerization and trimerization of H 2CO were first considered, but no process was found that could account for the low-temperature reactivity observed in the laboratory. Two ice-bound aminolysis reactions were then identified that are predicted to possess barriers low enough to be viable at 40 K: H 2CO-NH 3 → NH 2CH 2OH and (H 2CO) 2-NH 3 → NH 2CH 2OCH 2OH. The latter yields an amide-terminated polyoxymethylene polymer. Analogous hydrolysis reactions are enhanced in ice, but not sufficiently to occur at cold temperatures on their own, which is consistent with the experimental observation that NH 3 is a critical component and water alone is insufficient to catalyze H 2CO reactions.

  6. Connections between laser hydrodynamics experiments and astrophysics

    Science.gov (United States)

    Drake, R. P.; Robey, H. A.; Remington, B. A.; Ryutov, D. D.; Calder, A.; Rosner, R.; Fryxell, B.; Arnett, D.; Zhang, Y.; Glimm, J.; Knauer, J.

    2002-11-01

    Recent and ongoing experiments have studied mechanisms that affect the evolution of supernovae, supernova remnants, and related systems. These experiments are designed to be well scaled from astrophysical systems to the laboratory. The experiments and some of the astrophysical systems involve time-dependent flows with very large Reynolds number. In contrast, numerical viscosity limits computer simulations of these phenomena to a Reynolds number of order 1000. Using our own experiments and other work in fluid dynamics as a guide, we will explore the implications for astrophysical systems. The key question is whether the astrophysical systems might evolve into a turbulent state that the computer simulations cannot reproduce. The US DOE and NASA supported this work.

  7. The NASA Astrophysics Program

    Science.gov (United States)

    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.

  8. CubeSats for Astrophysics: The Current Perspective

    Science.gov (United States)

    Ardila, David R.; Shkolnik, Evgenya; Gorjian, Varoujan

    2017-01-01

    Cubesats are small satellites built to multiples of 1U (1000 cm3). The 2016 NRC Report “Achieving Science with CubeSats” indicates that between 2013 and 2018 NASA and NSF sponsored 104 CubeSats. Of those, only one is devoted to astrophysics: HaloSat (PI: P. Kaaret), a 6U CubeSat with an X-ray payload to study the hot galactic halo.Despite this paucity of missions, CubeSats have a lot of potential for astrophysics. To assess the science landscape that a CubeSat astrophysics mission may occupy, we consider the following parameters:1-Wavelength: CubeSats are not competitive in the visible, unless the application (e.g. high precision photometry) is difficult to do from the ground. Thermal IR science is limited by the lack of low-power miniaturized cryocoolers and by the large number of infrared astrophysical missions launched or planned. In the UV, advances in δ-doping processes result in larger sensitivity with smaller apertures. Commercial X-ray detectors also allow for competitive science.2-Survey vs. Pointed observations: All-sky surveys have been done at most wavelengths from X-rays to Far-IR and CubeSats will not be able to compete in sensitivity with them. CubeSat science should then center on specific objects or object classes. Due to poor attitude control, unresolved photometry is scientifically more promising that extended imaging.3-Single-epoch vs. time domain: CubeSat apertures cannot compete in sensitivity with big satellites when doing single-epoch observations. However, time-domain astrophysics is an area in which CubeSats can provide very valuable science return.Technologically, CubeSat astrophysics is limited by:1-Lack of large apertures: The largest aperture CubeSat launched is ~10 cm, although deployable apertures as large as 20 cm could be fitted to 6U buses.2-Poor attitude control: State-of-the-art systems have demonstrated jitter of ~10” on timescales of seconds. Jitter imposes limits on image quality and, coupled with detector errors

  9. Is Photolytic Production a Viable Source of HCN and HNC in Astrophysical Environments? A Laboratory-based Feasibility Study of Methyl Cyanoformate

    Science.gov (United States)

    Wilhelm, Michael J.; Martínez-Núñez, Emilio; González-Vázquez, Jesús; Vázquez, Saulo A.; Smith, Jonathan M.; Dai, Hai-Lung

    2017-11-01

    Motivated by the possibility that cyano-containing hydrocarbons may act as photolytic sources for HCN and HNC in astrophysical environments, we conducted a combined experimental and theoretical investigation of the 193 nm photolysis of the cyano-ester, methyl cyanoformate (MCF). Experimentally, nanosecond time-resolved infrared emission spectroscopy was used to detect the emission from nascent products generated in the photolysis reaction. The time-resolved spectra were analyzed using a recently developed spectral reconstruction analysis, which revealed spectral bands assignable to HCN and HNC. Fitting of the emission band shape and intensity allowed determination of the photolysis quantum yields of HCN, HNC, and {CN}({A}2{{{\\Pi }}}1) and an HNC/HCN ratio of ∼0.076 ± 0.059. Additionally, multiconfiguration self-consistent field calculations were used to characterize photoexcitation-induced reactions in the ground and four lowest singlet excited states of MCF. At 193 nm excitation, dissociation is predicted to occur predominantly on the repulsive S 2 state, with minor pathways via internal conversion from S 2 to highly excited ground state. An automated transition-state search algorithm was employed to identify the corresponding ground-state dissociation channels, and Rice–Ramsperger–Kassel–Marcus and Kinetic Monte Carlo simulations were used to calculate the associated branching ratios. The proposed mechanisms were validated using the experimentally measured and quasi-classical trajectory-deduced nascent internal energy distributions of HCN and HNC. This work, along with previous studies, illustrates the propensity for cyano-containing hydrocarbons to act as photolytic sources for astrophysical HCN and HNC and may help explain the observed overabundance of HNC in astrophysical environments.

  10. Allen's astrophysical quantities

    CERN Document Server

    2000-01-01

    This new, fourth, edition of Allen's classic Astrophysical Quantities belongs on every astronomer's bookshelf. It has been thoroughly revised and brought up to date by a team of more than ninety internationally renowned astronomers and astrophysicists. While it follows the basic format of the original, this indispensable reference has grown to more than twice the size of the earlier editions to accommodate the great strides made in astronomy and astrophysics. It includes detailed tables of the most recent data on: - General constants and units - Atoms, molecules, and spectra - Observational astronomy at all wavelengths from radio to gamma-rays, and neutrinos - Planetary astronomy: Earth, planets and satellites, and solar system small bodies - The Sun, normal stars, and stars with special characteristics - Stellar populations - Cataclysmic and symbiotic variables, supernovae - Theoretical stellar evolution - Circumstellar and interstellar material - Star clusters, galaxies, quasars, and active galactic nuclei ...

  11. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  12. Nuclear astrophysics at DRAGON

    Energy Technology Data Exchange (ETDEWEB)

    Hager, U. [Colorado School of Mines, Golden, Colorado (United States)

    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.

  13. The Astrophysical S-factor for the 2 H (, ) 6 Li Nuclear Reaction at ...

    Indian Academy of Sciences (India)

    The astrophysical S-factor for the process 2H(, )6Li has been calculated at the low-energies relevant to big-bang nucleosynthesis and in comparison with laboratory data. On the basis of the model, the alpha radiative capture process is studied by using the two-and three-body electromagnetic currents. The bound and ...

  14. Astrophysical fluid dynamics

    Science.gov (United States)

    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.

  15. Direct Reactions for Nuclear Structure and Nuclear Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Katherine Louise [Univ. of Tennessee, Knoxville, TN (United States). Experimental Low-Energy Nuclear Physics Group

    2014-12-18

    Direct reactions are powerful probes for studying the atomic nucleus. Modern direct reaction studies are illuminating both the fundamental nature of the nucleus and its role in nucleosynthetic processes occurring in the cosmos. This report covers experiments using knockout reactions on neutron-deficient fragmentation beams, transfer reactions on fission fragment beams, and theoretical sensitivity studies relating to the astrophysical r-process. Results from experiments on 108,106Sn at the NSCL, and on 131Sn at HRIBF are presented as well as the results from the nucleosynthesis study.

  16. Simulations of Astrophysical fluid instabilities

    Science.gov (United States)

    Calder, A. C.; Fryxell, B.; Rosner, R.; Dursi, L. J.; Olson, K.; Ricker, P. M.; Timmes, F. X.; Zingale, M.; MacNeice, P.; Tufo, H. M.

    2001-10-01

    We present direct numerical simulations of mixing at Rayleigh-Taylor unstable interfaces performed with the FLASH code, developed at the ASCI/Alliances Center for Astrophysical Thermonuclear Flashes at the University of Chicago. We present initial results of single-mode studies in two and three dimensions. Our results indicate that three-dimensional instabilities grow significantly faster than two-dimensional instabilities and that grid resolution can have a significant effect on instability growth rates. We also find that unphysical diffusive mixing occurs at the fluid interface, particularly in poorly resolved simulations. .

  17. Studying the r-process at FRIB and NSCL

    Science.gov (United States)

    Spyrou, Artemis

    2016-09-01

    The astrophysical r-process is responsible for the synthesis of about half of the isotopes of the heavy elements. Despite its well-known role in nucleosythesis, the astrophysical site where it takes place has not been unambiguously determined. Efforts for the better understanding of this important process span across many fields, from astronomical observations of metal-poor stars, gravitational-wave studies, and modeling of the possible scenarios, to sensitivity studies, nuclear theory calculations and nuclear experiments. This talk will focus on some of the experimental challenges, recent advances and future plans to provide reliable nuclear input data for r-process calculations. n particular, recent results on nuclear structure studies around A = 70 and implications for the r-process will be presented. In addition, the talk will discuss one of the important r-process inputs that is practically unconstrained by experiment, namely neutron capture reactions. The development of a new technique to experimentally constrain these important (n, γ) reaction rates will be presented. The relevant experiments were done at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University using the γ-calorimeter SuN. Future plans for exciting new opportunities at FRIB will also be discussed.

  18. Nuclear astrophysics and the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Spitaleri, C. [University of Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Laboratori Nazionali del Sud - INFN, Catania (Italy); La Cognata, M.; Pizzone, R.G. [Laboratori Nazionali del Sud - INFN, Catania (Italy); Lamia, L. [University of Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Mukhamedzhanov, A.M. [Texas A and M University, Cyclotron Institute, College Station, TX (United States)

    2016-04-15

    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. (orig.)

  19. Inverse Bremsstrahlung in Astrophysical Plasmas: The Absorption ...

    Indian Academy of Sciences (India)

    The electron–ion inverse Bremsstrahlung is considered here as a factor of the influence on the opacity of the different stellar atmospheres and other astrophysical plasmas. It is shown that this process can be successfully described in the frames of cut-off Coulomb potential model within the regions of the electron densities ...

  20. Towards Establishing an Open Access Repository of Indian Publications in Astronomy -- a Case Study of Indian Institute of Astrophysics Repository

    Science.gov (United States)

    Birdie, C.; Vagiswari, A.

    2007-10-01

    The continued escalation of journal prices, and inadequate access to scholarly journals along with a consistent reduction in library resources and the advent of new technologies have all contributed to a change in the present scholarly communication. The initiative towards establishing Open Access communication has been advocated among scholars and researchers. An Institutional Archive for holding pre- and post-prints of articles written by academic and research staff increases the accessibility, visibility and impact of research output. The Indian Institute of Astrophysics (IIA) is one of the astronomical research institutes in India pioneering the Open Access movement. The institute has set up a pilot project to store the institute's publications in an institutional repository (IR). The library at IIA plays an important role in setting up this archive. While the authors and publishers are the key players in this endeavor, the role of librarians needs to be redefined in the present paradigm shift of publishing. When the Institutes decide to develop their own repositories, the skills and expertise of librarians are needed to design, develop, manage and maintain a successful repository. These and the knowledge of copyright issues relevant to the digital content of IRs are highlighted in this paper. This paper also discusses the various opportunities and tools available for librarians to learn the procedures and involve themselves in establishing their institutional repositories.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Laboratory Astrophysics Division of the AAS (LAD)

    Science.gov (United States)

    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.

  3. Charge state distribution of {sup 16}O from the {sup 4}He({sup 12}C,{sup 16}O)γ reaction of astrophysical interest studied both experimentally and theoretically

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shengjin, E-mail: liusj@ihep.ac.cn [Institute of High Energy Physics, China Academy of Science, 19B YuquanLu, Shijingshan, Beijing 100049 (China); Department of Physics, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Sakurai, Makoto [Department of Physics, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Sagara, Kenshi; Teranishi, Takashi; Fujita, Kunihiro; Yamaguchi, Hiroyuki; Matsuda, Sayaka; Mitsuzumi, Tatsuki; Iwazaki, Makoto; Rosary, Mariya T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Kato, Daiji [Fusion Systems Research Division, National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Tolstikhina, I.Yu. [P.N. Lebedev Physical Institute, Leninskii pr. 53, Moscow 119991 (Russian Federation)

    2014-06-01

    In astrophysics, {sup 4}He({sup 12}C,{sup 16}O)γ reaction places an important role. At Kyushu University Tandem accelerator Laboratory (KUTL), the measurement of {sup 4}He({sup 12}C,{sup 16}O)γ cross section is in progress in the energy range of astrophysical nuclear reaction. Since the charge state of product {sup 16}O ions after passing through the gas target is spread and only one charge state can be measured at terminal detector, it is necessary to know the charge state distribution of {sup 16}O ions passing through the He gas target precisely. Here, we report the charge state distribution of the {sup 16}O recoils both experimentally and theoretically. Experimentally, we measured the equilibrium charge state distribution of {sup 16}O ions in the windowless helium gas target with the beam energy of primary {sup 16}O ions at 7.2, 4.5, and 3.45 MeV at KUTL. The measured results showed a Gaussian distribution for the charge state fraction. Theoretically, we proposed a framework for the charge state distribution study. Charge state distribution was computed by solving a set of differential equations including a series of charge exchange cross sections. For the ionization cross section, plane-wave Born approximation was applied and modified by taking target atomic screening as a function of momentum transfer into account. For the capture cross section, continuum distorted wave approximation was applied and the influence of the gas target density was taken into account in the process of electron capture. Using above charge exchange cross sections, the charge state evolution was simulated. According to the equilibrium distribution, we compared the theoretical calculation to the experimental data. After taking into account the density effects in the charge exchange process, the theoretical charge state distributions shows a good agreement with the experimental data. Both experimental and theoretical results are useful to understand the charge fraction of recoil oxygen

  4. On the saturation of astrophysical dynamos

    DEFF Research Database (Denmark)

    Dorch, Bertil; Archontis, Vasilis

    2004-01-01

    In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the li......In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate...

  5. FLARE: A New User Facility for Laboratory Studies of Multiple-Scale Physics of Magnetic Reconnection and Related Phenomena in Heliophysics and Astrophysics

    Science.gov (United States)

    Ji, H.; Bhattacharjee, A.; Goodman, A.; Prager, S.; Daughton, W.; Cutler, R.; Fox, W.; Hoffmann, F.; Kalish, M.; Kozub, T.; Jara-Almonte, J.; Myers, C.; Ren, Y.; Sloboda, P.; Yamada, M.; Yoo, J.; Bale, S. D.; Carter, T.; Dorfman, S.; Drake, J.; Egedal, J.; Sarff, J.; Wallace, J.

    2017-10-01

    The FLARE device (Facility for Laboratory Reconnection Experiments; flare.pppl.gov) is a new laboratory experiment under construction at Princeton with first plasmas expected in the fall of 2017, based on the design of Magnetic Reconnection Experiment (MRX; mrx.pppl.gov) with much extended parameter ranges. Its main objective is to provide an experimental platform for the studies of magnetic reconnection and related phenomena in the multiple X-line regimes directly relevant to space, solar, astrophysical and fusion plasmas. The main diagnostics is an extensive set of magnetic probe arrays, simultaneously covering multiple scales from local electron scales ( 2 mm), to intermediate ion scales ( 10 cm), and global MHD scales ( 1 m). Specific example space physics topics which can be studied on FLARE will be discussed.

  6. The Fascination of Far-UV Astrophysics

    Science.gov (United States)

    Linsky, J. L.

    1998-05-01

    A one-day topical session will review the observational and theoretical status of astrophysical problems where data in the 900 to 1200 Angstroms range are essential for future advances. The session will include the study of FUV rest wavelengths at high redshifts. For example, the deuterium-to-hydrogen abundance ratio will address the Milky Way and QSO absorption line systems. The FUV spectral region is well known for its unique spectral features and important scientific problems they address. The Lyman series of atomic hydrogen provides the only means to determine the production of deuterium in the Big Bang and its subsequent processing during galactic chemical evolution. The resonance doublet of the O VI ion is the highest temperature resonance line available to study the abundance and kinematics of diffuse hot gas in the disk and halo of the Galaxy and hot gas in accretion disks. The Lyman and Werner bands, the only electronic transitions of molecular hydrogen, probe cold gas in the diffuse ISM as well as the outer regions of dense molecular clouds. Strong transitions of several ionization states of carbon, nitrogen, oxygen, neon, sulphur, and argon provide unique diagnostics for studying interstellar gas and emission plasmas. This special session focuses on recent observational material and how the data limit the range of acceptable pictures. This session will highlight key puzzles and describe anticipated progress from new instrumentation, in particular the Far Ultraviolet Spectroscopic Explorer (FUSE) mission, due to be launched in early 1999. The first talk of the session will summarize the critically important spectral diagnostics that reside in the FUV spectral region and show how they allow FUSE to address the main scientific objectives of FUV astrophysics. FUSE spectra will also enhance the value of longer wavelength spectra provided by HST and IUE, shorter wavelength spectra of EUVE and soon AXAF, lower sensitivity FUV spectra of Copernicus, and lower

  7. Nuclear astrophysics projects at the low-energy RI beam separator CRIB

    Science.gov (United States)

    Yamaguchi, H.; Kahl, D.; Hayakawa, S.; Yang, L.; Shimizu, H.; Sakaguchi, Y.; Abe, K.; Nakao, T.; Suhara, T.; Iwasa, N.; Kim, A.; Kim, D. H.; Cha, S. M.; Kwag, M. S.; Lee, J. H.; Lee, E. J.; Chae, K. Y.; Wakabayashi, Y.; Imai, N.; Kitamura, N.; Lee, P.; Moon, J. Y.; Lee, K. B.; Akers, C.; Jung, H. S.; Duy, N. N.; Khiem, L. H.; Lee, C. S.; Hashimoto, T.; Kubono, S.; Kawabata, T.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.

    2018-01-01

    Studies on nuclear reactions relevant for astrophysics have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study (CNS), the University of Tokyo. A type of measurement to study astrophysical reactions at CRIB is by the elastic resonant scattering with the thick-target method in inverse kinematics. We introduce the α resonant scattering with 7Be beam, related to the astrophysical 7Be(α, γ) reactions, which is relevant in the hot p-p chain and νp-process in supernovae. Other α resonant scattering measurements with 30S, 10Be, 15O, and 18Ne beams have been performed at CRIB, using the thick-target method.

  8. Overview of NASA's Universe of Learning: An Integrated Astrophysics STEM Learning and Literacy Program

    Science.gov (United States)

    Smith, Denise; Lestition, Kathleen; Squires, Gordon; Biferno, Anya A.; Cominsky, Lynn; Manning, Colleen; NASA's Universe of Learning Team

    2018-01-01

    NASA's Universe of Learning creates and delivers science-driven, audience-driven resources and experiences designed to engage and immerse learners of all ages and backgrounds in exploring the universe for themselves. The project is the result of a unique partnership between the Space Telescope Science Institute, Caltech/IPAC, Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, and Sonoma State University, and is one of 27 competitively-selected cooperative agreements within the NASA Science Mission Directorate STEM Activation program. The NASA's Universe of Learning team draws upon cutting-edge science and works closely with Subject Matter Experts (scientists and engineers) from across the NASA Astrophysics Physics of the Cosmos, Cosmic Origins, and Exoplanet Exploration themes. Together we develop and disseminate data tools and participatory experiences, multimedia and immersive experiences, exhibits and community programs, and professional learning experiences that meet the needs of our audiences, with attention to underserved and underrepresented populations. In doing so, scientists and educators from the partner institutions work together as a collaborative, integrated Astrophysics team to support NASA objectives to enable STEM education, increase scientific literacy, advance national education goals, and leverage efforts through partnerships. Robust program evaluation is central to our efforts, and utilizes portfolio analysis, process studies, and studies of reach and impact. This presentation will provide an overview of NASA's Universe of Learning, our direct connection to NASA Astrophysics, and our collaborative work with the NASA Astrophysics science community.

  9. The Use of Abbreviations in English-Medium Astrophysics Research Paper Titles: A Problematic Issue

    Science.gov (United States)

    Méndez, David I.; Alcaraz, M. Ángeles

    2015-01-01

    In this study, we carry out a qualitative and quantitative analysis of abbreviations in 300 randomly collected research paper titles published in the most prestigious European and US-based Astrophysics journals written in English. Our main results show that the process of shortening words and groups of words is one of the most characteristic and…

  10. Technological challenges on the path to discovery in astrophysics

    Science.gov (United States)

    Perez, Mario R.

    2016-05-01

    Over the next decade, NASA's Astrophysics Division expects to undertake robotic or unmanned space flight missions that will explore the nature of the universe at its largest scales, its earliest moments, and its most extreme conditions. Current innovative and maturation technology programs are being conducted by NASA's Astrophysics Division to fill the technology gaps identified by the community. One of these efforts was to establish the Strategic Astrophysics Technology (SAT) program to support the maturation of key technologies. In this paper, these technology programs are described; in particular the SAT program will be presented describing the process to establish priorities, the technology management components, and the efforts to move these technologies into mission concepts and flight missions. The technology roadmap for a large mission concept such as ATLAST is presented as an example of the technology gaps derived and identified from these analyses, which could focus future efforts and investment priorities. Finally, the NASA preparation for the next decade, which will study and mature four large mission concepts, is briefly outlined.

  11. Parallel Information Phenomena of Biology and Astrophysics

    Science.gov (United States)

    Frieden, B. Roy; Soffer, Bernard H.

    The realms of biology and astrophysics are usually regarded as distinct, to be studied within individual frameworks. However, current searches for life in the universe, and the expectation of positive results, are guiding us toward a unification of biology and astrophysics called astrobiology. In this chapter the unifying aspect of Fisher information is shown to form two bridges of astrobiology: (i) In Section 5.1 quarter-power laws are found to both describe attributes of biology, such as metabolism rate, and attributes of the cosmos, in particular its universal constants, (ii) In Section 5.2 we find that the Lotka-Volterra growth equations of biology follow from quantum mechanics. Both these bridges follow, ultimately, from the extreme physical information EPI principle and, hence, are examples of the “cooperative” universe discussed in Chapter 1. That is, the universe cooperates with our goal of understanding it, through participatory observation. The participatory aspect of the effect (i) is the observation of biological and cosmological attributes obeying quarter-power laws. In the Lotka-Volterra quantum effect (ii) the participation is the observation of a general particle member that undergoes scattering by a complex potential. This potential causes the growth or depletion of the particle population levels to obey Lotka-Volterra equations. Effectively, the interaction potentials of a standard Hartree view of the scattering process become corresponding fitness coefficients of the L-V growth equations. The two ostensibly unrelated effects of scattering and biological growth are thereby intimately related; out of a common flow of Fisher information to the observer.

  12. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. K. Duorah. Articles written in Journal of Astrophysics and Astronomy. Volume 36 Issue 3 September 2015 pp 375-383. A Comparative Study on SN II Progenitors for the Synthesis of Li and B with the help of Neutrinos · N. Lahkar S. Kalita H. L. Duorah K. Duorah.

  13. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. Yuvraj Harsha Sreedhar. Articles written in Journal of Astrophysics and Astronomy. Volume 35 Issue 1 March 2014 pp 55-68 General Editorial on Publication Ethics. Comparative Studies of Population Synthesis Models in the Framework of Modified Strömgren Filters.

  14. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. U. S. Kamath. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 38 Review. Interstellar Medium and Star Formation Studies with the Square Kilometre Array · P. Manoj S. Vig G. Maheswar U. S. Kamath A. Tej.

  15. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. D. J. Saikia. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 471-474. A Multifrequency Study of Five Large Radio Galaxies · A. Pirya S. Nandi D. J. Saikia C. Konar M. Singh · More Details Abstract Fulltext PDF.

  16. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. C. Konar. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 471-474. A Multifrequency Study of Five Large Radio Galaxies · A. Pirya S. Nandi D. J. Saikia C. Konar M. Singh · More Details Abstract Fulltext PDF.

  17. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. Karl Rakos. Articles written in Journal of Astrophysics and Astronomy. Volume 35 Issue 1 March 2014 pp 55-68 General Editorial on Publication Ethics. Comparative Studies of Population Synthesis Models in the Framework of Modified Strömgren Filters.

  18. Numerical relativity beyond astrophysics

    Science.gov (United States)

    Garfinkle, David

    2017-01-01

    Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

  19. Numerical relativity beyond astrophysics.

    Science.gov (United States)

    Garfinkle, David

    2017-01-01

    Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

  20. High energy astrophysical techniques

    CERN Document Server

    Poggiani, Rosa

    2017-01-01

    This textbook presents ultraviolet and X-ray astronomy, gamma-ray astronomy, cosmic ray astronomy, neutrino astronomy, and gravitational wave astronomy as distinct research areas, focusing on the astrophysics targets and the requirements with respect to instrumentation and observation methods. The purpose of the book is to bridge the gap between the reference books and the specialized literature. For each type of astronomy, the discussion proceeds from the orders of magnitude for observable quantities. The physical principles of photon and particle detectors are then addressed, and the specific telescopes and combinations of detectors, presented. Finally the instruments and their limits are discussed with a view to assisting readers in the planning and execution of observations. Astronomical observations with high-energy photons and particles represent the newest additions to multimessenger astronomy and this book will be of value to all with an interest in the field.

  1. Exotic nuclei and astrophysics

    Directory of Open Access Journals (Sweden)

    Penionzhkevich Yu.

    2012-12-01

    Full Text Available In recent years, nuclear physics investigations of the laws of the microscopic world contributed significantly to extension of our knowledge of phenomena occurring in the macroscopic world (Universe and made a formidable contribution to the development of astrophysical and cosmological theories. First of all, this concerns the expanding universe model, the evolution of stars, and the abundances of elements, as well as the properties of various stars and cosmic objects, including “cold” and neutron stars, black holes, and pulsars. Without claiming to give a full account of all cosmological problems, we will dwell upon those of them that, in my opinion, have much in common with nuclear-matter properties manifesting themselves in nuclear interactions.

  2. Astrophysics Faces the Millennium

    Science.gov (United States)

    Trimble, Virginia

    2001-03-01

    The Medieval synthesis of Aristotelian philosophy and church doctrine, due largely to Thomas Aquinas, insisted that the universe outside the earth's atmosphere must be immutable, single-centered, fully inventoried, immaculate or perfect, including perfectly spherical, and much else that sounds strange to modern ears. The beginnings of modern astronomy can be largely described as the overthrow of these various concepts by a combination of new technologies and new ways of thinking, and many current questions in astrophysics can be directly tied to developments of those same concepts. Indeed they probably all can be, but not over time, ending with questions like: Do other stars have spots? What does it mean when quasar jets look like they are moving faster than the speed of light? Is there anything special about our star, our galaxy, our planet, or our universe? How did these all form, and what is their long-term fate?

  3. High precision In-113(alpha, alpha)In-113 elastic scattering at energies near the Coulomb barrier for the astrophysical gamma process

    OpenAIRE

    Kiss, G.G.(Institute for Nuclear Research (MTA ATOMKI), Debrecen, H-4001, Hungary); Mohr, P; Fülöp, Zs.; Rauscher, T.; Gyürky, Gy.(Institute for Nuclear Research (MTA ATOMKI), Debrecen, H-4001, Hungary); Szücs, T; Halász, Z.; Somorjai, E.; Ornelas, A.; Yalcin, C.; Güray, R T; Özkan, N

    2013-01-01

    The $\\gamma$ process in supernova explosions is thought to explain the origin of proton-rich isotopes between Se and Hg, the so-called $p$ nuclei. The majority of the reaction rates for $\\gamma$ process reaction network studies has to be predicted in Hauser-Feshbach statistical model calculations using global optical potential parameterizations. While the nucleon+nucleus optical potential is fairly known, for the $\\alpha$+nucleus optical potential several different parameterizations exist and...

  4. Structure of proton-rich nuclei of astrophysical interest

    Energy Technology Data Exchange (ETDEWEB)

    Roeckl, E. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)

    1998-06-01

    Recent experimental data concerning proton-rich nuclei between A=20 and A=100 are presented and discussed with respect to their relevance to the astrophysical rp process and to the calibration of solar neutrino detectors. (orig.)

  5. Focusing telescopes in nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Von Ballmoos, P.; Knodlseder, R.; Sazonov, S.; Griffiths, R.; Bastie, P.; Halloin, H.; Pareschi, G.; Ramsey, B.; Jensen, C.; Buis, E.J.; Ulmer, M.; Giommi, P.; Colafrancesco, S.; Comastri, A.; Barret, D.; Leising, M.; Hernanz, M.; Smith, D.; Abrosimov, N.; Smither, B.; Ubertini, P.; Olive, J.F.; Lund, N.; Pisa, A.; Courtois, P.; Roa, D.; Harrison, F.; Pareschi, G.; Frontera, F.; Von Ballmoos, P.; Barriere, N.; Rando, N.; Borde, J.; Hinglais, E.; Cledassou, R.; Duchon, P.; Sghedoni, M.; Huet, B.; Takahashi, T.; Caroli, E.; Quadrinin, L.; Buis, E.J.; Skinner, G.; Krizmanic, J.; Pareschi, G.; Loffredo, G.; Wunderer, C.; Weidenspointner, G.; Wunderer, C.; Koechlin, L.; Bignami, G.; Von Ballmoos, P.; Tueller, J.; Andritschke, T.; Laurens, A.; Evrard, J

    2005-07-01

    The objective of this workshop is to consider the next generation of instrumentation to be required within the domain of nuclear astrophysics. A small, but growing community has been pursuing various techniques for the focusing of hard X-rays and gamma-rays with the aim of achieving a factor of up to 100 improvement in sensitivity over present technologies. Balloon flight tests of both multilayer mirrors and a Laue lens have been performed and ideas abound. At present, implementation scenarios for space missions are being studied at Esa, CNES, and elsewhere. The workshop will provide a first opportunity for this new community to meet, exchange technological know-how, discuss scientific objectives and synergies, and consolidate implementation approaches within National and European Space Science programs. This document gathers the slides of all the presentations.

  6. Astronomical optical interferometry, II: Astrophysical results

    Directory of Open Access Journals (Sweden)

    Jankov S.

