Trojan Horse Method: recent applications in nuclear astrophysics

Energy Technology Data Exchange (ETDEWEB)

Spitaleri, C.; Cherubini, S.; La Cognata, M.; Lamia, L. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Chimiche e Fisiche per l' Ingegneria, Universita di Catania (Italy); Mukhamedzhanov, A. [Cyclotron Institute, Texas A and M University, College Station, Texas (United States); Pizzone, R.G.; Romano, S.; Sergi, M.L. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Chimiche e Fisiche per l' Ingegneria, Universita di Catania (Italy); Tumino, A. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud, Catania (Italy); Universita degli Studi di Enna ' Kore' , Enna (Italy)

2010-03-01

The Trojan Horse Method (THM) is a powerful indirect technique to extract the bare nucleus cross section (or equivalently the bare nucleus astrophysical factor) for astrophysically relevant reactions. The theory has been discussed in many works in relation to the different types of reactions studied. Here we present the methodology to select the quasi free mechanism in order to extract this important parameter.

A New ECR Ion Source for Nuclear Astrophysics Studies

Science.gov (United States)

Cesaratto, John M.

2008-10-01

The Laboratory for Experimental Nuclear Astrophysics (LENA) is a low energy facility designed to study nuclear reactions of astrophysical interest at energies which are important for nucleosysthesis. In general, these reactions have extremely small cross sections, requiring intense beams and efficient detection systems. Recently, a new, high intensity electron-cyclotron-resonance (ECR) ion source has been constructed (based on a design by Wills et al.[1]), which represents a substantial improvement in the capabilities of LENA. Beam is extracted from an ECR plasma excited at 2.45 GHz and confined by an array of permanent magnets. It has produced H^+ beams in excess of 1 mA on target over the energy range 100 - 200 keV, which greatly increases our ability to measure small cross sections. Initial measurements will focus on the ^23Na(p,γ)^24Mg reaction, which is of interest in a variety of astrophysical scenarios. The present uncertainty in the rate of this reaction is the result of an unobserved resonance expected at Elab =144 keV, which should be detectable using beams from the new ECR source. In collaboration with Arthur E. Champagne and Thomas B. Clegg, University of North Carolina, Chapel Hill and TUNL. [3pt] [1] J. S. C. Wills et al., Rev. Sci. Instrum. 69, 65 (1999).

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.

Nuclear astrophysics: An application of nuclear physics

International Nuclear Information System (INIS)

Fueloep, Z.

2005-01-01

Nuclear astrophysics, a fruitful combination of nuclear physics and astrophysics can be viewed as a special application of nuclear physics where the study of nuclei and their reactions are motivated by astrophysical problems. Nuclear astrophysics is also a good example for the state of the art interdisciplinary research. The origin of elements studied by geologists is explored by astrophysicists using nuclear reaction rates provided by the nuclear physics community. Due to the high interest in the field two recent Nuclear Physics Divisional Conferences of the European Physical Society were devoted to nuclear astrophysics and a new conference series entitled 'Nuclear Physics in Astrophysics' has been established. Selected problems of nuclear astrophysics will be presented emphasizing the interplay between nuclear physics and astrophysics. As an example the role of 14 N(p,r) 15 O reaction rate in the determination of the age of globular clusters will be discussed in details

Nuclear reactions in astrophysics

International Nuclear Information System (INIS)

Cardenas, M.

1976-01-01

It is revised the nuclear reactions which present an interest in astrophysics regarding the explanation of some problems such as the relative quantity of the elements, the structure and evolution of the stars. The principal object of the study is the determination of the experimental possibilities in the field of astrophysics, of an accelerator Van de Graaff's 700 KeV type. Two hundred nuclear reactions approximately, were found, and nothing or very little has been done in the intervals of energy which are of interest. Since the bombardment energies and the involved sections are low in some cases, there are real possibilities, for the largest number of stars to obtain important statistical data with the above mentioned accelerator, taking some necessary precautions. (author)

Advanced LIGO: sources and astrophysics

International Nuclear Information System (INIS)

Creighton, Teviet

2003-01-01

Second-generation detectors in LIGO will take us from the discovery phase of gravitational-wave observations to the phase of true gravitational-wave astrophysics, with hundreds or thousands of potential sources. This paper surveys the most likely and interesting potential sources for Advanced LIGO, and the astrophysical processes that each one will probe. I conclude that binary inspiral signals are expected, while continuous signals from pulsars are plausible but not guaranteed. Other sources, such as core-collapse bursts, cosmic strings and primordial stochastic backgrounds, are speculative sources for Advanced LIGO, but also potentially the most interesting, since they push the limits of our theoretical knowledge

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

Science.gov (United States)

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

2011-09-01

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

Important plasma problems in astrophysics

International Nuclear Information System (INIS)

Kulsrud, R.M.

1995-01-01

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

Statistics and Informatics in Space Astrophysics

Science.gov (United States)

Feigelson, E.

2017-12-01

The interest in statistical and computational methodology has seen rapid growth in space-based astrophysics, parallel to the growth seen in Earth remote sensing. There is widespread agreement that scientific interpretation of the cosmic microwave background, discovery of exoplanets, and classifying multiwavelength surveys is too complex to be accomplished with traditional techniques. NASA operates several well-functioning Science Archive Research Centers providing 0.5 PBy datasets to the research community. These databases are integrated with full-text journal articles in the NASA Astrophysics Data System (200K pageviews/day). Data products use interoperable formats and protocols established by the International Virtual Observatory Alliance. NASA supercomputers also support complex astrophysical models of systems such as accretion disks and planet formation. Academic researcher interest in methodology has significantly grown in areas such as Bayesian inference and machine learning, and statistical research is underway to treat problems such as irregularly spaced time series and astrophysical model uncertainties. Several scholarly societies have created interest groups in astrostatistics and astroinformatics. Improvements are needed on several fronts. Community education in advanced methodology is not sufficiently rapid to meet the research needs. Statistical procedures within NASA science analysis software are sometimes not optimal, and pipeline development may not use modern software engineering techniques. NASA offers few grant opportunities supporting research in astroinformatics and astrostatistics.

Astrophysics at nTOF facility

International Nuclear Information System (INIS)

Tagliente, G.; Colonna, N.; Maronne, S.; Terlizzi, R.; Abondanno, U.; Fujii, K.; Milazzo, P.M.; Moreau, C.; Belloni, F.; Aerts, G.; Berthoumieux, E.; Andriamonje, S.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Alvarez, H.; Duran, I.; Paradela, C.; Alvarez-Velarde, F.; Cano-Ott, D.; Embid-Segura, M.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C.; Gonzalez-Romero, E.; Andrzejewski, J.; Marganiec, J.; Assimakopoulos, P.; Karamanis, D.; Audouin, L.; Dillman, I.; Heil, M.; Kappeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wissak, K.; Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H.; Pigni, M.T.; Baumann, P.; David, S.; Kerveno, M.; Rudolf, G.; Lukic, S.; Becvar, F.; Krticka, M.; Bisterzo, S.; Ferrant, L.; Gallino, R.; Calvino, F.; Poch, A.; Pretel, C.; Calviani, M.; Gramegna, F.; Mastinu, P.; Capote, R.; Mengoni, A.; Capote, R.; Lozano, M.; Quesada, J.; Carrapico, C.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P.; Cennini, P.; Chiaveri, E.; Dahlfors, M.; Kadi, Y.; Sarchiapone, L.; Vlachoudis, V.; Wendler, H.; Chepel, V.; Ferreira-Marques, R.; Goncalves, I.; Lindote, A.; Lopes, I.; Neves, F.; Couture, A.; Cox, J.; O'Brien, S.; Wiescher, M.; Dominga-Pardo, C.; Tain, J.L.; Eleftheriadis, C.; Lamboudis, C.; Savvidis, I.; Stephan, C.; Tassan-Got, L.; Furman, W.; Haas, B.; Haight, R.; Reifarth, R.; Igashira, M.; Koehler, P.; Massimi, C.; Vannini, G.; Papadopoulos, C.; Pavlik, A.; Pavlopoulos, P.; Plomen, A.; Rullhusen, P.; Rauscher, T.; Rubbia, C.; Ventura, A.

2009-01-01

The neutron time of flight (n T OF) facility at CERN is a neutron spallation source, its white neutron energy spectrum ranges from thermal to several GeV, covering the full energy range of interest for nuclear astrophysics, in particular for measurements of the neutron capture cross-section required in s-process nucleosynthesis. This contribution gives an overview on the astrophysical program made at n T OF facility, the results and the implications will be considered.

76 FR 7882 - Astronomy and Astrophysics Advisory Committee; Notice of Meeting

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2011-02-11

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee; Notice of Meeting In... Foundation announces the following meeting: Name: Astronomy and Astrophysics Advisory Committee ( 13883... of astronomy and astrophysics that are of mutual interest and concern to the agencies. Agenda: To...

78 FR 2450 - Astronomy and Astrophysics Advisory Committee; Notice of Meeting

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2013-01-11

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee; Notice of Meeting In... Foundation announces the following meeting: Name: Astronomy and Astrophysics Advisory Committee ( 13883...) on issues within the field of astronomy and astrophysics that are of mutual interest and concern to...

77 FR 8288 - Astronomy and Astrophysics Advisory Committee; Notice of Meeting

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2012-02-14

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee; Notice of Meeting In... Foundation announces the following meeting: Name: Astronomy and Astrophysics Advisory Committee ( 13883... of astronomy and astrophysics that are of mutual interest and concern to the agencies. Agenda: To...

Determination by transfer reaction of alpha widths in fluorine for astrophysical interest

International Nuclear Information System (INIS)

Oliveira Santos, F. de

1995-04-01

The nucleosynthesis of fluorine is not known. Several astrophysical models predict the alpha radiative capture onto N 15 as the main fluorine production reaction. In the expression of the reaction rate, one parameter is missing: the alpha width of the resonance on the E = 4.377 MeV level in fluorine. A direct measurement is excluded due to the very low cross-section expected. We have determined this alpha width using a transfer reaction followed by analyses with FR-DWBA (Finite Range Distorted Wave Born Approximation) in a simple cluster alpha model. This experiment was carried out with a Li 7 beam with E = 28 MeV onto a N 15 gas target. The 16 first levels were studied. Spectroscopic factors were extracted for most of them. Alpha widths for unbound levels were determined. Many alpha width were compared with known values from direct reaction and the differences lie within the uncertainty range (factor 2). The alpha width for the E = 4.377 MeV level was determined (Γ α = 1.5*10 -15 MeV), its value is about 60 times weaker than the used value. The influence of our new rate was studied in AGB (Asymptotic Giant Branch) stars during thermal pulses. In this model the alteration is sensitive. (author)

77 FR 54615 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2012-09-05

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting... on issues within the field of astronomy and astrophysics that are of mutual interest and concern to...

78 FR 61400 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2013-10-03

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting...) on issues within the field of astronomy and astrophysics that are of mutual interest and concern to...

78 FR 22346 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2013-04-15

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following meeting: Name: Astronomy and Astrophysics Advisory Committee... of astronomy and astrophysics that are of mutual interest and concern to the agencies. Agenda: To...

75 FR 7295 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2010-02-18

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78 FR 11685 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2013-02-19

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77 FR 22614 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2012-04-16

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76 FR 5214 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

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2011-01-28

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting... within the field of astronomy and astrophysics that are of mutual interest and concern to the agencies...

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...

Technology Development for a Neutrino Astrophysical Observatory

International Nuclear Information System (INIS)

Chaloupka, V.; Cole, T.; Crawford, H.J.; He, Y.D.; Jackson, S.; Kleinfelder, S.; Lai, K.W.; Learned, J.; Ling, J.; Liu, D.; Lowder, D.; Moorhead, M.; Morookian, J.M.; Nygren, D.R.; Price, P.B.; Richards, A.; Shapiro, G.; Shen, B.; Smoot, George F.; Stokstad, R.G.; VanDalen, G.; Wilkes, J.; Wright, F.; Young, K.

1996-01-01

We propose a set of technology developments relevant to the design of an optimized Cerenkov detector for the study of neutrino interactions of astrophysical interest. Emphasis is placed on signal processing innovations that enhance significantly the quality of primary data. These technical advances, combined with field experience from a follow-on test deployment, are intended to provide a basis for the engineering design for a kilometer-scale Neutrino Astrophysical Observatory

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. P. Kharb. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 34 Review. From Nearby Low Luminosity AGN to High Redshift Radio Galaxies: Science Interests with Square Kilometre Array · P. Kharb D. V. Lal V. Singh J.

Searches for astrophysical neutrinos with IceCube

International Nuclear Information System (INIS)

Williams, D.

2014-01-01

Powerful astrophysical objects such as active galactic nuclei (AGN), core collapse supernovae and gamma ray bursts (GRBs) are potential sources of the highest energy cosmic rays. Many models of cosmic ray proton acceleration predict a corresponding flux of neutrinos in the TeV-PeV energy range. The detection of astrophysical neutrinos requires the largest neutrino detector ever built: IceCube, a cubic-kilometer array located near the geographic South Pole. IceCube has been collecting data throughout its construction, which was complete in December 2010. Data from the partial IceCube detector have already set interesting limits on astrophysical neutrino fluxes, including stringent limits on neutrino production in GRBs. (authors)

Direct measurement of nuclear cross-section of astrophysical interest: Results and perspectives

Science.gov (United States)

Cavanna, Francesca; Prati, Paolo

2018-03-01

Stellar evolution and nucleosynthesis are interconnected by a wide network of nuclear reactions: the study of such connection is usually known as nuclear astrophysics. The main task of this discipline is the determination of nuclear cross-section and hence of the reaction rate in different scenarios, i.e. from the synthesis of a few very light isotopes just after the Big Bang to the heavy element production in the violent explosive end of massive stars. The experimental determination of reaction cross-section at the astrophysical relevant energies is extremely difficult, sometime impossible, due to the Coulomb repulsion between the interacting nuclei which turns out in cross-section values down to the fbar level. To overcome these obstacles, several experimental approaches have been developed and the adopted techniques can be roughly divided into two categories, i.e. direct and indirect methods. In this review paper, the general problem of nuclear astrophysics is introduced and discussed from the point of view of experimental approach. We focus on direct methods and in particular on the features of low-background experiments performed at underground laboratory facilities. The present knowledge of reactions involved in the Big Bang and stellar hydrogen-burning scenarios is discussed as well as the ongoing projects aiming to investigate mainly the helium- and carbon-burning phases. Worldwide, a new generation of experiment in the MeV range is in the design phase or at the very first steps and decisive progresses are expected to come in the next years.

Study of the reaction of astrophysical interest 60Fe(n,γ)61Fe via (d,pγ) transfer reaction

International Nuclear Information System (INIS)

Giron, S.

2011-12-01

60 Fe is of special interest in nuclear astrophysics. Indeed the recent observations of 60 Fe characteristic gamma-ray lines by the RHESSI and INTEGRAL spacecrafts allowed to measure the total flux of 60 Fe over the Galaxy. Moreover the observation in presolar grains of an excess of the daughter-nuclei of 60 Fe, 60 Ni, gives constraints on the conditions of formation of the early solar system. However, the cross-sections of some reactions involved in 60 Fe nucleosynthesis and included to stellar models are still uncertain. The destruction reaction of 60 Fe, 60 Fe(n, γ) 61 Fe, is one of them. The total cross-section can be separate into two contributions: the direct one, involving states below the neutron separation threshold of 61 Fe, and the resonant one.We improved 61 Fe spectroscopy in order to evaluate the direct capture part of the 60 Fe(n, γ) 61 Fe reaction cross-section. 60 Fe(n, γ) 61 Fe was thus studied via d( 60 Fe, pγ) 61 Fe transfer reaction with the CATS/MUST2/EXOGAM setup at LISE-GANIL. DWBA analysis of experimental proton differential cross-sections allowed to extract orbital angular momentum and spectroscopic factors of different populated states identified below the neutron threshold. A comparison of experimental results for 61 Fe with experimental results for similar nuclei and with shell-model calculations was also performed. (author) [fr

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.

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.

76 FR 19793 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting via Teleconference

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2011-04-08

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting...), the National Science Foundation announces the following meeting: Name: Astronomy and Astrophysics... of astronomy and astrophysics that are of mutual interest and concern to the agencies. Agenda: To...

Astrophysics of Red Supergiants

Science.gov (United States)

Levesque, Emily M.

2017-12-01

'Astrophysics of Red Supergiants' is the first book of its kind devoted to our current knowledge of red supergiant stars, a key evolutionary phase that is critical to our larger understanding of massive stars. It provides a comprehensive overview of the fundamental physical properties of red supergiants, their evolution, and their extragalactic and cosmological applications. It serves as a reference for researchers from a broad range of fields (including stellar astrophysics, supernovae, and high-redshift galaxies) who are interested in red supergiants as extreme stages of stellar evolution, dust producers, supernova progenitors, extragalactic metallicity indicators, members of massive binaries and mergers, or simply as compelling objects in their own right. The book is accessible to a range of experience levels, from graduate students up to senior researchers.

Stark broadening of several Bi IV spectral lines of astrophysical interest

Science.gov (United States)

Colón, C.; Moreno-Díaz, C.; de Andrés-García, I.; Alonso-Medina, A.

2017-09-01

The presence of spectral lines of bismuth in stellar atmospheres has been reported in different stars. The anomalous values of the spectral intensities of Bi II and Bi III, compared to the theoretical Local Termodinamic Equilibrium (LTE) standards of Bi I/Bi II/Bi III, have been reported in the spectra obtained with the High Resolution Spectrograph of the Hubble/Goddard Space Telescope in the chemically peculiar stars HgMn stars χ Lupi and HR 7775. Spectral lines of 1436.8, 1902.3, 2630.9 and 2936.7 Å of Bi II and 1423.4 Å of Bi III were reported and their relative intensities were measured in these studies Litzén & Wahlgren 2002. These lines are overlapped with spectral lines of 1437.65, 2630.1 and 2937.1 Å of Bi IV. A study of the Stark broadening parameters of Bi IV spectral lines can help to study these overlaps. In this paper, using the Griem semi-empirical approach, we report calculated values of the Stark parameters for 64 spectral lines of Bi IV. The matrix elements used in these calculations have been determined from 17 configurations of Bi IV. They were calculated using the cowan code including core polarization effects. Data are displayed for an electron density of 1017 cm-3 and temperatures T = 10 000-160 000 K. Also calculated radiative lifetimes for 12 levels with experimental lifetime are presented, in order to test the goodness of our calculations. Theoretical trends of the Stark width and shift parameters versus the temperature for spectral lines of astrophysical interest are displayed.

The Astrophysical Multimessenger Observatory Network (AMON)

Science.gov (United States)

Smith. M. W. E.; Fox, D. B.; Cowen, D. F.; Meszaros, P.; Tesic, G.; Fixelle, J.; Bartos, I.; Sommers, P.; Ashtekar, Abhay; Babu, G. Jogesh;

The Trojan Horse Method in nuclear astrophysics

International Nuclear Information System (INIS)

Spitaleri, C.; Cherubini, S.; Del Zoppo, A.; Di Pietrob, A.; Figuerab, P.; Gulino, M.; Lattuadab, M.; Miljanic, Dstroke; Musumarra, A.; Pellegriti, M.G.; Pizzone, R.G.; Rolfs, C.; Romano, S.; Tudisco, S.; Tumino, A.

2003-01-01

The basic features of the Trojan Horse Method are discussed together with a review of recent applications, aimed to extract the bare astrophysical S(E)-factor for several two-body processes. In this framework information on electron screening potential U e was obtained from the comparison with direct experiments

Studies in nuclear structure relevant to Astrophysics: theoretical and experimental efforts

International Nuclear Information System (INIS)

Saha Sarkar, Maitreyee

2016-01-01

Experimental and theoretical investigations in the region around doubly magic neutron rich 132 Sn nucleus have recently revealed many intriguing issues concerning some newer aspects of nuclear structure in such exotic environments. These nuclei lie on or close to the path of the astrophysical r-process flow. A glimpse of the implication of these studies on the r-process nucleosynthesis will be discussed. Presently, the Nuclear Physics group in Saha Institute of Nuclear Physics is working for installation of a high-current, low energy Accelerator as the primary component of the Facility for Research in low Energy Nuclear Astrophysics (FRENA), a national facility, at Kolkata. Planning for future experiments has been undertaken for successful utilization of this facility. Implantation technique has been found to be one of the most effective methods to produce isotopically pure targets. We have prepared a few isotopically pure targets using this technique. Being the slowest process of the CNO cycle, study of the 14 N(p, γ) 15 O(Q = 7297 keV) capture reaction is of high astrophysical interest. From an experiment utilizing one of the newly prepared 14 N implanted targets, a preliminary estimate of the lifetime of 6792 keV state in 15 O has been obtained, using Doppler shift attenuation method (DSAM). The sensitivity of the results with respect to the uncertainties in various input quantities has been tested. This endeavour will be helpful to design a better experiment to extract more precise lifetime for this important state

Astrophysical Flows

Science.gov (United States)

Pringle, James E.; King, Andrew

2003-07-01

Almost all conventional matter in the Universe is fluid, and fluid dynamics plays a crucial role in astrophysics. This new graduate textbook provides a basic understanding of the fluid dynamical processes relevant to astrophysics. The mathematics used to describe these processes is simplified to bring out the underlying physics. The authors cover many topics, including wave propagation, shocks, spherical flows, stellar oscillations, the instabilities caused by effects such as magnetic fields, thermal driving, gravity, shear flows, and the basic concepts of compressible fluid dynamics and magnetohydrodynamics. The authors are Directors of the UK Astrophysical Fluids Facility (UKAFF) at the University of Leicester, and editors of the Cambridge Astrophysics Series. This book has been developed from a course in astrophysical fluid dynamics taught at the University of Cambridge. It is suitable for graduate students in astrophysics, physics and applied mathematics, and requires only a basic familiarity with fluid dynamics.• Provides coverage of the fundamental fluid dynamical processes an astrophysical theorist needs to know • Introduces new mathematical theory and techniques in a straightforward manner • Includes end-of-chapter problems to illustrate the course and introduce additional ideas

High-Energy Spectroscopic Astrophysics Swiss Society for Astrophysics and Astronomy

CERN Document Server

Kahn, Steven M; von Ballmoos, Peter

2005-01-01

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

Sources and astrophysical effects of gravitational waves

International Nuclear Information System (INIS)

Rees, M.J.

1974-01-01

The probable sources of short intense gravitational wave emissions are discussed and it is concluded, on the basis of current astrophysical ideas, that the number of events detected by an apparatus such as Weber's would not be more than one pulse par century. Some proposed explanations of a higher event rate are examined briefly but it is suggested that the sensitivity would probably have to be improved by a factor 10 8 if a few events per year due to extragalactic supernovae are to be detectable. The article concludes by mentioning several other kinds of gravitational waves of potential interest in astrophysics

VI European Summer School on Experimental Nuclear Astrophysics

Science.gov (United States)

The European Summer School on Experimental Nuclear Astrophysics has reached the sixth edition, marking the tenth year's anniversary. The spirit of the school is to provide a very important occasion for a deep education of young researchers about the main topics of experimental nuclear astrophysics. Moreover, it should be regarded as a forum for the discussion of the last-decade research activity. Lectures are focused on various aspects of primordial and stellar nucleosynthesis, including novel experimental approaches and detectors, indirect methods and radioactive ion beams. Moreover, in order to give a wide educational offer, some lectures cover complementary subjects of nuclear astrophysics such as gamma ray astronomy, neutron-induced reactions, short-lived radionuclides, weak interaction and cutting-edge facilities used to investigate nuclear reactions of interest for astrophysics. Large room is also given to young researcher oral contributions. Traditionally, particular attention is devoted to the participation of students from less-favoured countries, especially from the southern coast of the Mediterranean Sea. The school is organised by the Catania Nuclear Astrophysics research group with the collaboration of Dipartimento di Fisica e Astromomia - Università di Catania and Laboratori Nazionali del Sud - Istituto Nazionale di Fisica Nucleare.

Exploring Astrophysical Magnetohydrodynamics in the Laboratory

Science.gov (United States)

Manuel, Mario

2014-10-01

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

Technology development for a neutrino astrophysical observatory. Letter of intent

International Nuclear Information System (INIS)

Chaloupka, V.; Cole, T.; Crawford, H.J.

1996-02-01

The authors propose a set of technology developments relevant to the design of an optimized Cerenkov detector for the study of neutrino interactions of astrophysical interest. Emphasis is placed on signal processing innovations that enhance significantly the quality of primary data. These technical advances, combined with field experience from a follow-on test deployment, are intended to provide a basis for the engineering design for a kilometer-scale Neutrino Astrophysical Observatory

BigData as a Driver for Capacity Building in Astrophysics

Science.gov (United States)

Shastri, Prajval

2015-08-01

Exciting public interest in astrophysics acquires new significance in the era of Big Data. Since Big Data involves advanced technologies of both software and hardware, astrophysics with Big Data has the potential to inspire young minds with diverse inclinations - i.e., not just those attracted to physics but also those pursuing engineering careers. Digital technologies have become steadily cheaper, which can enable expansion of the Big Data user pool considerably, especially to communities that may not yet be in the astrophysics mainstream, but have high potential because of access to thesetechnologies. For success, however, capacity building at the early stages becomes key. The development of on-line pedagogical resources in astrophysics, astrostatistics, data-mining and data visualisation that are designed around the big facilities of the future can be an important effort that drives such capacity building, especially if facilitated by the IAU.

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

S-factor for radiative capture reactions for light nuclei at astrophysical energies

Science.gov (United States)

Ghasemi, Reza; Sadeghi, Hossein

2018-06-01

The astrophysical S-factors of thermonuclear reactions, including radiative capture reactions and their analysis in the frame of different theoretical models, are the main source of nuclear processes. We have done research on the radiative capture reactions importance in the framework of a potential model. Investigation of the reactions in the astrophysical energies is of great interest in the aspect of astrophysics and nuclear physics for developing correct models of burning and evolution of stars. The experimental measurements are very difficult and impossible because of these reactions occurrence at low-energies. In this paper we do a calculation on radiative capture astrophysical S-factors for nuclei in the mass region A theoretical methods.

360-degree videos: a new visualization technique for astrophysical simulations

Science.gov (United States)

Russell, Christopher M. P.

2017-11-01

360-degree videos are a new type of movie that renders over all 4π steradian. Video sharing sites such as YouTube now allow this unique content to be shared via virtual reality (VR) goggles, hand-held smartphones/tablets, and computers. Creating 360° videos from astrophysical simulations is not only a new way to view these simulations as you are immersed in them, but is also a way to create engaging content for outreach to the public. We present what we believe is the first 360° video of an astrophysical simulation: a hydrodynamics calculation of the central parsec of the Galactic centre. We also describe how to create such movies, and briefly comment on what new science can be extracted from astrophysical simulations using 360° videos.

Nuclear Astrophysics and Neutron Induced Reactions: Quasi-Free Reactions and RIBs

International Nuclear Information System (INIS)

Cherubini, S.; Spitaleri, C.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Coc, A.; Kubono, S.; Binh, D. N.; Hayakawa, S.; Wakabayashi, Y.; Yamaguchi, H.; Burjan, V.; Kroha, V.; De Sereville, N.

2010-01-01

The use of quasi-free reactions in studying nuclear reactions between charged particles of astrophysical interest has received much attention over the last two decades. The Trojan Horse Method is based on this approach and it has been used to study a number of reactions relevant for Nuclear Astrophysics. Recently we applied this method to the study of nuclear reactions that involve radioactive species, namely to the study of the 18 F+p→ 15 O+α process at temperatures corresponding to the energies available in the classical novae scenario. Quasi-free reactions can also be exploited to study processes induced by neutrons. This technique is particularly interesting when applied to reaction induced by neutrons on unstable short-lived nuclei. Such processes are very important in the nucleosynthesis of elements in the sand r-processes scenarios and this technique can give hints for solving key questions in nuclear astrophysics where direct measurements are practically impossible.

Investigating resonances above and below the threshold in nuclear reactions of astrophysical interest and beyond

Energy Technology Data Exchange (ETDEWEB)

La Cognata, M., E-mail: lacognata@lns.infn.it [Laboratori Nazionali del Sud - INFN, Catania (Italy); Kiss, G. G. [ATOMKI, Debrecen (Hungary); Mukhamedzhanov, A. M. [Cyclotron Institute, Texas A& M University, College Station, Texas (United States); Spitaleri, C. [Laboratori Nazionali del Sud - INFN, Catania (Italy); Department of Physics and Astronomy, University of Catania, Catania (Italy); Trippella, O. [Sezione di Perugia - INFN, Perugia (Italy)

2015-10-15

Resonances in nuclear cross sections dramatically change their trends. Therefore, the presence of unexpected resonances might lead to unpredicted consequences on astrophysics and nuclear physics. In nuclear physics, resonances allow one to study states in the intermediate compound systems, to evaluate their cluster structure, for instance, especially in the energy regions approaching particle decay thresholds. In astrophysics, resonances might lead to changes in the nucleosynthesis flow, determining different isotopic compositions of the nuclear burning ashes. For these reasons, the Trojan Horse method has been modified to investigate resonant reactions. Thanks to this novel approach, for the first time normalization to direct data might be avoided. Moreover, in the case of sub threshold resonances, the Trojan Horse method modified to investigate resonances allows one to deduce the asymptotic normalization coefficient, showing the close connection between the two indirect approaches.

Measurements of the Coulomb dissociation cross section of 156 MeV 6Li projectiles at extremely low relative fragment energies of astrophysical interest

International Nuclear Information System (INIS)

Kiener, J.; Gils, H.J.; Rebel, H.; Zagromski, S.; Gsottschneider, G.; Heide, N.; Jelitto, H.; Wentz, J.; Baur, G.

1991-04-01

Coulomb dissociation of light nuclear projectiles in the electric field of heavy target nuclei has been experimentally investigated as an alternative access to radiative capture cross sections at low relative energies of the fragments, which are of astrophysical interest. As a pilot experiment the breakup of 156 MeV 6 Li-projectiles at 208 Pb with small emission angles of the a particle and deuteron fragments has been studied. Both fragments were coincidentally detected in the focal plane of a magnetic spectrograph at several reaction angles well below the grazing angle and with relative angles between the fragments of 0deg-2deg. The experimental cross sections have been analyzed on the basis of the Coulomb breakup theory. The results for the resonant breakup give evidence for the strong dominance of the Coulomb dissociation mechanism and the absence of nuclear distortions, while the cross section for the nonresonant breakup follow theoretical predictions of the astrophysical S-factor and extrapolations of corresponding radiative capture reaction cross section to very low c. m. energies of the a particle and deuterons. Various implications of the approach are discussed. (orig.) [de

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Neutron stars involve extreme physics which is difficult (perhaps impossible) to explore in laboratory experiments. We have to turn to astrophysical observations, and try to extract information from the entire range of the electromagnetic spectrum. In addition, neutron stars may radiate gravitational waves through a range of ...

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.

2012-10-01

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

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.

Indirect techniques in nuclear astrophysics. Asymptotic normalization coefficient and trojan horse

International Nuclear Information System (INIS)

Mukhamedzhanov, A.M.; Gagliardi, C.A.; Pirlepesov, F.; Trache, L.; Tribble, R.E.; Blokhintsev, L.D.; Brown, B.A.; Nunes, F.M.; Burjan, V.; Kroha, V.; Cherubini, S.; Pizzone, R.G.; Romano, S.; Spitaleri, C.; Tumino, A.; Irgaziev, B.F.; Tang, X.D.

2006-01-01

Owing to the presence of the Coulomb barrier at astrophysically relevant kinetic energies it is very difficult, or sometimes impossible, to measure astrophysical reaction rates in the laboratory. That is why different indirect techniques are being used along with direct measurements. Here we address two important indirect techniques, the asymptotic normalization coefficient (ANC) and the Trojan Horse (TH) methods. We discuss the application of the ANC technique for calculation of the astrophysical processes in the presence of subthreshold bound states, in particular, two different mechanisms are discussed: direct capture to the subthreshold state and capture to the low-lying bound states through the subthreshold state, which plays the role of the subthreshold resonance. The ANC technique can also be used to determine the interference sign of the resonant and nonresonant (direct) terms of the reaction amplitude. The TH method is unique indirect technique allowing one to measure astrophysical rearrangement reactions down to astrophysically relevant energies. We explain why there is no Coulomb barrier in the sub-process amplitudes extracted from the TH reaction. The expressions for the TH amplitude for direct and resonant cases are presented. (orig.)

The fluorine destruction in stars: First experimental study of the 19F(p,α)16O reaction at astrophysical energies

International Nuclear Information System (INIS)

La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.