    2011-01-01

    Full Text Available Optical interferometry is entering a new age with several ground- based long-baseline observatories now making observations of unprecedented spatial resolution. Based on a great leap forward in the quality and quantity of interferometric data, the astrophysical applications are not limited anymore to classical subjects, such as determination of fundamental properties of stars; namely, their effective temperatures, radii, luminosities and masses, but the present rapid development in this field allowed to move to a situation where optical interferometry is a general tool in studies of many astrophysical phenomena. Particularly, the advent of long-baseline interferometers making use of very large pupils has opened the way to faint objects science and first results on extragalactic objects have made it a reality. The first decade of XXI century is also remarkable for aperture synthesis in the visual and near-infrared wavelength regimes, which provided image reconstructions from stellar surfaces to Active Galactic Nuclei. Here I review the numerous astrophysical results obtained up to date, except for binary and multiple stars milliarcsecond astrometry, which should be a subject of an independent detailed review, taking into account its importance and expected results at microarcsecond precision level. To the results obtained with currently available interferometers, I associate the adopted instrumental settings in order to provide a guide for potential users concerning the appropriate instruments which can be used to obtain the desired astrophysical information.

  7. Astronomical Optical Interferometry. II. Astrophysical Results

    Science.gov (United States)

    Jankov, S.

    2011-12-01

    Optical interferometry is entering a new age with several ground-based long-baseline observatories now making observations of unprecedented spatial resolution. Based on a great leap forward in the quality and quantity of interferometric data, the astrophysical applications are not limited anymore to classical subjects, such as determination of fundamental properties of stars; namely, their effective temperatures, radii, luminosities and masses, but the present rapid development in this field allowed to move to a situation where optical interferometry is a general tool in studies of many astrophysical phenomena. Particularly, the advent of long-baseline interferometers making use of very large pupils has opened the way to faint objects science and first results on extragalactic objects have made it a reality. The first decade of XXI century is also remarkable for aperture synthesis in the visual and near-infrared wavelength regimes, which provided image reconstructions from stellar surfaces to Active Galactic Nuclei. Here I review the numerous astrophysical results obtained up to date, except for binary and multiple stars milli-arcsecond astrometry, which should be a subject of an independent detailed review, taking into account its importance and expected results at micro-arcsecond precision level. To the results obtained with currently available interferometers, I associate the adopted instrumental settings in order to provide a guide for potential users concerning the appropriate instruments which can be used to obtain the desired astrophysical information.

  8. Atoms in astrophysics

    CERN Document Server

    Eissner, W; Hummer, D; Percival, I

    1983-01-01

    It is hard to appreciate but nevertheless true that Michael John Seaton, known internationally for the enthusiasm and skill with which he pursues his research in atomic physics and astrophysics, will be sixty years old on the 16th of January 1983. To mark this occasion some of his colleagues and former students have prepared this volume. It contains articles that de­ scribe some of the topics that have attracted his attention since he first started his research work at University College London so many years ago. Seaton's association with University College London has now stretched over a period of some 37 years, first as an undergraduate student, then as a research student, and then, successively, as Assistant Lecturer, Lecturer, Reader, and Professor. Seaton arrived at University College London in 1946 to become an undergraduate in the Physics Department, having just left the Royal Air Force in which he had served as a navigator in the Pathfinder Force of Bomber Command. There are a number of stories of ho...

  9. Astrophysical Aspects of Neutrino Dynamics in Ultradegenerate Quark Gluon Plasma

    Directory of Open Access Journals (Sweden)

    Souvik Priyam Adhya

    2017-01-01

    Full Text Available The cardinal focus of the present review is to explore the role of neutrinos originating from the ultradense core of neutron stars composed of quark gluon plasma in the astrophysical scenario. The collective excitations of the quarks involving the neutrinos through the different kinematical processes have been studied. The cooling of the neutron stars as well as pulsar kicks due to asymmetric neutrino emission has been discussed in detail. Results involving calculation of relevant physical quantities like neutrino mean free path and emissivity have been presented in the framework of non-Fermi liquid behavior as applicable to ultradegenerate plasma.

  10. Multiscale Modeling of Astrophysical Jets

    Directory of Open Access Journals (Sweden)

    James H. Beall

    2014-12-01

    Full Text Available We are developing the capability for a multi-scale code to model the energy deposition rate and momentum transfer rate of an astrophysical jet which generates strong plasma turbulence in its interaction with the ambient medium through which it propagates. We start with a highly parallelized version of the VH-1 Hydrodynamics Code (Coella and Wood 1984, and Saxton et al., 2005. We are also considering the PLUTO code (Mignone et al. 2007 to model the jet in the magnetohydrodynamic (MHD and relativistic, magnetohydrodynamic (RMHD regimes. Particle-in-Cell approaches are also being used to benchmark a wave-population models of the two-stream instability and associated plasma processes in order to determine energy deposition and momentum transfer rates for these modes of jet-ambient medium interactions. We show some elements of the modeling of these jets in this paper, including energy loss and heating via plasma processes, and large scale hydrodynamic and relativistic hydrodynamic simulations. A preliminary simulation of a jet from the galactic center region is used to lend credence to the jet as the source of the so-called the Fermi Bubble (see, e.g., Su, M. & Finkbeiner, D. P., 2012*It is with great sorrow that we acknowledge the loss of our colleague and friend of more than thirty years, Dr. John Ural Guillory, to his battle with cancer.

  11. Astronomy and Astrophysics in the Philosophy of Science

    CERN Document Server

    Anderl, Sibylle

    2015-01-01

    This article looks at philosophical aspects and questions that modern astrophysical research gives rise to. Other than cosmology, astrophysics particularly deals with understanding phenomena and processes operating at "intermediate" cosmic scales, which has rarely aroused philosophical interest so far. Being confronted with the attribution of antirealism by Ian Hacking because of its observational nature, astrophysics is equipped with a characteristic methodology that can cope with the missing possibility of direct interaction with most objects of research. In its attempt to understand the causal history of singular phenomena it resembles the historical sciences, while the search for general causal relations with respect to classes of processes or objects can rely on the "cosmic laboratory": the multitude of different phenomena and environments, naturally provided by the universe. Furthermore, the epistemology of astrophysics is strongly based on the use of models and simulations and a complex treatment of la...

  12. An introduction to observational astrophysics

    CERN Document Server

    Gallaway, Mark

    2016-01-01

    Observational Astrophysics follows the general outline of an astrophysics undergraduate curriculum targeting practical observing information to what will be covered at the university level. This includes the basics of optics and coordinate systems to the technical details of CCD imaging, photometry, spectography and radio astronomy.  General enough to be used by students at a variety of institutions and advanced enough to be far more useful than observing guides targeted at amateurs, the author provides a comprehensive and up-to-date treatment of observational astrophysics at undergraduate level to be used with a university’s teaching telescope.  The practical approach takes the reader from basic first year techniques to those required for a final year project. Using this textbook as a resource, students can easily become conversant in the practical aspects of astrophysics in the field as opposed to the classroom.

  13. Entrepreneurship and Process Studies

    DEFF Research Database (Denmark)

    Hjorth, Daniel; Holt, Robin; Steyaert, Chris

    2015-01-01

    and potential of processual approaches to studying, researching and practising entrepreneurship. The articles in the issue attest to an increasing sensitivity to processual thinking. We argue that appreciating entrepreneurial phenomena processually opens up the field to an understanding of entrepreneurship...... a variable as just that, a variable. The resonance with entrepreneurship studies is obvious. If any field is alive to, and fully resonant with, a processual understanding of, for example, the creation of firms, it is entrepreneurship studies. This special issue is an attempt to consider the promise...

  14. Nuclear astrophysics from direct reactions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, C. [Department of Physics, Texas A and M University, Commerce, TX 75429 (United States)]. e-mail: carlos_bertulani@tamu-commerce.edu

    2008-12-15

    Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation. (Author)

  15. An introduction to astrophysical hydrodynamics

    CERN Document Server

    Shore, Steven N

    1992-01-01

    This book is an introduction to astrophysical hydrodynamics for both astronomy and physics students. It provides a comprehensive and unified view of the general problems associated with fluids in a cosmic context, with a discussion of fluid dynamics and plasma physics. It is the only book on hydrodynamics that addresses the astrophysical context. Researchers and students will find this work to be an exceptional reference. Contents include chapters on irrotational and rotational flows, turbulence, magnetohydrodynamics, and instabilities.

  16. Nuclear Data for Astrophysical Modeling

    OpenAIRE

    Pritychenko, Boris

    2016-01-01

    Nuclear physics has been playing an important role in modern astrophysics and cosmology. Since the early 1950's it has been successfully applied for the interpretation and prediction of astrophysical phenomena. Nuclear physics models helped to explain the observed elemental and isotopic abundances and star evolution and provided valuable insights on the Big Bang theory. Today, the variety of elements observed in stellar surfaces, solar system and cosmic rays, and isotope abundances are calcul...

  17. Highlights of Spanish Astrophysics VII

    Science.gov (United States)

    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.

  18. Astrophysical neutrinos and atmospheric leptons

    Directory of Open Access Journals (Sweden)

    Gaisser T.K.

    2017-01-01

    Full Text Available IceCube measurements of the neutrino flux from TeV to PeV show the signal of astrophysical neutrinos standing out at high energy well above the steeply falling foreground of atmospheric neutrinos. The astrophysical signal appears both in measurements of neutrino-induced muons and in the starting event sample, which responds preferentially to electron and tau neutrinos, but which also includes muon neutrinos. Searches for point sources of astrophysical neutrinos have, however, not yet identified a single source or class of sources for the astrophysical component. Some constraints on astrophysical sources implied by the current observations will be described in this talk. Uncertainties in the fluxes of atmospheric leptons resulting from an incomplete knowledge of the primary cosmic-ray spectrum and from a limited understanding of meson production, including charm will also be reviewed. The ultimate goal is to improve the understanding of the astrophysical spectrum in the transition to lower energy where atmospheric neutrinos dominate. The main aspects of this presentation will be included in the author's Review Talk at the end of the Symposium.

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

    Science.gov (United States)

    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…

  20. Frontier Research in Astrophysics - II

    Science.gov (United States)

    2016-05-01

    . Planetology: Solar System, Sun-like Stars, Exoplanets. Science from large area multiwavelength surveys and deep-exposure pointings. Future Physics and Astrophysics: Ongoing and Planned Ground- and Space-based Experiments. The workshop will include a few 35-minute general review talks to introduce the current problems, and 20-minute talks to discuss new experimental and theoretical results. A series of 15-minute talks will discuss the ongoing and planned ground- based and space-based experiments. There will also be some general talks about the future directions of scientific research on cosmic sources. The papers will pass a peer-review process and the workshop proceedings will be edited by Franco Giovannelli & Lola Sabau-Graziati. The location of the workshop is the Splendid Hotel La Torre, located in Mondello beach in Palermo, Italy, a venue that will provide a friendly and collaborative atmosphere.

  1. Plasma physics of extreme astrophysical environments.

    Science.gov (United States)

    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

  2. Studies on process synthesis and process integration

    OpenAIRE

    Fien, Gert-Jan A. F.

    1994-01-01

    This thesis discusses topics in the field of process engineering that have received much attention over the past twenty years: (1) conceptual process synthesis using heuristic shortcut methods and (2) process integration through heat-exchanger networks and energy-saving power and refrigeration systems. The shortcut methods for conceptual process synthesis presented in Chapter 2, utilize Residue Curve Maps in ternary diagrams and are illustrated with examples of processes...

  3. The LAGUNA design study-towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches

    CERN Document Server

    Angus, D; Autiero, D.; Apostu, A.; Badertscher, A.; Bennet, T.; Bertola, G.; Bertola, P.F.; Besida, O.; Bettini, A.; Booth, C.; Borne, J.L.; Brancus, I.; Bujakowsky, W.; Campagne, J.E.; Danil, G.Cata; Chipesiu, F.; Chorowski, M.; Cripps, J.; Curioni, A.; Davidson, S.; Declais, Y.; Drost, U.; Duliu, O.; Dumarchez, J.; Enqvist, T.; Ereditato, A.; von Feilitzsch, F.; Fynbo, H.; Gamble, T.; Galvanin, G.; Gendotti, A.; Gizicki, W.; Goger-Neff, M.; Grasslin, U.; Gurney, D.; Hakala, M.; Hannestad, S.; Haworth, M.; Horikawa, S.; Jipa, A.; Juget, F.; Kalliokoski, T.; Katsanevas, S.; Keen, M.; Kisiel, J.; Kreslo, I.; Kudryastev, V.; Kuusiniemi, P.; Labarga, L.; Lachenmaier, T.; Lanfranchi, J.C.; Lazanu, I.; Lewke, T.; Loo, K.; Lightfoot, P.; Lindner, M.; Longhin, A.; Maalampi, J.; Marafini, M.; Marchionni, A.; Margineanu, R.M.; Markiewicz, A.; Marrodan-Undagoita, T.; Marteau, J.E.; Matikainen, R.; Meindl, Q.; Messina, M.; Mietelski, J.W.; Mitrica, B.; Mordasini, A.; Mosca, L.; Moser, U.; Nuijten, G.; Oberauer, L.; Oprina, A.; Paling, S.; Pascoli, S.; Patzak, T.; Pectu, M.; Pilecki, Z.; Piquemal, F.; Potzel, W.; Pytel, W.; Raczynski, M.; Rafflet, G.; Ristaino, G.; Robinson, M.; Rogers, R.; Roinisto, J.; Romana, M.; Rondio, E.; Rossi, B.; Rubbia, A.; Sadecki, Z.; Saenz, C.; Saftoiu, A.; Salmelainen, J.; Sima, O.; Slizowski, J.; Slizowski, K.; Sobczyk, J.; Spooner, N.; Stoica, S.; Suhonen, J.; Sulej, R.; Szarska, M.; Szeglowski, T.; Temussi, M.; Thompson, J.; Thompson, L.; Trzaska, W.H.; Tippmann, M.; Tonazzo, A.; Urbanczyk, K.; Vasseur, G.; Williams, A.; Winter, J.; Wojutszewska, K.; Wurm, M.; Zalewska, A.; Zampaolo, M.; Zito, M.

    2010-01-01

    The feasibility of a next generation neutrino observatory in Europe is being considered within the LAGUNA design study. To accommodate giant neutrino detectors and shield them from cosmic rays, a new very large underground infrastructure is required. Seven potential candidate sites in different parts of Europe and at several distances from CERN are being studied: Boulby (UK), Canfranc (Spain), Fr\\'ejus (France/Italy), Pyh\\"asalmi (Finland), Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The design study aims at the comprehensive and coordinated technical assessment of each site, at a coherent cost estimation, and at a prioritization of the sites within the summer 2010.

  4. Electrostatic shock waves in the laboratory and astrophysics: similarities and differences

    Science.gov (United States)

    Dieckmann, M. E.; Doria, D.; Sarri, G.; Romagnani, L.; Ahmed, H.; Folini, D.; Walder, R.; Bret, A.; Borghesi, M.

    2018-01-01

    Contemporary lasers allow us to create shocks in the laboratory that propagate at a speed that matches that of energetic astrophysical shocks like those that ensheath supernova blast shells. The rapid growth time of the shocks and the spatio-temporal resolution, with which they can be sampled, allow us to identify the processes that are involved in their formation and evolution. Some laser-generated unmagnetized shocks are mediated by collective electrostatic forces and effects caused by binary collisions between particles can be neglected. Hydrodynamic models, which are valid for many large-scale astrophysical shocks, assume that collisions enforce a local thermodynamic equilibrium in the medium; laser-generated shocks are thus not always representative for astrophysical shocks. Laboratory studies of shocks can improve the understanding of their astrophysical counterparts if we can identify processes that affect electrostatic shocks and hydrodynamic shocks alike. An example is the nonlinear thin-shell instability (NTSI). We show that the NTSI destabilises collisionless and collisional shocks by the same physical mechanism.

  5. Nuclear astrophysics: the unfinished quest for the origin of the elements

    Science.gov (United States)

    José, Jordi; Iliadis, Christian

    2011-09-01

    Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline has reached its maturity. Today, nuclear astrophysics constitutes a multidisciplinary crucible of knowledge that combines the achievements in theoretical astrophysics, observational astronomy, cosmochemistry and nuclear physics. New tools and developments have revolutionized our understanding of the origin of the elements: supercomputers have provided astrophysicists with the required computational capabilities to study the evolution of stars in a multidimensional framework; the emergence of high-energy astrophysics with space-borne observatories has opened new windows to observe the Universe, from a novel panchromatic perspective; cosmochemists have isolated tiny pieces of stardust embedded in primitive meteorites, giving clues on the processes operating in stars as well as on the way matter condenses to form solids; and nuclear physicists have measured reactions near stellar energies, through the combined efforts using stable and radioactive-ion beam facilities. This review provides comprehensive insight into the nuclear history of the Universe and related topics: starting from the Big Bang, when the ashes from the primordial explosion were transformed to hydrogen, helium and a few trace elements, to the rich variety of nucleosynthesis mechanisms and sites in the Universe. Particular attention is paid to the hydrostatic processes governing the evolution of low-mass stars, red giants and asymptotic giant-branch stars, as well as to the explosive nucleosynthesis occurring in core-collapse and thermonuclear supernovae, γ-ray bursts, classical novae, x-ray bursts, superbursts and stellar mergers.

  6. Results and prospects in multi-messenger particle astrophysics

    Science.gov (United States)

    Mostafa, Miguel

    2017-01-01

    In high-energy particle astrophysics the old days were certainly not better than these. Our field has thrived in the past decade with experiments covering thousands of square kilometers to measure the suppression in the flux of the highest energy cosmic rays ever observed, instrumenting a cubic kilometer of Antarctic ice to discover astrophysical neutrinos, and measuring a change in arm length as small as 10-19 m for the ground-breaking direct observation of gravitational waves. Additionally, the current generation of space-borne and ground-based gamma-ray experiments have revealed a plethora of gamma-ray sources, including pulsars, compact binaries, the galactic center, and extragalactic sources such as starburst galaxies and radio galaxies. Before the next generation of instruments bring us yet another order of magnitude in sensitivity, we can combine current observations to probe physics beyond the standard model, and to extend the high-energy frontier well above the energies accessible to laboratory accelerators. One example of this potential is the search for dark-matter annihilation and decay products. To use the multi-messenger approach effectively for probing dark-matter signatures and physics beyond the LHC energy requires understanding the origin (or acceleration mechanism) and the propagation processes. High energy protons and nuclei, neutrinos, gamma-rays, X-rays, and gravitational waves bring new and complementary views of the astrophysical sources. By comparing observations through different windows, we can use the sites of violent phenomena as a laboratory to probe the physical processes under extreme conditions throughout the Universe, and to test the fundamental laws of particle physics and gravitation. As a community we need to engage in a bold synergistic approach to understanding the violent processes that give rise to the high-energy cosmic phenomena in the Universe. In this invited talk, I will present on-going multi-messenger studies to

  7. Investigations in γ-Ray Astrophysics and Astroparticle Physics

    Energy Technology Data Exchange (ETDEWEB)

    Krennrich, Frank [Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy

    2016-06-28

    This report describes the status of data analysis efforts, results and publications of research grant DE-SC0009917. The research is focused on TeV gamma-ray studies of astrophysical sources and related particle physics questions.

  8. Creative Writing and Learning in a Conceptual Astrophysics Course

    Science.gov (United States)

    Berenson, R.

    2012-08-01

    Creative writing assignments in a conceptual astrophysics course for liberal arts students can reduce student anxiety. This study demonstrates that such assignments also can aid learning as demonstrated by significantly improved performance on exams.

  9. Nuclei in Astrophysics

    Science.gov (United States)

    Penionzhkevich, Yu. E.

    2016-06-01

    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 nuclearphysics methods for studying cosmic objects and properties of the Universe. The results of investigations in nuclear reactions, induced by radioactive nuclear beams, make it possible to analyze the nucleosynthesis scenario in the region of light elements in a new manner.

  10. Nuclear astrophysics with radioactive ions at FAIR

    Science.gov (United States)

    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.

  11. CASPAR - Nuclear Astrophysics Underground

    Science.gov (United States)

    Senarath, Chamaka; Caspar Collaboration

    2017-09-01

    The CASPAR mainly focuses on Stellar Nucleosynthesis, its impact on the production of heavy elements and study the strength of stellar neutron sources that propels the s-process, 13C(α,n)16O and 22Ne(α,n)25Mg. Currently, implementation of a 1MV fully refurbished Van de Graaff accelerator that can provide a high intensity Î+/- beam, is being done at the Sanford Underground Research Facility (SURF). The accelerator is built among a collaboration of South Dakota School of Mines and Technology, University of Notre Dame and Colorado School of Mines. It is understood that cosmic ray neutron background radiation hampers experimental Nucleosynthesis studies, hence the need to go underground in search for a neutron free environment, to study these reactions at low energies is evident. The first beam was produced in the middle of summer 2017. The entire accelerator will be run before the end of this year. A detailed overview of goals of CASPAR will be presented. NFS Grant-1615197.

  12. Studies of the structure of the Tz = -1 Nuclei 20Na and 30S for explosive astrophysics

    Science.gov (United States)

    Wallace, Jennifer Patrita

    Two and three-dimensional seismic data are used to investigate some stratigraphic relationships between sedimentation, deformation and fluid flow at the lateral margin of a gravity detachment system. Three themes were studied. In the Niger Delta, a right-lateral strike-slip fault with a displacement of around 7 km occurs across 75 km. It is interpreted as the lateral strike-slip domain, linked to the updip extensional domain and the downdip compression zone of a gravity detachment system. Structural and kinematic evidence, such as present-day propagating strike-slip faults, for possible future lateral expansions of the lateral strike-slip domain, is described. We expect to observe similar domains at the margins of other preserved gravitational collapse sliding over a detachment whose efficiency in causing downdip slip may vary laterally. Using 3D data from both Mauritania and Nigeria, the interactions between tear faults and deepwater channels are studied. Structural observations combined with channel analysis are performed in four case studies, illustrating that tear faults influence channel development throughout their evolution. Some examples across tear fault zones are presented, and it is expected to find such interactions elsewhere in the world. A simple model of development of vertical fluid flow pipes is established using two examples that are 400 - 600 m wide and ~ 2000 - 2500 m high. Both examples are located at the crest of rollover anticlines and rooted in buried channel-complexes tilted during fold growth. At the crest of the structures and within the connected permeable reservoir intervals of the channel complexes, lateral pressure transfer caused the pore pressure to reach critical levels, leading to hydraulic fracturing of the overburden. Although hydrocarbons may migrate upwards through the consequent chimney systems, the pipes are not necessarily indicators of hydrocarbon charge of the channel complexes.

  13. Resonance Strength Measurement at Astrophysical Energies: The 17O(p,α14N Reaction Studied via THM

    Directory of Open Access Journals (Sweden)

    Sergi M.L.

    2016-01-01

    Full Text Available In recent years, the Trojan Horse Method (THM has been used to investigate the low-energy cross sections of proton-induced reactions on 17O nuclei, overcoming extrapolation procedures and enhancement effects due to electron screening. We will report on the indirect study of the 17O(p,α14N reaction via the Trojan Horse Method by applying the approach developed for extracting the resonance strength of narrow resonance in the ultralow energy region. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature.

  14. Final Report for DoE Grant DE-SC-0011689 - Studies of Particle Astrophysics at the Cosmic Frontier

    Energy Technology Data Exchange (ETDEWEB)

    Nitz, David F. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics; Fick, Brian E. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics

    2016-05-13

    Our research focuses on the “Cosmic Frontier”, one of the three principle thrusts of the DoE Office of Science High Energy Physics research program. The 2013 community summer study “Snowmass on the Mississippi” catalyzed joint work to describe the status and future prospects of this research thrust. Over its history, the field of cosmic ray studies has provided many discoveries of central importance to the the progress of high energy physics, including the identification of new elementary particles, measurements of particle interactions far above accelerator energies, and the confirmation of neutrino oscillations. In our research we continued this tradition, employing 2 instruments (the Auger Observatory and the HAWC Observatory) to study high energy physics questions using cosmic rays. One approach to addressing particle physics questions at the cosmic frontier is to study the very highest energy cosmic rays. This has been the major thrust of our research effort. The two largest currently operating ultra-high energy cosmic ray (UHECR) observatories are the Pierre Auger Observatory in the Southern hemisphere, covering an area of 3000 km2 and the Telescope Array (TA) in the Northern hemisphere, covering about 700 km2. The observatories sample the cosmic ray air showers at ground level (with 1660 water Cerenkov stations in the Auger surface detector), and also measure the longitudinal development of air showers on clear moonless nights (approx. 10% of the events) using atmospheric fluorescence detectors. The observatories have recently installed low energy extensions, which provide an overlap with the LHC energy regime. The Auger and TA teams have established joint working groups to discuss experimental methods, compare data analyses and modeling, and perform cross calibrations. Another approach is to study high energy gamma rays. The High Altitude Water Cerenkov (HAWC) gamma-ray observatory is located at 4100 m above sea level near Pico

  15. Nuclear astrophysics: a new era

    Energy Technology Data Exchange (ETDEWEB)

    Wiescher, Michael; Aprahamian, Ani [Department of Physics, University of Notre Dame (United States); Regan, Paddy [Department of Physics, University of Surrey (United Kingdom)

    2002-02-01

    The latest generation of radioactive-ion-beam facilities promises to shed light on the complex nuclear processes that control the evolution of stars and stellar explosions. The most fundamental question in nature is where do we come from, or, put another way, what are we made of? The late Carl Sagan poetically said that we are all made of stardust, but the origin of the elements has fascinated scientists for thousands of years. Many of the greatest medieval and renaissance scientists dabbled in alchemy, trying to create the elements that make up the cosmos, but we had to wait until the early 20th century to recognize that elements are really defined by the number of protons in the nucleus. According to our current understanding, after the big bang most of the normal or baryonic material in the universe consisted of the lightest two elements, hydrogen and helium, with only trace amounts of lithium and beryllium. All the heavier elements that occur naturally on Earth were created from this original material via a series of nuclear reactions in the cores of stars or in stellar explosions. Over the last decade, ground-based telescopes and satellite-based Observatories have opened new windows on the stars across the electromagnetic spectrum, from infrared to gamma radiation. New technology now makes it possible to observe and analyse short-lived stellar explosions. Indeed, the distribution of elements in 'planetary nebula' and in the ejecta of supernovae and novae give a direct glimpse of individual nucleosynthesis processes. In the February issue of Physics World, Michael Wiescher, Paddy Regan and Ani Aprahamian describe how sate-of-the-art facilities are set to plug many of the gaps in our understanding of nuclear astrophysics. (U.K.)

  16. Cosmology and Particle Astrophysics at Kavli Ipmu

    Science.gov (United States)

    Aihara, Hiroaki

    2013-12-01

    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) currently undertakes two large-scale projects in cosmology and particle astrophysics. One is Subaru Measurement of Images and Redshifts, the Sumire project. It observes images and redshifts of the galaxies using Subaru telescope to study cosmology and astronomy. The other is XMASS experiment aiming to detect the cold dark matter using liquid Xenon. We provide a brief introductory description of these projects.

  17. On Validating an Astrophysical Simulation Code

    Science.gov (United States)

    Calder, A. C.; Fryxell, B.; Plewa, T.; Rosner, R.; Dursi, L. J.; Weirs, V. G.; Dupont, T.; Robey, H. F.; Kane, J. O.; Remington, B. A.; Drake, R. P.; Dimonte, G.; Zingale, M.; Timmes, F. X.; Olson, K.; Ricker, P.; MacNeice, P.; Tufo, H. M.

    2002-11-01

    We present a case study of validating an astrophysical simulation code. Our study focuses on validating FLASH, a parallel, adaptive-mesh hydrodynamics code for studying the compressible, reactive flows found in many astrophysical environments. We describe the astrophysics problems of interest and the challenges associated with simulating these problems. We describe methodology and discuss solutions to difficulties encountered in verification and validation. We describe verification tests regularly administered to the code, present the results of new verification tests, and outline a method for testing general equations of state. We present the results of two validation tests in which we compared simulations to experimental data. The first is of a laser-driven shock propagating through a multilayer target, a configuration subject to both Rayleigh-Taylor and Richtmyer-Meshkov instabilities. The second test is a classic Rayleigh-Taylor instability, where a heavy fluid is supported against the force of gravity by a light fluid. Our simulations of the multilayer target experiments showed good agreement with the experimental results, but our simulations of the Rayleigh-Taylor instability did not agree well with the experimental results. We discuss our findings and present results of additional simulations undertaken to further investigate the Rayleigh-Taylor instability.

  18. Astrophysics a very short introduction

    CERN Document Server

    Binney, James

    2016-01-01

    Astrophysics is the physics of the stars, and more widely the physics of the Universe. It enables us to understand the structure and evolution of planetary systems, stars, galaxies, interstellar gas, and the cosmos as a whole. In this Very Short Introduction, the leading astrophysicist James Binney shows how the field of astrophysics has expanded rapidly in the past century, with vast quantities of data gathered by telescopes exploiting all parts of the electromagnetic spectrum, combined with the rapid advance of computing power, which has allowed increasingly effective mathematical modelling. He illustrates how the application of fundamental principles of physics - the consideration of energy and mass, and momentum - and the two pillars of relativity and quantum mechanics, has provided insights into phenomena ranging from rapidly spinning millisecond pulsars to the collision of giant spiral galaxies. This is a clear, rigorous introduction to astrophysics for those keen to cut their teeth on a conceptual trea...

  19. Hyper-Kamiokande and Astrophysics

    Science.gov (United States)

    Yano, Takatomi; Hyper-Kamiokande proto Collaboration

    2017-09-01

    Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector. Recently a new detector design of Hyper-K is presented, as the two cylindrical pure water tanks. In the new design, each detector is surrounded by 40,000 newly developed photos sensors and provids the fiducial volume of 0.187 Mt. In total, the fiducial volume will be 0.37 Mt. Hyper-K will play the important role in several sciene of 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.

  20. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1966-01-01

    Advances in Astronomy and Astrophysics, Volume 4 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of five chapters, and starts with a description of objective prism and its application in space observations. The next chapter deals with the possibilities of deriving reliable models of the figure, density distribution, and gravity field of the Moon based on data obtained through Earth-bound telescopes. These topics are followed by a discussion on the ideal partially relativistic, partially degenerate gas in an exact manner. A ch

  1. Reactor neutrons in nuclear astrophysics

    Science.gov (United States)

    Reifarth, René; Glorius, Jan; Göbel, Kathrin; Heftrich, Tanja; Jentschel, Michael; Jurado, Beatriz; Käppeler, Franz; Köster, Ulli; Langer, Christoph; Litvinov, Yuri A.; Weigand, Mario

    2017-09-01

    The huge neutron fluxes offer the possibility to use research reactors to produce isotopes of interest, which can be investigated afterwards. An example is the half-lives of long-lived isotopes like 129I. A direct usage of reactor neutrons in the astrophysical energy regime is only possible, if the corresponding ions are not at rest in the laboratory frame. The combination of an ion storage ring with a reactor and a neutron guide could open the path to direct measurements of neutron-induced cross sections on short-lived radioactive isotopes in the astrophysically interesting energy regime.

  2. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1968-01-01

    Advances in Astronomy and Astrophysics, Volume 6 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of five chapters, and starts with the description of improved methods for analyzing and classifying families of periodic orbits in a conservative dynamical system with two degrees of freedom. The next chapter describes the variation of fractional luminosity of distorted components of close binary systems in the course of their revolution, or the accompanying changes in radial velocity. This topic is followed by discussions on vari

  3. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1963-01-01

    Advances in Astronomy and Astrophysics, Volume 2 brings together numerous research works on different aspects of astronomy and astrophysics. This volume is composed of six chapters and begins with a summary of observational record on twilight extensions of the Venus cusps. The next chapter deals with the common and related properties of binary stars, with emphasis on the evaluation of their cataclysmic variables. Cataclysmic variables refer to an object in one of three classes: dwarf nova, nova, or supernova. These topics are followed by discussions on the eclipse phenomena and the eclipses i

  4. Advances in astronomy and astrophysics

    CERN Document Server

    Kopal, Zdenek

    1962-01-01

    Advances in Astronomy and Astrophysics, Volume 1 brings together numerous research works on different aspects of astronomy and astrophysics. This book is divided into five chapters and begins with an observational summary of the shock-wave theory of novae. The subsequent chapter provides the properties and problems of T tauri stars and related objects. These topics are followed by discussions on the structure and origin of meteorites and cosmic dust, as well as the models for evaluation of mass distribution in oblate stellar systems. The final chapter describes the methods of polarization mea

  5. Astrophysically Relevant Instabilities at a Decelerating Interface.

    Science.gov (United States)

    Calder, A. C.; Fryxell, B.; Rosner, R.; Kane, J.; Remington, B. A.; Robey, H.; Keiter, P.; Drake, R. P.; Knauer, J.; Dursi, L. J.; Olson, K.; Ricker, P. M.; Timmes, F. X.; Zingale, M.; Tufo, H.; MacNeice, P.

    2000-10-01

    Hydrodynamic instabilities play an important role in many astrophysical phenomena, and modern intense lasers offer the chance to experimentally investigate these instabilities in similar environments in a laboratory. In this poster, we report on experimental and theoretical progress in ongoing research in laser astrophysics. We presents results of simulations of experiments performed using the University of Rochester's Omega laser facility. These experiments involve shock propagation through multi-layer targets, and are designed to replicate the complex hydrodynamic instabilities thought to arise during supernovae explosions. The simulations were performed with the FLASH code, developed by the ASCI/ASAP Center for Astrophysical Thermonuclear Flashes at the University of Chicago, and we are planning on a study making use of a realistic equation of state. We present results of an experimental study of 2-D vs. 3-D perturbation growth rates also performed at the Omega laser facility. Data from experiments with nominally identical two-layer targets, but 2-D or 3-D perturbations, show clear differences between the evolution of 2-D vs. 3-D perturbations. We also present simulations showing qualitatively similar features for comparison. This work is supported by the US Department of Energy.

  6. The neutron capture process in the He shell in core-collapse supernovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics

    Science.gov (United States)

    Pignatari, Marco; Hoppe, Peter; Trappitsch, Reto; Fryer, Chris; Timmes, F. X.; Herwig, Falk; Hirschi, Raphael

    2018-01-01

    Carbon-rich presolar grains are found in primitive meteorites, with isotopic measurements to date suggesting a core-collapse supernovae origin site for some of them. This holds for about 1-2% of presolar silicon carbide (SiC) grains, so-called Type X and C grains, and about 30% of presolar graphite grains. Presolar SiC grains of Type X show anomalous isotopic signatures for several elements heavier than iron compared to the solar abundances: most notably for strontium, zirconium, molybdenum, ruthenium and barium. We study the nucleosynthesis of zirconium and molybdenum isotopes in the He-shell of three core-collapse supernovae models of 15, 20 and 25 M⊙ with solar metallicity, and compare the results to measurements of presolar grains. We find the stellar models show a large scatter of isotopic abundances for zirconium and molybdenum, but the mass averaged abundances are qualitatively similar to the measurements. We find all models show an excess of 96Zr relative to the measurements, but the model abundances are affected by the fractionation between Sr and Zr since a large contribution to 90Zr is due to the radiogenic decay of 90Sr. Some supernova models show excesses of 95,97Mo and depletion of 96Mo relative to solar. The mass averaged distribution from these models shows an excess of 100Mo, but this may be alleviated by very recent neutron-capture cross section measurements. We encourage future explorations to assess the impact of the uncertainties in key neutron-capture reaction rates that lie along the n-process path.

  7. RP process studies with radioactive beams at ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.E. [Argonne National Lab., Physics Div., Argonne, IL (United States)

    1998-06-01

    Reactions of interest to nuclear astrophysics have been studied with radioactive beams at the ATLAS accelerator. Using a modified ISOL technique, beams of {sup 18}F(T{sub 1/2}=110 min) and {sup 56}Ni(T{sub 1/2}=6.1 d) have been produced. The reactions {sup 18}F(p,{alpha}){sup 15}O, {sup 18}F(p,{gamma}){sup 19}Ne, and {sup 56}Ni(d,p){sup 57}Ni have been investigated. The results indicate that the {sup 18}F(p,{gamma}) route is a small contributor to the breakout from the hot CNO cycle into the rp process, while the {sup 56}Ni(p,{gamma}){sup 57}Cu rate is about ten times larger than previously assumed. (orig.)

  8. Electric Currents along Astrophysical Jets

    Directory of Open Access Journals (Sweden)

    Ioannis Contopoulos

    2017-10-01

    Full Text Available Astrophysical black holes and their surrounding accretion disks are believed to be threaded by grand design helical magnetic fields. There is strong theoretical evidence that the main driver of their winds and jets is the Lorentz force generated by these fields and their associated electric currents. Several researchers have reported direct evidence for large scale electric currents along astrophysical jets. Quite unexpectedly, their directions are not random as would have been the case if the magnetic field were generated by a magnetohydrodynamic dynamo. Instead, in all kpc-scale detections, the inferred electric currents are found to flow away from the galactic nucleus. This unexpected break of symmetry suggests that a battery mechanism is operating around the central black hole. In the present article, we summarize observational evidence for the existence of large scale electric currents and their associated grand design helical magnetic fields in kpc-scale astrophysical jets. We also present recent results of general relativistic radiation magnetohydrodynamic simulations which show the action of the Cosmic Battery in the vicinity of astrophysical black holes.

  9. Astrophysics on the Lab Bench

    Science.gov (United States)

    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…

  10. Annual Report: Hydrodynamics and Radiative Hydrodynamics with Astrophysical Applications

    Energy Technology Data Exchange (ETDEWEB)

    R. Paul Drake

    2005-12-01

    We report the ongoing work of our group in hydrodynamics and radiative hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining high-quality scaling data using a backlit pinhole and obtaining the first (ever, anywhere) Thomson-scattering data from a radiative shock. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, obtaining the first (ever, anywhere) dual-axis radiographic data using backlit pinholes and ungated detectors. All these experiments have applications to astrophysics, discussed in the corresponding papers either in print or in preparation. We also have obtained preliminary radiographs of experimental targets using our x-ray source. The targets for the experiments have been assembled at Michigan, where we also prepare many of the simple components. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  11. Showing Complex Astrophysical Settings Through Virtual Reality

    Science.gov (United States)

    Green, Joel; Smith, Denise; Smith, Louis Chad; Lawton, Brandon; Lockwood, Alexandra; Jirdeh, Hussein

    2018-01-01

    The James Webb Space Telescope (JWST), NASA’s next great observatory launching in spring 2019, will routinely showcase astrophysical concepts that will challenge the public's understanding. Emerging technologies such as virtual reality bring the viewer into the data and the concept in previously unimaginable immersive detail. For example, we imagine a spacefarer inside a protoplanetary disk, seeing the accretion process directly. STScI is pioneering some tools related to JWST for showcasing at AAS, and in local events, which I highlight here. If we develop materials properly tailored to this medium, we can reach more diverse audiences than ever before.

  12. Indirect Study of the (2)H(d,p)(3)H and (2)H(d,n)(3)He Reactions at Astrophysical Energies via the Trojan Horse Method

    Czech Academy of Sciences Publication Activity Database

    Tumino, A.; Spitaleri, C.; Mukhamedzhanov, A.; Typel, S.; Aliotta, M.; Burjan, Václav; Del Santo, M. G.; Kiss, G.G.; Kroha, Václav; Hons, Zdeněk; La Cognata, M.; Lamia, L.; Mrázek, Jaromír; Pizzone, R. G.; Piskoř, Štěpán; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Sparta, R.

    2011-01-01

    Roč. 50, 1-4 (2011), s. 323-325 ISSN 0177-7963. [21st European Conference on Few-Body Problems in Physics Location. Salamanca, 30.08.2010-03092010] R&D Projects: GA ČR GAP203/10/0310 Institutional research plan: CEZ:AV0Z10480505 Keywords : CROSS-SECTIONS * REACTION-RATES * COMPILATION * D+D Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.438, year: 2011

  13. International Olympiad on Astronomy and Astrophysics

    Science.gov (United States)

    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.)

  14. Goddard's Astrophysics Science Divsion Annual Report 2014

    Science.gov (United States)

    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

  15. Astrophysics with Extraterrestrial Materials

    Science.gov (United States)

    Nittler, Larry R.; Ciesla, Fred

    2016-09-01

    Extraterrestrial materials, including meteorites, interplanetary dust, and spacecraft-returned asteroidal and cometary samples, provide a record of the starting materials and early evolution of the Solar System. We review how laboratory analyses of these materials provide unique information, complementary to astronomical observations, about a wide variety of stellar, interstellar and protoplanetary processes. Presolar stardust grains retain the isotopic compositions of their stellar sources, mainly asymptotic giant branch stars and Type II supernovae. They serve as direct probes of nucleosynthetic and dust formation processes in stars, galactic chemical evolution, and interstellar dust processing. Extinct radioactivities suggest that the Sun's birth environment was decoupled from average galactic nucleosynthesis for some tens to hundreds of Myr but was enriched in short-lived isotopes from massive stellar winds or explosions shortly before or during formation of the Solar System. Radiometric dating of meteorite components tells us about the timing and duration over which solar nebula solids were assembled into the building blocks of the planets. Components of the most primitive meteoritical materials provide further detailed constraints on the formation, processing, and transport of material and associated timescales in the Sun's protoplanetary disk as well as in other forming planetary systems.

  16. Towards an experimental constraint for the 56Ni(n,p)56Co reaction rate which is key for the astrophysical νp process

    Science.gov (United States)

    Perdikakis, Georgios; Gastis, Panagiotis; Frohlich, Carla; Horoi, Mihai; Kontos, Antonios; Liddick, Sean; Lin, Ling-Ying; Montes, Fernando; Nikas, Stelios; Redpath, Thomas; Redshaw, Matthew; Senkov, Roman; Spyrou, Artemis; Villari, Antonio; Wimmer, Kathrin; Zegers, Remco

    2017-09-01

    Neutrino-driven winds in core-collapse supernovae, are an important site for the production of elements heavier than iron. If the neutrino-driven wind is slightly proton-rich as predicted by modern hydrodynamics simulations, then some of the elements heavier than Fe could be synthesized by the νp-process making it a reasonable candidate for the Lighter Element Primary Process (LEPP), and a possible contributor to the abundances of light p-nuclei. The key 56Ni(n,p)56 Co reaction rate for the neutrino-p process will be constrained experimentally through the 56Co(p,n)56Ni cross section measurement in ReA3. This new experimental technique that enables the measurement of (p,n) reactions at low energies with radioactive beams and the corresponding proof-of-principle experiment using the 85Rb(p,n) reaction will be discussed. Supported by DOE under Grant No. DE-SC0014285.

  17. NASA Astrophysics Prioritizes Technology Development Funding for Strategic Missions

    Science.gov (United States)

    Thronson, Harley A.; Pham, Bruce; Ganel, Opher

    2017-01-01

    The Cosmic Origins (COR) and Physics of the Cosmos (PCOS) Program Offices (POs) reside at NASA GSFC and implement priorities for the NASA HQ Astrophysics Division (APD). One major aspect of the POs’ activities is managing our Strategic Astrophysics Technology (SAT) program to mature technologies for future strategic missions. The Programs follow APD guidance on which missions are strategic, currently informed by the NRC’s 2010 Decadal Survey report, as well as APD’s Implementation Plan and the Astrophysics Roadmap.In preparation for the upcoming 2020 Decadal Survey, the APD has established Science and Technology Definition Teams (STDTs) to study four large-mission concepts: the Origins Space Telescope, Habitable Exoplanet Imaging Mission, Large UV/Optical/IR Surveyor, and X-ray Surveyor. The STDTs will develop the science case and design reference mission, assess technology development needs, and estimate the cost of their concept. A fifth team, the L3 Study Team (L3ST), was charged to study potential US contributions to ESA’s planned L3 gravitational-wave observatory.The POs use a rigorous and transparent process to solicit technology gaps from the scientific and technical communities, and prioritize those entries based on strategic alignment, expected impact, cross-cutting applicability, and urgency. Starting in 2016, the technology-gap assessments of the four STDTs and the L3ST are included in our process. Until a study team submits its final report, community-proposed changes to gaps submitted or adopted by a study team are forwarded to that study team for consideration.We discuss our technology development process, with strategic prioritization informing calls for SAT proposals and informing investment decisions. We also present results of this year’s technology gap prioritization and showcase our current portfolio of technology development projects. To date, 77 COR and 80 PCOS SAT proposals have been received, of which 18 COR and 22 PCOS projects

  18. Turbulence and Self-Organization Modeling Astrophysical Objects

    CERN Document Server

    Marov, Mikhail Ya

    2013-01-01

    This book focuses on the development of continuum models of natural turbulent media. It provides a theoretical approach to the solutions of different problems related to the formation, structure and evolution of astrophysical and geophysical objects. A stochastic modeling approach is used in the mathematical treatment of these problems, which reflects self-organization processes in open dissipative systems. The authors also consider examples of ordering for various objects in space throughout their evolutionary processes. This volume is aimed at graduate students and researchers in the fields of mechanics, astrophysics, geophysics, planetary and space science.

  19. Distance Measurement Solves Astrophysical Mysteries

    Science.gov (United States)

    2003-08-01

    distance. "Our measurements showed that the pulsar is about 950 light-years from Earth, essentially the same distance as the supernova remnant," said Steve Thorsett, of the University of California, Santa Cruz. "That means that the two almost certainly were created by the same supernova blast," he added. With that problem solved. the astronomers then turned to studying the pulsar's neutron star itself. Using a variety of data from different telescopes and armed with the new distance measurement, they determined that the neutron star is between 16 and 25 miles in diameter. In such a small size, it packs a mass roughly equal to that of the Sun. The next result of learning the pulsar's actual distance was to provide a possible answer to a longstanding question about cosmic rays. Cosmic rays are subatomic particles or atomic nuclei accelerated to nearly the speed of light. Shock waves in supernova remnants are thought to be responsible for accelerating many of these particles. Scientists can measure the energy of cosmic rays, and had noted an excess of such rays in a specific energy range. Some researchers had suggested that the excess could come from a single supernova remnant about 1000 light-years away whose supernova explosion was about 100,000 years ago. The principal difficulty with this suggestion was that there was no accepted candidate for such a source. "Our measurement now puts PSR B0656+14 and the Monogem Ring at exactly the right place and at exactly the right age to be the source of this excess of cosmic rays," Brisken said. With the ability of the VLBA, one of the telescopes of the NRAO, to make extremely precise position measurements, the astronomers expect to improve the accuracy of their distance determination even more. "This pulsar is becoming a fascinating laboratory for studying astrophysics and nuclear physics," Thorsett said. In addition to Brisken and Thorsett, the team of astronomers includes Aaron Golden of the National University of Ireland, Robert

  20. Frontiers in nuclear astrophysics

    Science.gov (United States)

    Bertulani, C. A.; Kajino, T.

    2016-07-01

    The synthesis of nuclei in diverse cosmic scenarios is reviewed, with a summary of the basic concepts involved before a discussion of the current status in each case is made. We review the physics of the early universe, the proton to neutron ratio influence in the observed helium abundance, reaction networks, the formation of elements up to beryllium, the inhomogeneous Big Bang model, and the Big Bang nucleosynthesis constraints on cosmological models. Attention is paid to element production in stars, together with the details of the pp chain, the pp reaction, 3He formation and destruction, electron capture on 7Be, the importance of 8B formation and its relation to solar neutrinos, and neutrino oscillations. Nucleosynthesis in massive stars is also reviewed, with focus on the CNO cycle and its hot companion cycle, the rp-process, triple- α capture, and red giants and AGB stars. The stellar burning of carbon, neon, oxygen, and silicon is presented in a separate section, as well as the slow and rapid nucleon capture processes and the importance of medium modifications due to electrons also for pycnonuclear reactions. The nucleosynthesis in cataclysmic events such as in novae, X-ray bursters and in core-collapse supernovae, the role of neutrinos, and the supernova radioactivity and light-curve is further discussed, as well as the structure of neutron stars and its equation of state. A brief review of the element composition found in cosmic rays is made in the end.

  1. Nucleosynthesis in neutron star mergers. Insights from astrophysical conditions and nuclear physics input

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Dirk [Institut fuer Kernphysik, TU Darmstadt (Germany); Arcones, Almudena [Institut fuer Kernphysik, TU Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2016-07-01

    Half of the elements heavier than iron are created by the rapid neutron capture process (r-process). Neutron star mergers present the most promising astrophysical site for the r-process, being both an explosive and extremely neutron-rich scenario. We investigate the nucleosynthesis of matter ejected in different channels. Furthermore, we study the impact of nuclear masses on the yields. Using masses obtained with six Skyrme energy density functionals, we determine systematic uncertainty bands for r-process abundances and discuss how details of the underlying microphysics can lead to abundance peaks and troughs.

  2. Sensitivity studies for the main r process: β-decay rates

    Directory of Open Access Journals (Sweden)

    M. Mumpower

    2014-02-01

    Full Text Available The pattern of isotopic abundances produced in rapid neutron capture, or r-process, nucleosynthesis is sensitive to the nuclear physics properties of thousands of unstable neutron-rich nuclear species that participate in the process. It has long been recognized that the some of the most influential pieces of nuclear data for r-process simulations are β-decay lifetimes. In light of experimental advances that have pushed measurement capabilities closer to the classic r-process path, we revisit the role of individual β-decay rates in the r process. We perform β-decay rate sensitivity studies for a main (A > 120 r process in a range of potential astrophysical scenarios. We study the influence of individual rates during (n, γ-(γ, n equilibrium and during the post-equilibrium phase where material moves back toward stability. We confirm the widely accepted view that the most important lifetimes are those of nuclei along the r-process path for each astrophysical scenario considered. However, we find in addition that individual β-decay rates continue to shape the final abundance pattern through the post-equilibrium phase, for as long as neutron capture competes with β decay. Many of the lifetimes important for this phase of the r process are within current or near future experimental reach.

  3. A Euclid, LSST and WFIRST Joint Processing Study

    Science.gov (United States)

    Chary, Ranga-Ram; Joint Processing Working Group

    2018-01-01

    Euclid, LSST and WFIRST are the flagship cosmological projects of the next decade. By mapping several thousand square degrees of sky and covering the electromagnetic spectrum from the optical to the NIR with (sub-)arcsec resolution, these projects will provide exciting new constraints on the nature of dark energy and dark matter. The ultimate cosmological, astrophysical and time-domain science yield from these missions, which will detect several billions of sources, requires joint processing at the pixel-level. Three U.S. agencies (DOE, NASA and NSF) are supporting an 18-month study which aims to 1) assess the optimal techniques to combine these, and ancillary data sets at the pixel level; 2) investigate options for an interface that will enable community access to the joint data products; and 3) identify the computing and networking infrastructure to properly handle and manipulate these large datasets together. A Joint Processing Working Group (JPWG) is carrying out this study and consists of US-based members from the community and science/data processing centers of each of these projects. Coordination with European partners is envisioned in the future and European Euclid members are involved in the JPWG as observers. The JPWG will scope the effort and resources required to build up the capabilities to support scientific investigations using joint processing in time for the start of science surveys by LSST and Euclid.

  4. The Astrophysical Multipurpose Software Environment

    Science.gov (United States)

    Pelupessy, F. I.; van Elteren, A.; de Vries, N.; McMillan, S. L. W.; Drost, N.; Portegies Zwart, S. F.

    2013-09-01

    We present the open source Astrophysical Multi-purpose Software Environment (AMUSE), a component library for performing astrophysical simulations involving different physical domains and scales. It couples existing codes within a Python framework based on a communication layer using MPI. The interfaces are standardized for each domain and their implementation based on MPI guarantees that the whole framework is well-suited for distributed computation. It includes facilities for unit handling and data storage. Currently it includes codes for gravitational dynamics, stellar evolution, hydrodynamics and radiative transfer. Within each domain the interfaces to the codes are as similar as possible. We describe the design and implementation of AMUSE, as well as the main components and community codes currently supported and we discuss the code interactions facilitated by the framework. Additionally, we demonstrate how AMUSE can be used to resolve complex astrophysical problems by presenting example applications. http://www.amusecode.org The current version of the code is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A84

  5. Temperature-tuned Maxwell-Boltzmann neutron spectra for kT ranging from 30 up to 50 keV for nuclear astrophysics studies.

    Science.gov (United States)

    Martín-Hernández, G; Mastinu, P F; Praena, J; Dzysiuk, N; Capote Noy, R; Pignatari, M

    2012-08-01

    The need of neutron capture cross section measurements for astrophysics motivates present work, where calculations to generate stellar neutron spectra at different temperatures are performed. The accelerator-based (7)Li(p,n)(7)Be reaction is used. Shaping the proton beam energy and the sample covering a specific solid angle, neutron activation for measuring stellar-averaged capture cross section can be done. High-quality Maxwell-Boltzmann neutron spectra are predicted. Assuming a general behavior of the neutron capture cross section a weighted fit of the spectrum to Maxwell-Boltzmann distributions is successfully introduced. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Nuclear Astrophysics in underground laboratories: the LUNA experiment

    Science.gov (United States)

    2017-11-01

    One of the main ingredients of nuclear astrophysics is the knowledge of the thermonuclear reactions responsible for powering the stellar engine and for the synthesis of the chemical elements. At astrophysical energies the cross section of nuclear processes is extremely reduced by the effect of the Coulomb barrier. The low value of cross sections prevents their measurement at stellar energies on Earth surface and often extrapolations are needed. The Laboratory for Underground Nuclear Astrophysics (LUNA) is placed under the Gran Sasso mountain and thanks to the cosmic-ray background reduction provided by its position can investigate cross sections at energies close to the Gamow peak in stellar scenarios. Many crucial reactions involved in hydrogen burning has been measured directly at astrophysical energies with both the LUNA-50kV and the LUNA-400kV accelerators, and this intense work will continue with the installation of a MV machine able to explore helium and carbon burnings. Based on this progress, currently there are efforts in several countries to construct new underground accelerators. In this talk, the typical techniques adopted in underground nuclear astrophysics will be described and the most relevant results achieved by LUNA will be reviewed. The exciting science that can be probed with the new facilities will be highlighted.

  7. Neutrino Astrophysics And Cosmology

    CERN Document Server

    Abazajian, Kevork N

    2001-01-01

    Although physical cosmology is becoming a field rich in data, the theoretical basis for several aspects of standard cosmological models are spectacularly devoid of firm foundations. On the other hand, the standard model of particle physics has successfully described an enormous quantity of experimental data, with one exception lying in the neutrino sector from observations of the atmospheric neutrino flux. This dissertation intersects both fields, as an interplay of the problems confronting theoretical cosmology and the tremendous success of the standard model of particle physics. And, in return, the successes of the standard cosmology may give insights into new particle physics, particularly neutrino physics. In this interplay, this dissertation studies the production of sterile neutrino dark matter in the early universe, constraints on this scenario, including radiative decays in galactic clusters. The effects of nonthermal neutrinos resulting from neutrino transformation on big bang nucleosynthesis are stu...

  8. Social Studies: The Electoral Process.

    Science.gov (United States)

    Schrager, Donald M.

    This quinmester course of study for grades seven through nine provides a framework for analyzing election processes in a democracy by investigating democratic societies of the past, and contrasting democracies with totalitarian types of government. Major emphasis is upon analyzing the system of institutionalized political parties, the…

  9. Physics, Astrophysics and Cosmology with Gravitational Waves.

    Science.gov (United States)

    Sathyaprakash, B S; Schutz, Bernard F

    2009-01-01

    Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.

  10. Physics, Astrophysics and Cosmology with Gravitational Waves

    Directory of Open Access Journals (Sweden)

    Sathyaprakash B. S.

    2009-03-01

    Full Text Available Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers, and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.

  11. Dynamics and evolution of galactic nuclei (princeton series in astrophysics)

    CERN Document Server

    Merritt, David

    2013-01-01

    Deep within galaxies like the Milky Way, astronomers have found a fascinating legacy of Einstein's general theory of relativity: supermassive black holes. Connected to the evolution of the galaxies that contain these black holes, galactic nuclei are the sites of uniquely energetic events, including quasars, stellar tidal disruptions, and the generation of gravitational waves. This textbook is the first comprehensive introduction to dynamical processes occurring in the vicinity of supermassive black holes in their galactic environment. Filling a critical gap, it is an authoritative resource for astrophysics and physics graduate students, and researchers focusing on galactic nuclei, the astrophysics of massive black holes, galactic dynamics, and gravitational wave detection. It is an ideal text for an advanced graduate-level course on galactic nuclei and as supplementary reading in graduate-level courses on high-energy astrophysics and galactic dynamics. David Merritt summarizes the theoretical work of the las...

  12. Proton and $\\gamma$- partial widths of astrophysically important states of $^{30}$S studied by the $\\beta$-delayed decay of $^{31}$Ar

    CERN Document Server

    Koldste, G T; Borge, M J G; Briz, J A; Carmona-Gallardo, M; Fraile, L M; Fynbo, H O U; Giovinazzo, J; Johansen, J G; Jokinen, A; Jonson, B; Kurturkian-Nieto, T; Kusk, J H; Nilsson, T; Perea, A; Pesudo, V; Picado, E; Riisager, K; Saastamoinen, A; Tengblad, O; Thomas, J -C; Van de Walle, J

    2013-01-01

    Resonances just above the proton threshold in $^{30}$S affect the $^{29}$P$(p,\\gamma)^{30}$S reaction under astrophysical conditions. The ($p,\\gamma$)-reaction rate is currently determined indirectly and depends on the properties of the relevant resonances. We present here a method for finding the ratio between the proton- and $\\gamma$- partial widths of resonances in $^{30}$S. The widths are determined from the $\\beta -2p$ and $\\beta -p-\\gamma$-decay of $^{31}$Ar, which is produced at ISOLDE, CERN. Experimental limits on the ratio between the proton- and $\\gamma$- partial widths for astrophysical relevant levels in $^{30}$S have been found for the first time. A level at 4689.2(24)keV is identified in the $\\gamma$-spectrum, and an upper limit on the $\\Gamma_{p}/\\Gamma_{\\gamma}$ ratio of 0.26 (95% C.L.) is found. In the two-proton spectrum two levels at 5227(3)keV and 5847(4)keV are identified. These levels were previously seen to $\\gamma$-decay and upper limits on the $\\Gamma_{\\gamma}/\\Gamma_{p}$ ratio of 0.5...

  13. Thermochemistry and infrared spectroscopy of neutral and cationic iron-polycyclic aromatic hydrocarbon complexes of astrophysical interest: fundamental density functional theory studies.

    Science.gov (United States)

    Simon, Aude; Joblin, Christine

    2007-10-04

    This paper reports extensive calculations on the structural, thermodynamic, and mid-infrared spectroscopic properties of neutral and cationic model iron-polycyclic aromatic hydrocarbon (PAH) complexes of astrophysical interest for three PAHs of increasing size, namely, naphthalene (C10H8), pyrene (C16H10), and coronene (C24H12). Geometry optimizations and frequency calculations were performed using hybrid Hartree-Fock/density functional theory (DFT) methods. The use of DFT methods is mandatory in terms of computational cost and efficiency to describe the electronic and vibrational structures of such large organometallic unsaturated species that present several low-energy isomers of different structures and electronic and spin states. The calculated structures for the low-energy isomers of the model Fe-PAH and Fe-PAH+ complexes are presented and discussed. Iron-PAH binding energies are extracted, and the consequences of the coordination of iron on the infrared spectra of neutral and cationic PAHs are shown with systematic effects on band intensities and positions being demonstrated. The first results are discussed in terms of astrophysical implications. This work is the first step of an ongoing effort in our group to understand the photophysics and spectroscopy of iron-PAH complexes in the conditions of the interstellar medium using a synergy between observations, laboratory experiments, and theory.

  14. Spin light of neutrino in astrophysical environments

    Science.gov (United States)

    Grigoriev, Alexander; Lokhov, Alexey; Studenikin, Alexander; Ternov, Alexei

    2017-11-01

    The spin light of neutrino (SLν) is a new possible mechanism of electromagnetic radiation by a massive neutrino (with a nonzero magnetic moment) moving in media. Since the prediction of this mechanism, the question has been debated in a number of publications as whether the effect can be of any significance for realistic astrophysical conditions. Although this effect is strongly suppressed due to smallness of neutrino magnetic moment, for ultra-high energy neutrinos (PeV neutrinos recently observed by the IceCube collaboration, for instance) the SLν might be of interest in the case of neutrinos propagating in dense matter. An advanced view on the SLν in matter is given, and several astrophysical settings (a neutron star, supernova, Gamma-Ray Burst (GRB), and relic neutrino background) for which the effect can be realized are considered. Taking into account the threshold condition and also several competing processes, we determine conditions for which the SLν mechanism is possible. We conclude that the most favorable case of the effect manifestation is provided by ultra dense matter of neutron stars and ultrahigh energy of the radiating neutrino, and note that these conditions can be met within galaxy clusters. It is also shown that due to the SLν specific polarization properties this electromagnetic mechanism is of interest in the connection with the observed polarization of GRB emission.

  15. How unequal fluxes of high energy astrophysical neutrinos and antineutrinos can fake new physics

    OpenAIRE

    Nunokawa, Hiroshi; Panes, Boris; Funchal, Renata Zukanovich

    2016-01-01

    Flavor ratios of very high energy astrophysical neutrinos, which can be studied at the Earth by a neutrino telescope such as IceCube, can serve to diagnose their production mechanism at the astrophysical source. The flavor ratios for neutrinos and antineutrinos can be quite different as we do not know how they are produced in the astrophysical environment. Due to this uncertainty the neutrino and antineutrino flavor ratios at the Earth also could be quite different. Nonetheless, it is general...

  16. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy; Volume 36; Issue 1. Issue front cover thumbnail. Volume 36, Issue 1. March 2015, pages a-254. Dynamical Plasma Processes in the Sun and Sun-like Stars. pp a-b. General Editorial on Publication Ethics · More Details Fulltext PDF. pp 1-3. Editorial.