2012-01-01

The 19 F(p,α) 16 O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E cm ∼ 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the 2 H( 19 F,α 16 O)n reaction. The TH measurement of the α 0 channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

Nuclear astrophysics

International Nuclear Information System (INIS)

Lehoucq, Roland; Klotz, Gregory

2015-11-01

Astronomy deals with the position and observation of the objects in our Universe, from planets to galaxies. It is the oldest of the sciences. Astrophysics is the study of the physical properties of these objects. It dates from the start of the 20. century. Nuclear astrophysics is the marriage of nuclear physics, a laboratory science concerned with the infinitely small, and astrophysics, the science of what is far away and infinitely large. Its aim is to explain the origin, evolution and abundance of the elements in the Universe. It was born in 1938 with the work of Hans Bethe, an American physicist who won the Nobel Prize for physics in 1967, on the nuclear reactions that can occur at the center of stars. It explains where the incredible energy of the stars and the Sun comes from and enables us to understand how they are born, live and die. The matter all around us and from which we are made, is made up of ninety-two chemical elements that can be found in every corner of the Universe. Nuclear astrophysics explains the origin of these chemical elements by nucleosynthesis, which is the synthesis of atomic nuclei in different astrophysical environments such as stars. Nuclear astrophysics provides answers to fundamental questions: - Our Sun and the stars in general shine because nuclear reactions are taking place within them. - The stars follow a sequence of nuclear reaction cycles. Nucleosynthesis in the stars enables us to explain the origin and abundance of elements essential to life, such as carbon, oxygen, nitrogen and iron. - Star explosions, in the form of supernovae, disperse the nuclei formed by nucleosynthesis into space and explain the formation of the heaviest chemical elements such as gold, platinum and lead. Nuclear astrophysics is still a growing area of science. (authors)

Nuclear astrophysics: Recent results on CNO-cycle reactions and AGB nucleosynthesis

International Nuclear Information System (INIS)

La Cognata, M.

2011-01-01

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, < 100 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 and new experimental facilities such as deep underground laboratories have been devised yielding new cutting-edge results.

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.

Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics

International Nuclear Information System (INIS)

Klein, R I; Stone, J M

2007-01-01

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

Challenges and opportunities in laboratory plasma astrophysics

Science.gov (United States)

Drake, R. Paul

2017-06-01

We are in a period of explosive success and opportunity in the laboratory study of plasma phenomena that are relevant to astrophysics. In this talk I will share with you several areas in which recent work, often foreshadowed 20 or 30 years ago, has produced dramatic initial success with prospects for much more. To begin, the talk will provide a brief look at the types of devices used and the regimes they access, showing how they span many orders of magnitude in parameters of interest. It will then illustrate the types of work one can do with laboratory plasmas that are relevant to astrophysics, which range from direct measurement of material properties to the production of scaled models of certain dynamics to the pursuit of complementary understanding. Examples will be drawn from the flow of energy and momentum in astrophysics, the formation and structure of astrophysical systems, and magnetization and its consequences. I hope to include some discussion of collisionless shocks, very dense plasmas, work relevant to the end of the Dark Ages, reconnection, and dynamos. The talk will conclude by highlighting some topics where it seems that we may be on the verge of exciting new progress.The originators of work discussed, and collaborators and funding sources when appropriate, will be included in the talk.

Improved predictions of nuclear data: A continued challenge in astrophysics

International Nuclear Information System (INIS)

Goriely, S.

2001-01-01

Although important effort has been devoted in the last decades to measure reaction cross sections and decay half-lives of interest in astrophysics, most of the nuclear astrophysics applications still require the use of theoretical predictions to estimate experimentally unknown rates. The nuclear ingredients to the reaction or weak interaction models should preferentially be estimated from microscopic or semi-microscopic global predictions based on sound and reliable nuclear models which, in turn, can compete with more phenomenological highly-parametrized models in the reproduction of experimental data. The latest developments made in deriving the nuclear inputs of relevance in astrophysics applications are reviewed. It mainly concerns nuclear structure properties (atomic masses, deformations, radii, etc...), nuclear level densities, nucleon and α-optical potentials, γ-ray and Gamow-Teller strength functions

Relativistic Astrophysics

International Nuclear Information System (INIS)

Font, J. A.

2015-01-01

The relativistic astrophysics is the field of astrophysics employing the theory of relativity Einstein as physical-mathematical model is to study the universe. This discipline analyzes astronomical contexts in which the laws of classical mechanics of Newton's law of gravitation are not valid. (Author)

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.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Selected topics in nuclear- and astro-physics

International Nuclear Information System (INIS)

Sujkowski, Z.; Szeflinska, G.

1991-11-01

The subjects cover the properties of hot and dense matter created in laboratory (the dynamics of the nucleus-nucleus collisions, the structure of hot and spinning nuclei), the properties of hot and dense stellar matter, the nuclear reactions of astrophysical interest (including the latest developments of the tools such as e.g. the radioactive beams) and the nucleosynthesis (esp. R-processes). (author)

Relativistic Astrophysics and Cosmology: A Primer

International Nuclear Information System (INIS)

Abramowicz, Marek A

2007-01-01

'Relativistic Astrophysics and Cosmology: A Primer' by Peter Hoyng, was published last year by Springer. The book is based on lectures given by the author at University of Utrecht to advanced undergraduates. This is a short and scholarly book. In about 300 pages, the author has covered the most interesting and important applications of Albert Einstein's general relativity in present-day astrophysics and cosmology: black holes, neutron stars, gravitational waves, and the cosmic microwave background. The book stresses theory, but also discusses several experimental and observational topics, such as the Gravity Probe B mission, interferometer detectors of gravitational waves and the power spectrum of the cosmic microwave background. The coverage is not uniform. Some topics are discussed in depth, others are only briefly mentioned. The book obviously reflects the author's own research interests and his preferences for specific mathematical methods, and the choice of the original artwork that illustrates the book (and appears on its cover) is a very personal one. I consider this personal touch an advantage, even if I do not always agree with the author's choices. For example, I employ Killing vectors as a very useful mathematical tool not only in my research on black holes, but also in my classes. I find that my students prefer it when discussions of particle, photon and fluid motion in the Schwarzschild and Kerr spacetimes are based explicitly and directly on the Killing vectors rather than on coordinate calculations. The latter approach is, of course, the traditional one, and is used in Peter Hoyng's book. Reading the book is a stimulating experience, because the reader can almost feel the author's presence. The author's opinions, his mathematical taste, his research pleasures, and his pedagogical passion are apparent everywhere. Lecturers contemplating a new course on relativistic astrophysics could adopt Hoyng's book as the text. Their students will be in the author

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... Astronomy is a very interesting subject for undergraduate students studying physics. In this paper, we report astronomy education for undergraduate students in the Physics Department of Guangzhou University, and how we are teaching astronomy to the students. Astrophysics has been rapidly developing ...

BOOK REVIEW: Astrophysics (Advanced Physics Readers)

Science.gov (United States)

Kibble, Bob

2000-07-01

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

Sliding Window-Based Region of Interest Extraction for Finger Vein Images

Science.gov (United States)

Yang, Lu; Yang, Gongping; Yin, Yilong; Xiao, Rongyang

2013-01-01

Region of Interest (ROI) extraction is a crucial step in an automatic finger vein recognition system. The aim of ROI extraction is to decide which part of the image is suitable for finger vein feature extraction. This paper proposes a finger vein ROI extraction method which is robust to finger displacement and rotation. First, we determine the middle line of the finger, which will be used to correct the image skew. Then, a sliding window is used to detect the phalangeal joints and further to ascertain the height of ROI. Last, for the corrective image with certain height, we will obtain the ROI by using the internal tangents of finger edges as the left and right boundary. The experimental results show that the proposed method can extract ROI more accurately and effectively compared with other methods, and thus improve the performance of finger vein identification system. Besides, to acquire the high quality finger vein image during the capture process, we propose eight criteria for finger vein capture from different aspects and these criteria should be helpful to some extent for finger vein capture. PMID:23507824

Kepler Planet Reliability Metrics: Astrophysical Positional Probabilities for Data Release 25

Science.gov (United States)

Bryson, Stephen T.; Morton, Timothy D.

2017-01-01

This document is very similar to KSCI-19092-003, Planet Reliability Metrics: Astrophysical Positional Probabilities, which describes the previous release of the astrophysical positional probabilities for Data Release 24. The important changes for Data Release 25 are:1. The computation of the astrophysical positional probabilities uses the Data Release 25 processed pixel data for all Kepler Objects of Interest.2. Computed probabilities now have associated uncertainties, whose computation is described in x4.1.3.3. The scene modeling described in x4.1.2 uses background stars detected via ground-based high-resolution imaging, described in x5.1, that are not in the Kepler Input Catalog or UKIRT catalog. These newly detected stars are presented in Appendix B. Otherwise the text describing the algorithms and examples is largely unchanged from KSCI-19092-003.

Nuclear astrophysics with indirect methods

International Nuclear Information System (INIS)

Shubhchintak

2016-01-01

In the area of astrophysics, it is well known that several different type of nuclear reactions are involved in the production of elements and for energy generation in stars. The knowledge of rates and cross section of these reactions is necessary in order to understand the origin of elements in the universe. Particularly, interests are there in the processes like pp-chain, CNO cycle, r-process and s-process, which are responsible for the formation of majority of the nuclei via various reactions like (p, γ), (n, γ), (α, γ) etc

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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.

The fluorine destruction in stars: First experimental study of the {sup 19}F(p,{alpha}){sup 16}O reaction at astrophysical energies

Energy Technology Data Exchange (ETDEWEB)

La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S. [INFN-LNS, Catania (Italy); Cyclotron Institute, Texas A and M University, College Station, Texas (United States); University of Catania and INFN-LNS, Catania (Italy); and others

2012-11-12

The {sup 19}F(p,{alpha}){sup 16}O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E{sub cm}{approx} 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the {sup 2}H({sup 19}F,{alpha}{sup 16}O)n reaction. The TH measurement of the {alpha}{sub 0} channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

Nuclear astrophysics

International Nuclear Information System (INIS)

Arnould, M.; Takahashi, K.

1999-01-01

Nuclear astrophysics is that branch of astrophysics which helps understanding of the Universe, or at least some of its many faces, through the knowledge of the microcosm of the atomic nucleus. It attempts to find as many nuclear physics imprints as possible in the macrocosm, and to decipher what those messages are telling us about the varied constituent objects in the Universe at present and in the past. In the last decades much advance has been made in nuclear astrophysics thanks to the sometimes spectacular progress made in the modelling of the structure and evolution of the stars, in the quality and diversity of the astronomical observations, as well as in the experimental and theoretical understanding of the atomic nucleus and of its spontaneous or induced transformations. Developments in other subfields of physics and chemistry have also contributed to that advance. Notwithstanding the accomplishment, many long-standing problems remain to be solved, and the theoretical understanding of a large variety of observational facts needs to be put on safer grounds. In addition, new questions are continuously emerging, and new facts endangering old ideas. This review shows that astrophysics has been, and still is, highly demanding to nuclear physics in both its experimental and theoretical components. On top of the fact that large varieties of nuclei have to be dealt with, these nuclei are immersed in highly unusual environments which may have a significant impact on their static properties, the diversity of their transmutation modes, and on the probabilities of these modes. In order to have a chance of solving some of the problems nuclear astrophysics is facing, the astrophysicists and nuclear physicists are obviously bound to put their competence in common, and have sometimes to benefit from the help of other fields of physics, like particle physics, plasma physics or solid-state physics. Given the highly varied and complex aspects, we pick here some specific nuclear

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.

Scaling law in laboratory astrophysics

International Nuclear Information System (INIS)

Xia Jiangfan; Zhang Jie

2001-01-01

The use of state-of-the-art lasers makes it possible to produce, in the laboratory, the extreme conditions similar to those in astrophysical processes. The introduction of astrophysics-relevant ideas in laser-plasma interaction experiments is propitious to the understanding of astrophysical phenomena. However, the great difference between laser-produced plasma and astrophysical objects makes it awkward to model the latter by laser-plasma experiments. The author presents the physical reasons for modeling astrophysical plasmas by laser plasmas, connecting these two kinds of plasmas by scaling laws. This allows the creation of experimental test beds where observation and models can be quantitatively compared with laboratory data

Nuclear astrophysics

International Nuclear Information System (INIS)

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

Experimental studies of nuclear astrophysics

International Nuclear Information System (INIS)

He Jianjun; Zhou Xiaohong; Zhang Yuhu

2013-01-01

Nuclear astrophysics is an interdisciplinary subject combining micro-scale nuclear physics and macro-scale astrophysics. Its main aims are to understand the origin and evolution of the elements in the universe, the time scale of stellar evolution, the stellar environment and sites, the energy generation of stars from thermonuclear processes and its impact on stellar evolution and the mechanisms driving astrophysical phenomena, and the structure and property of compact stars. This paper presents the significance and current research status of nuclear astrophysics; we introduce some fundamental concepts, the nuclear physics input parameters required by certain astrophysics models, and some widely-used experimental approaches in nuclear astrophysics research. The potential and feasibility of research in this field using China’s current and planned large-scale scientific facilities are analyzed briefly. Finally, the prospects of the establishing a deep underground science and engineering laboratory in China are envisaged. (authors)

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

Relativistic astrophysics and theory of gravity

International Nuclear Information System (INIS)

Zel'dovich, Ya.B.

1982-01-01

A brief historical review of the development of astrophysical science in the State Astrophysical Institute named after Shternberg (SAISh) has been given in a popular form. The main directions of the SAISh astrophysical investigations have been presented: relativistic theory of gravity, relativistic astrophysics of interplanetary medium and cosmology

78Kr(α,γ) reaction of astrophysical interest in inverse kinematics and the electronic screening effect on the beta decay

International Nuclear Information System (INIS)

Ujic, P.

2011-12-01

The thesis is constituted of two different topics related to astrophysics. The titles of these topics are: 'Alpha capture reaction in inverse kinematics, measurement of 78 Kr(α,γ) 82 Sr reaction' and 'Measurement of the radioactive decay of 19 O and 19 Ne implanted in niobium'. The goal of the first part of the thesis was to establish an experimental technique for measuring radiative alpha capture reaction at low energies in inverse kinematics. The measurement of these reactions is very important in astrophysics since it will help to improve the reliability of alpha particle optical model potentials which are used for prediction of cross sections of nuclear reaction used in different astrophysical models of supernovae explosions. In this part we insisted on a technical feasibility of this type of experiment. In the second part of the thesis, we examined the influence of the environment on the beta decay probability, in particular the influence of the electronic screening of Coulomb barrier of nuclei induced by Cooper pairs in superconductors. The indication of an extremely weak effect was noticed. (author)

‘Firewall’ phenomenology with astrophysical neutrinos

Science.gov (United States)

Afshordi, Niayesh; Yazdi, Yasaman K.

2016-12-01

One of the most fundamental features of a black hole in general relativity is its event horizon: a boundary from which nothing can escape. There has been a recent surge of interest in the nature of these event horizons and their local neighbourhoods. In an attempt to resolve black hole information paradox(es), and more generally, to better understand the path towards quantum gravity, ‘firewalls’ have been proposed as an alternative to black hole event horizons. In this paper, we explore the phenomenological implications of black holes possessing a surface or ‘firewall’, and predict a potentially detectable signature of these firewalls in the form of a high energy astrophysical neutrino flux. We compute the spectrum of this neutrino flux in different models and show that it is a possible candidate for the source of the PeV neutrinos recently detected by IceCube. This opens up a new area of research, bridging the non-perturbative physics of quantum gravity with the observational black hole and high energy astrophysics.

‘Firewall’ phenomenology with astrophysical neutrinos

International Nuclear Information System (INIS)

Afshordi, Niayesh; Yazdi, Yasaman K

2016-01-01

One of the most fundamental features of a black hole in general relativity is its event horizon: a boundary from which nothing can escape. There has been a recent surge of interest in the nature of these event horizons and their local neighbourhoods. In an attempt to resolve black hole information paradox(es), and more generally, to better understand the path towards quantum gravity, ‘firewalls’ have been proposed as an alternative to black hole event horizons. In this paper, we explore the phenomenological implications of black holes possessing a surface or ‘firewall’, and predict a potentially detectable signature of these firewalls in the form of a high energy astrophysical neutrino flux. We compute the spectrum of this neutrino flux in different models and show that it is a possible candidate for the source of the PeV neutrinos recently detected by IceCube. This opens up a new area of research, bridging the non-perturbative physics of quantum gravity with the observational black hole and high energy astrophysics. (paper)

AtomPy: A Cloud Atomic-data Service for Astrophysical Applications

Science.gov (United States)

Mendoza, Claudio; Boswell, J. S.; Bautista, M.

2013-06-01

Apart from our long-term commitment to the computing of accurate atomic data for astrophysical applications, we have also been interested in the problems of data access and dissemination. In this respect, one of us took part in the developments of TIPTOPbase [1, 2, 3], the astrophysical opacity server referred to as OPserver [4, 5], and, more recently, of the Virtual Atomic and Molecular Data Center [6, 7]. Our present effort is now with the establishment of a cloud atomic data web service, AtomPy, implemented by means of SOAP web services, Google Drive spreadsheets and Python modules. In the present poster we will describe the outline of this ambitious project, illustrated with some prototypes that are already operational.