  17. Time process study with UML.

    Science.gov (United States)

    Shiki, N; Ohno, Y; Fujii, A; Murata, T; Matsumura, Y

    2009-01-01

    We propose a new business-process analysis approach, Time Process Study (TPS), which comprises process analysis and time and motion studies (TMS). TPS offsets weaknesses of TMS; the cost of field studies and the difficulties in applying them to tasks whose time span differs from those of usual tasks. In TPS, the job procedures are first displayed using a unified modeling language (UML). Next, time and manpower for each procedure are studied through interviews and TMS, and the information is appended to the UML diagram. We applied TPS in the case of a hospital-based cancer registry (HCR) of a university hospital to clarify the work procedure and the time required, and investigated TPS's availability. Meetings for the study were held once a month from July to September in 2008, and one inquirer committed a total of eight hours to the hospital survey. TPS revealed that HCR consisted of three tasks and 14 functions. The registration required 123 hours/month/person, the quality control required 6.5 hours/ 6 months/person and filing data into the population-based cancer registry required 0.5 hours/6 months/person. Of the total tasks involved in registration, 116.5 hours/month/person were undertaken by a registration worker, which shows the necessity of employing one full-time staff. With TPS, it is straightforward to share the concept among the study-team because the job procedure is first displayed using UML. Therefore, it requires a few workload to conduct TMS and interview. The obtained results were adopted for the review of staff assignment of HCR by Japanese government.

  18. $\\alpha$-cluster ANCs for nuclear astrophysics

    CERN Document Server

    Avila, M L; Koshchiy, E; Baby, L T; Belarge, J; Kemper, K W; Kuchera, A N; Santiago-Gonzalez, D

    2014-01-01

    Background. Many important $\\alpha$-particle induced reactions for nuclear astrophysics may only be measured using indirect techniques due to small cross sections at the energy of interest. One of such indirect technique, is to determine the Asymptotic Normalization Coefficients (ANC) for near threshold resonances extracted from sub-Coulomb $\\alpha$-transfer reactions. This approach provides a very valuable tool for studies of astrophysically important reaction rates since the results are practically model independent. However, the validity of the method has not been directly verified. Purpose. The aim of this letter is to verify the technique using the $^{16}$O($^6$Li,$d$)$^{20}$Ne reaction as a benchmark. The $^{20}$Ne nucleus has a well known $1^-$ state at excitation energy of 5.79 MeV with a width of 28 eV. Reproducing the known value with this technique is an ideal opportunity to verify the method. Method. The 1$^-$ state at 5.79 MeV is studied using the $\\alpha$-transfer reaction $^{16}$O($^6$Li,$d$)$^...

  19. Accretion disks and magnetic fields in astrophysics; Proceedings of the European Physical Society Study Conference, Noto, Italy, June 16-21, 1988

    Science.gov (United States)

    Belvedere, G.

    Various papers on accretion disks (ADs) and magnetic fields in astrophysics are presented. Individual topics addressed include: relevance of magnetic fields to stars and ADs, nonlinear breakup of the sun's toroidal field, accretion and particle acceleration by spiral shock wages, MHD flows in ADs and jets, slender flux tubes in ADs, magnetic fields in the ADs of cataclysmic variables (CVs), accretion disks and magnetic CVs, radio emission of dwarf novae, jets and magnetic fields, early stages of star formation, ADs and jets in protostellar systems, Monte Carlo simulation of H2 formation by cosmic rays, magnetic field generation during galaxy formation, numerical simulation of weakly magnetized propagating slab jets, numerical simulation of mass outflows from star-forming regions, outflows from AGN, relativistic radiative transfer using moment formalism, fluid models for relativistic warm plasmas, time variability of the X-ray emission from Seyfert galaxies, slim accretion disks.

  20. General Astrophysics with the HabEx Workhorse Camera

    Science.gov (United States)

    Stern, Daniel; Clarke, John; Gaudi, B. Scott; Kiessling, Alina; Krause, Oliver; Martin, Stefan; Scowen, Paul; Somerville, Rachel; HabEx STDT

    2018-01-01

    The Habitable Exoplanet Imaging Mission (HabEx) concept has been designed to enable an extensive suite of science, broadly put under the rubric of General Astrophysics, in addition to its exoplanet direct imaging science. General astrophysics directly addresses multiple NASA programmatic branches, and HabEx will enable investigations ranging from cosmology, to galaxy evolution, to stellar population studies, to exoplanet transit spectroscopy, to Solar System studies. This poster briefly describes one of the two primary HabEx General Astrophysics instruments, the HabEx Workhorse Camera (HWC). HWC will be a dual-detector UV-to-near-IR imager and multi-object grism spectrometer with a microshutter array and a moderate (3' x 3') field-of-view. We detail some of the key science we expect HWC to undertake, emphasizing unique capabilities enabled by a large-aperture, highly stable space-borne platform at these wavelengths.

  1. High Energy Astrophysics Science Archive Research Center

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Energy Astrophysics Science Archive Research Center (HEASARC) is the primary archive for NASA missions dealing with extremely energetic phenomena, from...

  2. Astrophysical Model Selection in Gravitational Wave Astronomy

    Science.gov (United States)

    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%.

  3. Nuclear and High-Energy Astrophysics

    Science.gov (United States)

    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.

  4. Time-symmetric integration in astrophysics

    Science.gov (United States)

    Hernandez, David M.; Bertschinger, Edmund

    2018-01-01

    Calculating the long term solution of ordinary differential equations, such as those of the N-body problem, is central to understanding a wide range of dynamics in astrophysics, from galaxy formation to planetary chaos. Because generally no analytic solution exists to these equations, researchers rely on numerical methods which are prone to various errors. In an effort to mitigate these errors, powerful symplectic integrators have been employed. But symplectic integrators can be severely limited because they are not compatible with adaptive stepping and thus they have difficulty accommodating changing time and length scales. A promising alternative is time-reversible integration, which can handle adaptive time stepping, but the errors due to time-reversible integration in astrophysics are less understood. The goal of this work is to study analytically and numerically the errors caused by time-reversible integration, with and without adaptive stepping. We derive the modified differential equations of these integrators to perform the error analysis. As an example, we consider the trapezoidal rule, a reversible non-symplectic integrator, and show it gives secular energy error increase for a pendulum problem and for a Hénon-Heiles orbit. We conclude that using reversible integration does not guarantee good energy conservation and that, when possible, use of symplectic integrators is favored. We also show that time-symmetry and time-reversibility are properties that are distinct for an integrator.

  5. The Astrophysics Source Code Library by the numbers

    Science.gov (United States)

    Allen, Alice; Teuben, Peter; Berriman, G. Bruce; DuPrie, Kimberly; Mink, Jessica; Nemiroff, Robert; Ryan, PW; Schmidt, Judy; Shamir, Lior; Shortridge, Keith; Wallin, John; Warmels, Rein

    2018-01-01

    The Astrophysics Source Code Library (ASCL, ascl.net) was founded in 1999 by Robert Nemiroff and John Wallin. ASCL editors seek both new and old peer-reviewed papers that describe methods or experiments that involve the development or use of source code, and add entries for the found codes to the library. Software authors can submit their codes to the ASCL as well. This ensures a comprehensive listing covering a significant number of the astrophysics source codes used in peer-reviewed studies. The ASCL is indexed by both NASA’s Astrophysics Data System (ADS) and Web of Science, making software used in research more discoverable. This presentation covers the growth in the ASCL’s number of entries, the number of citations to its entries, and in which journals those citations appear. It also discusses what changes have been made to the ASCL recently, and what its plans are for the future.

  6. Particles and astrophysics a multi-messenger approach

    CERN Document Server

    Spurio, Maurizio

    2015-01-01

    This book is an introduction to “multi-messenger” astrophysics. It covers the many different aspects connecting particle physics with astrophysics and cosmology and introduces astrophysics using numerous experimental findings recently obtained through the study of high-energy particles. Taking a systematic approach, it comprehensively presents experimental aspects from the most advanced laboratories and detectors, as well as the theoretical background. The book is aimed at graduate students and post-graduate researchers with a basic understanding of particle and nuclear physics. It will also be of interest to particle physicists working in accelerator/collider physics who are keen to understand the mechanisms of the largest accelerators in the Universe. The book draws on the extensive lecturing experience of Professor Maurizio Spurio from the University of Bologna.

  7. 14th International School of Cosmic Ray Astrophysics

    CERN Document Server

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

    2005-01-01

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

  8. Fundamental Questions in Astrophysics: Guidelines for Future UV Observatories

    CERN Document Server

    Gómez de Castro, Ana I

    2006-01-01

    Modern astrophysics is a mature science that has evolved from its early phase of discovery and classification to a physics-oriented discipline focused in finding answers to fundamental problems ranging from cosmology to the origin and diversity of life-sustainable systems in the Universe. For this very reason, progress of modern astrophysics requires the access to the electromagnetic spectrum in the broadest energy range. The Ultraviolet is a fundamental energy domain since it is one of the most powerful tool to study plasmas at temperatures in the 3,000-300,000~K range as well as electronic transitions of the most abundant molecules in the Universe. Moreover, the UV radiation field is a powerful astrochemical and photoionizing agent. This book describes the fundamental problems in modern astrophysics that cannot progress without easy and wide-spread access to modern UV instrumentation.

  9. Magneto-hydrodynamics Simulation in Astrophysics

    Science.gov (United States)

    Pang, Bijia

    2011-08-01

    Magnetohydrodynamics (MHD) studies the dynamics of an electrically conducting fluid under the influence of a magnetic field. Many astrophysical phenomena are related to MHD, and computer simulations are used to model these dynamics. In this thesis, we conduct MHD simulations of non-radiative black hole accretion as well as fast magnetic reconnection. By performing large scale three dimensional parallel MHD simulations on supercomputers and using a deformed-mesh algorithm, we were able to conduct very high dynamical range simulations of black hole accretion of Sgr A* at the Galactic Center. We find a generic set of solutions, and make specific predictions for currently feasible observations of rotation measure (RM). The magnetized accretion flow is subsonic and lacks outward convection flux, making the accretion rate very small and having a density slope of around -1. There is no tendency for the flows to become rotationally supported, and the slow time variability of th! e RM is a key quantitative signature of this accretion flow. We also provide a constructive numerical example of fast magnetic reconnection in a three-dimensional periodic box. Reconnection is initiated by a strong, localized perturbation to the field lines and the solution is intrinsically three-dimensional. Approximately 30% of the magnetic energy is released in an event which lasts about one Alfvén time, but only after a delay during which the field lines evolve into a critical configuration. In the co-moving frame of the reconnection regions, reconnection occurs through an X-like point, analogous to the Petschek reconnection. The dynamics appear to be driven by global flows rather than local processes. In addition to issues pertaining to physics, we present results on the acceleration of MHD simulations using heterogeneous computing systems te{shan2006heterogeneous}. We have implemented the MHD code on a variety of heterogeneous and multi-core architectures (multi-core x86, Cell, Nvidia and

  10. Astrophysics with small satellites in Scandinavia

    DEFF Research Database (Denmark)

    Lund, Niels

    2003-01-01

    The small-satellites activities in the Scandinavian countries are briefly surveyed with emphasis on astrophysics research. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.......The small-satellites activities in the Scandinavian countries are briefly surveyed with emphasis on astrophysics research. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved....

  11. Student Research in Computational Astrophysics

    Science.gov (United States)

    Blondin, J. M.

    1999-12-01

    Computational physics can shorten the long road from freshman physics major to independent research by providing students with powerful tools to deal with the complexities of modern research problems. At North Carolina State University we have introduced dozens of students to astrophysics research using the tools of computational fluid dynamics. We have used several formats for working with students, including the traditional approach of one-on-one mentoring, a more group-oriented format in which several students work together on one or more related projects, and a novel attempt to involve an entire class in a coordinated semester research project. The advantages and disadvantages of these formats will be discussed at length, but the single most important influence has been peer support. Having students work in teams or learn the tools of research together but tackle different problems has led to more positive experiences than a lone student diving into solo research. This work is supported by an NSF CAREER Award.

  12. Astrophysically Interesting Resonances; Another Approach

    Science.gov (United States)

    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.

  13. A Review of Astrophysical Jets

    Directory of Open Access Journals (Sweden)

    James H. Beall

    2014-12-01

    Full Text Available Astrophysical jets are ubiquitous: this simple statement has become a commonplace over the last three decades and more as a result of observing campaigns using detectors sensitive from radio to gamma-ray energies. During this epoch, theoretical models of these sources have become more complex, moving from assumptions of isotropy that made analytic calculations possible, to fully anisotropic models of emission from the jets and their interactions with the interstellar and intra-cluster medium. Such calculations are only possible because we have extensive computational resources. In addition, the degree of international cooperation required for observing campaigns of these sorts is remarkable, since the instruments include among others the Very Large Array (VLA, the Very Long Baseline Array (VLBA, and entire constellations of satellite instruments, often working in concert. In this paper, I discuss some relevant observations from these eorts and the theoretical interpretations they have occasioned.

  14. Transfer reactions in nuclear astrophysics

    Science.gov (United States)

    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.

  15. Axions in astrophysics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    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)

  16. Building a visionary astrophysics program from the ground up

    Science.gov (United States)

    Mathews, Geoffrey S.; Barnes, Joshua Edward; Coleman, Paul; Gal, Roy R.; Meech, Karen J.; Mendez, Roberto Hugo; Nassir, Michael A.; Sanders, David B.

    2015-08-01

    The University of Hawaii’s Institute for Astronomy is in the process of implementing a new Bachelor of Science in Astrophysics at UH Manoa. This requires a significant adjustment in the role of the IfA, which has long been at the forefront of modern astronomy in Hawaii and is now broadening its educational mission. The IfA’s history of excellence in research and access to observational resources are expected to draw students from around the nation and the world. These factors have inspired our programmatic focus culminating in a senior year research experience. We expect that the program will produce many undergraduate astrophysics majors, making it an ideal testbed to apply modern theories of learning to the teaching of astrophysics. We have explicitly designed the major around three pillars: physical theory, the application of physics to astrophysical phenomena, and the development of core observational astronomy skills. We describe our cooperative approach to developing a program-level curriculum map of key concepts and skills, as well as descriptors of student success throughout the program. These are central tools for course design, program assessment, and professional development.

  17. General relativity with applications to astrophysics

    CERN Document Server

    Straumann, Norbert

    2004-01-01

    This text provides a comprehensive and timely introduction to general relativity The foundations of the theory in Part I are thoroughly developed together with the required mathematical background from differential geometry in Part III The six chapters in Part II are devoted to tests of general relativity and to many of its applications Binary pulsars are studied in considerable detail Much space is devoted to the study of compact objects, especially to black holes This includes a detailed derivation of the Kerr solution, Israel's proof of his uniqueness theorem, and derivations of the basic laws of black hole physics The final chapter of this part contains Witten's proof of the positive energy theorem The book addresses undergraduate and graduate students in physics, astrophysics and mathematics It is very well structured and should become a standard text for a modern treatment of gravitational physics The clear presentation of differential geometry makes it also useful for string theory and other fields of ...

  18. Astrophysical black holes in screened modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Anne-Christine; Jha, Rahul; Muir, Jessica [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Gregory, Ruth, E-mail: acd@damtp.cam.ac.uk, E-mail: r.a.w.gregory@durham.ac.uk, E-mail: r.jha@damtp.cam.ac.uk, E-mail: jlmuir@umich.edu [Centre for Particle Theory, South Road, Durham, DH1 3LE (United Kingdom)

    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.

  19. A Complete Equation of State for Astrophysical Simulations

    Science.gov (United States)

    Shen, H.

    2015-11-01

    We construct a complete equation of state (EOS) covering a wide range oftemperature, proton fraction, and baryon density for the use of astrophysical simulations. We employ the relativistic mean-field (RMF) theory to describe nuclear interactions, and adopt the Thomas-Fermi approximation to describe thenonuniform nuclear matter. The uniform matter and nonuniform matter are studied consistently using the same RMF theory.

  20. A general method of estimating stellar astrophysical parameters from photometry

    NARCIS (Netherlands)

    Belikov, A. N.; Roeser, S.

    2008-01-01

    Context. Applying photometric catalogs to the study of the population of the Galaxy is obscured by the impossibility to map directly photometric colors into astrophysical parameters. Most of all-sky catalogs like ASCC or 2MASS are based upon broad-band photometric systems, and the use of broad

  1. POEMMA: Probe Of Extreme Multi-Messenger Astrophysics

    DEFF Research Database (Denmark)

    Olinto, A. V.; Adams, J. H.; Aloisio, R.

    2017-01-01

    The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission is being designed to establish charged-particle astronomy with ultra-high energy cosmic rays (UHECRs) and to observe cosmogenic tau neutrinos (CTNs). The study of UHECRs and CTNs from space will yield orders-of-magnitude increase...

  2. Studying through the Bologna process

    DEFF Research Database (Denmark)

    Sarauw, Laura Louise

    the relationship between the official policy level and everyday lives of academics and students in the Bologna process. Over the last decades, the traditional approach to policy reforms as linear processes and its vocabularies of dichotomy (structure-actor, cause-effect, action-reaction etc.) has found a valuable...

  3. New isotopes of interest to astrophysics

    CERN Document Server

    Davids, C N; Pardo, R C; Parks, L A

    1976-01-01

    The beta decays of the new isotopes /sup 53/Ti and /sup 59/Mn have been studied. These neutron-rich isotopes have half-lives of 32.7+or-0.9 s and 4.75+or-0.14 s, respectively. They were produced via the /sup 48/Ca(/sup 7/Li, pn)/sup 53/Ti and /sup 48/Ca(/sup 13/C, pn) /sup 59/Mn reactions using beams from the Argonne National Laboratory FN Tandem Van de Graaff accelerator. Measurement of gamma singles, gamma - gamma coincidences, and beta - gamma coincidences were facilitated by a pneumatic target-transfer system ('rabbit'). Decay schemes are presented, and the measured masses compared with various predictions. The relevance to astrophysics will be discussed. In addition, a new 8-target multiple rabbit system will be described. (7 refs).

  4. Promising lines of research in the realms of laboratory nuclear astrophysics by means of powerful lasers

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, V. S., E-mail: belyaev@tsniimash.ru; Zagreev, B. V.; Kedrov, A. Yu.; Lobanov, A. V.; Matafonov, A. P. [Russian Space Agency, Pionerskaya, Central Research Institute for Machine Building (TsNIIMash) (Russian Federation); Bolshakov, V. V.; Savel’ev, A. B.; Mordvintsev, I. M.; Tsymbalov, I. N.; Shulyapov, S. A. [Moscow State University, International Laser Center (Russian Federation); Pikuz, S. A.; Skobelev, I. Yu.; Filippov, E. D.; Faenov, A. Ya. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Krainov, V. P. [Moscow Institute of Physics and Technology (State University) (Russian Federation)

    2016-09-15

    Basic nuclear-astrophysics problems that can be studied under laboratory conditions at a laserradiation intensity of 10{sup 18} W/cm{sup 2} or more are specified. These are the lithium problem, the problem of determining neutron sources for s-processes of heavy-element formation, the formation of bypassed stable p-nuclei, and nuclear reactions involving isotopes used by astronomers for diagnostics purposes. The results of experiments at the Neodym laser facility are presented, and proposals for further studies in these realms are formulated.

  5. Earthdata Search Usability Study Process

    Science.gov (United States)

    Reese, Mark

    2016-01-01

    User experience (UX) design is the process of enhancing user satisfaction by improving various aspects of the user's interaction with an application or website. One aspect of UX design is usability, or the extent to which an application can be used to to accomplish tasks efficiently, effectively, and with satisfaction. NASA's Earthdata Search Client recently underwent a focused usability testing project to measure usability and gain valuable user feedback and insights to increase usability for its end-users. This presentation focuses on the process by which the usability tests were administered and the lessons learned throughout the process.

  6. Trojan horse particle invariance: The impact on nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Pizzone, R. G.; La Cognata, M. [Laboratori Nazionali del Sud - INFN, Catania (Italy); Spitaleri, C. [Universitá di Catania and Laboratori Nazionali del Sud - INFN (Italy); Bertulani, C. A. [Texas A and M University, Commerce (United States); Mukhamedzhanov, A. M. [Texas A and M University, College Station, Texas (United States); Blokhintsev, L. D. [Moscow State University, Moscow (Russian Federation); Lamia, L.; Spartá, R. [Universitá di Catania and Laboratori Nazionali del Sud - INFN, Catania (Italy); Tumino, A. [Universitá Kore, Enna (Italy)

    2014-05-02

    In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previous studies will be extended to the cases of the binary d(d, p)t and {sup 6}Li(d,α){sup 4}He reactions, which were tested using different quasi-free break-up's, namely {sup 6}Li and {sup 3}He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions.

  7. Multi-scale and multi-domain computational astrophysics.

    Science.gov (United States)

    van Elteren, Arjen; Pelupessy, Inti; Zwart, Simon Portegies

    2014-08-06

    Astronomical phenomena are governed by processes on all spatial and temporal scales, ranging from days to the age of the Universe (13.8 Gyr) as well as from kilometre size up to the size of the Universe. This enormous range in scales is contrived, but as long as there is a physical connection between the smallest and largest scales it is important to be able to resolve them all, and for the study of many astronomical phenomena this governance is present. Although covering all these scales is a challenge for numerical modellers, the most challenging aspect is the equally broad and complex range in physics, and the way in which these processes propagate through all scales. In our recent effort to cover all scales and all relevant physical processes on these scales, we have designed the Astrophysics Multipurpose Software Environment (AMUSE). AMUSE is a Python-based framework with production quality community codes and provides a specialized environment to connect this plethora of solvers to a homogeneous problem-solving environment. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  8. Multi-scale and multi-domain computational astrophysics

    Science.gov (United States)

    van Elteren, A.; Pelupessy, I.; Portegies Zwart, S.

    2014-06-01

    Astronomical phenomena are governed by processes on all spatial and temporal scales, ranging from days to the age of the Universe (13.8,Gyr) as well as from km size up to the size of the Universe. This enormous range in scales is contrived, but as long as there is a physical connection between the smallest and largest scales it is important to be able to resolve them all, and for the study of many astronomical phenomena this governance is present. Although covering all these scales is a challenge for numerical modelers, the most challenging aspect is the equally broad and complex range in physics, and the way in which these processes propagate through all scales. In our recent effort to cover all scales and all relevant physical processes on these scales we have designed the Astrophysics Multipurpose Software Environment (AMUSE). AMUSE is a Python-based framework with production quality community codes and provides a specialized environment to connect this plethora of solvers to a homogeneous problem solving environment.

  9. Astrophysics and Big Data: Challenges, Methods, and Tools

    Science.gov (United States)

    Garofalo, Mauro; Botta, Alessio; Ventre, Giorgio

    2017-06-01

    Nowadays there is no field research which is not flooded with data. Among the sciences, astrophysics has always been driven by the analysis of massive amounts of data. The development of new and more sophisticated observation facilities, both ground-based and spaceborne, has led data more and more complex (Variety), an exponential growth of both data Volume (i.e., in the order of petabytes), and Velocity in terms of production and transmission. Therefore, new and advanced processing solutions will be needed to process this huge amount of data. We investigate some of these solutions, based on machine learning models as well as tools and architectures for Big Data analysis that can be exploited in the astrophysical context.

  10. Study of the ( p, γ) and ( α, γ) reactions for 96,98,104Ru and 112,114,116Sn at astrophysically relevant energies

    Science.gov (United States)

    Bajpeyi, Awanish; Shukla, A.; Koning, A. J.; Åberg, Sven

    2017-05-01

    Cross section and S factor of the proton- and alpha-induced reactions have been studied for the Ruthenium and tin isotopes in the effective energy range, i.e. Gamow window. These reactions are important for developing the understanding for nucleosynthesis, particularly for the synthesis of p nuclei ( p process). In this work, cross sections and S factor have been calculated through TALYS in Hauser-Feshbach formalism using nuclear densities calculated in relativistic mean field (RMF) formalism. Calculated results of cross sections, S factor and nuclear structure have been compared with existing theoretical as well as experimental results available and are found to be in good agreement.

  11. IronMaking Process Alternatives Screening Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2000-10-01

    This study by Lockwood Greene evaluates a number ironmaking processes. The appendices provide greater detail and further exploration of the ironmaking processes, including components, relative costs, and comparisons.

  12. Local models of astrophysical discs

    Science.gov (United States)

    Latter, Henrik N.; Papaloizou, John

    2017-12-01

    Local models of gaseous accretion discs have been successfully employed for decades to describe an assortment of small-scale phenomena, from instabilities and turbulence, to dust dynamics and planet formation. For the most part, they have been derived in a physically motivated but essentially ad hoc fashion, with some of the mathematical assumptions never made explicit nor checked for consistency. This approach is susceptible to error, and it is easy to derive local models that support spurious instabilities or fail to conserve key quantities. In this paper we present rigorous derivations, based on an asympototic ordering, and formulate a hierarchy of local models (incompressible, Boussinesq and compressible), making clear which is best suited for a particular flow or phenomenon, while spelling out explicitly the assumptions and approximations of each. We also discuss the merits of the anelastic approximation, emphasizing that anelastic systems struggle to conserve energy unless strong restrictions are imposed on the flow. The problems encountered by the anelastic approximation are exacerbated by the disc's differential rotation, but also attend non-rotating systems such as stellar interiors. We conclude with a defence of local models and their continued utility in astrophysical research.

  13. Gas dynamics an introduction with examples from astrophysics and geophysics

    CERN Document Server

    Achterberg, Abraham

    2016-01-01

    This book lays the foundations of gas- and fluid dynamics. The basic equations are developed from first principles, building on the (assumed) knowledge of Classical Mechanics. This leads to the discussion of the mathematical properties of flows, conservation laws, perturbation analysis, waves and shocks. Most of the discussion centers on ideal (frictionless) fluids and gases. Viscous flows are discussed when considering flows around obstacles and shocks. Many of the examples used to illustrate various processes come from astrophysics and geophysical phenomena.

  14. Nuclear astrophysics measurements with ELISSA at ELI-NP

    Science.gov (United States)

    Matei, C.; Balabanski, D. L.; Tesileanu, O.; Xu, Y.; La Cognata, M.; Spitaleri, C.

    2017-09-01

    ELISSA is a new silicon-strip detector array under development at the Extreme Light Infrastructure - Nuclear Physics facility in collaboration with INFN-LNS, Catania. ELI-NP will provide very intense, brilliant gamma beams, tunable from 200keV to 19.5MeV. Several reactions important for the astrophysical p-process, Big Bang Nucleosynthesis and supernova explosion have been selected for the first measurement campaigns starting in 2019.

  15. Research in Neutrino Physics and Particle Astrophysics: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Kearns, Edward [Boston Univ., MA (United States)

    2016-06-30

    The Boston University Neutrino Physics and Particle Astrophysics Group investigates the fundamental laws of particle physics using natural and man-made neutrinos and rare processes such as proton decay. The primary instrument for this research is the massive Super-Kamiokande (SK) water Cherenkov detector, operating since 1996 at the Kamioka Neutrino Observatory, one kilometer underground in a mine in Japan. We study atmospheric neutrinos from cosmic rays, which were first used to discover that neutrinos have mass, as recognized by the 2015 Nobel Prize in Physics. Our latest measurements with atmospheric neutrinos are giving valuable information, complementary to longbaseline experiments, on the ordering of massive neutrino states and as to whether neutrinos violate CP symmetry. We have studied a variety of proton decay modes, including the most frequently predicted modes such as p → e+π0 and p → ν K+, as well as more exotic baryon number violating processes such as dinucleon decay and neutronantineutron oscillation. We search for neutrinos from dark matter annihilation or decay in the universe. Our group has made significant contributions to detector operation, particularly in the area of electronics. Most recently, we have contributed to planning for an upgrade to the SK detector by the addition of gadolinium to the water, which will enable efficient neutron capture detection.

  16. Neutron capture cross section of $^{25}$Mg and its astrophysical implications

    CERN Multimedia

    We propose to measure the neutron capture cross section of the stable $^{25}$Mg isotope. This experiment aims at the improvement of existing results for nuclear astrophysics.The measurement will be carried out under similar conditions as for the Mgexperiment that was completed at n_TOF during 2003. A metal $^{25}$Mg-enriched sample will be used in the proposed experiment instead of a MgO powder sample, which was used in the previous measurement and prevented us to minimize the uncertainty of the measured cross section. This experiment will be part of an ongoing study for a comprehensive discussion of the s-process abundances in massive stars.

  17. Problem-based learning in astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Raine, Derek [Department of Physics and Astronomy, University of Leicester, Leicester (United Kingdom); Collett, James [Department of Physical Sciences, University of Hertfordshire, Hatfield (United Kingdom)

    2003-03-01

    Problem-based learning (PBL) can be integrated into the curriculum in many different ways. We compare three examples of PBL in undergraduate astrophysics programmes, and discuss the strengths and weaknesses of the various approaches.

  18. The Astrophysics Major at the University of California, Berkeley

    Science.gov (United States)

    Arons, J.; Heiles, C.

    2001-12-01

    The Astrophysics major offered by the Berkeley Astronomy Department has been redesigned to reflect broad educational goals. Students preparing for graduate school study mostly Physics and Mathematics, leavened with four semesters of astrophysics at the sophomore and senior level. These courses make heavy use of their concurrent Physics and Math. Astrophysics and Physics majors differ in the astrophysics courses replacing other electives which a Physics major might choose. The major's redesign also opened the door to students who wish to pursue a major which gives them broad technical training without having graduate school as a goal. Many such students follow the same track as those pursuing the graduate school option; others take courses specifically designed for people with alternate careers in mind. The major change has been a laboratory requirement for all Astrophysics majors, in either track. We now have advanced undergraduate laboratories: optical, radio, and near infrared; details are on our web page. These share the common thread of development of deep capabilities in data gathering, analysis, and presentation. Students achieve expertise in these areas because the labs include the complete range of activities normally encountered in observational or experimental research. Students use laboratory equipment to measure the fundamental parameters of devices and systems, make astronomical observations with those systems, write software in UNIX and IDL to control equipment and analyze the results, and write formal lab reports in LATEX. We avoid ``black box'' or ``cookbook'' procedures . The students leave the course having gained experience and knowledge, and a ``feel'' for how to proceed when faced with sometimes recalcitrant equipment and imperfect data. A by product of the training has been an increase in student involvement in undergraduate research projects. These innovations have led to a major that has doubled in size and, in a quite unanticipated

  19. BRAVO (Brazilian Astrophysical Virtual Observatory): data mining development

    Science.gov (United States)

    De Carvalho, R. R.; Capelato, H. V.; Velho, H. C.