The Belgian repository of fundamental atomic data and stellar spectra (BRASS). I. Cross-matching atomic databases of astrophysical interest

Science.gov (United States)

Laverick, M.; Lobel, A.; Merle, T.; Royer, P.; Martayan, C.; David, M.; Hensberge, H.; Thienpont, E.

2018-04-01

Context. Fundamental atomic parameters, such as oscillator strengths, play a key role in modelling and understanding the chemical composition of stars in the Universe. Despite the significant work underway to produce these parameters for many astrophysically important ions, uncertainties in these parameters remain large and can propagate throughout the entire field of astronomy. Aims: The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide the largest systematic and homogeneous quality assessment of atomic data to date in terms of wavelength, atomic and stellar parameter coverage. To prepare for it, we first compiled multiple literature occurrences of many individual atomic transitions, from several atomic databases of astrophysical interest, and assessed their agreement. In a second step synthetic spectra will be compared against extremely high-quality observed spectra, for a large number of BAFGK spectral type stars, in order to critically evaluate the atomic data of a large number of important stellar lines. Methods: Several atomic repositories were searched and their data retrieved and formatted in a consistent manner. Data entries from all repositories were cross-matched against our initial BRASS atomic line list to find multiple occurrences of the same transition. Where possible we used a new non-parametric cross-match depending only on electronic configurations and total angular momentum values. We also checked for duplicate entries of the same physical transition, within each retrieved repository, using the non-parametric cross-match. Results: We report on the number of cross-matched transitions for each repository and compare their fundamental atomic parameters. We find differences in log(gf) values of up to 2 dex or more. We also find and report that 2% of our line list and Vienna atomic line database retrievals are composed of duplicate transitions. Finally we provide a number of examples of atomic spectral lines

Second advanced research workshop: Gravity, astrophysics and strings at the Black Sea. Proceedings

International Nuclear Information System (INIS)

Fiziev, P.; Todorov, M.

2005-01-01

The Second Advanced Workshop ‘Gravity, Astrophysics, and Strings’ held on 10-16 June 2004. It served four purposes: 1) Bringing together scientists from various branches of gravitational physics, astrophysics, and string theory gave an opportunity for interdisciplinary exchange of views and enhanced possible collaborations; 2) Provided a unique opportunity to scientists from various countries to communicate with colleagues on the hottest topics of gravitational physics, astrophysics, and string theory; 3) Opened new venue to young talented scientists to communicate and work with major research groups on the topics of the conference; 4) Stimulated creation of a new generation of young physicists for further development of the above basic topics in fundamental science. The workshop covered wide aspects of gravity, astrophysics, and string theory concerning the topics: Astrophysics; Mathematical Modeling and Numerical Simulations in Relativity; Relativistic Gravity; (Super)Strings. About 35 participants from Europe, America and Asia gave 28 invited talks and contributed presentations. They and guided general discussion as well, which took place confirmed the considerable interest to the themes of the workshop. The full text of 16 of the presented papers are included in this book

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.

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.)

The Trojan horse method in nuclear astrophysics

International Nuclear Information System (INIS)

Aliotta, M.; Rolfs, C.; Lattuada, M.; Pellegriti, M.G.; Pizzone, R.G.; Spitaleri, C.; Miljanic, Dj.; Typel, S.; Wolter, H.H.

2001-01-01

Because of the Coulomb barrier, reaction cross sections in astrophysics cannot be accessed directly at the relevant Gamow energies, unless very favourable conditions are met (e.g. LUNA--underground experiments). Theoretical extrapolations of available data are then needed to derive the astrophysical S(0)-factor. Various indirect processes have been used in order to obtain additional information on the parameters entering these extrapolations. The Trojan Horse Method is an indirect method which might help to bypass some of the problems typically encountered in direct measurements, namely the presence of the Coulomb barrier and the effect of the electron screening. However, a comparison with direct data in an appropriate energy region (e.g. around the Coulomb barrier) is crucial before extending the method to the relevant Gamow energy. Additionally, experimental and theoretical tests are needed to validate the assumptions underlying the method. The application of the Trojan Horse Method to some cases of interest is discussed

First evidences for 19F(α, p)22Ne at astrophysical energies

International Nuclear Information System (INIS)

D’Agata, G.; Spitaleri, C.; Pizzone, R.G.; Figuera, P.; Guardo, G.L.; Gulino, M.; Indelicato, I.; La Cognata, M.; Lattuada, M.; Sergi, M.L.; Blagus, S.; Mijatović, T.; Milin, M.; Miljanic, D.; Prepolec, L.; Skukan, N.; Grassi, L.; Lamia, L.; Hayakawa, S.; Kshetri, R.

2016-01-01

19 F experimental abundances is overestimated in respect to the theoretical one: it is therefore clear that further investigations are needed. We focused on the 19 F(α, p) 22 Ne reaction, representing the main destruction channel in He-rich environments. The lowest energy at which this reaction has been studied with direct methods is E C.M. ≈ 0.91 MeV, while the Gamow region is between 0.39 ÷ 0.8 MeV, far below the Coulomb barrier (3.8 MeV). For this reason, an experiment at Rudjer Boskovic Institute (Zagreb) was performed, applying the Trojan Horse Method. Following this method we selected the quasi-free contribution coming from 6 Li( 19 F,p 22 Ne) 2 H at E beam =6 MeV at kinematically favourable angles, and the cross section at energies 0 < E C.M. < 1.4 MeV was extracted in arbitrary units, covering the astrophysical region of interest. (paper)

Gravity, particles and astrophysics

International Nuclear Information System (INIS)

Wesson, P.S.

1980-01-01

The author deals with the relationship between gravitation and elementary particle physics, and the implications of these subjects for astrophysics. The text is split up into two parts. The first part represents a relatively non-technical overview of the subject, while the second part represents a technical examination of the most important aspects of non-Einsteinian gravitational theory and its relation to astrophysics. Relevant references from the fields of gravitation, elementary particle theory and astrophysics are included. (Auth.)

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...

Encyclopedia of Astronomy and Astrophysics

CERN Document Server

2002-01-01

Interstellar medium, Light, Magnetisphere, Matter, Planet Earth, Public Impact, Solar Activity, Solar Heliosphere, Solar Interior, Solar Systems, Space, Stellar Astrophysics, Stellar Populations, Telescopes, Time The Encyclopedia of Astronomy and Astrophysics covers 30 major subject areas, such as Active galaxies, Astrometry, Astrophysical theory, Atmospheres, Binary stars, Biography, Clusters, Coordinates, Cosmology, Earth, Education, Galaxies,

Plasma in astrophysics

International Nuclear Information System (INIS)

Kulsrud, R.M.

1982-10-01

Two examples of plasma phenomena of importance to astrophysics are reviewed. These are examples where astrophysical understanding hinges on further progress in plasma physics understanding. The two examples are magnetic reconnection and the collisionless interaction between a population of energetic particles and a cooler gas or plasma, in particular the interaction between galactic cosmic rays and the interstellar medium

Measurement of reaction rates of interest in stellar structure and evolution

International Nuclear Information System (INIS)

Terrasi, F.; D''Onofrio, A.; Campajola, L.; Imbriani, G.; Gialanella, L.; Greife, U.; Rolfs, C.; Strieder, F.; Trautvetter, H.P.; Roca, V.; Romano, M.; Straniero, O.

1998-01-01

Accurate determinations of reaction rates at astrophysical energies are very important in stellar structure and evolution studies. The cases of two key reactions, namely 7 Be(p,γ) 8 B and 12 C(α,γ) 16 O are discussed, both from the point of view of their astrophysical interest and of the experimental difficulties in the measurement of their cross section. (orig.)

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

Astrophysical constraints on scalar field models

International Nuclear Information System (INIS)

Bertolami, O.; Paramos, J.

2005-01-01

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

Astrophysical Institute, Potsdam

Science.gov (United States)

Murdin, P.

2000-11-01

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

Black hole astrophysics

International Nuclear Information System (INIS)

Blandford, R.D.; Thorne, K.S.

1979-01-01

Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

Proceedings of the 2nd Iberian Nuclear Astrophysics Meeting on Compact Stars

CERN Document Server

Pons, J; Albertus, C

2012-01-01

This volume contains most of the links to the presentations delivered at this international workshop. This meeting was the second in the series following the previous I Encuentro Ib\\'erico de Compstar, held at the University of Coimbra, Portugal in 2010. The main purpose of this meeting was to strengthen the scientific collaboration between the participants of the Iberian and the rest of the southern European branches of the European Nuclear Astrophysics network, formerly, COMPSTAR. This ESF (European Science Foundation) supported network has been crucial in helping to make a broader audience for the the most interesting and relevant research lines being developed currently in Nuclear Astrophysics, especially related to the physics of neutron stars. The program of the meeting was tailored to theoretical descriptions of the physics of neutron stars although some input from experimental observers and other condensed matter and optics areas of interest was also included.

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

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

Measurement of reaction rates of interest in stellar structure and evolution

Energy Technology Data Exchange (ETDEWEB)

Terrasi, F; D` Onofrio, A [Dipt. di Scienze Ambientali, Seconda Univ. di Napoli, Caserta (Italy); [INFN, Napoli (Italy); Campajola, L; Imbriani, G [INFN, Napoli (Italy); [Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy); Gialanella, L [INFN, Napoli (Italy); [Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy); [Inst. fuer Experimentalphysik III, Ruhr-Univ. Bochum, Bochum (Germany); Greife, U; Rolfs, C; Strieder, F; Trautvetter, H P [Inst. fuer Experimentalphysik III, Ruhr-Univ. Bochum, Bochum (Germany); Roca, V; Romano, M [INFN, Napoli (Italy); [Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy); Straniero, O [Osservatorio Astronomico di Collurania, Teramo (Italy)

1998-06-01

Accurate determinations of reaction rates at astrophysical energies are very important in stellar structure and evolution studies. The cases of two key reactions, namely {sup 7}Be(p,{gamma}){sup 8}B and {sup 12}C({alpha},{gamma}){sup 16}O are discussed, both from the point of view of their astrophysical interest and of the experimental difficulties in the measurement of their cross section. (orig.)

Multi-resolution analysis for region of interest extraction in thermographic nondestructive evaluation

Science.gov (United States)

Ortiz-Jaramillo, B.; Fandiño Toro, H. A.; Benitez-Restrepo, H. D.; Orjuela-Vargas, S. A.; Castellanos-Domínguez, G.; Philips, W.

2012-03-01

Infrared Non-Destructive Testing (INDT) is known as an effective and rapid method for nondestructive inspection. It can detect a broad range of near-surface structuring flaws in metallic and composite components. Those flaws are modeled as a smooth contour centered at peaks of stored thermal energy, termed Regions of Interest (ROI). Dedicated methodologies must detect the presence of those ROIs. In this paper, we present a methodology for ROI extraction in INDT tasks. The methodology deals with the difficulties due to the non-uniform heating. The non-uniform heating affects low spatial/frequencies and hinders the detection of relevant points in the image. In this paper, a methodology for ROI extraction in INDT using multi-resolution analysis is proposed, which is robust to ROI low contrast and non-uniform heating. The former methodology includes local correlation, Gaussian scale analysis and local edge detection. In this methodology local correlation between image and Gaussian window provides interest points related to ROIs. We use a Gaussian window because thermal behavior is well modeled by Gaussian smooth contours. Also, the Gaussian scale is used to analyze details in the image using multi-resolution analysis avoiding low contrast, non-uniform heating and selection of the Gaussian window size. Finally, local edge detection is used to provide a good estimation of the boundaries in the ROI. Thus, we provide a methodology for ROI extraction based on multi-resolution analysis that is better or equal compared with the other dedicate algorithms proposed in the state of art.

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.

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

International Nuclear Information System (INIS)

Arcones, Almudena; Bardayan, Dan W.

2016-01-01

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 also 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). Our white paper is informed 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. Answers to long standing key questions are well within reach in the coming decade because of the developments outlined in this white paper.

AN ITERATIVE SEGMENTATION METHOD FOR REGION OF INTEREST EXTRACTION

Directory of Open Access Journals (Sweden)

Volkan CETIN

2013-01-01

Full Text Available In this paper, a method is presented for applications which include mammographic image segmentation and region of interest extraction. Segmentation is a very critical and difficult stage to accomplish in computer aided detection systems. Although the presented segmentation method is developed for mammographic images, it can be used for any medical image which resembles the same statistical characteristics with mammograms. Fundamentally, the method contains iterative automatic thresholding and masking operations which is applied to the original or enhanced mammograms. Also the effect of image enhancement to the segmentation process was observed. A version of histogram equalization was applied to the images for enhancement. Finally, the results show that enhanced version of the proposed segmentation method is preferable because of its better success rate.

Third advanced research workshop: Gravity, astrophysics and strings at the Black Sea. Proceedings

International Nuclear Information System (INIS)

Fiziev, P.; Todorov, M.

2006-01-01

The Third Advanced Workshop ‘Gravity, Astrophysics, and Strings’ held on 13-20 June 2005. The workshop: 1) Bringing together scientists from various branches of gravitational physics, astrophysics, particle physics, fundamental interactions and string theory gave an opportunity for interdisciplinary exchange of views and enhanced possible collaborations; 2) Provided a unique opportunity to scientists from various countries to communicate with colleagues on the hottest topics of gravitational physics, astrophysics, particle physics, fundamental interactions and string theory; 3) Opened new venue to young talented scientists to communicate and work with major research groups on the topics of the conference; 4) Stimulated creation of a new generation of young physicists for further development of the above basic topics in fundamental science. The workshop covered wide aspects of gravitational physics, astrophysics, particle physics, fundamental interactions and string theory concerning the topics: Astrophysics; Mathematical Modeling and Numerical Simulations in Relativity; Relativistic Gravity; Particle Physics and Fundamental Interactions; (Super)Strings. About 40 participants from Europe, America and Asia gave 32 invited talks and contributed presentations. They and guided general discussion as well, which took place confirmed the considerable interest to the themes of the workshop. The full text of 22 of the presented papers are included in this book

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…

Neutrino astrophysics

International Nuclear Information System (INIS)

Roulet, E.

2001-01-01

A general overview of neutrino physics and astrophysics is given, starting with a historical account of the development of our understanding of neutrinos and how they helped to unravel the structure of the Standard Model. We discuss why it is so important to establish if neutrinos are massive and introduce the main scenarios to provide them a mass. The present bounds and the positive indications in favor of non-zero neutrino masses are discussed, including the recent results on atmospheric and solar neutrinos. The major role that neutrinos play in astrophysics and cosmology is illustrated. (author)

Investigations of astrophysically interesting nuclear reactions by the use of gas target techniques

Energy Technology Data Exchange (ETDEWEB)

Hammer, J W [Inst. fuer Strahlenphysik, Univ. Stuttgart, Stuttgart (Germany)

1998-06-01

A brief review of the common properties of windowless and recirculating gas targets is presented. As example the Stuttgart gas target facility Rhinoceros in the extended and in the supersonic jet mode with its properties and techniques is explained, also with respect to gas purification techniques. Furthermore several typical experiments from the field of nuclear astrophysics with characteristic results are described (D({alpha},{gamma}){sup 6}Li, {sup 15}N({alpha},{gamma}){sup 19}F, {sup 16}O(p,{gamma}){sup 17}F, {sup 16}O({alpha},{gamma}){sup 20}Ne, {sup 20}Ne({alpha},{gamma}){sup 24}Mg, {sup 21}Ne({alpha},n){sup 24}Mg, {sup 18}O({alpha},n){sup 21}Ne, {sup 17}O({alpha},n){sup 20}Ne). In several cases the experimental sensitivity could be raised by up to a factor of 10{sup 6}. (orig.)

Hydrodynamic Instability, Integrated Code, Laboratory Astrophysics, and Astrophysics

Science.gov (United States)

Takabe, Hideaki

2016-10-01

This is an article for the memorial lecture of Edward Teller Medal and is presented as memorial lecture at the IFSA03 conference held on September 12th, 2003, at Monterey, CA. The author focuses on his main contributions to fusion science and its extension to astrophysics in the field of theory and computation by picking up five topics. The first one is the anomalous resisitivity to hot electrons penetrating over-dense region through the ion wave turbulence driven by the return current compensating the current flow by the hot electrons. It is concluded that almost the same value of potential as the average kinetic energy of the hot electrons is realized to prevent the penetration of the hot electrons. The second is the ablative stabilization of Rayleigh-Taylor instability at ablation front and its dispersion relation so-called Takabe formula. This formula gave a principal guideline for stable target design. The author has developed an integrated code ILESTA (ID & 2D) for analyses and design of laser produced plasma including implosion dynamics. It is also applied to design high gain targets. The third is the development of the integrated code ILESTA. The forth is on Laboratory Astrophysics with intense lasers. This consists of two parts; one is review on its historical background and the other is on how we relate laser plasma to wide-ranging astrophysics and the purposes for promoting such research. In relation to one purpose, I gave a comment on anomalous transport of relativistic electrons in Fast Ignition laser fusion scheme. Finally, I briefly summarize recent activity in relation to application of the author's experience to the development of an integrated code for studying extreme phenomena in astrophysics.

The new astrophysics

International Nuclear Information System (INIS)

Longair, M.

1989-01-01

The author offers a review of advances in astrophysics since 1945 when astronomers started to explore the universe beyond the bounds of the optical wavelength of the electromagnetic spectrum, especially in the fields of radio, x ray and gamma ray, cosmic ray, ultraviolet and infrared astronomies, as well as neutral hydrogen and molecular line studies. Theoretical and technological advances have also kept pace. An overview of the new astrophysics is offered focusing on the large-scale distribution of matter and the background microwave radiation, galaxies, stellar evolution and the interstellar media (dust, gas and high energy particles). Nucleosynthesis in stars is mentioned in a broader discussion of stellar evolution, and dead stars including supernovae. Active galaxies and quasars are discussed. After considering what should be included in astrophysical cosmology, the author looks to the future of the science. (U.K.)

A Companion to Astronomy and Astrophysics Chronology and Glossary with Data Tables

CERN Document Server

Lang, Kenneth R

2006-01-01

Astronomy and Astrophysics is a comprehensive, fundamental, up-to-date reference book. It is filled with vital information and basic facts for amateur astronomers and professional astrophysicists, and for anyone interested in the Universe, from the Earth and other planets to the stars, galaxies and beyond. Although serious and thorough, the language, and ideas will attract the general reader, as well as students and professionals. Astronomy and Astrophysics consists of two main parts, a Timeline and a Dictionary. The Timeline is a concise history, arranged chronologically, which provides the complete story of cosmic discovery from early Chinese and Greek astronomy to the latest findings of modern astrophysics and robotic spacecraft. It provides a sense of destination and flow in our growing awareness of the Universe. Each entry in the unfolding narrative is written in a concise, light and friendly style that will be appreciated by all, without being weighted down with incomprehensible specialized terms. The s...

THD-Module Extractor: An Application for CEN Module Extraction and Interesting Gene Identification for Alzheimer's Disease.

Science.gov (United States)

Kakati, Tulika; Kashyap, Hirak; Bhattacharyya, Dhruba K

2016-11-30

There exist many tools and methods for construction of co-expression network from gene expression data and for extraction of densely connected gene modules. In this paper, a method is introduced to construct co-expression network and to extract co-expressed modules having high biological significance. The proposed method has been validated on several well known microarray datasets extracted from a diverse set of species, using statistical measures, such as p and q values. The modules obtained in these studies are found to be biologically significant based on Gene Ontology enrichment analysis, pathway analysis, and KEGG enrichment analysis. Further, the method was applied on an Alzheimer's disease dataset and some interesting genes are found, which have high semantic similarity among them, but are not significantly correlated in terms of expression similarity. Some of these interesting genes, such as MAPT, CASP2, and PSEN2, are linked with important aspects of Alzheimer's disease, such as dementia, increase cell death, and deposition of amyloid-beta proteins in Alzheimer's disease brains. The biological pathways associated with Alzheimer's disease, such as, Wnt signaling, Apoptosis, p53 signaling, and Notch signaling, incorporate these interesting genes. The proposed method is evaluated in regard to existing literature.

A database of astrophysical interest covering the UV region

International Nuclear Information System (INIS)

Biemont, E.; Quinet, P.; University of Mons-Hainaut

2004-01-01

Full text: Our knowledge of the spectra of the rare-earths is still very poor due to the fragmentary laboratory analyses on the one hand and to the complexity of the configurations involving unfilled 4f shells on the other hand. The aim of the database DREAM is to supply the astrophysicists and the physicists with accurate atomic data (wave- lengths, energy levels, oscillator strengths, radiative lifetimes) of neutral, singly or multiply ionized lanthanides. Calculations of atomic structures and spectra in heavy ions like the lanthanides are frequently the only way to obtain the large amount of atomic data required by astrophysics, particularly for the analysis of the spectra of chemically peculiar stars. Such calculations, extremely complex, need to be tested by comparisons with experiment in order to deduce some information about their predictive power. For that reason, we have systematically compared the results obtained with our theoretical models (HFR approach including core-polarisation effects) with new lifetime measurements carried out with time-resolved laser-induced fluorescence laser techniques (collaboration with the Lund Laser Center in Sweden). The database DREAM (Database on Rare-Earths at Mons University) contains presently data for over 60 000 transitions and is continuously updated. The different tables, which cover the UV, the visible and near infrared regions, are located on the web page: http://www.umh.ac.be/ astro/dream.shtm. Up to now data are tabulated for the following ions : La III, Ce II, Ce III, Pr II, Pr III, Nd II, Nd III, Sm II, Sm III, Eu III, Gd III, Tb III, Dy III, Ho III, Er II, Er III, Tm II, Tm III, Yb II, Yb III, Yb IV, Lu I, Lu II and Lu III. Some information is also provided for Th III. All the references (about 40 papers), summarizing and discussing the new experimental and theoretical results obtained during the past few years, are given on this web site. Some specific examples of the results obtained will be discussed at

X-ray polarimetry and new prospects in high-energy astrophysics

International Nuclear Information System (INIS)

Sgrò, C.

2016-01-01

Polarimetry is universally recognized as one of the new frontiers in X-ray astrophysics. It is a powerful tool to investigate a variety of astrophysical processes, as well as a mean to study fundamental physics in space. A renewed interest is testified by dedicated missions approved for phase A by ESA and NASA. The main advance is the availability of a gas pixel detector that is able to add polarization measurement to imaging and spectroscopy, and can be used at the focus of a conventional X-ray optics. The detector exploits the photoelectric effect in gas and a finely segmented ASIC as a collecting anode. In this work I will describe in detail the experimental technique and the detector concept, and illustrate the scientific prospects of these new missions.

Extracting factors for interest rate scenarios

Science.gov (United States)

Molgedey, L.; Galic, E.

2001-04-01

Factor based interest rate models are widely used for risk managing purposes, for option pricing and for identifying and capturing yield curve anomalies. The movements of a term structure of interest rates are commonly assumed to be driven by a small number of orthogonal factors such as SHIFT, TWIST and BUTTERFLY (BOW). These factors are usually obtained by a Principal Component Analysis (PCA) of historical bond prices (interest rates). Although PCA diagonalizes the covariance matrix of either the interest rates or the interest rate changes, it does not use both covariance matrices simultaneously. Furthermore higher linear and nonlinear correlations are neglected. These correlations as well as the mean reverting properties of the interest rates become crucial, if one is interested in a longer time horizon (infrequent hedging or trading). We will show that Independent Component Analysis (ICA) is a more appropriate tool than PCA, since ICA uses the covariance matrix of the interest rates as well as the covariance matrix of the interest rate changes simultaneously. Additionally higher linear and nonlinear correlations may be easily incorporated. The resulting factors are uncorrelated for various time delays, approximately independent but nonorthogonal. This is in contrast to the factors obtained from the PCA, which are orthogonal and uncorrelated for identical times only. Although factors from the ICA are nonorthogonal, it is sufficient to consider only a few factors in order to explain most of the variation in the original data. Finally we will present examples that ICA based hedges outperforms PCA based hedges specifically if the portfolio is sensitive to structural changes of the yield curve.

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.

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.

Space astronomy and astrophysics program by NASA

Science.gov (United States)

Hertz, Paul L.

2014-07-01

The National Aeronautics and Space Administration recently released the NASA Strategic Plan 20141, and the NASA Science Mission Directorate released the NASA 2014 Science Plan3. These strategic documents establish NASA's astrophysics strategic objectives to be (i) to discover how the universe works, (ii) to explore how it began and evolved, and (iii) to search for life on planets around other stars. The multidisciplinary nature of astrophysics makes it imperative to strive for a balanced science and technology portfolio, both in terms of science goals addressed and in missions to address these goals. NASA uses the prioritized recommendations and decision rules of the National Research Council's 2010 decadal survey in astronomy and astrophysics2 to set the priorities for its investments. The NASA Astrophysics Division has laid out its strategy for advancing the priorities of the decadal survey in its Astrophysics 2012 Implementation Plan4. With substantial input from the astrophysics community, the NASA Advisory Council's Astrophysics Subcommittee has developed an astrophysics visionary roadmap, Enduring Quests, Daring Visions5, to examine possible longer-term futures. The successful development of the James Webb Space Telescope leading to a 2018 launch is an Agency priority. One important goal of the Astrophysics Division is to begin a strategic mission, subject to the availability of funds, which follows from the 2010 decadal survey and is launched after the James Webb Space Telescope. NASA is studying a Wide Field Infrared Survey Telescope as its next large astrophysics mission. NASA is also planning to partner with other space agencies on their missions as well as increase the cadence of smaller Principal Investigator led, competitively selected Astrophysics Explorers missions.

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.

Nuclear Astrophysics Experiments at CIAE

International Nuclear Information System (INIS)

Liu Weiping; Li Zhihong; Bai Xixiang; Lian Gang; Guo Bing; Zeng, Sheng; Yan Shengquan; Wang Baoxiang; Shu Nengchuan; Wu Kaisu; Chen Yongshou

2005-01-01

This paper describes nuclear astrophysical studies using the unstable ion beam facility GIRAFFE. We measured the angular distributions for some low energy reactions, such as 7 Be(d, n) 8 B, 11 C(d, n) 12 N, 8 Li(d, n) 9 Be and 8 Li(d, p) 9 Li in inverse kinematics, and indirectly derived the astrophysical S-factors or reaction rates of 7 Be(p, γ) 8 B, 11 C(p, γ) 12 N, 8 Li(n, γ) 9 Li at astrophysically relevant energies

Photo and thermochemical evolution of astrophysical ice analogues as a source for soluble and insoluble organic materials in Solar system minor bodies

Science.gov (United States)

de Marcellus, Pierre; Fresneau, Aurelien; Brunetto, Rosario; Danger, Gregoire; Duvernay, Fabrice; Meinert, Cornelia; Meierhenrich, Uwe J.; Borondics, Ferenc; Chiavassa, Thierry; Le Sergeant d'Hendecourt, Louis

2017-01-01

Soluble and insoluble organic matter (IOM) is a key feature of primitive carbonaceous chondrites. We observe the formation of organic materials in the photothermochemical treatment of astrophysical ices in the laboratory. Starting from a low vacuum ultraviolet (VUV) irradiation dose on templates of astrophysical ices at 77 K, we obtain first a totally soluble form of organic matter at room temperature. Once this organic residue is formed, irradiating it further in vacuum results in the production of a thin altered dark crust on top of the initial soluble one. The whole residue is studied here by non-destructive methods inducing no alteration of samples, visible microscopy and mid-infrared (micro-)spectroscopy. After water extraction of the soluble part, an insoluble fraction remains on the sample holder which provides a largely different infrared spectrum when compared to the one of the soluble sample. Therefore, from the same VUV and thermal processing of initial simple ices, we produce first a soluble material from which a much larger irradiation dose leads to an insoluble one. Interestingly, this insoluble fraction shows some spectral similarities with natural samples of IOM extracted from two meteorites (Tagish Lake and Murchison), selected as examples of primitive materials. It suggests that the organic molecular diversity observed in meteorites may partly originate from the photo and thermal processing of interstellar/circum-stellar ices at the final stages of molecular cloud evolution towards the build-up of our Solar system.

Large-Scale Astrophysical Visualization on Smartphones

Science.gov (United States)

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

2011-07-01

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

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.

Nonlinear dynamics and astrophysics

International Nuclear Information System (INIS)

Vallejo, J. C.; Sanjuan, M. A. F.

2000-01-01

Concepts and techniques from Nonlinear Dynamics, also known as Chaos Theory, have been applied successfully to several astrophysical fields such as orbital motion, time series analysis or galactic dynamics, providing answers to old questions but also opening a few new ones. Some of these topics are described in this review article, showing the basis of Nonlinear Dynamics, and how it is applied in Astrophysics. (Author)

Laboratory Astrophysics Prize: Laboratory Astrophysics with Nuclei

Science.gov (United States)

Wiescher, Michael

2018-06-01

Nuclear astrophysics is concerned with nuclear reaction and decay processes from the Big Bang to the present star generation controlling the chemical evolution of our universe. Such nuclear reactions maintain stellar life, determine stellar evolution, and finally drive stellar explosion in the circle of stellar life. Laboratory nuclear astrophysics seeks to simulate and understand the underlying processes using a broad portfolio of nuclear instrumentation, from reactor to accelerator from stable to radioactive beams to map the broad spectrum of nucleosynthesis processes. This talk focuses on only two aspects of the broad field, the need of deep underground accelerator facilities in cosmic ray free environments in order to understand the nucleosynthesis in stars, and the need for high intensity radioactive beam facilities to recreate the conditions found in stellar explosions. Both concepts represent the two main frontiers of the field, which are being pursued in the US with the CASPAR accelerator at the Sanford Underground Research Facility in South Dakota and the FRIB facility at Michigan State University.

Nuclear astrophysics with radioactive beams

International Nuclear Information System (INIS)

Bertulani, C.A.; Gade, A.

2010-01-01

The quest to comprehend how nuclear processes influence astrophysical phenomena is driving experimental and theoretical research programs worldwide. One of the main goals in nuclear astrophysics is to understand how energy is generated in stars, how elements are synthesized in stellar events and what the nature of neutron stars is. New experimental capabilities, the availability of radioactive beams and increased computational power paired with new astronomical observations have advanced the present knowledge. This review summarizes the progress in the field of nuclear astrophysics with a focus on the role of indirect methods and reactions involving beams of rare isotopes.

Nuclear reactions in astrophysics

International Nuclear Information System (INIS)

Arnould, M.; Rayet, M.

1990-01-01

At all times and at all astrophysical scales, nuclear reactions have played and continue to play a key role. This concerns the energetics as well as the production of nuclides (nucleosynthesis). After a brief review of the observed composition of various objects in the universe, and especially of the solar system, the basic ingredients that are required in order to build up models for the chemical evolution of galaxies are sketched. Special attention is paid to the evaluation of the stellar yields through an overview of the important burning episodes and nucleosynthetic processes that can develop in non-exploding or exploding stars. Emphasis is put on the remaining astrophysical and nuclear physics uncertainties that hamper a clear understanding of the observed characteristics, and especially compositions, of a large variety of astrophysical objects

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

Cyberinfrastructure for Computational Relativistic Astrophysics

OpenAIRE

Ott, Christian

2012-01-01

Poster presented at the NSF Office of Cyberinfrastructure CyberBridges CAREER PI workshop. This poster discusses the computational challenges involved in the modeling of complex relativistic astrophysical systems. The Einstein Toolkit is introduced. It is an open-source community infrastructure for numerical relativity and computational astrophysics.

Laboratory astrophysics. Model experiments of astrophysics with large-scale lasers

International Nuclear Information System (INIS)

Takabe, Hideaki

2012-01-01

I would like to review the model experiment of astrophysics with high-power, large-scale lasers constructed mainly for laser nuclear fusion research. The four research directions of this new field named 'Laser Astrophysics' are described with four examples mainly promoted in our institute. The description is of magazine style so as to be easily understood by non-specialists. A new theory and its model experiment on the collisionless shock and particle acceleration observed in supernova remnants (SNRs) are explained in detail and its result and coming research direction are clarified. In addition, the vacuum breakdown experiment to be realized with the near future ultra-intense laser is also introduced. (author)

The importance of CNO isotopes in astrophysics

International Nuclear Information System (INIS)

Audoze, J.

1977-01-01

The research into CNO isotopes in astrophysics includes many different subfields of astrophysics such as meteoretical studies, experimental and theoretical nuclear astrophysics, optical astronomy, radio astronomy, etc. The purpose of this paper is to give some overview of the topic and guideline among these different subfields. (G.T.H.)