    2007-08-01

    The primary goal of the BRAVO project is to generate investment in information technology, with particular emphasis on datamining and statistical analysis. From a scientific standpoint, the participants assembled to date are engaged in several scientific projects in various fields of cosmology, astrophysics, and data analysis, with significant contributions from international partners. These scientists conduct research on clusters of galaxies, small groups of galaxies, elliptical galaxies, population synthesis, N-body simulations, and a variety of studies in stellar astrophysics. One of the main aspects of this project is the incorporation of these disparate areas of astrophysical research within the context of the coherent development of database technology.Observational cosmology is one of the branches of science experiencing the largest growth in the past few decades. large photometric and spectroscopic surveys have been carried out in both hemispheres. As a result, an extraordinary amount of data in all portions of the electromagnetic spectrum exists, but without standard techniques for storage and distribution. This project will utilize several specific astronomical databases, created to store data generated by several instruments (including SOAR, Gemini, BDA, etc), uniting them within a common framework and with standard interfaces. We are inviting members of the entire Brazilian astronomical community to partake in this effort. This will certainly impact both education and outreach efforts, as well as the future development of astrophysical research. Finally, this project will provide a constant investment in human resources. First, it will do so by stimulating ongoing short technical visits to Johns Hopkins University and Caltech. These will allow us to bring software technology and expertise in datamining back to Brazil. Second, we will organize the Summer School on Software Technology in Astrophysics, which will be designed to ensure that the Brazilian

  20. Cosmological and astrophysical neutrino mass measurements

    DEFF Research Database (Denmark)

    Abazajian, K.N.; Calabrese, E.; Cooray, A.

    2011-01-01

    Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach.......Cosmological and astrophysical measurements provide powerful constraints on neutrino masses complementary to those from accelerators and reactors. Here we provide a guide to these different probes, for each explaining its physical basis, underlying assumptions, current and future reach....

  1. EMPIRE: A code for nuclear astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Palumbo, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2013-12-11

    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 directsemidirect 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.

  2. Dictionary of geophysics, astrophysics, and astronomy

    CERN Document Server

    Matzner, Richard A

    2001-01-01

    The Dictionary of Geophysics, Astrophysics, and Astronomy provides a lexicon of terminology covering fields such as astronomy, astrophysics, cosmology, relativity, geophysics, meteorology, Newtonian physics, and oceanography. Authors and editors often assume - incorrectly - that readers are familiar with all the terms in professional literature. With over 4,000 definitions and 50 contributing authors, this unique comprehensive dictionary helps scientists to use terminology correctly and to understand papers, articles, and books in which physics-related terms appear.

  3. Studies in astronomical time series analysis: Modeling random processes in the time domain

    Science.gov (United States)

    Scargle, J. D.

    1979-01-01

    Random process models phased in the time domain are used to analyze astrophysical time series data produced by random processes. A moving average (MA) model represents the data as a sequence of pulses occurring randomly in time, with random amplitudes. An autoregressive (AR) model represents the correlations in the process in terms of a linear function of past values. The best AR model is determined from sampled data and transformed to an MA for interpretation. The randomness of the pulse amplitudes is maximized by a FORTRAN algorithm which is relatively stable numerically. Results of test cases are given to study the effects of adding noise and of different distributions for the pulse amplitudes. A preliminary analysis of the optical light curve of the quasar 3C 273 is given.

  4. Astrophysical applications of gravitational microlensing

    Science.gov (United States)

    Mao, Shude

    2012-08-01

    Since the first discovery of microlensing events nearly two decades ago, gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications. The review starts with a theoretical overview of the field and then proceeds to discuss the scientific highlights. (1) Microlensing observations toward the Magellanic Clouds rule out the Milky Way halo being dominated by MAssive Compact Halo Objects (MACHOs). This confirms most dark matter is non-baryonic, consistent with other observations. (2) Microlensing has discovered about 20 extrasolar planets (16 published), including the first two Jupiter-Saturn like systems and the only five “cold Neptunes" yet detected. They probe a different part of the parameter space and will likely provide the most stringent test of core accretion theory of planet formation. (3) Microlensing provides a unique way to measure the mass of isolated stars, including brown dwarfs and normal stars. Half a dozen or so stellar mass black hole candidates have also been proposed. (4) High-resolution, target-of-opportunity spectra of highly-magnified dwarf stars provide intriguing “age" determinations which may either hint at enhanced helium enrichment or unusual bulge formation theories. (5) Microlensing also measured limb-darkening profiles for close to ten giant stars, which challenges stellar atmosphere models. (6) Data from surveys also provide strong constraints on the geometry and kinematics of the Milky Way bar (through proper motions); the latter indicates predictions from current models appear to be too anisotropic compared with observations. The future of microlensing is bright given the new capabilities of current surveys and forthcoming new telescope networks from the ground and from space. Some open issues in the field are identified and briefly discussed.

  5. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Editorial Board. Journal of Astrophysics and Astronomy. Chief Editor. Ram Sagar, Indian Institute of Astrophysics, Bengaluru. Associate Editor. Annapurni Subramaniam, Indian Institute of Astrophysics, Bengaluru T.P. Prabhu, Indian Institute of Astrophysics, Bengaluru. Editorial Board. P. Ajith, International Center for ...

  6. Comprehensive x-ray spectral code for high energy astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Liedahl, D A; Fournier, K B; Mauche, C W

    2000-08-18

    The aim of this project has been to develop a spectral analysis tool with a level of quality and completeness commensurate to that expected in data from the current generation of X-ray observatories. The code is called LXSS (Livermore X-Ray Spectral Synthesizer). X-ray-emitting astrophysical plasmas are rarely, if ever, in LTE, so they have adopted the detailed level accounting approach, in which rates for processes that populate or depopulate atomic energy levels are treated explicitly. This entails the generation of a large quantity of atomic data, most of which is calculated using ''in-house'' computer codes. Calculations are benchmarked against laboratory data, and spectral models have been used to provide first-time interpretations of astrophysical X-ray spectra. The design of a versatile graphical user interface that allows access to and manipulation of the atomic database comprises the second major part of the project.

  7. The Nuclear Astrophysics program at n_TOF (CERN

    Directory of Open Access Journals (Sweden)

    Colonna N.

    2017-01-01

    Full Text Available An important experimental program on Nuclear Astrophysics is being carried out at the n_TOF since several years, in order to address the still open issues in stellar and primordial nucleosynthesis. Several neutron capture reactions relevant to s-process nucleosynthesis have been measured so far, some of which on important branching point radioisotopes. Furthermore, the construction of a second experimental area has recently opened the way to challenging measurements of (n, charged particle reactions on isotopes of short half-life. The Nuclear Astrophysics program of the n_TOF Collaboration is here described, with emphasis on recent results relevant for stellar nucleosynthesis, stellar neutron sources and primordial nucleosynthesis.

  8. MHD Flows in Compact Astrophysical Objects Accretion, Winds and Jets

    CERN Document Server

    Beskin, Vasily S

    2010-01-01

    Accretion flows, winds and jets of compact astrophysical objects and stars are generally described within the framework of hydrodynamical and magnetohydrodynamical (MHD) flows. Analytical analysis of the problem provides profound physical insights, which are essential for interpreting and understanding the results of numerical simulations. Providing such a physical understanding of MHD Flows in Compact Astrophysical Objects is the main goal of this book, which is an updated translation of a successful Russian graduate textbook. The book provides the first detailed introduction into the method of the Grad-Shafranov equation, describing analytically the very broad class of hydrodynamical and MHD flows. It starts with the classical examples of hydrodynamical accretion onto relativistic and nonrelativistic objects. The force-free limit of the Grad-Shafranov equation allows us to analyze in detail the physics of the magnetospheres of radio pulsars and black holes, including the Blandford-Znajek process of energy e...

  9. Sunfall: a collaborative visual analytics system for astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Aragon, Cecilia R.; Aragon, Cecilia R.; Bailey, Stephen J.; Poon, Sarah; Runge, Karl; Thomas, Rollin C.

    2008-07-07

    Computational and experimental sciences produce and collect ever-larger and complex datasets, often in large-scale, multi-institution projects. The inability to gain insight into complex scientific phenomena using current software tools is a bottleneck facing virtually all endeavors of science. In this paper, we introduce Sunfall, a collaborative visual analytics system developed for the Nearby Supernova Factory, an international astrophysics experiment and the largest data volume supernova search currently in operation. Sunfall utilizes novel interactive visualization and analysis techniques to facilitate deeper scientific insight into complex, noisy, high-dimensional, high-volume, time-critical data. The system combines novel image processing algorithms, statistical analysis, and machine learning with highly interactive visual interfaces to enable collaborative, user-driven scientific exploration of supernova image and spectral data. Sunfall is currently in operation at the Nearby Supernova Factory; it is the first visual analytics system in production use at a major astrophysics project.

  10. Using Visual Analytics to Maintain Situation Awareness in Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Aragon, Cecilia R.; Poon, Sarah S.; Aldering, Gregory S.; Thomas, Rollin C.; Quimby, Robert

    2008-07-01

    We present a novel collaborative visual analytics application for cognitively overloaded users in the astrophysics domain. The system was developed for scientists needing to analyze heterogeneous, complex data under time pressure, and then make predictions and time-critical decisions rapidly and correctly under a constant influx of changing data. The Sunfall Data Taking system utilizes severalnovel visualization and analysis techniques to enable a team of geographically distributed domain specialists to effectively and remotely maneuver a custom-built instrument under challenging operational conditions. Sunfall Data Taking has been in use for over eighteen months by a major international astrophysics collaboration (the largest data volume supernova search currently in operation), and has substantially improved the operational efficiency of its users. We describe the system design process by an interdisciplinary team, the system architecture, and the results of an informal usability evaluation of the production system by domain experts in the context of Endsley?s three levels of situation awareness.

  11. Astrophysical targets of the Fresnel diffractive imager

    Science.gov (United States)

    Koechlin, L.; Deba, P.; Raksasataya, T.

    2017-11-01

    The Fresnel Diffractive imager is an innovative concept of distributed space telescope, for high resolution (milli arc-seconds) spectro-imaging in the IR, visible and UV domains. This paper presents its optical principle and the science that can be done on potential astrophysical targets. The novelty lies in the primary optics: a binary Fresnel array, akin to a binary Fresnel zone plate. The main interest of this approach is the relaxed manufacturing and positioning constraints. While having the resolution and imaging capabilities of lens or mirrors of equivalent size, no optical material is involved in the focusing process: just vacuum. A Fresnel array consists of millions void subapertures punched into a large and thin opaque membrane, that focus light by diffraction into a compact and highly contrasted image. The positioning law of the aperture edges drives the image quality and contrast. This optical concept allows larger and lighter apertures than solid state optics, aiming to high angular resolution and high dynamic range imaging, in particular for UV applications. Diffraction focusing implies very long focal distances, up to dozens of kilometers, which requires at least a two-vessel formation flying in space. The first spacecraft, "the Fresnel Array spacecraft", holds the large punched foil: the Fresnel Array. The second, the "Receiver spacecraft" holds the field optics and focal instrumentation. A chromatism correction feature enables moderately large (20%) relative wavebands, and fields of a few to a dozen arc seconds. This Fresnel imager is adapted to high contrast stellar environments: dust disks, close companions and (we hope) exoplanets. Specific to the particular grid-like pattern of the primary focusing zone plate, is the very high dynamic range achieved in the images, in the case of compact objects. Large stellar photospheres may also be mapped with Fresnel arrays of a few meters opertaing in the UV. Larger and more complex fields can be imaged with

  12. Mechanisms for the formation of thymine under astrophysical conditions and implications for the origin of life.

    Science.gov (United States)

    Bera, Partha P; Nuevo, Michel; Materese, Christopher K; Sandford, Scott A; Lee, Timothy J

    2016-04-14

    Nucleobases are the carriers of the genetic information in ribonucleic acid and deoxyribonucleic acid (DNA) for all life on Earth. Their presence in meteorites clearly indicates that compounds of biological importance can form via non-biological processes in extraterrestrial environments. Recent experimental studies have shown that the pyrimidine-based nucleobases uracil and cytosine can be easily formed from the ultraviolet irradiation of pyrimidine in H2O-rich ice mixtures that simulate astrophysical processes. In contrast, thymine, which is found only in DNA, is more difficult to form under the same experimental conditions, as its formation usually requires a higher photon dose. Earlier quantum chemical studies confirmed that the reaction pathways were favorable provided that several H2O molecules surrounded the reactants. However, the present quantum chemical study shows that the formation of thymine is limited because of the inefficiency of the methylation of pyrimidine and its oxidized derivatives in an H2O ice, as supported by the laboratory studies. Our results constrain the formation of thymine in astrophysical environments and thus the inventory of organic molecules delivered to the early Earth and have implications for the role of thymine and DNA in the origin of life.

  13. Mechanisms for the formation of thymine under astrophysical conditions and implications for the origin of life

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Partha P., E-mail: Partha.P.Bera@nasa.gov, E-mail: Timothy.J.Lee@nasa.gov; Nuevo, Michel; Materese, Christopher K. [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035 (United States); Bay Area Environmental Research Institute, Petaluma, California 94952 (United States); Sandford, Scott A.; Lee, Timothy J., E-mail: Partha.P.Bera@nasa.gov, E-mail: Timothy.J.Lee@nasa.gov [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035 (United States)

    2016-04-14

    Nucleobases are the carriers of the genetic information in ribonucleic acid and deoxyribonucleic acid (DNA) for all life on Earth. Their presence in meteorites clearly indicates that compounds of biological importance can form via non-biological processes in extraterrestrial environments. Recent experimental studies have shown that the pyrimidine-based nucleobases uracil and cytosine can be easily formed from the ultraviolet irradiation of pyrimidine in H{sub 2}O-rich ice mixtures that simulate astrophysical processes. In contrast, thymine, which is found only in DNA, is more difficult to form under the same experimental conditions, as its formation usually requires a higher photon dose. Earlier quantum chemical studies confirmed that the reaction pathways were favorable provided that several H{sub 2}O molecules surrounded the reactants. However, the present quantum chemical study shows that the formation of thymine is limited because of the inefficiency of the methylation of pyrimidine and its oxidized derivatives in an H{sub 2}O ice, as supported by the laboratory studies. Our results constrain the formation of thymine in astrophysical environments and thus the inventory of organic molecules delivered to the early Earth and have implications for the role of thymine and DNA in the origin of life.

  14. Astrophysical Probes of Dark Matter Interactions

    Science.gov (United States)

    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

  15. On the Quantification of Incertitude in Astrophysical Simulation Codes

    Science.gov (United States)

    Hoffman, Melissa; Katz, Maximilian P.; Willcox, Donald E.; Ferson, Scott; Swesty, F. Douglas; Calder, Alan

    2017-01-01

    We present a pedagogical study of uncertainty quantification (UQ) due to epistemic uncertainties (incertitude) in astrophysical modeling using the stellar evolution software instrument MESA (Modules and Experiments for Stellar Astrophysics). We present a general methodology for UQ and examine the specific case of stars evolving from the main sequence to carbon/oxygen white dwarfs. Our study considers two epistemic variables: the wind parameters during the Red Giant and Asymptotic Giant branch phases of evolution. We choose uncertainty intervals for each variable, and use these as input to MESA simulations. Treating MESA as a "black box," we apply two UQ techniques, Cauchy deviates and Quadratic Response Surface Models, to obtain bounds for the final white dwarf masses. Our study is a proof of concept applicable to other computational problems to enable a more robust understanding of incertitude. This work was supported in part by the US Department of Energy under grant DE-FG02-87ER40317.

  16. THE SZ EFFECT IN THE PLANCK ERA: ASTROPHYSICAL AND COSMOLOGICAL IMPACT

    Directory of Open Access Journals (Sweden)

    Sergio Colafrancesco

    2013-12-01

    Full Text Available The Sunyaev–Zel’dovich effect (SZE is a relevant probe for cosmology and particle astrophysics. The Planck Era marks a definite step forward in the use of this probe for astrophysics and cosmology. Astrophysical applications to galaxy clusters, galaxies, radiogalaxies and large-scale structures are discussed. Cosmological relevance for the Dark Energy equation of state, modified Gravity scenarios, Dark Matter search, cosmic magnetism and other cosmological applications is also reviewed. Future directions for the study of the SZE and its polarization are finally outlined.

  17. Stellar structure and compact objects before 1940: Towards relativistic astrophysics

    Science.gov (United States)

    Bonolis, Luisa

    2017-06-01

    Since the mid-1920s, different strands of research used stars as "physics laboratories" for investigating the nature of matter under extreme densities and pressures, impossible to realize on Earth. To trace this process this paper is following the evolution of the concept of a dense core in stars, which was important both for an understanding of stellar evolution and as a testing ground for the fast-evolving field of nuclear physics. In spite of the divide between physicists and astrophysicists, some key actors working in the cross-fertilized soil of overlapping but different scientific cultures formulated models and tentative theories that gradually evolved into more realistic and structured astrophysical objects. These investigations culminated in the first contact with general relativity in 1939, when J. Robert Oppenheimer and his students George Volkoff and Hartland Snyder systematically applied the theory to the dense core of a collapsing neutron star. This pioneering application of Einstein's theory to an astrophysical compact object can be regarded as a milestone in the path eventually leading to the emergence of relativistic astrophysics in the early 1960s.

  18. The Advanced Telescope for High Energy Astrophysics

    Science.gov (United States)

    Guainazzi, Matteo

    2017-08-01

    Athena (the Advanced Telescope for High Energy Astrophysics) is a next generation X-ray observatory currently under study by ESA for launch in 2028. Athena is designed to address the Hot and Energetic Universe science theme, which addresses two key questions: 1) How did ordinary matter evolve into the large scale structures we see today? 2) How do black holes grow and shape the Universe. To address these topics Athena employs an innovative X-ray telescope based on Silicon Pore Optics technology to deliver extremely light weight and high throughput, while retaining excellent angular resolution. The mirror can be adjusted to focus onto one of two focal place instruments: the X-ray Integral Field Unit (X-IFU) which provides spatially-resolved, high resolution spectroscopy, and the Wide Field Imager (WFI) which provides spectral imaging over a large field of view, as well as high time resolution and count rate tolerance. Athena is currently in Phase A and the study status will be reviewed, along with the scientific motivations behind the mission.

  19. Prospects of Optical Single Atom Detection for Nuclear Astrophysics

    Science.gov (United States)

    Singh, Jaideep

    2015-10-01

    We will discuss the prospects of optically detecting single atoms captured in a cryogenic thin film of a noble gas such as neon. This proposed detection scheme, when coupled with a recoil separator, could be used to measure rare nuclear reactions relevant for nuclear astrophysics. In particular, we will focus on the 22Ne(α, n)25Mg reaction, which is an important source of neutrons for the s-process. Noble gas solids are an attractive medium because they are optically transparent and provide efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Atoms embedded inside of noble gas solids have a fluorescence spectrum that is often significantly shifted from its absorption spectrum. This makes possible the detection of individual fluorescence photons against a background of intense excitation light, which can be suppressed using the appropriate optical filters. We will report on our efforts to optically detect single Yb atoms in solid Ne. Yb is an ideal candidate for initial studies because it emits a strong green fluorescence when excited by blue light and it has an atomic structure that very closely resembles that of Mg. This work is supported by funds from Michigan State University.

  20. r-Java 2.0: the astrophysics

    OpenAIRE

    M. Kostka; De Koning, N; Shand, Z.; Ouyed, R.; Jaikumar, P.

    2014-01-01

    [Context:] This article is the second in a two part series introducing r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations and provides a suite of other analysis tools. [Aims:] The first paper discussed the nuclear physics inherent to r-Java 2.0 and in this article the astrophysics incorporated into the software will be detailed. [Methods:] R-Java 2.0 allows the user to specify the density and temperature evolution for an r-process simulation. Defining how the...

  1. Plasma Astrophysics, Part I Fundamentals and Practice

    CERN Document Server

    Somov, Boris V

    2006-01-01

    This well-illustrated monograph is devoted to classic fundamentals, current practice, and perspectives of modern plasma astrophysics. The first part is unique in covering all the basic principles and practical tools required for understanding and working in plasma astrophysics. The second part presents the physics of magnetic reconnection and flares of electromagnetic origin in space plasmas within the solar system; single and double stars, relativistic objects, accretion disks, and their coronae are also covered. This book is designed mainly for professional researchers in astrophysics. However, it will also be interesting and useful to graduate students in space sciences, geophysics, as well as advanced students in applied physics and mathematics seeking a unified view of plasma physics and fluid mechanics.

  2. Plasma Astrophysics, part II Reconnection and Flares

    CERN Document Server

    Somov, Boris V

    2007-01-01

    This well-illustrated monograph is devoted to classic fundamentals, current practice, and perspectives of modern plasma astrophysics. The first part is unique in covering all the basic principles and practical tools required for understanding and working in plasma astrophysics. The second part presents the physics of magnetic reconnection and flares of electromagnetic origin in space plasmas within the solar system; single and double stars, relativistic objects, accretion disks, and their coronae are also covered. This book is designed mainly for professional researchers in astrophysics. However, it will also be interesting and useful to graduate students in space sciences, geophysics, as well as advanced students in applied physics and mathematics seeking a unified view of plasma physics and fluid mechanics.

  3. The Astrophysics Science Division Annual Report 2008

    Science.gov (United States)

    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.

  4. Review of Astrophysics Experiments on Intense Lasers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Sausage and kink oscillations in astrophysical disk configurations.

    Science.gov (United States)

    Griv, Evgeny

    2011-05-13

    The development of hydrodynamic oscillations in various rotating astrophysical disks ranging from planetary rings to galaxies is studied analytically. The dispersion relation of wave propagation is derived. Modes of oscillation are examined from this dispersion relation that are suitable for obtaining information not just on oscillations but also on some instability properties of the disk-shaped structure. It is shown that unstable oscillations of different types, sausage compression and kink bending, may be excited effectively due to the Jeans gravitational instability and the kink transverse instability, respectively. The obtained results for the sausage oscillations may be applicable for such phenomena as the appearance of the in-plane spiral and circular structures, while the case for the kink mode is more relevant for the systematic vertical corrugations of astrophysical disks.

  6. The Astrophysics of Emission-Line Stars

    CERN Document Server

    Kogure, Tomokazu

    2007-01-01

    Many types of stars show conspicuous emission lines in their optical spectra. These stars are broadly referred to as emission line stars. Emission line stars are attractive to many people because of their spectacular phenomena and their variability. The Astrophysics of Emission Line Stars offers general information on emission line stars, starting from a brief introduction to stellar astrophysics, and then moving toward a broad overview of emission line stars including early and late type stars as well as pre-main sequence stars. Detailed references have been prepared along with an index for further reading.

  7. Byurakan Astrophysical Observatory as Cultural Centre

    Science.gov (United States)

    Mickaelian, A. M.; Farmanyan, S. V.

    2017-07-01

    NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts. Keywords: Byurakan Astrophysical Observatory, architecture, botanic garden, tourism, Cultural Astronomy.

  8. Advances in astronomy and astrophysics 9

    CERN Document Server

    Kopal, Zdenek

    1972-01-01

    Advances in Astronomy and Astrophysics, Volume 9 covers reviews on the advances in astronomy and astrophysics. The book presents reviews on the Roche model and its applications to close binary systems. The text then describes the part played by lunar eclipses in the evolution of astronomy; the classical theory of lunar eclipses; deviations from geometrical theory; and the methods of photometric observations of eclipses. The problems of other phenomena related in one way or another to lunar eclipses are also considered. The book further tackles the infrared observation on the eclipsed moon, as

  9. Advances in astronomy and astrophysics 7

    CERN Document Server

    Kopal, Zdenek

    2013-01-01

    Advances in Astronomy and Astrophysics, Volume 7 covers reviews about the advances in astronomy and astrophysics. The book presents reviews on the scattering of electrons by diatomic molecules and on Babcock's theory of the 22-year solar cycle and the latitude drift of the sunspot zone. The text then describes reviews on the structures of the terrestrial planets (Earth, Venus, Mars, Mercury) and on type III solar radio bursts. The compact and dispersed cosmic matter is also considered with regard to the search for new cosmic objects and phenomena and on the nature of the ref shift from compact

  10. White Paper on Nuclear Astrophysics and Low Energy Nuclear Physics - Part 1. Nuclear Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Arcones, Almudena [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Escher, Jutta E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Others, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-04

    This white paper informs the nuclear astrophysics community and funding agencies about the scientific directions and priorities of the field and provides input from this community for the 2015 Nuclear Science Long Range Plan. It summarizes the outcome of the nuclear astrophysics town meeting that was held on August 21 - 23, 2014 in College Station at the campus of Texas A&M University in preparation of the NSAC Nuclear Science Long Range Plan. It also reflects the outcome of an earlier town meeting of the nuclear astrophysics community organized by the Joint Institute for Nuclear Astrophysics (JINA) on October 9 - 10, 2012 Detroit, Michigan, with the purpose of developing a vision for nuclear astrophysics in light of the recent NRC decadal surveys in nuclear physics (NP2010) and astronomy (ASTRO2010). The white paper is furthermore informed by the town meeting of the Association of Research at University Nuclear Accelerators (ARUNA) that took place at the University of Notre Dame on June 12 - 13, 2014. In summary we find that nuclear astrophysics is a modern and vibrant field addressing fundamental science questions at the intersection of nuclear physics and astrophysics. These questions relate to the origin of the elements, the nuclear engines that drive life and death of stars, and the properties of dense matter. A broad range of nuclear accelerator facilities, astronomical observatories, theory efforts, and computational capabilities are needed. With the developments outlined in this white paper, answers to long-standing key questions are well within reach in the coming decade.

  11. When astrophysics meets lay and specialized audiences: titles in popular and scientific papers

    OpenAIRE

    Alcaraz Ariza, María Ángeles; Méndez Alcaraz, David Israel

    2016-01-01

    In this study we carry out a comparative analysis between titles of research papers published in the most authoritative specialized European and US-based astrophysics journals written in English and titles of articles on astrophysics published in Scientific American Magazine, the most prestigious English-written journal in the divulgation of science. We specifically address issues related to three linguistic variables: title length, title lexical density and title type. Our main results show ...

  12. Very-high-energy astrophysical neutrinos with IceCube

    Directory of Open Access Journals (Sweden)

    Taboada Ignacio

    2016-01-01

    Full Text Available IceCube is a ≳TeV neutrino observatory operating at the South Pole. Ice-Cube has observed a flux of neutrinos of astrophysical origin, with energies beyond 2 PeV. However the sources of these neutrinos have not yet been identified. A summary of various IceCube observations is presented. The results discussed were obtained through several different analysis methods, which have varying sensitivity to the different neutrino flavors. A discussion of the spectral fit obtained for the various event selections is included, as well as the constraints on the astrophysical neutrino flavor flux ratio. Several attempts by IceCube to identify the sources of these neutrinos are described. These include studies correlating neutrino events with catalogs of sources as well as selfcorrelations among IceCube’s neutrinos. The observations of astrophysical neutrinos are limited by statistics. So an upgrade of IceCube, including a larger detector and a surface veto is planned. This upgrade is briefly discussed.

  13. Workshop on gravitational waves and relativistic astrophysics

    Indian Academy of Sciences (India)

    Discussions related to gravitational wave experiments viz. LIGO and LISA as well as to observations of supermassive black holes dominated the workshop sessions on gravitational waves and relativistic astrophysics in the ICGC-2004. A summary of seven papers that were presented in these workshop sessions has been ...

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

    Science.gov (United States)

    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…

  15. Virtually Lossless Compression of Astrophysical Images

    Directory of Open Access Journals (Sweden)

    Stefano Baronti

    2005-09-01

    Full Text Available We describe an image compression strategy potentially capable of preserving the scientific quality of astrophysical data, simultaneously allowing a consistent bandwidth reduction to be achieved. Unlike strictly lossless techniques, by which moderate compression ratios are attainable, and conventional lossy techniques, in which the mean square error of the decoded data is globally controlled by users, near-lossless methods are capable of locally constraining the maximum absolute error, based on user's requirements. An advanced lossless/near-lossless differential pulse code modulation (DPCM scheme, recently introduced by the authors and relying on a causal spatial prediction, is adjusted to the specific characteristics of astrophysical image data (high radiometric resolution, generally low noise, etc.. The background noise is preliminarily estimated to drive the quantization stage for high quality, which is the primary concern in most of astrophysical applications. Extensive experimental results of lossless, near-lossless, and lossy compression of astrophysical images acquired by the Hubble space telescope show the advantages of the proposed method compared to standard techniques like JPEG-LS and JPEG2000. Eventually, the rationale of virtually lossless compression, that is, a noise-adjusted lossles/near-lossless compression, is highlighted and found to be in accordance with concepts well established for the astronomers' community.

  16. Evolution and seismic tools for stellar astrophysics

    CERN Document Server

    Monteiro, Mario JPFG

    2008-01-01

    A collection of articles published by the journal "Astrophysics and Space Science, Volume 316, Number 1-4", August 2008. This work covers 10 evolution codes and 9 oscillation codes. It is suitable for researchers and research students working on the modeling of stars and on the implementation of seismic test of stellar models.

  17. SiMon: Simulation Monitor for Computational Astrophysics

    Science.gov (United States)

    Qian, Penny Xuran; Cai, Maxwell Xu; Portegies Zwart, Simon; Zhu, Ming

    2017-09-01

    Scientific discovery via numerical simulations is important in modern astrophysics. This relatively new branch of astrophysics has become possible due to the development of reliable numerical algorithms and the high performance of modern computing technologies. These enable the analysis of large collections of observational data and the acquisition of new data via simulations at unprecedented accuracy and resolution. Ideally, simulations run until they reach some pre-determined termination condition, but often other factors cause extensive numerical approaches to break down at an earlier stage. In those cases, processes tend to be interrupted due to unexpected events in the software or the hardware. In those cases, the scientist handles the interrupt manually, which is time-consuming and prone to errors. We present the Simulation Monitor (SiMon) to automatize the farming of large and extensive simulation processes. Our method is light-weight, it fully automates the entire workflow management, operates concurrently across multiple platforms and can be installed in user space. Inspired by the process of crop farming, we perceive each simulation as a crop in the field and running simulation becomes analogous to growing crops. With the development of SiMon we relax the technical aspects of simulation management. The initial package was developed for extensive parameter searchers in numerical simulations, but it turns out to work equally well for automating the computational processing and reduction of observational data reduction.