Few-body models for nuclear astrophysics

Energy Technology Data Exchange (ETDEWEB)

Descouvemont, P., E-mail: pdesc@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Baye, D., E-mail: dbaye@ulb.ac.be [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Physique Quantique, C.P. 165/82, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Suzuki, Y., E-mail: suzuki@nt.sc.niigata-u.ac.jp [Department of Physics, Niigata University, Niigata 950-2181 (Japan); RIKEN Nishina Center, Wako 351-0198 (Japan); Aoyama, S., E-mail: aoyama@cc.niigata-u.ac.jp [Center for Academic Information Service, Niigata University, Niigata 950-2181 (Japan); Arai, K., E-mail: arai@nagaoka-ct.ac.jp [Division of General Education, Nagaoka National College of Technology, 888 Nishikatakai, Nagaoka, Niigata 940-8532 (Japan)

2014-04-15

We present applications of microscopic models to nuclear reactions of astrophysical interest, and we essentially focus on few-body systems. The calculation of radiative-capture and transfer cross sections is outlined, and we discuss the corresponding reaction rates. Microscopic theories are briefly presented, and we emphasize on the matrix elements of four-body systems. The microscopic extension of the R-matrix theory to nuclear reactions is described. Applications to the {sup 2}H(d, γ){sup 4}He, {sup 2}H(d, p){sup 3}H and {sup 2}H(d, n){sup 3}He reactions are presented. We show the importance of the tensor force to reproduce the low-energy behaviour of the cross sections.

Astrophysical opacity library

International Nuclear Information System (INIS)

Huebner, W.F.; Merts, A.L.; Magee, N.H. Jr.; Argo, M.F.

1977-08-01

The astrophysical elements opacity library includes equation of state data, various mean opacities, and 2000 values of the frequency-dependent extinction coefficients in equally spaced intervals u identical with hν/kT from 0 to 20 for 41 degeneracy parameters eta from -28 (nondegenerate) to 500 and 46 temperatures kT from 1 eV to 100 keV. Among available auxiliary quantities are the free electron density, mass density, and plasma cutoff frequency. A library-associated program can produce opacities for mixtures with up to 20 astrophysically abundant constituent elements at 4 levels of utility for the user

Advances in instrumentation for nuclear astrophysics

Directory of Open Access Journals (Sweden)

S. D. Pain

2014-04-01

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

Numerical simulation in astrophysics

International Nuclear Information System (INIS)

Miyama, Shoken

1985-01-01

There have been many numerical simulations of hydrodynamical problems in astrophysics, e.g. processes of star formation, supernova explosion and formation of neutron stars, and general relativistic collapse of star to form black hole. The codes are made to be suitable for computing such problems. In astrophysical hydrodynamical problems, there are the characteristics: problems of self-gravity or external gravity acting, objects of scales very large or very short, objects changing by short period or long time scale, problems of magnetic force and/or centrifugal force acting. In this paper, we present one of methods of numerical simulations which may satisfy these requirements, so-called smoothed particle methods. We then introduce the methods briefly. Then, we show one of the applications of the methods to astrophysical problem (fragmentation and collapse of rotating isothermal cloud). (Mori, K.)

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.

Recent results in nuclear astrophysics

Energy Technology Data Exchange (ETDEWEB)

Coc, Alain; Kiener, Juergen [CNRS/IN2P3 et Universite Paris Sud 11, UMR 8609, Centre de Sciences Nucleaires et de Sciences de la Matiere (CSNSM), Orsay Campus (France); Hammache, Fairouz [CNRS/IN2P3 et Universite Paris Sud 11, UMR 8608, Institut de Physique Nucleaire d' Orsay (IPNO), Orsay Campus (France)

2015-03-01

In this review, we emphasize the interplay between astrophysical observations, modeling, and nuclear physics laboratory experiments. Several important nuclear cross sections for astrophysics have long been identified, e.g., {sup 12}C(α, γ){sup 16}O for stellar evolution, or {sup 13}C(α, n){sup 16}O and {sup 22}Ne(α, n){sup 25}Mg as neutron sources for the s-process. More recently, observations of lithium abundances in the oldest stars, or of nuclear gamma-ray lines from space, have required new laboratory experiments. New evaluation of thermonuclear reaction rates now includes the associated rate uncertainties that are used in astrophysical models to i) estimate final uncertainties on nucleosynthesis yields and ii) identify those reactions that require further experimental investigation. Sometimes direct cross section measurements are possible, but more generally the use of indirect methods is compulsory in view of the very low cross sections. Non-thermal processes are often overlooked but are also important for nuclear astrophysics, e.g., in gamma-ray emission from solar flares or in the interaction of cosmic rays with matter, and also motivate laboratory experiments. Finally, we show that beyond the historical motivations of nuclear astrophysics, understanding i) the energy sources that drive stellar evolution and ii) the origin of the elements can also be used to give new insights into physics beyond the standard model. (orig.)

Recent results in nuclear astrophysics

International Nuclear Information System (INIS)

Coc, Alain; Kiener, Juergen; Hammache, Fairouz

2015-01-01

In this review, we emphasize the interplay between astrophysical observations, modeling, and nuclear physics laboratory experiments. Several important nuclear cross sections for astrophysics have long been identified, e.g., 12 C(α, γ) 16 O for stellar evolution, or 13 C(α, n) 16 O and 22 Ne(α, n) 25 Mg as neutron sources for the s-process. More recently, observations of lithium abundances in the oldest stars, or of nuclear gamma-ray lines from space, have required new laboratory experiments. New evaluation of thermonuclear reaction rates now includes the associated rate uncertainties that are used in astrophysical models to i) estimate final uncertainties on nucleosynthesis yields and ii) identify those reactions that require further experimental investigation. Sometimes direct cross section measurements are possible, but more generally the use of indirect methods is compulsory in view of the very low cross sections. Non-thermal processes are often overlooked but are also important for nuclear astrophysics, e.g., in gamma-ray emission from solar flares or in the interaction of cosmic rays with matter, and also motivate laboratory experiments. Finally, we show that beyond the historical motivations of nuclear astrophysics, understanding i) the energy sources that drive stellar evolution and ii) the origin of the elements can also be used to give new insights into physics beyond the standard model. (orig.)

Radiative capture of nucleons at astrophysical energies with single-particle states

International Nuclear Information System (INIS)

Huang, J.T.; Bertulani, C.A.; Guimaraes, V.

2010-01-01

Radiative capture of nucleons at energies of astrophysical interest is one of the most important processes for nucleosynthesis. The nucleon capture can occur either by a compound nucleus reaction or by a direct process. The compound reaction cross sections are usually very small, especially for light nuclei. The direct capture proceeds either via the formation of a single-particle resonance or a non-resonant capture process. In this work we calculate radiative capture cross sections and astrophysical S-factors for nuclei in the mass region A<20 using single-particle states. We carefully discuss the parameter fitting procedure adopted in the simplified two-body treatment of the capture process. Then we produce a detailed list of cases for which the model works well. Useful quantities, such as spectroscopic factors and asymptotic normalization coefficients, are obtained and compared to published data.

Astrophysics and the evolution of the universe

CERN Document Server

Kisslinger, Leonard S

2014-01-01

The aim of this book is to teach undergraduate college or university students the basic physics concepts needed to understand the mathematics which describes the evolution of the universe, and based on this to teach the astrophysical theories behind evolution from very early times to the present. The book does not require students to have extensive knowledge of mathematics, like calculus, and includes material that explains concepts such as velocity, acceleration, and force. Based on this, fascinating topics such as Dark Matter, measuring Dark Energy via supernovae velocities, and the creation of mass via the Higgs mechanism are explained. All college students with an interest in science, especially astronomy, without extensive mathematical backgrounds should be able to use and learn from this book. Adults interested in topics like dark energy and the Higgs boson, which are in the news, can make use of this book as well.

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.)

Computational Infrastructure for Nuclear Astrophysics

International Nuclear Information System (INIS)

Smith, Michael S.; Hix, W. Raphael; Bardayan, Daniel W.; Blackmon, Jeffery C.; Lingerfelt, Eric J.; Scott, Jason P.; Nesaraja, Caroline D.; Chae, Kyungyuk; Guidry, Michael W.; Koura, Hiroyuki; Meyer, Richard A.

2006-01-01

A Computational Infrastructure for Nuclear Astrophysics has been developed to streamline the inclusion of the latest nuclear physics data in astrophysics simulations. The infrastructure consists of a platform-independent suite of computer codes that is freely available online at nucastrodata.org. Features of, and future plans for, this software suite are given

Precise mass measurements of astrophysical interest made with the Canadian Penning trap mass spectrometer

International Nuclear Information System (INIS)

Clark, J.A.; Barber, R.C.; Blank, B.; Boudreau, C.; Buchinger, F.; Crawford, J.E.; Gulick, S.; Hardy, J.C.; Heinz, A.; Lee, J.K.P.; Levand, A.F.; Moore, R.B.; Savard, G.; Seweryniak, D.; Sharma, K.S.; Sprouse, G.D.; Trimble, W.; Vaz, J.; Wang, J.C.; Zhou, Z.

2004-01-01

The processes responsible for the creation of elements more massive than iron are not well understood. Possible production mechanisms involve the rapid capture of protons (rp-process) or the rapid capture of neutrons (r-process), which are thought to occur in explosive astrophysical events such as novae, x-ray bursts, and supernovae. Mass measurements of the nuclides involved with uncertainties on the order of 100 keV or better are critical to determine the process 'paths', the energy output of the events, and the resulting nuclide abundances. Particularly important are the masses of 'waiting-point' nuclides along the rp-process path where the process stalls until the subsequent β decay of the nuclides. This paper will discuss the precise mass measurements made of isotopes along the rp-process and r-process paths using the Canadian Penning Trap mass spectrometer, including the mass of the critical waiting-point nuclide 68 Se

Modeling the astrophysical dynamical process with laser-plasmas

International Nuclear Information System (INIS)

Xia Jiangfan; Zhang Jun; Zhang Jie

2001-01-01

The use of the state-of-the-art laser facility makes it possible to create conditions of the same or similar to those in the astrophysical processes. The introduction of the astrophysics-relevant ideas in laser-plasma experiments is propitious to the understanding of the astrophysical phenomena. However, the great difference between the laser-produced plasmas and the astrophysical processes makes it awkward to model the latter by laser-plasma experiments. The author addresses the physical backgrounds for modeling the astrophysical plasmas by laser plasmas, connecting these two kinds of plasmas by scaling laws. Thus, allowing the creation of experimental test beds where observations and models can be quantitatively compared with laser-plasma data. Special attentions are paid on the possibilities of using home-made laser facilities to model astrophysical phenomena

The Explorer program for astronomy and astrophysics

International Nuclear Information System (INIS)

Savage, B.D.; Becklin, E.E.; Cassinelli, J.P.; Dupree, A.K.; Elliot, J.L.; Hoffmann, W.F.; Hudson, H.S.; Jura, M.; Kurfess, J.; Murray, S.S.

1986-01-01

This report was prepared to provide NASA with a strategy for proceeding with Explorer-class programs for research in space astronomy and astrophysics. The role of Explorers in astronomy and astrophysics and their past accomplishments are discussed, as are current and future astronomy and astrophysics Explorers. Specific cost needs for an effective Explorer program are considered

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

International Nuclear Information System (INIS)

Velazquez, L

2016-01-01

Aspects concerning the thermodynamics of astrophysical systems are discussed, generally, and also more specifically those relating to astrophysical systems in mutual interaction (or the so-called open astrophysical systems). A special interest is devoted in this paper to clarifying several misconceptions that are still common in the recent literature, such as the direct application to the astrophysical scenario of notions and theoretical frameworks that were originally conceived to deal with extensive systems of everyday practice (large systems with short-range interactions). This discussion starts by reviewing the current understanding of the notion of negative heat capacity. Beyond this, to clarify its physical relevance, the conciliation of this notion with classical fluctuation theory is discussed, as well as equilibrium conditions concerning systems with negative heat capacities. These results prompt a revision of our understanding about critical phenomena, phase transitions and the so-called zeroth law of thermodynamics. Afterwards, general features about the thermodynamics of astrophysical systems are presented through the consideration of simple models available in the literature. Particular attention is devoted to the influence of evaporation on the macroscopic behavior of these systems. These antecedents are then applied to a critical approach towards the thermodynamics of astrophysical systems in mutual interaction. It is discussed that the long-range character of gravitation leads to the incidence of long-range correlations. This peculiarity imposes a series of important consequences, such as the non-separability of a single astrophysical structure into independent subsystems, the breakdown of additivity and conventional thermodynamic limit, a great sensibility of the macroscopic behavior to the external conditions, the restricted applicability of the so-called thermal contact in astrophysics, and hence, the non-relevance of conventional statistical

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.

Astrophysics at RIA (ARIA) Working Group

International Nuclear Information System (INIS)

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

2006-01-01

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

5th International conference on High Energy Density Laboratory Astrophysics

CERN Document Server

Kyrala, G.A

2005-01-01

During the past several years, research teams around the world have developed astrophysics-relevant utilizing high energy-density facilities such as intense lasers and z-pinches. Research is underway in many areas, such as compressible hydrodynamic mixing, strong shock phenomena, radiation flow, radiative shocks and jets, complex opacities, equations o fstat, and relativistic plasmas. Beyond this current research and the papers it is producing, plans are being made for the application, to astrophysics-relevant research, of the 2 MJ National Ignition Facility (NIF) laser at Lawrence Livermore National Laboratory; the 600 kj Ligne d'Intergration Laser (LIL) and the 2 MJ Laser Megajoule (LMJ) in Bordeaux, France; petawatt-range lasers now under construction around the world; and current and future Z pinches. The goal of this conference and these proceedings is to continue focusing and attention on this emerging research area. The conference brought together different scientists interested in this emerging new fi...

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%.

Study of aluminum emission spectra in astrophysical plasmas

International Nuclear Information System (INIS)

Jin Zhan; Zhang Jie

2001-01-01

High temperature, high density and strong magnetic fields in plasmas produced by ultra-high intensity and ultrashort laser pulses are similar to the main characteristics of astrophysical plasmas. This makes it possible to simulate come astrophysical processes at laboratories. The author presents the theoretic simulation of aluminum emission spectra in astrophysical plasmas. It can be concluded that using laser produced plasmas, the authors can obtain rich information on astrophysical spectroscopy, which is unobservable for astronomer

Hydrodynamic instabilities in astrophysics and ICF

International Nuclear Information System (INIS)

Paul Drake, R.

2005-01-01

Inertial fusion systems and astrophysical systems both involve hydrodynamic effects, including sources of pressure, shock waves, rarefactions, and plasma flows. In the evolution of such systems, hydrodynamic instabilities naturally evolve. As a result, a fundamental understanding of hydrodynamic instabilities is necessary to understand their behavior. In addition, high-energy-density facilities designed for ICF purposes can be used to provide and experimental basis for understanding astrophysical processes. In this talk. I will discuss the instabilities that appear in astrophysics and ICF from the common perspective of the basic mechanisms at work. Examples will be taken from experiments aimed at ICF, from astrophysical systems, and from experiments using ICF systems to address issues in astrophysics. The high-energy-density research facilities of today can accelerate small but macroscopic amounts of material to velocities above 100 km/s, can heat such material to temperature above 100 eV, can produce pressures far above a million atmospheres (10''12 dybes/cm''2 or 0.1 TPascal), and can do experiments under these conditions that address basic physics issues. This enables on to devise experiments aimed directly at important process such as the Rayleigh Taylor instability at an ablating surface or at an embedded interface that is accelerating, the Richtmeyer Meshkov evolution of shocked interfaces, and the Kelvin-Helmholtz instability of shear flows. The talk will include examples of such phenomena from the laboratory and from astrophysics, and will discuss experiments to study them. (Author)

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

AstroMail: Electronic mail for the astrophysics community

Science.gov (United States)

Scherrer, Phillip H.; Bogart, Richard S.

1993-01-01

As part of the NASA Science Internet User Support Services program, NASA Goddard was interested in R&D which could extend the SolarMail system developed by members of the Wilcox Space Observatory at Stanford University to support a larger astrophysics user community. Specific objectives of the R&D effort were to include: a clone of the existing SolarMail system with additional documentation, enabling a parallel mail system to be established by populating the database; a cloned version of SolarMail functioning with a user database similar to that of the High Energy Astrophysics Division (HEAD) of the American Astronomical Society; a report on the status and surveyed usage of SolarMail and its clones into an extendable distributed mail system to serve as the basis for AstroMail, including a draft declaration of policy; a prototype AstroMail system based on the above specifications and including at least SolarMail and one of its clones supporting a set of astronomy user databases as subsets; and a report on the status of the prototype AstroMail with recommendations for future modifications to AstroMail.

Toward observational neutrino astrophysics

International Nuclear Information System (INIS)

Koshiba, M.

1988-01-01

It is true that: (1) The first observation of the neutrino burst from the supernova SN1987a by Kamiokande-II which was immediately confirmed by IBM; and (2) the first real-time, directional, and spectral observation of solar 8 B neutrinos also by Kamiokande-II could perhaps be considered as signalling the birth of observational astrophysics. The field, however, is still in its infancy and is crying out for tender loving care. Namely, while the construction of astronomy requires the time and the direction of the signal and that of astrophysics requires, in addition to the spectral information, the observations of (1) could not give the directional information and the results of both (1) and (2) are still suffering from the meager statistics. How do we remedy this situation to let this new born science of observational neutrino astrophysics grow healthy. This is what the author addresses in this talk. 15 refs., 8 figs

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

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...

Observational astrophysics

CERN Document Server

Smith, Robert C

1995-01-01

Combining a critical account of observational methods (telescopes and instrumentation) with a lucid description of the Universe, including stars, galaxies and cosmology, Smith provides a comprehensive introduction to the whole of modern astrophysics beyond the solar system. The first half describes the techniques used by astronomers to observe the Universe: optical telescopes and instruments are discussed in detail, but observations at all wavelengths are covered, from radio to gamma-rays. After a short interlude describing the appearance of the sky at all wavelengths, the role of positional astronomy is highlighted. In the second half, a clear description is given of the contents of the Universe, including accounts of stellar evolution and cosmological models. Fully illustrated throughout, with exercises given in each chapter, this textbook provides a thorough introduction to astrophysics for all physics undergraduates, and a valuable background for physics graduates turning to research in astronomy.

Nuclear physics in astrophysics. Part 2. Abstracts

International Nuclear Information System (INIS)

Gyuerky, Gy.; Fueloep, Zs.

2005-01-01

The proceedings of the 20. International Nuclear Physics Divisional Conference of the European Physical Society covers a wide range of topics in nuclear astrophysics. The topics addressed are big bang nucleosynthesis, stellar nucleosynthesis, measurements and nuclear data for astrophysics, nuclear structure far from stability, neutrino physics, and rare-ion-beam facilities and experiments. The perspectives of nuclear physics and astrophysics are also overviewed. 77 items are indexed separately for the INIS database. (K.A.)

Magnetohydrodynamic models of astrophysical jets

International Nuclear Information System (INIS)

Beskin, Vasily S

2010-01-01

In this review, analytical results obtained for a wide class of stationary axisymmetric flows in the vicinity of compact astrophysical objects are analyzed, with an emphasis on quantitative predictions for specific sources. Recent years have witnessed a great increase in understanding the formation and properties of astrophysical jets. This is due not only to new observations but also to advances in analytical theory which has produced fairly simple relations, and to what can undoubtedly be called a breakthrough in numerical simulation which has enabled confirmation of theoretical predictions. Of course, we are still very far from fully understanding the physical processes occurring in compact sources. Nevertheless, the progress made raises hopes for near-future test observations that can give insight into the physical processes occurring in active astrophysical objects. (reviews of topical problems)

The Trojan Horse Method for nuclear astrophysics and its recent applications

Science.gov (United States)

Lamia, L.; Spitaleri, C.; Mazzocco, M.; Boiano, A.; Boiano, C.; Broggini, C.; Caciolli, A.; Depalo, R.; Di Pietro, A.; Figuera, P.; Galtarossa, F.; Guardo, G. L.; Gulino, M.; Hayakawa, S.; Kubono, S.; La Cognata, M.; La Commara, M.; La Rana, G.; Lattuada, M.; Menegazzo, R.; Pakou, A.; Parascandolo, C.; Piatti, D.; Pierroutsakou, D.; Pizzone, R. G.; Puglia, S. M. R.; Romano, S.; Rapisarda, G. G.; Sanchez-Benitez, A. M.; Sergi, M. L.; Sgouros, O.; Silva, H.; Soramel, F.; Soukeras, V.; Strano, E.; Torresi, D.; Trippella, O.; Tumino, A.; Yamaguchi, H.; Villante, F. L.; Zhang, G. L.

2018-01-01

The Trojan Horse Method (THM) has been applied extensively for the last 25 years to measure nuclear reaction cross sections of interest for astrophysics. Although it has been mainly applied for charged particle-induced reactions, recently it has been found to have also a relevant role for neutron-induced reactions. Here, some advantages of THM will be discussed and the preliminary results of the cosmological relevant 7Be(n,α)4He cross section measurement are discussed.

Astrophysics at very high energies

International Nuclear Information System (INIS)

Aharonian, Felix; Bergstroem, Lars; Dermer, Charles

2013-01-01

Presents three complementary lectures on very-high-energy astrophysics given by worldwide leaders in the field. Reviews the recent advances in and prospects of gamma-ray astrophysics and of multi-messenger astronomy. Prepares readers for using space and ground-based gamma-ray observatories, as well as neutrino and other multi-messenger detectors. With the success of Cherenkov Astronomy and more recently with the launch of NASA's Fermi mission, very-high-energy astrophysics has undergone a revolution in the last years. This book provides three comprehensive and up-to-date reviews of the recent advances in gamma-ray astrophysics and of multi-messenger astronomy. Felix Aharonian and Charles Dermer address our current knowledge on the sources of GeV and TeV photons, gleaned from the precise measurements made by the new instrumentation. Lars Bergstroem presents the challenges and prospects of astro-particle physics with a particular emphasis on the detection of dark matter candidates. The topics covered by the 40th Saas-Fee Course present the capabilities of current instrumentation and the physics at play in sources of very-high-energy radiation to students and researchers alike. This book will encourage and prepare readers for using space and ground-based gamma-ray observatories, as well as neutrino and other multi-messenger detectors.

Analogue Hawking radiation from astrophysical black-hole accretion

International Nuclear Information System (INIS)

Das, Tapas K

2004-01-01

We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass

Recent progress on astrophysical opacity

International Nuclear Information System (INIS)

Rogers, F.J.; Iglesias, C.A.

1992-08-01

Improvements in the calculation of the opacity of astrophysical plasmas has helped to resolve several long-standing puzzles in the modeling of variable stars. The most significant opacity enhancements over the Los Alamos Astrophysical Library (LAOL) are due to improvements in the equation of state and atomic physics. Comparison with experiment has corroborated the predicted large opacity increases due to transitions in M-shell iron. We give a summary of recent developments

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.

Introduction to Nuclear Astrophysics

International Nuclear Information System (INIS)

Iliadis, Christian

2010-01-01

In the first lecture of this volume, we will present the basic fundamental ideas regarding nuclear processes occurring in stars. We start from stellar observations, will then elaborate on some important quantum-mechanical phenomena governing nuclear reactions, continue with how nuclear reactions proceed in a hot stellar plasma and, finally, we will provide an overview of stellar burning stages. At the end, the current knowledge regarding the origin of the elements is briefly summarized. This lecture is directed towards the student of nuclear astrophysics. Our intention is to present seemingly unrelated phenomena of nuclear physics and astrophysics in a coherent framework.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Indian Institute of Astrophysics, Koramangala, Bangalore 560 034, India. Kavli Institute for Astronomy & Astrophysics, Peking University, Beijing 100871, China. National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, British Columbia, Canada. Thirty Meter Project Office, ...

New Improved Indirect Measurement of the {sup 19}F( p , α ){sup 16}O Reaction at Energies of Astrophysical Relevance

Energy Technology Data Exchange (ETDEWEB)

Indelicato, I.; La Cognata, M.; Spitaleri, C.; Cherubini, S.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Romano, S.; Tumino, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J. [Nuclear Physics Institute of ASCR, Rez near Prague (Czech Republic); Hayakawa, S. [RIKEN, CNS, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mazzocco, M.; Strano, E.; Torresi, D., E-mail: indelicato@lns.infn.it [INFN, Sezione di Padova, Padova (Italy)

2017-08-10

Fluorine abundance determination is of great importance in stellar physics to understand s-elements production and mixing processes in asymptotic giant branch (AGB) stars. Up to now, theoretical models overproduce F abundances in AGB stars with respect to the observed values, thus calling for further investigation of the reactions involving fluorine. In particular, the {sup 19}F( p , α ){sup 16}O reaction is the main destruction channel of fluorine at the bottom of the convective envelope in AGB stars, an H-rich environment where it can experience temperatures high enough to determine its destruction, owing to additional mixing processes. In this paper the Trojan horse method (THM) was used to extract the {sup 19}F( p , α {sub 0}){sup 16}O S-factor in the energy range of astrophysical interest ( E {sub cm} ≈ 0–1 MeV). This is the most relevant channel at the low temperatures (few 10{sup 7} K) characterizing the bottom of the convective envelope, according to current knowledge. A previous indirect experiment using the THM has observed three resonances in the energy regions below E {sub cm} ≈ 450 keV. These energies correspond to typical AGB temperatures, thus implying a significant increase in the reaction rate. Statistics are scarce for performing an accurate separation between resonances, preventing one from drawing a quantitative conclusion about their total widths and spin parities. Before THM measurement, only extrapolations were available below about 500 keV, showing a non-resonant behavior that sharply contradicts the trend of the astrophysical factor at higher energies. A new experiment has been performed to verify the measured TH astrophysical factor and to perform more accurate spectroscopy of the involved resonances.

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....

Computational Laboratory Astrophysics to Enable Transport Modeling of Protons and Hydrogen in Stellar Winds, the ISM, and other Astrophysical Environments

Science.gov (United States)

Schultz, David

As recognized prominently by the APRA program, interpretation of NASA astrophysical mission observations requires significant products of laboratory astrophysics, for example, spectral lines and transition probabilities, electron-, proton-, or heavy-particle collision data. Availability of these data underpin robust and validated models of astrophysical emissions and absorptions, energy, momentum, and particle transport, dynamics, and reactions. Therefore, measured or computationally derived, analyzed, and readily available laboratory astrophysics data significantly enhances the scientific return on NASA missions such as HST, Spitzer, and JWST. In the present work a comprehensive set of data will be developed for the ubiquitous proton-hydrogen and hydrogen-hydrogen collisions in astrophysical environments including ISM shocks, supernova remnants and bubbles, HI clouds, young stellar objects, and winds within stellar spheres, covering the necessary wide range of energy- and charge-changing channels, collision energies, and most relevant scattering parameters. In addition, building on preliminary work, a transport and reaction simulation will be developed incorporating the elastic and inelastic collision data collected and produced. The work will build upon significant previous efforts of the principal investigators and collaborators, will result in a comprehensive data set required for modeling these environments and interpreting NASA astrophysical mission observations, and will benefit from feedback from collaborators who are active users of the work proposed.

360-degree videos: a new visualization technique for astrophysical simulations, applied to the Galactic Center

Science.gov (United States)

Russell, Christopher

2018-01-01

360-degree videos are a new type of movie that renders over all 4π steradian. Video sharing sites such as YouTube now allow this unique content to be shared via virtual reality (VR) goggles, hand-held smartphones/tablets, and computers. Creating 360-degree videos from astrophysical simulations not only provide a new way to view these simulations due to their immersive nature, but also yield engaging content for outreach to the public. We present our 360-degree video of an astrophysical simulation of the Galactic center: a hydrodynamics calculation of the colliding and accreting winds of the 30 Wolf-Rayet stars orbiting within the central parsec. Viewing the movie, which renders column density, from the location of the supermassive black hole gives a unique and immersive perspective of the shocked wind material inspiraling and tidally stretching as it plummets toward the black hole. We also describe how to create such movies, discuss what type of content does and does not look appealing in 360-degree format, and briefly comment on what new science can be extracted from astrophysical simulations using 360-degree videos.

Charged-particle transfer reactions and nuclear astrophysics problems

International Nuclear Information System (INIS)

Artemov, S.V.; Yarmukhamedov, R.; Yuldashev, B.S.; Burtebaev, N.; Duysebaev, A.; Kadyrzhanov, K.K.

2002-01-01

In the report a review of the recent results of calculation of the astrophysical S-factors S(E) for the D(α, γ) 6 Li, 3 He(α, γ) 7 Be, 7 Be(p, γ) 8 Be, 12,13 C(p, γ) 13, 14 N and 12 C(p,γ) 16 O* reactions at extremely low energies E, including value E=0 , performed within the framework of a new method taking into account the additional information about the nuclear vertex constant (Nc) (or the respective asymptotic normalization coefficient) are presented. The required values of Nc can be obtained from an analysis of measured differential cross-sections of proton and α-particle transfer reactions (for example A( 3 He,d)B, 6 Li(d, 6 Li)d, 6 Li(α, 6 Li)α, 12 C( 6 Li, d) 16 O* etc.). A comparative analysis between the results obtained by different authors is also done. Taking into account an important role of the NVC's values for the nuclear astrophysical A(p, γ)B and A(α, γ)B reactions, a possibility of obtaining the reliable NVC values for the virtual decay B→A+p and B→A+α from the analysis of differential cross sections both sub- and above-barrier A( 3 He, d) and A( 6,7 Li, 2,3 H)B reactions is discussed in detail. In this line the use the isochronous cyclotron U-150 M, the 'DC-60' heavy ion machine and electrostatic charge-exchanging accelerator UKP-2-1 of Institute of Nuclear Physics of National Nuclear Center of the Republic of Kazakhstan for carrying out the needed experiments is considered and the possibility of the obtained data application for the astrophysical interest is also discussed

Recent Results In Nuclear Astrophysics At The n_TOF Facility At CERN

CERN Document Server

Tagliente, Giuseppe; Andrzejewski, J; Audouin, L; Bacak, M; Balibrea, J; Barbagallo, M; Bečvář, F; Berthoumieux, E; Billowes, J; Bosnar, D; Brown, A; Caamaño, M; Calviño, F; Calviani, M; Cano-Ott, D; Cardella, R; Casanovas, A; Cerutti, F; Chen, Y H; Chiaveri, E; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Cosentino; Damone, L A; Diakaki, M; Domingo-Pardo, C; Dressler, L R; Dupont, E; Durán, I; Fernández-Domínguez, B; Ferrari, A; Ferreira, P; Finocchiaro, P; Furman, V; Göbel, K; García, A R; Gawlik, A; Gilardoni, S; Glodariu, T; Gonçalves, I F; González, E; Griesmayer, E; Guerrero, C; Gunsing, F; Harada, H; Heinitz, S; Heyse, J; Jenkins, D G; Jericha, E; Käppeler, F; Kadi, Y; Kalamara, A; Kavrigin, P; Kimura, A; Kivel, N; Kokkoris, M; Krtička, M; Kurtulgil, D; Leal-Cidoncha, E; Lederer, C; Lerendegui-Marco, J; Leeb, H; Lo Meo, S; Lonsdale, S J; Macina, D; Marganiec, J; Martínez, T; Masi, A; Massimi, C; Mastinu, P; Mastromarco, M; Maugeri, E A; Mazzone, A; Mendoza, E; Mengoni, A; Mingrone, F; Milazzo, P M; Musumarra, A; Negret, A; Nolte, R; Oprea, A; Patronis, N; Pavlik, A; Perkowski, J; Porras, I; Praena, J; Quesada, J M; Radeck, D; Rauscher, T; Reifarth, R; Rubbia, C; Ryan, J A; Sabaté-Gilarte, M; Saxena, A; Schillebeeckx, P; Schumann, D; Sedyshev, P; Smith, A G; Sosnin, N V; Stamatopoulos, A; Tain, J L; Tarifeño-Saldivia, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Vlachoudis, V; Vlastou, R; Wallner, A; Warren, S; Woods, P J; Żugec, P Č

2017-01-01

The neutron time of flight (n_TOF) facility at CERN is a spallation source characterized by a white neutron spectrum. The innovative features of the facility, in the two experimental areas, (20 m and 185 m), allow for an accurate determination of the neutron cross section for radioactive samples or for isotopes with small neutron capture cross section, of interest for Nuclear Astrophysics. The recent results obtained at n_TOF facility are presented.

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.

SA-Mot: a web server for the identification of motifs of interest extracted from protein loops.

Science.gov (United States)

Regad, Leslie; Saladin, Adrien; Maupetit, Julien; Geneix, Colette; Camproux, Anne-Claude

2011-07-01

The detection of functional motifs is an important step for the determination of protein functions. We present here a new web server SA-Mot (Structural Alphabet Motif) for the extraction and location of structural motifs of interest from protein loops. Contrary to other methods, SA-Mot does not focus only on functional motifs, but it extracts recurrent and conserved structural motifs involved in structural redundancy of loops. SA-Mot uses the structural word notion to extract all structural motifs from uni-dimensional sequences corresponding to loop structures. Then, SA-Mot provides a description of these structural motifs using statistics computed in the loop data set and in SCOP superfamily, sequence and structural parameters. SA-Mot results correspond to an interactive table listing all structural motifs extracted from a target structure and their associated descriptors. Using this information, the users can easily locate loop regions that are important for the protein folding and function. The SA-Mot web server is available at http://sa-mot.mti.univ-paris-diderot.fr.