  18. Annual Report 2006 for Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications

    Energy Technology Data Exchange (ETDEWEB)

    R. Paul Drake

    2007-04-05

    We report the ongoing work of our group in hydrodynamics and radiation hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining data using a backlit pinhole with a 100 ps backlighter and beginning to develop the ability to look into the shock tube with optical or x-ray diagnostics. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, using dual-axis radiographic data with backlit pinholes and ungated detectors to complete the data set for a Ph.D. student. We lead a team that is developing a proposal for experiments at the National Ignition Facility and are involved in experiments at NIKE and LIL. All these experiments have applications to astrophysics, discussed in the corresponding papers. We assemble the targets for the experiments at Michigan, where we also prepare many of the simple components. We also have several projects underway in our laboratory involving our x-ray source. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  19. Astrophysical Probes of New Models of Dark Matter

    Science.gov (United States)

    Zurek, Kathryn

    One of the most pressing and relevant cosmological questions is on the nature of the dark matter. I propose a comprehensive program at the boundary of astrophysics and cosmology with particle physics, focused on the question on the nature of the Dark Matter (DM). Research at the boundary of the two fields is critically important as a plethora of experiments in both particle physics and astrophysics, such as direct and indirect detection of Dark Matter (DM) by the Fermi Gamma Ray Space Telescope (FGST), AMS-02, and Cosmic Microwave Background probes such as Planck, come online. At the same time, data from the Large Hadron Collider (LHC) will probe fundamental questions about Electroweak Symmetry Breaking and its implications for astrophysics and cosmology, as concerns especially the nature of the DM and the generation of the baryon asymmetry. Physics beyond the Standard Model (SM) is required to explain the astrophysical observation that DM dominates over ordinary matter by a ratio 5:1, as we learned through WMAP, as well as large scale structure surveys. Despite lacking an understanding of the properties of the DM, its presence is crucial for the formation of structure in the universe. Particle physics provides a framework for understanding what the DM could be. This proposal centers on building new models of DM, as well as studying their signatures both in the galaxy and on earth. While particle physics has provided a few popular candidates for DM (such as the supersymmetric neutralino), whose signatures have been extensively studied in the literature, it is important to consider other theoretically motivated candidates which provide distinct signatures. This proposal focuses on such new models of DM, especially models of DM from hidden sectors. For example, recently, the PAMELA experiment has observed a rise in the ratio of positron to electron flux at high energies. The flux may likely come from astrophysical objects nearby, such as pulsars. An intriguing

  20. A plasma formulary for physics, technology, and astrophysics

    CERN Document Server

    Diver, Declan

    2011-01-01

    Plasma physics has matured rapidly as a discipline, and now touches on many different research areas, including manufacturing processes. This collection of fundamental formulae and definitions in plasma physics is vital to anyone with an interest in plasmas or ionized gases, whether in physics, astronomy or engineering.Both theorists and experimentalists will find this book useful, as it incorporates the latest results and findings.The text treats astrophysical plasmas, fusion plasmas, industrial plasmas and low temperature plasmas as aspects of the same discipline - a unique approach made pos

  1. Astrophysics of Collapsing Axion Stars

    Science.gov (United States)

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L. C. R.

    2017-01-01

    Axion stars are condensed states of large numbers of axion particles, bound by self-gravitation and quantum self-interactions. The mass of weakly bound axion stars is limited by gravitational stability, with condensates exceeding the maximum mass subject to collapse. During the collapse process, the axion density increases and higher-order self-interactions become increasingly relevant. By taking these terms into account, we provide evidence that in spite of a leading attractive interaction, collapsing axion stars stabilize in a dense state which is larger than its Schwarzschild radius, and so do not form black holes. During the last moments of collapse, number changing processes take place in the axion star with a very large rate, leading to emission of many highly energetic axions which escape from galaxies and galaxy clusters. Finally, if axion stars are a significant fraction of cold dark matter, then frequent collisions with each other or with ordinary stars could catalyze this collapse process as well.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Development of a high-density gas-jet target for nuclear astrophysics and reaction studies with rare isotope beams. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Uwe, Greife [Colorado School of Mines, Golden, CO (United States)

    2014-08-12

    The purpose of this project was to develop a high-density gas jet target that will enable a new program of transfer reaction studies with rare isotope beams and targets of hydrogen and helium that is not currently possible and will have an important impact on our understanding of stellar explosions and of the evolution of nuclear shell structure away from stability. This is the final closeout report for the project.

  4. Promising lines of investigations in the realms of laboratory astrophysics with the aid of powerful lasers

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, V. S., E-mail: belyaev@tsniimash.ru; Batishchev, P. A.; Bolshakov, V. V.; Elkin, K. S.; Karabadzhak, G. F.; Kovkov, D. V.; Matafonov, A. P.; Raykunov, G. G.; Yakhin, R. A. [Russian Space Agency, Central Research Institute of Machine Building (TsNIIMash) (Russian Federation); Pikuz, S. A.; Skobelev, I. Yu.; Faenov, A. Ya.; Fortov, V. E. [Russian Academy of Sciences (IVTAN), Joint Institute for High Temperatures (Russian Federation); Krainov, V. P. [Moscow Institute of Physics and Technology (State University) (Russian Federation); Rozanov, V. B. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation)

    2013-04-15

    The results of work on choosing and substantiating promising lines of research in the realms of laboratory astrophysics with the aid of powerful lasers are presented. These lines of research are determined by the possibility of simulating, under laboratory conditions, problematic processes of presentday astrophysics, such as (i) the generation and evolution of electromagnetic fields in cosmic space and the role of magnetic fields there at various spatial scales; (ii) the mechanisms of formation and evolution of cosmic gamma-ray bursts and relativistic jets; (iii) plasma instabilities in cosmic space and astrophysical objects, plasma jets, and shock waves; (iv) supernova explosions and mechanisms of the explosion of supernovae featuring a collapsing core; (v) nuclear processes in astrophysical objects; (vi) cosmic rays and mechanisms of their production and acceleration to high energies; and (vii) astrophysical sources of x-ray radiation. It is shown that the use of existing powerful lasers characterized by an intensity in the range of 10{sup 18}-10{sup 22} W/cm{sup 2} and a pulse duration of 0.1 to 1 ps and high-energy lasers characterized by an energy in excess of 1 kJ and a pulse duration of 1 to 10 ns makes it possible to perform investigations in laboratory astrophysics along all of the chosen promising lines. The results obtained by experimentally investigating laser plasma with the aid of the laser facility created at Central Research Institute of Machine Building (TsNIIMash) and characterized by a power level of 10 TW demonstrate the potential of such facilities for performing a number of experiments in the realms of laboratory astrophysics.

  5. Resonance strength measurement at astrophysical energies: The {sup 17}O(p,α){sup 14}N reaction studied via Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Sergi, M. L., E-mail: sergi@lns.infn.it; La Cognata, M.; Pizzone, R. G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Spitaleri, C. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli studi di Catania, Catania (Italy); Lamia, L.; Rapisarda, G. G. [Dipartimento di Fisica e Astronomia, Università degli studi di Catania, Catania (Italy); Mukhamedzhanov, A. [Cyclotron Institute, Texas A& M University, College Station, Texas 77843 (United States); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology, Topi, Districti Swabi, Khyber Pakhtunkhwa (Pakistan); Tang, X. D.; Wiescher, M. [Department of Physics, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame 46556, Indiana (United States); Mrazek, J.; Kroha, V. [Nuclear Physics Institute of ASCR, Rez (Czech Republic)

    2015-10-15

    In recent years, the Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of proton-induced reactions on {sup 17}O nuclei, overcoming extrapolation procedures and enhancement effects due to electron screening. We will report on the indirect study of the {sup 17}O(p,α){sup 14}N reaction via the THM by applying the approach developed for extracting the resonance strength of narrow resonance in the ultralow energy region. Two measurements will be described and the experimental THM cross sections will be shown for both experiments.

  6. Muon capture reaction on 100Mo to study the nuclear response for double-β decay and neutrinos of astrophysics origin

    Science.gov (United States)

    Hashim, I. H.; Ejiri, H.; Shima, T.; Takahisa, K.; Sato, A.; Kuno, Y.; Ninomiya, K.; Kawamura, N.; Miyake, Y.

    2018-01-01

    Ordinary muon capture (OMC) on enriched 100Mo isotopes was studied for the first time to investigate neutrino nuclear responses for neutrinoless double-β decays and supernova neutrino nuclear interactions. Muon capture on 100Mo proceeds mainly as 100Mo(μ ,x n )Nb-x100 with x being the number of neutrons emitted from negative muon capture. The Nb isotope mass distribution was obtained by measuring delayed γ rays from radioactive Nb-x100. By using the neutron emission model after the muon capture, the neutrino response (the strength distribution) for OMC was derived. The OMC strength distribution shows a giant resonance (GR) at the peak energy around 11-14 MeV, suggesting the concentration of the OMC strength at the muon GR region.

  7. Astrophysical constraints on singlet scalars at LHC

    Science.gov (United States)

    Hertzberg, Mark P.; Masoumi, Ali

    2017-04-01

    We consider the viability of new heavy gauge singlet scalar particles at colliders such as the LHC . Our original motivation for this study came from the possibility of a new heavy particle of mass ~ TeV decaying significantly into two photons at colliders, such as LHC, but our analysis applies more broadly. We show that there are significant constraints from astrophysics and cosmology on the simplest UV complete models that incorporate such new particles and its associated collider signal. The simplest and most obvious UV complete model that incorporates such signals is that it arises from a new singlet scalar (or pseudo-scalar) coupled to a new electrically charged and colored heavy fermion. Here we show that these new fermions (and anti-fermions) would be produced in the early universe, then form new color singlet heavy mesons with light quarks, obtain a non-negligible freeze-out abundance, and remain in kinetic equilibrium until decoupling. These heavy mesons possess interesting phenomenology, dependent on their charge, including forming new bound states with electrons and protons. We show that a significant number of these heavy states would survive for the age of the universe and an appreciable number would eventually be contained within the earth and solar system. We show that this leads to detectable consequences, including the production of highly energetic events from annihilations on earth, new spectral lines, and, spectacularly, the destabilization of stars. The lack of detection of these consequences rules out such simple UV completions, putting pressure on the viability of such new particles at LHC . To incorporate such a scalar would require either much more complicated UV completions or even further new physics that provides a decay channel for the associated fermion.

  8. 3rd Session of the Sant Cugat Forum on Astrophysics

    CERN Document Server

    Gravitational wave astrophysics

    2015-01-01

    This book offers review chapters written by invited speakers of the 3rd Session of the Sant Cugat Forum on Astrophysics — Gravitational Waves Astrophysics. All chapters have been peer reviewed. The book goes beyond normal conference proceedings in that it provides a wide panorama of the astrophysics of gravitational waves and serves as a reference work for researchers in the field.

  9. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy. Anjan A. Sen. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 33 Review. Cosmology and Astrophysics using the Post-Reionization HI · Tapomoy Guha Sarkar Anjan A. Sen · More Details Abstract Fulltext PDF.

  10. A comparative study via Monte Carlo simulation of new inorganic scintillator Cs2HfCl6 for applications in nuclear medicine, security and defense, and astrophysics

    Science.gov (United States)

    Chen, Henry; Raby, Paul

    2016-09-01

    Cs2HfCl6 (CHC) is one of the most promising recently discovered new inorganic single crystal scintillator that has high light output, non-hygroscopic, no self-activity, having energy resolution significantly better than NaI(Tl), even approaching that of LaBr3 yet can also potentially be at a much lower cost than LaBr3. This study attempts to use Monte Carlo simulation to examine the great potential offered by this new scintillator. CHC's detector performance is compared via simulation with that of 4 typical existing scintillators of the same size and same PMT readout. Two halide-scintillators: NaI(Tl) and LaBr3 and two oxide-scintillators: GSO and LSO were used in this simulation to compare their 122 keV and 511 keV gamma responses with that of CHC with both spectroscopy application and imaging applications in mind. Initial simulation results are very promising and consistent with reported experimental measurements. Beside detector energy resolution, image-quality measurement parameters commonly used to characterize imaging detectors as in nuclear medicine such as Light Response Function (LRF) which goes in parallel with spatial resolution and simulated position spectra will also be presented and discussed.

  11. Language Editing at Astronomy & Astrophysics

    Science.gov (United States)

    Adams, J.

    2011-07-01

    In 2002, the A&A Board of Directors voted that all articles must be written in English and decided to improve the overall quality of the language in the articles with the help of a team of language editors. This article reviews the general advantages of editing the English expression and describes both the aims of this effort and its place in the full publication process. This is followed by the Guide to language editing that has been available on the Journal's website for several years now.

  12. 78 FR 20356 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

    Science.gov (United States)

    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 Space...

  13. 76 FR 66998 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting.

    Science.gov (United States)

    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 Director...

  14. Study on Processing Method of Image Shadow

    Directory of Open Access Journals (Sweden)

    Wang Bo

    2014-07-01

    Full Text Available In order to effectively remove disturbance of shadow and enhance robustness of information processing of computer visual image, this paper makes study on inspection and removal of image shadow. It makes study the continual removal algorithm of shadow based on integration, the illumination surface and texture, it respectively introduces their work principles and realization method, it can effectively carrying processing for shadow by test.

  15. Extragalactic Gamma-Ray Astrophysics

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    During the last decades, various classes of radio-loud active galactic nuclei have been established as sources of high-energy radiation extending over a very broad range from soft gamma-rays (photon energies E~MeV) up to very-high-energy gamma-rays (E>100 GeV). These include blazars of different types, as well as young and evolved radio galaxies. The observed gamma-ray emission from such implies efficient particle acceleration processes taking place in highly magnetized and relativistic jets produced by supermassive black holes, processes that have yet to be identified and properly understood. In addition, nearby starforming and starburst galaxies, some of which host radio-quiet Seyfert-type nuclei, have been detected in the gamma-ray range as well. In their cases, the observed gamma-ray emission is due to non-thermal activity in the interstellar medium, possibly including also a contribution from accretion disks and nuclear outflows. Finally, the high-energy emission from clusters of galaxies remains elusive...

  16. Constraining the astrophysical origin of the p-nuclei through nuclear physics and meteoritic data.

    Science.gov (United States)

    Rauscher, T; Dauphas, N; Dillmann, I; Fröhlich, C; Fülöp, Zs; Gyürky, Gy

    2013-06-01

    A small number of naturally occurring, proton-rich nuclides (the p-nuclei) cannot be made in the s- and r-processes. Their origin is not well understood. Massive stars can produce p-nuclei through photodisintegration of pre-existing intermediate and heavy nuclei. This so-called γ-process requires high stellar plasma temperatures and occurs mainly in explosive O/Ne burning during a core-collapse supernova. Although the γ-process in massive stars has been successful in producing a large range of p-nuclei, significant deficiencies remain. An increasing number of processes and sites has been studied in recent years in search of viable alternatives replacing or supplementing the massive star models. A large number of unstable nuclei, however, with only theoretically predicted reaction rates are included in the reaction network and thus the nuclear input may also bear considerable uncertainties. The current status of astrophysical models, nuclear input and observational constraints is reviewed. After an overview of currently discussed models, the focus is on the possibility to better constrain those models through different means. Meteoritic data not only provide the actual isotopic abundances of the p-nuclei but can also put constraints on the possible contribution of proton-rich nucleosynthesis. The main part of the review focuses on the nuclear uncertainties involved in the determination of the astrophysical reaction rates required for the extended reaction networks used in nucleosynthesis studies. Experimental approaches are discussed together with their necessary connection to theory, which is especially pronounced for reactions with intermediate and heavy nuclei in explosive nuclear burning, even close to stability.

  17. The Trojan Horse method for nuclear astrophysics: Recent results for direct reactions

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Gulino, M. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy and Università degli Studi di Enna Kore, Enna (Italy); Spitaleri, C.; Cherubini, S.; Romano, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy and Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Cognata, M. La; Pizzone, R. G.; Rapisarda, G. G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Lamia, L. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy)

    2014-05-09

    The Trojan Horse method is a powerful indirect technique to determine the astrophysical factor for binary rearrangement processes A+x→b+B at astrophysical energies by measuring the cross section for the Trojan Horse (TH) reaction A+a→B+b+s in quasi free kinematics. The Trojan Horse Method has been successfully applied to many reactions of astrophysical interest, both direct and resonant. In this paper, we will focus on direct sub-processes. The theory of the THM for direct binary reactions will be shortly presented based on a few-body approach that takes into account the off-energy-shell effects and initial and final state interactions. Examples of recent results will be presented to demonstrate how THM works experimentally.

  18. The gamma-ray spectrometer HORUS and its applications for nuclear astrophysics

    CERN Document Server

    Netterdon, L; Endres, J; Fransen, C; Hennig, A; Mayer, J; Müller-Gatermann, C; Sauerwein, A; Scholz, P; Spieker, M; Zilges, A

    2014-01-01

    A dedicated setup for the in-beam measurement of absolute cross sections of astrophysically relevant charged-particle induced reactions is presented. These, usually very low, cross sections at energies of astrophysical interest are important to improve the modeling of the nucleosynthesis processes of heavy nuclei. Particular emphasis is put on the production of the $p$ nuclei during the astrophysical $\\gamma$ process. The recently developed setup utilizes the high-efficiency $\\gamma$-ray spectrometer HORUS, which is located at the 10 MV FN tandem ion accelerator of the Institute for Nuclear Physics in Cologne. The design of this setup will be presented and results of the recently measured $^{89}$Y(p,$\\gamma$)$^{90}$Zr reaction will be discussed. The excellent agreement with existing data shows, that the HORUS spectrometer is a powerful tool to determine total and partial cross sections using the in-beam method with high-purity germanium detectors.

  19. Advanced Architectures for Astrophysical Supercomputing

    Science.gov (United States)

    Barsdell, B. R.; Barnes, D. G.; Fluke, C. J.

    2010-12-01

    Astronomers have come to rely on the increasing performance of computers to reduce, analyze, simulate and visualize their data. In this environment, faster computation can mean more science outcomes or the opening up of new parameter spaces for investigation. If we are to avoid major issues when implementing codes on advanced architectures, it is important that we have a solid understanding of our algorithms. A recent addition to the high-performance computing scene that highlights this point is the graphics processing unit (GPU). The hardware originally designed for speeding-up graphics rendering in video games is now achieving speed-ups of O(100×) in general-purpose computation - performance that cannot be ignored. We are using a generalized approach, based on the analysis of astronomy algorithms, to identify the optimal problem-types and techniques for taking advantage of both current GPU hardware and future developments in computing architectures.

  20. Quantum mechanical and astrophysical studies of methanol

    Directory of Open Access Journals (Sweden)

    Pineau des Forêts G.

    2012-10-01

    Full Text Available Interstellar methanol has been observed extensively at radio frequencies from the ground, and, very recently, it has been observed at higher frequencies, by means of the Herschel satellite. Being a complex molecule, methanol has a rich spectrum exhibiting rotational and internal torsional motions. However, by the same token, the determination of the cross sections and rate coefficients for the excitation of methanol by the principal perturbers, helium and molecular hydrogen, is a far from trivial task. We have recently extended and considerably improved previous calculations of these data. In the case of molecular hydrogen, results are now available for the excitation of both A- and E-type methanol, not only by para- but also by ortho-H2. These data have been used to model the HIFI observations of the outflow source L1157 B1. The methanol emission is computed self-consistently, in parallel with the dynamics and the chemistry, allowing for the optical depths in the emission lines by means of the LVG approximation. The results of these calculations are summarized.

  1. Special issue on current research in astrophysical magnetism

    Science.gov (United States)

    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

  2. White paper on nuclear astrophysics and low energy nuclear physics Part 1: Nuclear astrophysics

    Science.gov (United States)

    Arcones, Almudena; Bardayan, Dan W.; Beers, Timothy C.; Bernstein, Lee A.; Blackmon, Jeffrey C.; Messer, Bronson; Brown, B. Alex; Brown, Edward F.; Brune, Carl R.; Champagne, Art E.; Chieffi, Alessandro; Couture, Aaron J.; Danielewicz, Pawel; Diehl, Roland; El-Eid, Mounib; Escher, Jutta E.; Fields, Brian D.; Fröhlich, Carla; Herwig, Falk; Hix, William Raphael; Iliadis, Christian; Lynch, William G.; McLaughlin, Gail C.; Meyer, Bradley S.; Mezzacappa, Anthony; Nunes, Filomena; O'Shea, Brian W.; Prakash, Madappa; Pritychenko, Boris; Reddy, Sanjay; Rehm, Ernst; Rogachev, Grigory; Rutledge, Robert E.; Schatz, Hendrik; Smith, Michael S.; Stairs, Ingrid H.; Steiner, Andrew W.; Strohmayer, Tod E.; Timmes, F. X.; Townsley, Dean M.; Wiescher, Michael; Zegers, Remco G. T.; Zingale, Michael

    2017-05-01

    This white paper informs the nuclear astrophysics community and funding agencies about the scientific directions and priorities of the field and provides input from this community for the 2015 Nuclear Science Long Range Plan. It summarizes the outcome of the nuclear astrophysics town meeting that was held on August 21-23, 2014 in College Station at the campus of Texas A&M University in preparation of the NSAC Nuclear Science Long Range Plan. It also reflects the outcome of an earlier town meeting of the nuclear astrophysics community organized by the Joint Institute for Nuclear Astrophysics (JINA) on October 9-10, 2012 Detroit, Michigan, with the purpose of developing a vision for nuclear astrophysics in light of the recent NRC decadal surveys in nuclear physics (NP2010) and astronomy (ASTRO2010). The white paper is furthermore informed by the town meeting of the Association of Research at University Nuclear Accelerators (ARUNA) that took place at the University of Notre Dame on June 12-13, 2014. In summary we find that nuclear astrophysics is a modern and vibrant field addressing fundamental science questions at the intersection of nuclear physics and astrophysics. These questions relate to the origin of the elements, the nuclear engines that drive life and death of stars, and the properties of dense matter. A broad range of nuclear accelerator facilities, astronomical observatories, theory efforts, and computational capabilities are needed. With the developments outlined in this white paper, answers to long standing key questions are well within reach in the coming decade.

  3. Laboratory Plasma Source as an MHD Model for Astrophysical Jets

    Science.gov (United States)

    Mayo, Robert M.

    1997-01-01

    The significance of the work described herein lies in the demonstration of Magnetized Coaxial Plasma Gun (MCG) devices like CPS-1 to produce energetic laboratory magneto-flows with embedded magnetic fields that can be used as a simulation tool to study flow interaction dynamic of jet flows, to demonstrate the magnetic acceleration and collimation of flows with primarily toroidal fields, and study cross field transport in turbulent accreting flows. Since plasma produced in MCG devices have magnetic topology and MHD flow regime similarity to stellar and extragalactic jets, we expect that careful investigation of these flows in the laboratory will reveal fundamental physical mechanisms influencing astrophysical flows. Discussion in the next section (sec.2) focuses on recent results describing collimation, leading flow surface interaction layers, and turbulent accretion. The primary objectives for a new three year effort would involve the development and deployment of novel electrostatic, magnetic, and visible plasma diagnostic techniques to measure plasma and flow parameters of the CPS-1 device in the flow chamber downstream of the plasma source to study, (1) mass ejection, morphology, and collimation and stability of energetic outflows, (2) the effects of external magnetization on collimation and stability, (3) the interaction of such flows with background neutral gas, the generation of visible emission in such interaction, and effect of neutral clouds on jet flow dynamics, and (4) the cross magnetic field transport of turbulent accreting flows. The applicability of existing laboratory plasma facilities to the study of stellar and extragalactic plasma should be exploited to elucidate underlying physical mechanisms that cannot be ascertained though astrophysical observation, and provide baseline to a wide variety of proposed models, MHD and otherwise. The work proposed herin represents a continued effort on a novel approach in relating laboratory experiments to

  4. Plasma Astrophysics, Part II Reconnection and Flares

    CERN Document Server

    Somov, Boris V

    2013-01-01

    This two-part book is devoted to classic fundamentals and current practices and perspectives of modern plasma astrophysics. This second part discusses the physics of magnetic reconnection and flares of electromagnetic origin in space plasmas in the solar system, single and double stars, relativistic objects, accretion disks and their coronae. More than 25% of the text is updated from the first edition, including the additions of new figures, equations and entire sections on topics such as topological triggers for solar flares and the magnetospheric physics problem. This book is aimed at professional researchers in astrophysics, but it will also be useful to graduate students in space sciences, geophysics, applied physics and mathematics, especially those seeking a unified view of plasma physics and fluid mechanics.

  5. The Future of Gamma Ray Astrophysics

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Over the past decade, gamma ray astrophysics has entered the astrophysical mainstream. Extremely successful space-borne (GeV) and ground-based (TeV) detectors, combined with a multitude of partner telescopes, have revealed a fascinating “astroscape" of active galactic nuclei, pulsars, gamma ray bursts, supernova remnants, binary stars, star-forming galaxies, novae much more, exhibiting major pathways along which large energy releases can flow. From  a basic physics perspective, exquisitely sensitive measurements have constrained the nature of dark matter, the cosmological origin of magnetic field and the properties of black holes. These advances have motivated the development of new facilities, including HAWC, DAMPE, CTA and SVOM, which will further our understanding of the high energy universe. Topics that will receive special attention include merging neutron star binaries, clusters of galaxies, galactic cosmic rays and putative, TeV dark matter.

  6. Doppler tomography in fusion plasmas and astrophysics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Heidbrink, W. W.

    2015-01-01

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion Dα (FIDA) spectroscopy measurements in magnetically confined plasma......, the Dα-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright...... spots, spiral structures and flow patterns. Fusion plasma Doppler tomography has led to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its promise...

  7. Modern fluid dynamics for physics and astrophysics

    CERN Document Server

    Regev, Oded; Yecko, Philip A

    2016-01-01

    This book grew out of the need to provide students with a solid introduction to modern fluid dynamics. It offers a broad grounding in the underlying principles and techniques used, with some emphasis on applications in astrophysics and planetary science. The book comprehensively covers recent developments, methods and techniques, including, for example, new ideas on transitions to turbulence (via transiently growing stable linear modes), new approaches to turbulence (which remains the enigma of fluid dynamics), and the use of asymptotic approximation methods, which can give analytical or semi-analytical results and complement fully numerical treatments. The authors also briefly discuss some important considerations to be taken into account when developing a numerical code for computer simulation of fluid flows. Although the text is populated throughout with examples and problems from the field of astrophysics and planetary science, the text is eminently suitable as a general introduction to fluid dynamics. It...

  8. Neutrino particle astrophysics: status and outlook

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The discovery of astrophysical neutrinos at high energy by IceCube raises a host of questions: What are the sources? Is there a Galactic as well as an extragalactic component? How does the astrophysical spectrum continue to lower energy where the dominant signal is from atmospheric neutrinos? Is there a measureable flux of cosmogenic neutrinos at higher energy? What is the connection to cosmic rays? At what level and in what energy region should we expect to see evidence of the π0 decay photons that must accompany the neutrinos at production? Such questions are stimulating much theoretical activity and many multi-wavelength follow-up observations as well as driving plans for new detectors. My goal in this presentation will be to connect the neutrino data and their possible interpretations to ongoing multi-messenger observations and to the design of future detectors.

  9. Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. International Conference on Particle Physics and Astrophysics

    CERN Document Server

    2015-01-01

    The International Conference on Particle Physics and Astrophysics (ICPPA-2015) will be held in Moscow, Russia, from October 5 to 10, 2015. The conference is organized by Center of Basic 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. Therefore we will bring together experts and young scientists working on experimental and theoretical aspects of nuclear, particle, astroparticle physics and cosmology. ICPPA-2015, aims to present the most recent results in astrophysics and collider physics and reports from the main experiments currently taking data. The working languages of the conference are English and Russian.

  11. Electrodynamics and spacetime geometry: Astrophysical applications

    CERN Document Server

    Cabral, Francisco

    2016-01-01

    After a brief review of the foundations of (pre-metric) electromagnetism in differential forms, we proceed with the tensor formulation and explore physical consequences of Maxwell's equations in curved spacetime. The generalized Gauss and Maxwell-Amp\\`ere laws, as well as the wave equations, reveal potentially interesting astrophysical applications. The physical implications of these equations are explored and some solutions are obtained. In all cases new electromagnetic couplings and related phenomena are induced by the spacetime curvature. The applications of astrophysical interest considered here correspond essentially to the following geometries: the Schwarzschild spacetime and the spacetime around a rotating spherical mass in the weak field and slow rotation regime. In the latter, we use the Parameterised Post-Newtonian (PPN) formalism. In general, new electromagnetic effects induced by spacetime curvature include the following: Gravitational contributions for the decay of electric and magnetic fields in...

  12. Exploring the Digital Universe with Europe's Astrophysical Virtual Observatory

    Science.gov (United States)

    2001-12-01

    used globally and repeatedly to achieve substantial progress in the quest for knowledge. The AVO project, funded by the European Commission, is a three-year study of the design and implementation of a virtual observatory for European astronomy. A virtual observatory is a collection of connected data archives and software tools that utilise the Internet to form a scientific research environment in which new multi-wavelength astronomical research programs can be conducted. In much the same way as a real observatory consists of telescopes, each with a collection of unique astronomical instruments, the virtual observatory consists of a collection of data centres each with unique collections of astronomical data, software systems and processing capabilities. The programme will implement and test a prototype virtual observatory , focussing on the key areas of scientific requirements, interoperability and new technologies such as the GRID, needed to link powerful computers to the newly formed large data repositories. The GRID and the Future of the Internet The technical problems astronomers have to solve are similar to those being worked on by particle physicists, by biologists, and by commercial companies who want to search and fill customer databases across the world. The emerging idea is that of the GRID where computers collaborate across the Internet. The World Wide Web made words and pictures available to anybody at the click of a mouse. The GRID will do the same for data, and for computer processing power. Anybody can have the power of a supercomputer sitting on their desktop. The Astrophysical Virtual Observatory, and GRID projects like the ASTROGRID project in the United Kingdom (funding 5 million UK Pounds or 8 million Euro), are closely linked to these developments.

  13. Neutrino masses in astrophysics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Raffelt, G.G. [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    1996-11-01

    Astrophysical and cosmological arguments and observations give us the most restrictive constraints on neutrino masses, electromagnetic couplings, and other properties. Conversely, massive neutrinos would contribute to the cosmic dark-matter density and would play an important role for the formation of structure in the universe. Neutrino oscillations may well solve the solar neutrino problem, and can have a significant impact on supernova physics. (author) 14 figs., tabs., 33 refs.

  14. Color-charged Quark Matter in Astrophysics?

    OpenAIRE

    Qiu, Congxin; Xu, Renxin

    2006-01-01

    Color confinement is only a supposition, which has not been proved in QCD yet. It is proposed here that macroscopic quark gluon plasma in astrophysics could hardly maintain colorless because of causality. The authors expected that the existence of chromatic strange quark stars as well as chromatic strangelets preserved from the QCD phase transition in the early universe could be unavoidable if their colorless correspondents do exist.

  15. Goddard's Astrophysics Science Division Annual Report 2013

    Science.gov (United States)

    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.

  16. Goddard's Astrophysics Science Division Annual Report 2011

    Science.gov (United States)

    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.

  17. The Astrophysics Science Division Annual Report 2009

    Science.gov (United States)

    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.

  18. Femtosecond laser studies of ultrafast intramolecular processes

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, C. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this research is to better understand the detailed mechanisms of chemical reactions by observing, directly in time, the dynamics of fundamental chemical processes. In this work femtosecond laser pulses are used to initiate chemical processes and follow the progress of these processes in time. The authors are currently studying ultrafast internal conversion and subsequent intramolecular relaxation in unsaturated hydrocarbons. In addition, the authors are developing nonlinear optical techniques to prepare and monitor the time evolution of specific vibrational motions in ground electronic state molecules.

  19. Swift heavy ion modifications of astrophysical water ice

    Energy Technology Data Exchange (ETDEWEB)

    Dartois, E., E-mail: emmanuel.dartois@ias.u-psud.fr [CNRS-INSU, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, bât. 121, 91405 Orsay (France); Augé, B. [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CEA, CNRS, ENSICAEN, Université de Caen-Basse Normandie), UMR 6252, CIMAP – CIRIL – Ganil, Boulevard Henri Becquerel, BP 5133, 14070 Caen Cedex 05 (France); CNRS-INSU, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, bât. 121, 91405 Orsay (France); Rothard, H.; Boduch, P. [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CEA, CNRS, ENSICAEN, Université de Caen-Basse Normandie), UMR 6252, CIMAP – CIRIL – Ganil, Boulevard Henri Becquerel, BP 5133, 14070 Caen Cedex 05 (France); Brunetto, R. [CNRS-INSU, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, bât. 121, 91405 Orsay (France); and others

    2015-12-15

    In the relatively shielded environments provided by interstellar dense clouds in our Galaxy, infrared astronomical observations have early revealed the presence of low temperature (10–100 K) ice mantles covering tiny grain “cores” composed of more refractory material. These ices are of specific interest because they constitute an interface between a solid phase under complex evolution triggered by energetic processes and surface reactions, with a rich chemistry taking place in the gas phase. The interstellar ice mantles present in these environments are immersed, in addition to other existing radiations fields, in a flux of cosmic ray particles that can produce new species via radiolysis processes, but first affects their structure, which may change and also induces desorption of molecules and radicals from these grains. Theses cosmic rays are simulated by swift ions in the laboratory for a better understanding of astrophysical processes.

  20. Tides in astronomy and astrophysics

    CERN Document Server

    Mathis, Stéphane; Tokieda, Tadashi

    2013-01-01

    Based on the lecture notes of a school titled ‘Tides in Astronomy and Astrophysics’ that brought together students and researchers, this book focuses on the fundamental theories of tides at different scales of the universe—from tiny satellites to whole galaxies—and on the most recent developments. It also attempts to place the study of tides in a historical perspective. Starting with a general tutorial on tides, the theme of tides is approached in 9 chapters from many directions. They allow non-experts to pick up a physical intuition and a sense of orders of magnitude in the theory of tides. These carefully prepared lecture notes by leaders in the field include many illustrative figures and drawings. Some even offer a variety of simple back-of the-envelope problems.

  1. Using vignettes to study family consumption processes

    DEFF Research Database (Denmark)

    Grønhøj, Alice; Bech-Larsen, Tino

    2010-01-01

    The use of vignettes for qualitative consumer research is discussed in this article. More specifically, vignettes are proposed as a useful research technique for conducting systematic and rigorous studies of consumer interaction processes, in particular as these relate to family consumption issues....... Following an overview of methodological and practical problems of studying consumption interaction processes in families, a discussion of how vignettes may be used to enhance knowledge of family decision-making processes in real-life contexts is presented. Design implications are discussed and strategies...... for applying the vignette method are outlined and illustrated by two recent studies of proenvironmental consumer behavior in a family context. The paper concludes with a discussion of the benefits and the possible pitfalls of using vignettes....

  2. Physics and astrophysics a selection of key problems

    CERN Document Server

    Ginzburg, V L

    2013-01-01

    Physics and Astrophysics discusses some major problems concerned with macrophysics. Such topics as the controlled thermonuclear fusion, high- temperature superconductivity, and metallic exciton liquid in semiconductors are covered. The definition and elements related to microphysics are discussed. This section focuses on mass spectrum, quarks and gluons, and the interaction of particles at high and super high energies. The book gives a brief overview of the general theory of relativity. The production and origin of gravitational waves are discussed in detail. Cosmology is the study of space an

  3. Resolving astrophysical uncertainties in dark matter direct detection

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Kahlhoefer, Felix; McCabe, Christopher

    2012-01-01

    We study the impact of the assumed velocity distribution of galactic dark matter particles on the interpretation of results from nuclear recoil detectors. By converting experimental data to variables that make the astrophysical unknowns explicit, different experiments can be compared without...... implicit assumptions concerning the dark matter halo. We extend this framework to include the annual modulation signal, as well as multiple target elements. Recent results from DAMA, CoGeNT and CRESST-II can be brought into agreement if the velocity distribution is very anisotropic and thus allows a large...

  4. The EXIST Mission for High-Energy Astrophysics

    Science.gov (United States)

    Fishman, G. J.; Grindlay, J. E.; Hong, J.

    2006-01-01

    The Energetic X-ray Imaging Survey Telescope (EXIST), under study to be the Black Hole Finder Probe in NASA's Beyond Einstein Program, would image the sky every 95min in the energy range 1 OkeV to 600 keV. Although the main scientific objectives of EXIST are the systematic, all-sky survey of heavily obscured AGNs and gamma-ray bursts, there is a substantial capability of EXIST for the observation of transient and persistent hard x-ray lines from several astrophysical sources.

  5. Astrophysical Sources of High-Energy Neutrinos in the IceCube Era

    Science.gov (United States)

    Mészáros, P.

    2017-10-01

    High-energy neutrino astrophysics has come of age with IceCube's discovery of neutrinos in the TeV to PeV energy range, attributable to extragalactic sources at cosmological distances. At such energies, astrophysical neutrinos must originate in cosmic-ray interactions, providing information about the sources of high-energy cosmic rays, as well as leading to the coproduction of high-energy γ-rays. The intimate link with these two independently observed types of radiation provides important tools for the quest to identify and understand the nature of the astrophysical sources of the neutrinos. These neutrinos can set important constraints on the cosmic-ray acceleration process, and because they travel essentially unimpeded, they can probe our Universe out to the farthest cosmological distances.

  6. Astrophysical phenomena related to supermassive black holes

    Science.gov (United States)

    Pott, Jörg-Uwe

    2006-12-01

    astrophysical context of the observation. The observational techniques chosen vary in dependence of the observed phenomenon. One major goal of especially Chapters 3 and 4 is to prove by successful explorative observations the scientific perspectives of the new instruments. Chapter 3 deals with the pioneering interferometric infrared study of stellar sources and their surroundings in the immediate vicinity of the SMBH at the center of the Milky Way. I was able to use the resolving power of an optical large baseline interferometer (OLBI) to investigate for the first time the different structures and excitation conditions of interstellar and circumstellar dust in 200 mpc distance to the SMBH. It is unknown whether the standard models for star and dust formation, which themselves dominate the infrared appearance of an inactive galaxy as the Milky Way, still apply under the strong tidal forces of gravity, exerted by the central SMBH. During the course of my doctoral research, I worked 2.5 years within the VLT Interferometry (VLTI) group of the European Southern Observatory (ESO) in M"unchen and Chile. I obtained the very first infrared fringes on GC sources and investigated the different instrument capabilities at the current sensitivity limit of the VLTI. The VLTI is the world leading stellar interferometric facility providing the infrastructure to combine the light of up to four 8m-class Adaptive Optics corrected telescopes, which themselves represent the state-of-the-art of optical-infrared telescope technology. The accomplished work includes the investigation of different data reduction techniques with respect to maximum accuracy and signal-to-noise ratios. The VLTI is right in the process of construction. While first modes are already open to the astronomical community, several advanced modes and instruments are still at different preliminary stages, ranging from early design studies to advanced instrument commissioning. The experiences of my VLTI observations, fully exploiting

  7. Light element opacities of astrophysical interest from ATOMIC

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, J.; Kilcrease, D. P.; Magee, N. H. Jr.; Armstrong, G. S. J.; Abdallah, J. Jr.; Sherrill, M. E. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fontes, C. J.; Zhang, H. L.; Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-07-11

    We present new calculations of local-thermodynamic-equilibrium (LTE) light element opacities from the Los Alamos ATOMIC code for systems of astrophysical interest. ATOMIC is a multi-purpose code that can generate LTE or non-LTE quantities of interest at various levels of approximation. Our calculations, which include fine-structure detail, represent a systematic improvement over previous Los Alamos opacity calculations using the LEDCOP legacy code. The ATOMIC code uses ab-initio atomic structure data computed from the CATS code, which is based on Cowan's atomic structure codes, and photoionization cross section data computed from the Los Alamos ionization code GIPPER. ATOMIC also incorporates a new equation-of-state (EOS) model based on the chemical picture. ATOMIC incorporates some physics packages from LEDCOP and also includes additional physical processes, such as improved free-free cross sections and additional scattering mechanisms. Our new calculations are made for elements of astrophysical interest and for a wide range of temperatures and densities.

  8. FIRST KODAI-TRIESTE WORKSHOP ON PLASMA ASTROPHYSICS

    CERN Document Server

    Hasan, S. S; Krishan, V; TURBULENCE, DYNAMOS, ACCRETION DISKS, PULSARS AND COLLECTIVE PLASMA PROCESSES

    2008-01-01

    It is well established and appreciated by now that more than 99% of the baryonic matter in the universe is in the plasma state. Most astrophysical systems could be approximated as conducting fluids in a gravitational field. It is the combined effect of these two that gives rise to the mind boggling variety of configurations in the form of filaments, loops , jets and arches. The plasma structures that cannot last for more than a second or less in a laboratory remain intact for astronomical time and spatial scales in an astrophysical setting. The case in point is the well known extragalactic jets whose collimation and stability has remained an enigma inspite of the efforts of many for many long years. The high energy radiation sources such as the active galactic nuclei again summon the coherent plasma radiation processes for their exceptionally large output from regions of relatively small physical sizes. The generation of magnetic field, anomalous transport of angular momentum with decisive bearing on star for...

  9. CHOLLA: A New Massively Parallel Hydrodynamics Code for Astrophysical Simulation

    Science.gov (United States)

    Schneider, Evan E.; Robertson, Brant E.

    2015-04-01

    We present Computational Hydrodynamics On ParaLLel Architectures (Cholla ), a new three-dimensional hydrodynamics code that harnesses the power of graphics processing units (GPUs) to accelerate astrophysical simulations. Cholla models the Euler equations on a static mesh using state-of-the-art techniques, including the unsplit Corner Transport Upwind algorithm, a variety of exact and approximate Riemann solvers, and multiple spatial reconstruction techniques including the piecewise parabolic method (PPM). Using GPUs, Cholla evolves the fluid properties of thousands of cells simultaneously and can update over 10 million cells per GPU-second while using an exact Riemann solver and PPM reconstruction. Owing to the massively parallel architecture of GPUs and the design of the Cholla code, astrophysical simulations with physically interesting grid resolutions (≳2563) can easily be computed on a single device. We use the Message Passing Interface library to extend calculations onto multiple devices and demonstrate nearly ideal scaling beyond 64 GPUs. A suite of test problems highlights the physical accuracy of our modeling and provides a useful comparison to other codes. We then use Cholla to simulate the interaction of a shock wave with a gas cloud in the interstellar medium, showing that the evolution of the cloud is highly dependent on its density structure. We reconcile the computed mixing time of a turbulent cloud with a realistic density distribution destroyed by a strong shock with the existing analytic theory for spherical cloud destruction by describing the system in terms of its median gas density.

  10. X-Ray Calorimeter Arrays for Astrophysics

    Science.gov (United States)

    Kilbourne, Caroline A.

    2009-01-01

    High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

  11. Astrobites: Blogging Astrophysics Research, Bringing it to the Classroom, and beyond

    Science.gov (United States)

    Tsang, Benny Tsz Ho; Kohler, Susanna; Astrobites Team

    2017-06-01

    Transitioning from undergraduate studies to a career in scientific research is not without its difficulties. Astrobites (astrobites.com) is a graduate student-organized website that aims to decipher the research process in astrophysics and present the latest discoveries in form of daily digestible blog posts. Astrobites posts paint vivid mental pictures of diverse research topics without jargon or extensive presumed knowledge, helping readers to make the connections between topics. Besides summarizing research papers, our posts feature reviews on selected subjects, sharing in career development, live-blogging in conferences, and keynote speakers’ personal encounters with science! The accessibility of Astrobites attracts readers beyond undergraduate students, from professional astrophysicists exploring unfamiliar territory outside of their research to science educators looking for exciting and topical ideas for lesson plans. We will present our goals, readership, latest endeavors, and future initiatives.

  12. Traversable geometric dark energy wormholes constrained by astrophysical observations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Deng [Nankai University, Theoretical Physics Division, Chern Institute of Mathematics, Tianjin (China); Meng, Xin-he [Nankai University, Department of Physics, Tianjin (China); Institute of Theoretical Physics, CAS, State Key Lab of Theoretical Physics, Beijing (China)

    2016-09-15

    In this paper, we introduce the astrophysical observations into the wormhole research. We investigate the evolution behavior of the dark energy equation of state parameter ω by constraining the dark energy model, so that we can determine in which stage of the universe wormholes can exist by using the condition ω < -1. As a concrete instance, we study the Ricci dark energy (RDE) traversable wormholes constrained by astrophysical observations. Particularly, we find from Fig. 5 of this work, when the effective equation of state parameter ω{sub X} < -1 (or z < 0.109), i.e., the null energy condition (NEC) is violated clearly, the wormholes will exist (open). Subsequently, six specific solutions of statically and spherically symmetric traversable wormhole supported by the RDE fluids are obtained. Except for the case of a constant redshift function, where the solution is not only asymptotically flat but also traversable, the five remaining solutions are all non-asymptotically flat, therefore, the exotic matter from the RDE fluids is spatially distributed in the vicinity of the throat. Furthermore, we analyze the physical characteristics and properties of the RDE traversable wormholes. It is worth noting that, using the astrophysical observations, we obtain the constraints on the parameters of the RDE model, explore the types of exotic RDE fluids in different stages of the universe, limit the number of available models for wormhole research, reduce theoretically the number of the wormholes corresponding to different parameters for the RDE model, and provide a clearer picture for wormhole investigations from the new perspective of observational cosmology. (orig.)

  13. A simulation study on garment manufacturing process

    Science.gov (United States)

    Liong, Choong-Yeun; Rahim, Nur Azreen Abdul

    2015-02-01

    Garment industry is an important industry and continues to evolve in order to meet the consumers' high demands. Therefore, elements of innovation and improvement are important. In this work, research studies were conducted at a local company in order to model the sewing process of clothes manufacturing by using simulation modeling. Clothes manufacturing at the company involves 14 main processes, which are connecting the pattern, center sewing and side neating, pockets sewing, backside-sewing, attaching the front and back, sleeves preparation, attaching the sleeves and over lock, collar preparation, collar sewing, bottomedge sewing, buttonholing sewing, removing excess thread, marking button, and button cross sewing. Those fourteen processes are operated by six tailors only. The last four sets of processes are done by a single tailor. Data collection was conducted by on site observation and the probability distribution of processing time for each of the processes is determined by using @Risk's Bestfit. Then a simulation model is developed using Arena Software based on the data collected. Animated simulation model is developed in order to facilitate understanding and verifying that the model represents the actual system. With such model, what if analysis and different scenarios of operations can be experimented with virtually. The animation and improvement models will be presented in further work.

  14. Mechanisms for the Formations of the Thymine Under Astrophysical Conditions and Implications for the Origin of Life

    Science.gov (United States)

    Bera, Partha P.; Nuevo, Michel; Materese, Christopher K.; Sandford, Scott A.; Lee, Timothy J.

    2016-01-01

    Nucleobases are the carriers of the genetic information in ribonucleic acid and deoxyribonucleic acid (DNA) for all life on Earth. Their presence in meteorites clearly indicates that compounds of biological importance can form via non-biological processes in extraterrestrial environments. Recent experimental studies have shown that the pyrimidine-based nucleobases uracil and cytosine can be easily formed from the ultraviolet irradiation of pyrimidine in H2O-rich ice mixtures that simulate astrophysical processes. In contrast, thymine, which is found only in DNA, is more difficult to form under the same experimental conditions, as its formation usually requires a higher photon dose. Earlier quantum chemical studies confirmed that the reaction pathways were favorable provided that several H2O molecules surrounded the reactants. However, the present quantum chemical study shows that the formation of thymine is limited because of the inefficiency of the methylation of pyrimidine and its oxidized derivatives in an H2O ice, as supported by the laboratory studies. Our results constrain the formation of thymine in astrophysical environments and thus the inventory of organic molecules delivered to the early Earth and have implications for the role of thymine and DNA in the origin of life.

  15. Ironmaking Process Alternative Screening Study, Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood Greene, . .

    2005-01-06

    Iron in the United States is largely produced from iron ore mined in the United States or imported from Canada or South America. The iron ore is typically smelted in Blast Furnaces that use primarily iron ore, iron concentrate pellets metallurgical coke, limestone and lime as the raw materials. Under current operating scenarios, the iron produced from these Blast Furnaces is relatively inexpensive as compared to current alternative iron sources, e.g. direct iron reduction, imported pig iron, etc. The primary problem the Blast Furnace Ironmaking approach is that many of these Blast furnaces are relatively small, as compared to the newer, larger Blast Furnaces; thus are relatively costly and inefficient to operate. An additional problem is also that supplies of high-grade metallurgical grade coke are becoming increasingly in short supply and costs are also increasing. In part this is due to the short supply and costs of high-grade metallurgical coals, but also this is due to the increasing necessity for environmental controls for coke production. After year 2003 new regulations for coke product environmental requirement will likely be promulgated. It is likely that this also will either increase the cost of high-quality coke production or will reduce the available domestic U.S. supply. Therefore, iron production in the United States utilizing the current, predominant Blast Furnace process will be more costly and would likely be curtailed due to a coke shortage. Therefore, there is a significant need to develop or extend the economic viability of Alternate Ironmaking Processes to at least partially replace current and declining blast furnace iron sources and to provide incentives for new capacity expansion. The primary conclusions of this comparative Study of Alternative Ironmaking Process scenarios are: (1) The processes with the best combined economics (CAPEX and OPEX impacts in the I.R.R. calculation) can be grouped into those Fine Ore based processes with no scrap

  16. Exploratory study of complexant concentrate waste processing

    Energy Technology Data Exchange (ETDEWEB)

    Lumetta, G.J.; Bray, L.A.; Kurath, D.E.; Morrey, J.R.; Swanson, J.L.; Wester, D.W.

    1993-02-01

    The purpose of this exploratory study, conducted by Pacific Northwest Laboratory for Westinghouse Hanford Company, was to determine the effect of applying advanced chemical separations technologies to the processing and disposal of high-level wastes (HLW) stored in underground tanks. The major goals of this study were to determine (1) if the wastes can be partitioned into a small volume of HLW plus a large volume of low-level waste (LLW), and (2) if the activity in the LLW can be lowered enough to meet NRC Class LLW criteria. This report presents the results obtained in a brief scouting study of various processes for separating radionuclides from Hanford complexant concentrate (CC) waste.

  17. Modules for Experiments in Stellar Astrophysics (MESA)

    Science.gov (United States)

    Paxton, Bill; Bildsten, Lars; Dotter, Aaron; Herwig, Falk; Lesaffre, Pierre; Timmes, Frank

    2011-01-01

    Stellar physics and evolution calculations enable a broad range of research in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a suite of open source, robust, efficient, thread-safe libraries for a wide range of applications in computational stellar astrophysics. A one-dimensional stellar evolution module, MESAstar, combines many of the numerical and physics modules for simulations of a wide range of stellar evolution scenarios ranging from very low mass to massive stars, including advanced evolutionary phases. MESAstar solves the fully coupled structure and composition equations simultaneously. It uses adaptive mesh refinement and sophisticated timestep controls, and supports shared memory parallelism based on OpenMP. State-of-the-art modules provide equation of state, opacity, nuclear reaction rates, element diffusion data, and atmosphere boundary conditions. Each module is constructed as a separate Fortran 95 library with its own explicitly defined public interface to facilitate independent development. Several detailed examples indicate the extensive verification and testing that is continuously performed and demonstrate the wide range of capabilities that MESA possesses. These examples include evolutionary tracks of very low mass stars, brown dwarfs, and gas giant planets to very old ages; the complete evolutionary track of a 1 M sun star from the pre-main sequence (PMS) to a cooling white dwarf; the solar sound speed profile; the evolution of intermediate-mass stars through the He-core burning phase and thermal pulses on the He-shell burning asymptotic giant branch phase; the interior structure of slowly pulsating B Stars and Beta Cepheids; the complete evolutionary tracks of massive stars from the PMS to the onset of core collapse; mass transfer from stars undergoing Roche lobe overflow; and the evolution of helium accretion onto a neutron star. MESA can be downloaded from the project Web site (http://mesa.sourceforge.net/).

  18. Bibliometric indicators of young authors in astrophysics

    DEFF Research Database (Denmark)

    Havemann, Frank; Larsen, Birger

    2015-01-01

    their first landmark paper with the distributions of these indicators over a random control group of young authors in astronomy and astrophysics. We find that field and citation-window normalisation substantially improves the predicting power of citation indicators. The sum of citation numbers normalised...... with expected citation numbers is the only indicator which shows differences between later stars and random authors significant on a 1 % level. Indicators of paper output are not very useful to predict later stars. The famous h-index makes no difference at all between later stars and the random control group....

  19. 3D Immersive Visualization with Astrophysical Data

    Science.gov (United States)

    Kent, Brian R.

    2017-01-01

    We present the refinement of a new 3D immersion technique for astrophysical data visualization.Methodology to create 360 degree spherical panoramas is reviewed. The 3D software package Blender coupled with Python and the Google Spatial Media module are used together to create the final data products. Data can be viewed interactively with a mobile phone or tablet or in a web browser. The technique can apply to different kinds of astronomical data including 3D stellar and galaxy catalogs, images, and planetary maps.

  20. Dimensional analysis and group theory in astrophysics

    CERN Document Server

    Kurth, Rudolf

    2013-01-01

    Dimensional Analysis and Group Theory in Astrophysics describes how dimensional analysis, refined by mathematical regularity hypotheses, can be applied to purely qualitative physical assumptions. The book focuses on the continuous spectral of the stars and the mass-luminosity relationship. The text discusses the technique of dimensional analysis, covering both relativistic phenomena and the stellar systems. The book also explains the fundamental conclusion of dimensional analysis, wherein the unknown functions shall be given certain specified forms. The Wien and Stefan-Boltzmann Laws can be si

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

    Science.gov (United States)

    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.

  2. Light dark matter versus astrophysical constraints

    OpenAIRE

    Cline, James M.; Frey, Andrew R.

    2011-01-01

    Hints of direct dark matter detection coming from the DAMA, CoGeNT experiments point toward light dark matter with isospin-violating and possibly inelastic couplings. However an array of astrophysical constraints are rapidly closing the window on light dark matter. We point out that if the relic density is determined by annihilation into invisible states, these constraints can be evaded. As an example we present a model of quasi-Dirac dark matter, interacting via two U(1) gauge bosons, one of...

  3. High energy particles and quanta in astrophysics

    Science.gov (United States)

    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.

  4. Parametric Model for Astrophysical Proton-Proton Interactions and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Niklas [KTH Royal Institute of Technology, Stockholm (Sweden)

    2007-01-01

    Observations of gamma-rays have been made from celestial sources such as active galaxies, gamma-ray bursts and supernova remnants as well as the Galactic ridge. The study of gamma rays can provide information about production mechanisms and cosmic-ray acceleration. In the high-energy regime, one of the dominant mechanisms for gamma-ray production is the decay of neutral pions produced in interactions of ultra-relativistic cosmic-ray nuclei and interstellar matter. Presented here is a parametric model for calculations of inclusive cross sections and transverse momentum distributions for secondary particles--gamma rays, e±, ve, $\\bar{v}$e, vμ and $\\bar{μ}$e--produced in proton-proton interactions. This parametric model is derived on the proton-proton interaction model proposed by Kamae et al.; it includes the diffraction dissociation process, Feynman-scaling violation and the logarithmically rising inelastic proton-proton cross section. To improve fidelity to experimental data for lower energies, two baryon resonance excitation processes were added; one representing the Δ(1232) and the other multiple resonances with masses around 1600 MeV/c2. The model predicts the power-law spectral index for all secondary particle to be about 0.05 lower in absolute value than that of the incident proton and their inclusive cross sections to be larger than those predicted by previous models based on the Feynman-scaling hypothesis. The applications of the presented model in astrophysics are plentiful. It has been implemented into the Galprop code to calculate the contribution due to pion decays in the Galactic plane. The model has also been used to estimate the cosmic-ray flux in the Large Magellanic Cloud based on HI, CO and gamma-ray observations. The transverse momentum distributions enable calculations when the proton distribution is anisotropic. It is shown that the gamma-ray spectrum and flux due to a

  5. Predicting the statistics of high-energy astrophysical backgrounds

    NARCIS (Netherlands)

    Feyereisen, M.R.

    2017-01-01

    This thesis presents improvements to a methodology for predicting the probability distribution of diffuse isotropic astrophysical backgrounds, applied to high-energy extragalactic gamma rays and neutrinos.

  6. Solar, Stellar and Galactic Connections between Particle Physics and Astrophysics

    CERN Document Server

    Carraminana, Alberto

    2007-01-01

    This book collects extended and specialized reviews on topics linking astrophysics and particle physics at a level intermediate between a graduate student and a young researcher. The book includes also three reviews on observational techniques used in forefront astrophysics and short articles on research performed in Latin America. The reviews, updated and written by specialized researchers, describe the state of the art in the related research topics. This book is a valuable complement not only for research but also for lecturers in specialized course of high energy astrophysics, cosmic ray astrophysics and particle physics.

  7. Electrodynamics and spacetime geometry: Astrophysical applications

    Science.gov (United States)

    Cabral, Francisco; Lobo, Francisco S. N.

    2017-07-01

    After a brief review of the foundations of (pre-metric) electromagnetism, we explore some physical consequences of electrodynamics in curved spacetime. In general, new electromagnetic couplings and related phenomena are induced by the spacetime curvature. The applications of astrophysical interest considered here correspond essentially to the following geometries: the Schwarzschild spacetime and the spacetime around a rotating spherical mass in the weak field and slow rotation regime. In the latter, we use the Parameterised Post-Newtonian (PPN) formalism. We also explore the hypothesis that the electric and magnetic properties of vacuum reflect the spacetime isometries. Therefore, the permittivity and permeability tensors should not be considered homogeneous and isotropic a priori. For spherical geometries we consider the effect of relaxing the homogeneity assumption in the constitutive relations between the fields and excitations. This affects the generalized Gauss and Maxwell-Ampère laws, where the electric permittivity and magnetic permeability in vacuum depend on the radial coordinate in accordance with the local isometries of space. For the axially symmetric geometries we relax both the assumptions of homogeneity and isotropy. We explore simple solutions and discuss the physical implications related to different phenomena, such as the decay of electromagnetic fields in the presence of gravity, magnetic terms in Gauss law due to the gravitomagnetism of the spacetime around rotating objects, a frame-dragging effect on electric fields and the possibility of a spatial (radial) variability of the velocity of light in vacuum around spherical astrophysical objects for strong gravitational fields.

  8. Highlights of the NASA particle astrophysics program

    Energy Technology Data Exchange (ETDEWEB)

    Jones, William Vernon, E-mail: w.vernon.jones@nasa.gov [Astrophysics Division DH000, Science Mission Directorate, NASA Headquarters, Washington DC (United States)

    2014-07-01

    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 2015. 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. (author)

  9. Advancing Astrophysics with the Square Kilometre Array

    CERN Document Server

    Fender, Rob; Govoni, Federica; Green, Jimi; Hoare, Melvin; Jarvis, Matt; Johnston-Hollitt, Melanie; Keane, Evan; Koopmans, Leon; Kramer, Michael; Maartens, Roy; Macquart, Jean-Pierre; Mellema, Garrelt; Oosterloo, Tom; Prandoni, Isabella; Pritchard, Jonathan; Santos, Mario; Seymour, Nick; Stappers, Ben; Staveley-Smith, Lister; Tian, Wen Wu; Umana, Grazia; Wagg, Jeff; Bourke, Tyler L; AASKA14

    2015-01-01

    In 2014 it was 10 years since the publication of the comprehensive ‘Science with the Square Kilometre Array’ book and 15 years since the first such volume appeared in 1999. In that time numerous and unexpected advances have been made in the fields of astronomy and physics relevant to the capabilities of the Square Kilometre Array (SKA). The SKA itself progressed from an idea to a developing reality with a baselined Phase 1 design (SKA1) and construction planned from 2017. To facilitate the publication of a new, updated science book, which will be relevant to the current astrophysical context, the meeting "Advancing Astrophysics with the Square Kilometre Array" was held in Giardina Naxos, Sicily. Articles were solicited from the community for that meeting to document the scientific advances enabled by the first phase of the SKA and those pertaining to future SKA deployments, with expected gains of 5 times the Phase 1 sensitivity below 350 MHz, about 10 times the Phase 1 sensitivity above 350 MHz and with f...

  10. Astrophysical Plasmas: Codes, Models, and Observations

    Science.gov (United States)

    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.

  11. The CATS Service: An Astrophysical Research Tool

    Directory of Open Access Journals (Sweden)

    O V Verkhodanov

    2009-03-01

    Full Text Available We describe the current status of CATS (astrophysical CATalogs Support system, a publicly accessible tool maintained at Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS (http://cats.sao.ru allowing one to search hundreds of catalogs of astronomical objects discovered all along the electromagnetic spectrum. Our emphasis is mainly on catalogs of radio continuum sources observed from 10 MHz to 245 GHz, and secondly on catalogs of objects such as radio and active stars, X-ray binaries, planetary nebulae, HII regions, supernova remnants, pulsars, nearby and radio galaxies, AGN and quasars. CATS also includes the catalogs from the largest extragalactic surveys with non-radio waves. In 2008 CATS comprised a total of about 109 records from over 400 catalogs in the radio, IR, optical and X-ray windows, including most source catalogs deriving from observations with the Russian radio telescope RATAN-600. CATS offers several search tools through different ways of access, e.g. via Web-interface and e-mail. Since its creation in 1997 CATS has managed about 105requests. Currently CATS is used by external users about 1500 times per day and since its opening to the public in 1997 has received about 4000 requests for its selection and matching tasks.

  12. Black Hole Astrophysics The Engine Paradigm

    CERN Document Server

    Meier, David L

    2012-01-01

    As a result of significant research over the past 20 years, black holes are now linked to some of the most spectacular and exciting phenomena in the Universe, ranging in size from those that have the same mass as stars to the super-massive objects that lie at the heart of most galaxies, including our own Milky Way. This book first introduces the properties of simple isolated holes, then adds in complications like rotation, accretion, radiation, and magnetic fields, finally arriving at a basic understanding of how these immense engines work. Black Hole Astrophysics • reviews our current knowledge of cosmic black holes and how they generate the most powerful observed pheonomena in the Universe; • highlights the latest, most up-to-date theories and discoveries in this very active area of astrophysical research; • demonstrates why we believe that black holes are responsible for important phenomena such as quasars, microquasars and gammaray bursts; • explains to the reader the nature of the violent and spe...

  13. Art as a Vehicle for Nuclear Astrophysics

    Science.gov (United States)

    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.

  14. β-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process.

    Science.gov (United States)

    Lorusso, G; Nishimura, S; Xu, Z Y; Jungclaus, A; Shimizu, Y; Simpson, G S; Söderström, P-A; Watanabe, H; Browne, F; Doornenbal, P; Gey, G; Jung, H S; Meyer, B; Sumikama, T; Taprogge, J; Vajta, Zs; Wu, J; Baba, H; Benzoni, G; Chae, K Y; Crespi, F C L; Fukuda, N; Gernhäuser, R; Inabe, N; Isobe, T; Kajino, T; Kameda, D; Kim, G D; Kim, Y-K; Kojouharov, I; Kondev, F G; Kubo, T; Kurz, N; Kwon, Y K; Lane, G J; Li, Z; Montaner-Pizá, A; Moschner, K; Naqvi, F; Niikura, M; Nishibata, H; Odahara, A; Orlandi, R; Patel, Z; Podolyák, Zs; Sakurai, H; Schaffner, H; Schury, P; Shibagaki, S; Steiger, K; Suzuki, H; Takeda, H; Wendt, A; Yagi, A; Yoshinaga, K

    2015-05-15

    The β-decay half-lives of 110 neutron-rich isotopes of the elements from _{37}Rb to _{50}Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A≈130) and the rare-earth-element (A≈160) abundance peaks may result from the freeze-out of an (n,γ)⇄(γ,n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events.

  15. FOREWORD: Workshop on "Very Hot Astrophysical Plasmas"

    Science.gov (United States)

    Koch-Miramond, Lydie; Montemerie, Thierry

    1984-01-01

    A Workshop on "Very Hot Astrophysical Plasmas" was held in Nice, France, on 8-10 November 1982. Dedicated mostly to theoretical, observational, and experimental aspects of X-ray astronomy and related atomic physics, it was the first of its kind to be held in France. The Workshop was "European" in the sense that one of its goals (apart from pure science) was to gather the European astronomical community in view of the forthcoming presentation of the "X-80" project for final selection to be the next scientific satellite of the European Space Agency. We now know that the Infrared Space Observatory has been chosen instead, but the recent successful launch of EXOSAT still keeps X-ray astronomy alive, and should be able to transfer, at least for a time, the leadership in this field from the U.S. to Europe, keeping in mind the competitive level of our Japanese colleagues. (With respect to the selection of ISO, one should also keep in mind that observations in the infrared often bring material relevant to the study of X-ray sources!) On a longer time scale, the Workshop also put emphasis on several interesting projects for the late eighties-early nineties, showing the vitality of the field in Europe. Some proposals have already taken a good start, like XMM, the X-ray Multi-Mirror project, selected by ESA last December for an assessment study in 1983. The present proceedings contain most of the papers that were presented at the Workshop. Only the invited papers were presented orally, contributed papers being presented in the form of posters but summarized orally by rapporteurs. To make up this volume, the written versions of these papers were either cross-reviewed by the Invited Speakers, or refereed by the Rapporteurs (for contributed papers) and edited by us, when necessary. Note, however, that the conclusions of the Workshop, which were kindly presented by Richard McCray, have already appeared in the "News and Views" section of Nature (301, 372, 1983). Altogether, the

  16. LAD Dissertation Prize Talk: Molecular Collisional Excitation in Astrophysical Environments

    Science.gov (United States)

    Walker, Kyle M.

    2017-06-01

    While molecular excitation calculations are vital in determining particle velocity distributions, internal state distributions, abundances, and ionization balance in gaseous environments, both theoretical calculations and experimental data for these processes are lacking. Reliable molecular collisional data with the most abundant species - H2, H, He, and electrons - are needed to probe material in astrophysical environments such as nebulae, molecular clouds, comets, and planetary atmospheres. However, excitation calculations with the main collider, H2, are computationally expensive and therefore various approximations are used to obtain unknown rate coefficients. The widely-accepted collider-mass scaling approach is flawed, and alternate scaling techniques based on physical and mathematical principles are presented here. The most up-to-date excitation data are used to model the chemical evolution of primordial species in the Recombination Era and produce accurate non-thermal spectra of the molecules H2+, HD, and H2 in a primordial cloud as it collapses into a first generation star.

  17. The immediate environment of an astrophysical black hole

    Science.gov (United States)

    Contopoulos, I.

    2018-01-01

    In view of the upcoming observations with the Event Horizon Telescope (EHT), we present our thoughts on the immediate environment of an astrophysical black hole. We are concerned that two approximations used in general relativistic magnetohydrodynamic numerical simulations, namely numerical density floors implemented near the base of the black hole jet, and a magnetic field that comes from large distances, may mislead our interpretation of the observations. We predict that three physical processes will manifest themselves in EHT observations, namely dynamic pair formation just above the horizon, electromagnetic energy dissipation along the boundary of the black hole jet, and a region of weak magnetic field separating the black hole jet from the disc wind.

  18. High Energy Neutrino Emission from Astrophysical Jets in the Galaxy

    Directory of Open Access Journals (Sweden)

    T. Smponias

    2015-01-01

    Full Text Available We address simulated neutrino emission originated from astrophysical jets of compact objects within the Galaxy. These neutrinos are of high energies (Eν of the order up to a few TeV and for their observation specialized instruments are in operation, both on Earth and in orbit. Furthermore, some next generation telescopes and detector facilities are in the process of design and construction. The jet flow simulations are performed using the modern PLUTO hydrocode in its relativistic magnetohydrodynamic version. One of the main ingredients of the present work is the presence of a toroidal magnetic field that confines the jet flow and furthermore greatly affects the distribution of the high energy neutrinos.

  19. Atomic and molecular physics and data activities for astrophysics at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Jeffery, D.J.; Kristic, P.S.; Liu, W.; Schultz, D.R.; Stancil, P.C.

    1998-04-01

    The atomic astrophysics group at ORNL produces, collects, evaluates, and disseminates atomic and molecular data relevant to astrophysics and actively models various astrophysical environments utilizing this information. With the advent of the World Wide Web, these data are also being placed on-line to facilitate their use by end-users. In this brief report, the group`s recent activities in data production and in modeling are highlighted. For example, the authors describe recent calculations of elastic and transport cross sections relevant to ionospheric and heliospheric studies, charge transfer between metal ions and metal atoms and novel supernova nebular spectra modeling, ion-molecule collision data relevant to planetary atmospheres and comets, and data for early universe modeling.

  20. Astrophysics in the Era of Massive Time-Domain Surveys

    Science.gov (United States)

    Djorgovski, G.

    Synoptic sky surveys are now the largest data producers in astronomy, entering the Petascale regime, opening the time domain for a systematic exploration. A great variety of interesting phenomena, spanning essentially all subfields of astronomy, can only be studied in the time domain, and these new surveys are producing large statistical samples of the known types of objects and events for further studies (e.g., SNe, AGN, variable stars of many kinds), and have already uncovered previously unknown subtypes of these (e.g., rare or peculiar types of SNe). These surveys are generating a new science, and paving the way for even larger surveys to come, e.g., the LSST; our ability to fully exploit such forthcoming facilities depends critically on the science, methodology, and experience that are being accumulated now. Among the outstanding challenges, the foremost is our ability to conduct an effective follow-up of the interesting events discovered by the surveys in any wavelength regime. The follow-up resources, especially spectroscopy, are already and, for the predictable future, will be severely limited, thus requiring an intelligent down-selection of the most astrophysically interesting events to follow. The first step in that process is an automated, real-time, iterative classification of events, that incorporates heterogeneous data from the surveys themselves, archival and contextual information (spatial, temporal, and multiwavelength), and the incoming follow-up observations. The second step is an optimal automated event prioritization and allocation of the available follow-up resources that also change in time. Both of these challenges are highly non-trivial, and require a strong cyber-infrastructure based on the Virtual Observatory data grid, and the various astroinformatics efforts. Time domain astronomy is inherently an astronomy of telescope-computational systems, and will increasingly depend on novel machine learning and artificial intelligence tools

  1. Breakup of radioactive nuclear beams at intermediate energies as indirect method for nuclear astrophysics

    Science.gov (United States)

    Trache, L.; Carstoiu, F.; Gagliardi, C. A.; Tribble, R. E.; Banu, A.

    2008-05-01

    We discuss the use of one-nucleon removal reactions of loosely bound nuclei at intermediate energies as an indirect method in nuclear astrophysics. These breakup reactions are good spectroscopic tools and can be used to study a large number of loosely bound proton- or neutron-rich nuclei over a wide range of beam energies. They are peripheral processes that can be used to extract asymptotic normalization coefficients (ANC) from which direct capture proton reaction rates of astrophysical interest can be calculated parameter free. We emphasize the importance of reaction model calculations and of exclusive measurements to check them. We review several cases: the breakup of 8B, 9C, 15C and 23Al. Firrst we review how we have used the data for the breakup of 8B at energies from 30 to 1000 MeV/nucleon on light and heavy targets to extract the astrophysical factor S17(0) = 18.7+/-1.9 eV.b for the key reaction for solar neutrino production. Glauber model calculations in the eikonal approximation and in the optical limit using different effective NN interactions were found to give consistent, though slightly different results, for both 8B and 9C cases, enabling also us to evaluate the precision of the method. The third case is that of a neutron-rich nucleus and the ANC alone does not lead to unambiguous estimates of the associated (n,γ) capture reaction. The 23Al case is that of an sd-shell nucleus, suspected of halo properties, for which our recent GANIL experiment revealed a complex configuration mixing in its ground state. The method outlined here has the big advantage that it can be used for beams of low quality, such as cocktail beams, and intensities as low as a few pps. As such it is very appropriate for the existing and future radioactive beam facilities. The breakup reactions are therefore complementary or a very good alternative to the use of proton and neutron transfer reactions (the ANC method) which require radioactive nuclear beams of much better purity and

  2. Hydrodynamic Study Of Column Bioleaching Processes

    Directory of Open Access Journals (Sweden)

    Sadowski Zygmunt

    2015-06-01

    Full Text Available The modelling of flow leaching solution through the porous media has been considered. The heap bioleaching process can be tested using the column experimental equipment. This equipment was employed to the hydrodynamic studies of copper ore bioleaching. The copper ore (black shale ore with the support, inertial materials (glass small balls and polyethylene beads was used to the bioleaching tests. The packed beds were various composition, the ore/support ratio was changed. The correlation between the bed porosity and bioleaching kinetics, and copper recovery was investigated.

  3. Business practice: The rise of American astrophysics, 1859--1919

    Science.gov (United States)

    Nisbett, Catherine Elaine

    This dissertation takes seriously the production of astrophysical data by examining observatory practices through the lens of business models. The post- Civil War American industrial and commercial landscape experienced large-scale reorganization and expansion; alongside that transformation, astrophysics became a discipline unto itself, and practitioners developed a professional identity. During this time the Harvard College Observatory (HCO), in particular, came into the business of catalogue production and the staff and management adopted many of the industrial and commercial processes that became standards of American business, such as forms of mass production and modern management. The projects astrophysicists chose, and those that came to define astrophysics as distinct from the "old" astronomy of celestial mechanics and astrometry, required substantially more funding for expensive instruments than other observational astronomy projects. These constraints consolidated the discipline in the hands of fewer, established professionals at institutions usually affiliated with universities or the government. The HCO, though it adopted industrial organizational models, was not a for-profit business, and the match between business practices and knowledge production was sometimes uneasy. The dissertation is concerned with this match between business models and scientific enterprise, and is motivated by three general questions. First, what compelled people to invest in an undertaking for which the benefit was in recognition rather than in dividends? Second, what did employees think they were working toward, in terms of products of their labor and in terms of pay--- both symbolic and financial? And third, what were the products of this scientific production; what were the criteria for success? These were active, though not explicit, concerns in the lives of donors, observatory employees and upper management. The HCO's fourth director, Edward Pickering, would come to court

  4. The Neutrino: A Better Understanding Through Astrophysics: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kneller, James P. [North Carolina State Univ., Raleigh, NC (United States)

    2016-10-12

    The final report for the award "The Neutrino: A Better Understanding Through Astrophysics" is given. The goals of the work were the following: to construct new theoretical approaches to the problem of neutrino propagation in media including where neutrino-neutrino interactions are important; to pioneer the use of new approaches, including super-scattering operators, for the evolution of neutrino thermal and statistical ensembles; to implement these new approaches in computer codes to study neutrino evolution in supernovae and other hot, dense environments; to increase the realism of simulated signals of a Galactic supernovae neutrino burst in current and future neutrino detectors; to study the simulated signals to determine the ability to extract information on the missing neutrino mixing parameters and the dynamics of the supernova explosion; and to study sterile neutrinos and non-standard interactions of neutrinos in supernovae and their effect upon the signal. Accomplishments made in these areas are described.

  5. Planck CMB Anomalies: Astrophysical and Cosmological Secondary Effects and the Curse of Masking

    Science.gov (United States)

    Rassat, Anais

    2016-07-01

    Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is fundamental to either validate the standard model of cosmology or to explore new physics. We investigate three other possible issues: 1) the trade-off between minimising systematics due to foreground contamination (with a conservative mask) and minimising systematics due to masking, 2) astrophysical secondary effects (the kinetic Doppler quadrupole and kinetic Sunyaev-Zel'dovich effect), and 3) secondary cosmological signals (the integrated Sachs-Wolfe effect). We address the masking issue by considering new procedures that use both WMAP and Planck to produce higher quality full-sky maps using the sparsity methodology (LGMCA maps). We show the impact of masking is dominant over that of residual foregrounds, and the LGMCA full-sky maps can be used without further processing to study anomalies. We consider four official Planck PR1 and two LGMCA CMB maps. Analysis of the observed CMB maps shows that only the low quadrupole and quadrupole-octopole alignment seem significant, but that the planar octopole, Axis of Evil, mirror parity and cold spot are not significant in nearly all maps considered. After subtraction of astrophysical and cosmological secondary effects, only the low quadrupole may still be considered anomalous, meaning the significance of only one anomaly is affected by secondary effect subtraction out of six anomalies considered. In the spirit of reproducible research all reconstructed maps and codes are available online.

  6. Some New Results in Astrophysical Problems of Nonlinear Theory of Radiative Transfer

    Science.gov (United States)

    Pikichyan, H. V.

    2017-07-01

    In the interpretation of the observed astrophysical spectra, a decisive role is related to nonlinear problems of radiative transfer, because the processes of multiple interactions of matter of cosmic medium with the exciting intense radiation ubiquitously occur in astrophysical objects, and in their vicinities. Whereas, the intensity of the exciting radiation changes the physical properties of the original medium, and itself was modified, simultaneously, in a self-consistent manner under its influence. In the present report, we show that the consistent application of the principle of invariance in the nonlinear problem of bilateral external illumination of a scattering/absorbing one-dimensional anisotropic medium of finite geometrical thickness allows for simplifications that were previously considered as a prerogative only of linear problems. The nonlinear problem is analyzed through the three methods of the principle of invariance: (i) an adding of layers, (ii) its limiting form, described by differential equations of invariant imbedding, and (iii) a transition to the, so-called, functional equations of the "Ambartsumyan's complete invariance". Thereby, as an alternative to the Boltzmann equation, a new type of equations, so-called "kinetic equations of equivalence", are obtained. By the introduction of new functions - the so-called "linear images" of solution of nonlinear problem of radiative transfer, the linear structure of the solution of the nonlinear problem under study is further revealed. Linear images allow to convert naturally the statistical characteristics of random walk of a "single quantum" or their "beam of unit intensity", as well as widely known "probabilistic interpretation of phenomena of transfer", to the field of nonlinear problems. The structure of the equations obtained for determination of linear images is typical of linear problems.

  7. Planck CMB anomalies: astrophysical and cosmological secondary effects and the curse of masking

    Energy Technology Data Exchange (ETDEWEB)

    Rassat, A. [Laboratoire d' Astrophysique (LASTRO), École Polytechnique Fédérale de Lausanne (EPFL), 51 Chemin des Maillettes, Observatoire de Sauverny, Versoix, CH-1290 (Switzerland); Starck, J.-L.; Paykari, P.; Sureau, F.; Bobin, J., E-mail: anais.rassat@epfl.ch, E-mail: jstarck@cea.fr, E-mail: paniez.paykari@cea.fr, E-mail: florent.sureau@cea.fr, E-mail: jbobin@cea.fr [Laboratoire AIM, UMR CEA-CNRS-Paris, Irfu, SAp, CEA Saclay, Gif-Sur-Yvette Cedex, F-91191 France (France)

    2014-08-01

    Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is fundamental to either validate the standard model of cosmology or to explore new physics. We investigate three other possible issues: 1) the trade-off between minimising systematics due to foreground contamination (with a conservative mask) and minimising systematics due to masking, 2) astrophysical secondary effects (the kinetic Doppler quadrupole and kinetic Sunyaev-Zel'dovich effect), and 3) secondary cosmological signals (the integrated Sachs-Wolfe effect). We address the masking issue by considering new procedures that use both WMAP and Planck to produce higher quality full-sky maps using the sparsity methodology (LGMCA maps). We show the impact of masking is dominant over that of residual foregrounds, and the LGMCA full-sky maps can be used without further processing to study anomalies. We consider four official Planck PR1 and two LGMCA CMB maps. Analysis of the observed CMB maps shows that only the low quadrupole and quadrupole-octopole alignment seem significant, but that the planar octopole, Axis of Evil, mirror parity and cold spot are not significant in nearly all maps considered. After subtraction of astrophysical and cosmological secondary effects, only the low quadrupole may still be considered anomalous, meaning the significance of only one anomaly is affected by secondary effect subtraction out of six anomalies considered. In the spirit of reproducible research all reconstructed maps and codes will be made available for download here http://www.cosmostat.org/anomaliesCMB.html.

  8. Photochemistry of Pyrimidine in Astrophysical Ices: Formation of Nucleobases and Other Prebiotic Species

    Science.gov (United States)

    Nuevo, Michel; Sandford, Scott A.; Materese, Christopher K.; Milam, Stefanie N.

    2012-01-01

    Nucleobases are N-heterocycles that are the informational subunits of DNA and RNA. They are divided into two molecular groups: pyrimidine bases (uracil, cytosine, and thymine) and purine bases (adenine and guanine). Nucleobases have been detected in meteorites, and their extraterrestrial origin confirmed by isotopic measurements. Although no N-heterocycles have ever been observed in the ISM, the positions of the 6.2- m interstellar emission features suggest a population of such molecules is likely to be present. However, laboratory experiments have shown that the ultraviolet (UV) irradiation of pyrimidine in ices of astrophysical relevance such as H2O, NH3, CH3OH, CH4, CO, or combinations of these at low temperature (less than or equal to 20 K) leads to the formation of several pyrimidine derivatives including the nucleobases uracil and cytosine, as well as precursors such as 4(3H)-pyrimidone and 4-aminopyrimidine. Quantum calculations on the formation of 4(3H)-pyrimidone and uracil from the irradiation of pyrimidine in pure H2O ices are in agreement with their experimental formation pathways.10 In those residues, other species of prebiotic interest such as urea as well as the amino acids glycine and alanine could also be identified. However, only very small amounts of pyrimidine derivatives containing CH3 groups could be detected, suggesting that the addition of methyl groups to pyrimidine is not an efficient process. For this reason, the nucleobase thymine was not observed in any of the samples. In this work, we study the formation of nucleobases and other photo-products of prebiotic interest from the UV irradiation of pyrimidine in ices containing H2O, NH3, CH3OH, and CO, mixed in astrophysical proportions.

  9. Refining mass formulas for astrophysical applications: A Bayesian neural network approach

    Science.gov (United States)

    Utama, R.; Piekarewicz, J.

    2017-10-01

    Background: Exotic nuclei, particularly those near the drip lines, are at the core of one of the fundamental questions driving nuclear structure and astrophysics today: What are the limits of nuclear binding? Exotic nuclei play a critical role in both informing theoretical models as well as in our understanding of the origin of the heavy elements. Purpose: Our aim is to refine existing mass models through the training of an artificial neural network that will mitigate the large model discrepancies far away from stability. Methods: The basic paradigm of our two-pronged approach is an existing mass model that captures as much as possible of the underlying physics followed by the implementation of a Bayesian neural network (BNN) refinement to account for the missing physics. Bayesian inference is employed to determine the parameters of the neural network so that model predictions may be accompanied by theoretical uncertainties. Results: Despite the undeniable quality of the mass models adopted in this work, we observe a significant improvement (of about 40%) after the BNN refinement is implemented. Indeed, in the specific case of the Duflo-Zuker mass formula, we find that the rms deviation relative to experiment is reduced from σrms=0.503 MeV to σrms=0.286 MeV. These newly refined mass tables are used to map the neutron drip lines (or rather "drip bands") and to study a few critical r -process nuclei. Conclusions: The BNN approach is highly successful in refining the predictions of existing mass models. In particular, the large discrepancy displayed by the original "bare" models in regions where experimental data are unavailable is considerably quenched after the BNN refinement. This lends credence to our approach and has motivated us to publish refined mass tables that we trust will be helpful for future astrophysical applications.

  10. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. P. Venkatakrishnan. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 171-172 Session III – Sunspots & Solar Cycle. Is a Sunspot in Static or Dynamic Equilibrium? P. Venkatakrishnan · More Details ...

  11. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. Shibu K. Mathew. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 233-236 Session V – Vector Magnetic Fields, Prominences, CMEs & Flares. A Rapidly Evolving Active Region NOAA ...

  12. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. Samir Dhurde. Articles written in Journal of Astrophysics and Astronomy. Volume 28 Issue 1 March 2007 pp 29-40. Kinematical Diagrams for Conical Relativistic Jets · Gopal-Krishna Pronoy Sircar Samir Dhurde · More Details Abstract Fulltext PDF. We present ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Visweshwar Ram Marthi. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 1 March 2017 pp 12 Review Article. Prowess – A Software Model for the Ooty Wide Field Array · Visweshwar Ram Marthi · More Details Abstract Fulltext PDF.

  14. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. Liu Zhong-bao. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 2 June 2016 pp 12. Stellar Spectral Classification with Locality Preserving Projections and Support Vector Machine · Liu Zhong-bao · More Details Abstract Fulltext PDF.

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    Home; Journals; Journal of Astrophysics and Astronomy. F. Reale. Articles written in Journal of Astrophysics and Astronomy. Volume 29 Issue 1-2 March-June 2008 pp 339-343. SphinX: A Fast Solar Photometer in X-rays · J. Sylwester S. Kuzin Yu. D. Kotov F. Farnik F. Reale · More Details Abstract Fulltext PDF. The scientific ...

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    Home; Journals; Journal of Astrophysics and Astronomy. C. Mito. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 4 December 2017 pp 71 Research Article. Relativistic Dynamics in a Matter-Dominated Friedmann Universe · M. Langa D. S. Wamalwa C. Mito · More Details Abstract Fulltext PDF.

  18. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. Sagar Sethi. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 41 Review. Tracking Galaxy Evolution Through Low-Frequency Radio Continuum Observations using SKA and Citizen-Science Research using ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Siddharth S. Malu. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 541-544. 18 GHz SZ Measurements of the Bullet Cluster · Siddharth S. Malu Ravi Subrahmanyan · More Details Abstract Fulltext PDF. We present 18 ...

  20. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. A. A. Yeghiazaryan. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 1 March 2016 pp 1. H α Velocity Fields and Galaxy Interaction in the Quartet of Galaxies NGC 7769, 7770, 7771 and 7771A · A. A. Yeghiazaryan T. A. ...

  1. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. S. Kuzin. Articles written in Journal of Astrophysics and Astronomy. Volume 29 Issue 1-2 March-June 2008 pp 339-343. SphinX: A Fast Solar Photometer in X-rays · J. Sylwester S. Kuzin Yu. D. Kotov F. Farnik F. Reale · More Details Abstract Fulltext ...

  2. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. M. A. Banajh. Articles written in Journal of Astrophysics and Astronomy. Volume 28 Issue 1 March 2007 pp 9-16. Homotopy Continuation Method of Arbitrary Order of Convergence for Solving the Hyperbolic Form of Kepler's Equation · M. A. Sharaf M. A. Banajh A. A. ...

  3. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. H. M. Antia. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 353-356 Session VIII – Helioseismology. Temporal Variation of Large Scale Flows in the Solar Interior · Sarbani Basu H. M. ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Somak Raychaudhury. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 4 December 2017 pp 68 Research Article. Active Galactic Nucleus Feedback with the Square Kilometre Array and Implications for Cluster Physics and Cosmology.

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    Home; Journals; Journal of Astrophysics and Astronomy. A. Gopakumar. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 36 Review. Neutron Star Physics in the Square Kilometre Array Era: An Indian Perspective · Sushan Konar Manjari Bagchi Debades Bandyopadhyay ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Mukul Mhaskey. Articles written in Journal of Astrophysics and Astronomy. Volume 34 Issue 3 September 2013 pp 273-296. On the Photometric Error Calibration for the Differential Light Curves of Point-like Active Galactic Nuclei · Arti Goyal Mukul Mhaskey ...

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  8. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. S. J. Kang. Articles written in Journal of Astrophysics and Astronomy. Volume 35 Issue 3 September 2014 pp 385-386 Posters. Delta-function Approximation SSC Model in 3C 273 · S. J. Kang Y. G. Zheng Q. Wu · More Details Abstract Fulltext PDF. We obtain an ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Nagendra Kumar. Articles written in Journal of Astrophysics and Astronomy. Volume 29 Issue 1-2 March-June 2008 pp 243-248. Damping of Slow Magnetoacoustic Waves in an Inhomogeneous Coronal Plasma · Nagendra Kumar Pradeep Kumar Shiv Singh Anil ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Gerard Vauclair. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 319-322 Session VII – Magnetoconvection & Stellar Activity. The Space Stellar Photometry Mission COROT: Asteroseismology and Search ...

  11. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. A. V. Ananth. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 241-244 Session V – Vector Magnetic Fields, Prominences, CMEs & Flares. Stokes Polarimetry at the Kodaikanal Tower Tunnel Telescope.

  12. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. Journal of Astrophysics and Astronomy. Volumes & Issues. Volume 39. Issue 1. Feb 2018. Volume 38. Issue 1. Mar 2017; Issue 2. Jun 2017; Issue 3. Sep 2017; Issue 4. Dec 2017. Volume 37. Issue 1. Mar 2016; Issue 2. Jun 2016; Issue 3. Sep 2016; Issue 4. Dec 2016 ...

  13. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. J. Tao. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 1-2 March-June 2011 pp 67-71 Part 2. Blazar Observations in Infrared and Optical. Variability of Blazars · J. H. Fan Y. Liu Y. Li Q. F. Zhang J. Tao O. Kurtanidze.

  14. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. A. S. Pandya. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 30 Review Article. Large Area X-Ray Proportional Counter (LAXPC) Instrument on AstroSat and Some Preliminary Results from its Performance in the Orbit.

  15. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. I. S. Veselovsky. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 423-429 Session XI – Solar Wind & Interplanetary Magnetic Fields. Solar Wind Variation with the Cycle · I. S. Veselovsky A. V. Dmitriev ...

  16. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. Chetana Jain. Articles written in Journal of Astrophysics and Astronomy. Volume 28 Issue 4 December 2007 pp 175-184. Search for Orbital Motion of the Pulsar 4U 1626-67: Candidate for a Neutron Star with a Supernova Fall-back Accretion Disk.

  17. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. Biswajit Paul. Articles written in Journal of Astrophysics and Astronomy. Volume 28 Issue 4 December 2007 pp 175-184. Search for Orbital Motion of the Pulsar 4U 1626-67: Candidate for a Neutron Star with a Supernova Fall-back Accretion Disk.

  18. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    2016-01-27

    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. S. Ananthakrishnan. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 439-444 Session XI – Solar Wind & Interplanetary Magnetic Fields. Remote Sensing of the Heliospheric Solar Wind ...

  19. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. Annie Baglin. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 319-322 Session VII – Magnetoconvection & Stellar Activity. The Space Stellar Photometry Mission COROT: Asteroseismology and Search ...

  20. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. G. C. Anupama. Articles written in Journal of Astrophysics and Astronomy. Volume 34 Issue 2 June 2013 pp 175-192. Generation of a Near Infra-Red Guide Star Catalog for Thirty-Meter Telescope Observations · Smitha Subramanian Annapurni Subramaniam Luc ...

  1. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

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    Home; Journals; Journal of Astrophysics and Astronomy. J. O. Stenflo. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 451-457 Session XII – Conclusion. Summary Lecture · J. O. Stenflo · More Details Abstract Fulltext PDF. This summary lecture makes no ...

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    Home; Journals; Journal of Astrophysics and Astronomy. C. R. Subrahmanya. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 1 March 2017 pp 10 Review Article. The Ooty Wide Field Array · C. R. Subrahmanya P. K. Manoharan Jayaram N. Chengalur · More Details Abstract Fulltext PDF.

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy. You-Dong Hu. Articles written in Journal of Astrophysics and Astronomy. Volume 35 Issue 3 September 2014 pp 423-427 Part V: Black Holes (or Binary Black Holes) in Blazars. Joint Spectral Analysis for Early Bright X-ray Flares of -Ray Bursts with ...

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    Home; Journals; Journal of Astrophysics and Astronomy. Manjari Bagchi. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 28 Review. Neutron Stars in the Light of Square Kilometre Array: Data, Statistics and Science · Mihir Arjunwadkar Akanksha Kashikar Manjari Bagchi.

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    Home; Journals; Journal of Astrophysics and Astronomy. R. K. Manchanda. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 1-2 June 2000 pp 39-52. X-ray Measurements of Black Hole X-ray Binary Source GRS 1915+105 and the Evolution of Hard X-ray Spectrum · R. K. Manchanda.

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    Home; Journals; Journal of Astrophysics and Astronomy. Siddharth Malu. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 529-532. Discovery of a Giant Radio Halo in a Massive Merging Cluster at = 0.443 · K. S. Dwarakanath Siddharth Malu Ruta Kale · More Details ...

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    Home; Journals; Journal of Astrophysics and Astronomy. K. M. Hiremath. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 263-264 Session V – Vector Magnetic Fields, Prominences, CMEs & Flares. Emergence of Twisted Magnetic Flux Related Sigmoidal ...

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    Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy; Volume 36; Issue 4. Volume 36, Issue 4. December 2015, pages 421-703. Special Issue on Spectral Line Shapes in Astrophysics. pp 421-425. Editorial · Milan S. Dimitrijević Luka Č. Popović · More Details Fulltext PDF. pp 427-432 Review.

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    Home; Journals; Journal of Astrophysics and Astronomy. Sudhir Kumar Gupta. Articles written in Journal of Astrophysics and Astronomy. Volume 27 Issue 2-3 June-September 2006 pp 315-320 Oral Presentations. Development of Solar Scintillometer · Sudhir Kumar Gupta Shibu K. Mathew P. Venkatakrishnan · More Details ...

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    Home; Journals; Journal of Astrophysics and Astronomy. H. Poon. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 1-2 March-June 2011 pp 97-103 Part 2. Blazar Observations in Infrared and Optical. The Optical Microvariability and Spectral Changes of the BL Lacertae Object S5 0716+714.

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    Home; Journals; Journal of Astrophysics and Astronomy. G. Srinivasan. Articles written in Journal of Astrophysics and Astronomy. Volume 25 Issue 3-4 September-December 2004 pp 143-183. A High Galactic Latitude HI 21 cm-line Absorption Survey using the GMRT: I. Observations and Spectra · Rekhesh Mohan K. S. ...

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