High energy astrophysics

International Nuclear Information System (INIS)

Engel, A.R.

1979-01-01

High energy astrophysical research carried out at the Blackett Laboratory, Imperial College, London is reviewed. Work considered includes cosmic ray particle detection, x-ray astronomy, gamma-ray astronomy, gamma and x-ray bursts. (U.K.)

2004 ASTRONOMY & ASTROPHYSICS

Indian Academy of Sciences (India)

user

This publication of the Academy on Astronomy and Astrophysics is unique in ... bring out position papers on societal issues where science plays a major ..... funding agencies, the Astronomical Society of ..... orbit very close to the parent star.

78 FR 2293 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

Science.gov (United States)

2013-01-10

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics... meeting includes the following topics: --Astrophysics Division Update --NASA Astrophysics Roadmapping It...

78 FR 66384 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

Science.gov (United States)

2013-11-05

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics...: --Astrophysics Division Update --Presentation of Astrophysics Roadmap --Reports from Program Analysis Groups...

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

Science.gov (United States)

2010-08-18

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics... topics: --Astrophysics Division Update --2010 Astronomy and Astrophysics Decadal Survey --Update on...

White Paper on Nuclear Astrophysics

OpenAIRE

Arcones, Almudena; Bardayan, Dan W.; Beers, Timothy C.; Berstein, 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

2016-01-01

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 mee...

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

Science.gov (United States)

2010-01-19

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... of the Astrophysics Subcommittee of the NASA Advisory Council (NAC). This Subcommittee reports to the... following topics: --Astrophysics Division Update --Updates on Select Astrophysics Missions --Discussion of...

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.

The path to improved reaction rates for astrophysics

International Nuclear Information System (INIS)

Rauscher, T.

2011-01-01

This review focuses on nuclear reactions in astrophysics and, more specifically, on reactions with light ions (nucleons and α particles) proceeding via the strong interaction. It is intended to present the basic definitions essential for studies in nuclear astrophysics, to point out the differences between nuclear reactions taking place in stars and in a terrestrial laboratory, and to illustrate some of the challenges to be faced in theoretical and experimental studies of those reactions. The discussion revolves around the relevant quantities for astrophysics, which are the astrophysical reaction rates. The sensitivity of the reaction rates to the uncertainties in the prediction of various nuclear properties is explored and some guidelines for experimentalists are also provided. (author)

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...

High energy astrophysics an introduction

CERN Document Server

Courvoisier, Thierry J -L

2013-01-01

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...

Some nuclear data needs in astrophysics

International Nuclear Information System (INIS)

Mathews, G.J.; Bauer, R.W.; Bloom, S.D.; Haight, R.C.; Howard, W.M.; Takahashi, K.; Ward, R.A.

1985-05-01

In this paper we discuss a number of astrophysical environments and how improved nuclear data could facilitate a better understanding of them. One area of interest includes proton and alpha-particle reactions with unstable nuclei which are necessary for understanding the nucleosynthesis and energy generation in hot hydrogen-burning environments. Efforts underway at LLNL and elsewhere to develop the technology for the measurement of these reaction rates are discussed. Heavy-element nucleosynthesis in the late stages of red-giant stars and supernovae requires a complete network of neutron capture rates and beta-decay rates for nuclei near and far from stability. Experimental and theoretical efforts at LLNL to supply the input data and to model the nucleosynthetic environments will be outlined. Suggestions are made as to which nuclear data are most critical for the various scenarios. 42 refs., 11 figs., 1 tab

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 ...

Recent applications of the the Trojan Horse method to nuclear astrophysics

Energy Technology Data Exchange (ETDEWEB)

Spitaleri, Claudio [Dipartimento di Fisica e Astronomia, Catania University (Italy) and INFN-Laboratoti Nazionali del Sud, Catania (Italy)

2012-11-20

Light elements lithium, beryllium and boron (LiBeB) have been used in the last years as possible probes for stellar structure. They are mainly destroyed by (p,a) reactions and cross section measurements for such channels are then needed. The Trojan Horse Method (THM) allows one to extract the astrophysical S(E)-factor without the experience of tunneling through the Coulomb barrier. In this work a resume of the recent new results about the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be and {sup 7}Li(p,{alpha}){sup 4}He reactions are shown.

Worrying about the LHC, a lesson from astrophysics?

CERN Multimedia

CERN. Geneva

2008-01-01

To worry about the LHC is a popular sport. I shall share my own worries, hopefully original, and do it via a parable (for this method, I can quote earlier authors). The parable concerns a topic in astrophysics (gamma-ray bursts) which happens to be a simple exercise --but quite an interesting one-- on elementary particle-physics and beam dynamics, topics not unrelated to the LHC. Though most of the talk will be dedicated to the physics and, in particular, to its recent developments, the allegory will allow me to detect what, I shall argue, may be dangerous 'viruses' invading science. I do not have the decisive antidotes, but I shall discuss some possible ones.

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

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...

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.

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.

Two families of astrophysical diverging lens models

Science.gov (United States)

Er, Xinzhong; Rogers, Adam

2018-03-01

In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

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

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

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

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

Nuclear astrophysics data at ORNL

International Nuclear Information System (INIS)

Smith, M.S.; Blackmon, J.C.

1998-01-01

There is a new program of evaluation and dissemination of nuclear data of critical importance for nuclear astrophysics within the Physics Division of Oak Ridge National Laboratory. Recent activities include determining the rates of the important 14 O(α,p) 17 F and 17 F(p,γ) 18 Ne reactions, disseminating the Caughlan and Fowler reaction rate compilation on the World Wide Web, and evaluating the 17 O(p,α) 14 N reaction rate. These projects, which are closely coupled to current ORNL nuclear astrophysics research, are briefly discussed along with future plans

Nuclear Data for Astrophysics Research: A New Online Paradigm

International Nuclear Information System (INIS)

Smith, Michael Scott

2011-01-01

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

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.

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...

Astrophysical S factor for 13C(p,γ)14N and asymptotic normalization coefficients

International Nuclear Information System (INIS)

Mukhamedzhanov, A.M.; Azhari, A.; Gagliardi, C.A.; Sattarov, A.; Tang, X.; Trache, L.; Tribble, R.E.; Burjan, V.; Kroha, V.

2002-01-01

We reanalyze the 13 C(p,γ) 14 N radiative capture reaction within the R-matrix approach. The low-energy astrophysical S factor has important contributions from both resonant and onresonant captures. The normalization of the nonresonant component of the transition to a particular 14 N bound state is expressed in terms of the asymptotic normalization coefficient (ANC). In the analysis we use the experimental ANC's inferred from the 13 C( 14 N, 13 C) 14 N and 13 C( 3 He,d) 14 N reactions. The fits of the calculated S factors to the experimental data are sensitive to the ANC values and are used to test the extracted ANC's. We find that for transitions to all the states in 14 N, except the third excited state, the ANC's determined from the transfer reactions provide the best fit. The astrophysical factor we obtain, S(0)=7.7±1.1 keV b, is in excellent agreement with previous results

Astrophysics of Super-Massive Black Hole Mergers

Science.gov (United States)

Schnittman, Jeremy D.

2013-01-01

We present here an overview of recent work in the subject of astrophysical manifestations of super-massive black hole (SMBH) mergers. This is a field that has been traditionally driven by theoretical work, but in recent years has also generated a great deal of interest and excitement in the observational astronomy community. In particular, the electromagnetic (EM) counterparts to SMBH mergers provide the means to detect and characterize these highly energetic events at cosmological distances, even in the absence of a space-based gravitational-wave observatory. In addition to providing a mechanism for observing SMBH mergers, EM counterparts also give important information about the environments in which these remarkable events take place, thus teaching us about the mechanisms through which galaxies form and evolve symbiotically with their central black holes.

Java 3D Interactive Visualization for Astrophysics

Science.gov (United States)

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

2003-05-01

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

Particle Astrophysics after COBE- Blois 92- Summary Talk

Science.gov (United States)

Primack, J. R.

The IV Rencontres de Blois, on Particle Astrophysics, held at the Ch\\^ateau de Blois, June 15-20, 1992, was a meeting well-timed for a reconsideration of the issues in particle astrophysics in the light of the COBE discovery of the cosmic microwave background (CMB) fluctuations. This is a summary of what I thought were the most interesting things discussed at Blois: (1) The near-success of Cold Dark Matter (CDM) in predicting the COBE fluctuation amplitude, which favors the hypothesis that structure formed in the universe through gravitational collapse. (2) The indications that $\\Omega\\approx1$ and that the power spectrum has a little more power on supercluster and larger scales than CDM. These are suggested by the IRAS and CfA redshift surveys and POTENT galaxy peculiar velocity analysis, and also by the COBE data. (3) The consequent demise of CDM and the rise of hybrid schemes such as Cold+Hot Dark Matter (C+HDM). (4) The possible implications for neutrino masses and mixings, and for cosmology, of the recent results on solar neutrinos. (5) The first discovery of TeV $\\gamma$ rays from an extragalactic source, which was announced at Blois. I also summarize here a number of the exciting ongoing and planned experiments and observations discussed at Blois: CERN experiments on $\

Workshop on the origin of the heavy elements: Astrophysical models and experimental challenges, Santa Fe, New Mexico, September 3-4, 1999

International Nuclear Information System (INIS)

Haight, Robert C.; Ullmann, John L.; Strottman, Daniel D.; Koehler, Paul E.; Kaeppeler, Franz

2000-01-01

This Workshop was held on September 3--4, 1999, following the 10th International Symposium on Capture Gamma-Ray Spectroscopy. Presentations were made by 14 speakers, 6 from the US and 8 from other countries on topics relevant to s-, r- and rp-process nucleosynthesis. Laboratory experiments, both present and planned, and astrophysical observations were represented as were astrophysical models. Approximately 50 scientists participated in this Workshop. These Proceedings consist of copies of vu-graphs presented at the Workshop. For further information, the interested readers are referred to the authors

Trojin horse method for indirect measurement of astrophysic S factor

International Nuclear Information System (INIS)

Fu Yuanyong; Zhou Shuhua; Li Chengbo; Wen Qungang

2014-01-01

The nuclear reaction rates in the astrophysical environment are indispensable input parameters in different astrophysics theories, and play important roles in understanding the astrophysical nuclear synthesis and the evolution of the universe. However, at the astrophysical temperature, the nuclear reactions proceed at very low energies. Due to the Coulomb barrier the reaction cross sections are very small, so that the direct measurement is almost impossible. The Trojin horse theory provides a useful method to measure indirectly the low energy two body cross sections by measuring the suitable three body reactions. Some approximations are applied in the theory to get convenient formula. This paper introduces the Trojin horse theory and its application in astrophysics nuclear reactions. (authors)

Astrophysics today

International Nuclear Information System (INIS)

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

High energy astrophysics

International Nuclear Information System (INIS)

Shklorsky, I.S.

1979-01-01

A selected list of articles of accessible recent review articles and conference reports, wherein up-to-date summaries of various topics in the field of high energy astrophysics can be found, is presented. A special report outlines work done in the Soviet Union in this area. (Auth.)

Emotion Discrimination using spatially Compact Regions of Interest extracted from Imaging EEG Activity

Directory of Open Access Journals (Sweden)

Jorge Ivan Padilla-Buritica

2016-07-01

Full Text Available Lately, research on computational models of emotion had been getting much attention due to their potential for understanding the mechanisms of emotions and their promising broad range of applications that potentially bridge the gap between human and machine interactions. We propose a new method for emotion classification that relies on features extracted from those active brain areas that are most likely related to emotions. To this end, we carry out the selection of spatially compact regions of interest that are computed using the brain neural activity reconstructed from electroencephalography data. Throughout this study, we consider three representative feature extraction methods widely applied to emotion detection tasks, including Power spectral density, Wavelet, and Hjorth parameters. Further feature selection is carried out using principal component analysis. For validation purpose, these features are used to feed a support vector machine classifier that is trained under the leave-one-out cross-validation strategy. Obtained results on real affective data show that incorporation of the proposed training method in combination with the enhanced spatial resolution provided by the source estimation allows improving the performed accuracy of discrimination in most of the considered emotions, namely: dominance, valence, and linking.

Astrophysical observations: lensing and eclipsing Einstein's theories.

Science.gov (United States)

Bennett, Charles L

2005-02-11

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

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...... and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography and what can be learned by comparison of these applications....

Nuclear astrophysics away from stability

International Nuclear Information System (INIS)

Mathews, G.J.; Howard, W.M.; Takahashi, K.; Ward, R.A.

1985-08-01

Explosive astrophysical environments invariably lead to the production of nuclei away from stability. An understanding of the dynamics and nucleosynthesis in such environments is inextricably coupled to an understanding of the properties of the synthesized nuclei. In this talk a review is presented of the basic explosive nucleosynthesis mechanisms (s-process, r-process, n-process, p-process, and rp-process). Specific stellar model calculations are discussed and a summary of the pertinent nuclear data is presented. Possible experiments and nuclear-model calculations are suggested that could facilitate a better understanding of the astrophysical scenarios. 39 refs., 4 figs

12th Italian-Korean Symposium on Relativistic Astrophysics

International Nuclear Information System (INIS)

Won Lee, Hyung; Remo Riffini; Vereshchagin

2013-01-01

This series of biannual symposia, since 1987, has been boosting exchange of information and collaborations between Italian and Korean astrophysicists on new and hot issues in the field of Relativistic Astrophysics. These symposia cover relativistic field theories, astrophysics and cosmology, topics such as gamma-ray bursts and compact stars, high energy cosmic rays, dark energy and dark matter, general relativity, black holes, and new physics related to cosmology. The organizers are confident that this symposium could deepen the understanding of not only astrophysics and cosmology but also Eastern and Western cultures.

Groups of galaxies in the Center for Astrophysics redshift survey

International Nuclear Information System (INIS)

Ramella, M.; Geller, M.J.; Huchra, J.P.

1989-01-01

By applying the Huchra and Geller (1982) objective group identification algorithm to the Center for Astrophysics' redshift survey, a catalog of 128 groups with three or more members is extracted, and 92 of these are used as a statistical sample. A comparison of the distribution of group centers with the distribution of all galaxies in the survey indicates qualitatively that groups trace the large-scale structure of the region. The physical properties of groups may be related to the details of large-scale structure, and it is concluded that differences among group catalogs may be due to the properties of large-scale structures and their location relative to the survey limits. 28 refs

Topics in Nuclear Astrophysics

International Nuclear Information System (INIS)

Chung, K.C.

1982-01-01

Some topics in nuclear astrophysics are discussed, e.g.: highly evolved stellar cores, stellar evolution (through the temperature analysis of stellar surface), nucleosynthesis and finally the solar neutrino problem. (L.C.) [pt

Highlights of modern astrophysics: Concepts and controversies

International Nuclear Information System (INIS)

Shapiro, S.L.; Teukolsky, V.

1986-01-01

In this book, physicists and astronomers review issues in astrophysics. The book stresses accomplishments of observational and theoretical work, and demonstrates how to reveal information about stars and galaxies by applying the basic principles of physics. It pinpoints conflicting views and findings on important topics and indicates possibilities for future research in the field of modern astrophysics

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....

Astrophysical hints of axion-like particles

Science.gov (United States)

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

2015-01-01

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

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.

Stellar astrophysics

International Nuclear Information System (INIS)

1987-01-01

A number of studies in the field of steller astrophysics were undertaken by the South African Astronomical Observatory in 1986. These studies included; evolutionary effects on the surface abundances of an early-type supergiant; hydrogen deficient stars; t tauri stars; rotational modulation and flares on RS CVn and BY Dra stars; carbon and heavy element stars, and slow variability and circumstellar shells of red variable stars. 4 figs

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.

The High-Energy Astrophysics Learning Center, Version 1. [CD-ROM].

Science.gov (United States)

Whitlock, Laura A.; Allen, Jesse S.; Lochner, James C.

The High-Energy Astrophysics (HEA) Learning Center gives students, teachers, and the general public a window into the world of high-energy astrophysics. The universe is revealed through x-rays and gamma rays where matter exists under extreme conditions. Information is available on astrophysics at a variety of reading levels, and is illustrated…

Balance in the NASA Astrophysics Program

Science.gov (United States)

Elvis, Martin

2017-08-01

The Decadal studies are usually instructed to come up with a “balanced program” for the coming decade of astrophysics initiatives, both on the ground and in space. The meaning of “balance” is left up to the Decadal panels. One meaning is that there should be a diversity of mission costs in the portfolio. Another that there should be a diversity of science questions addressed. A third is that there should be a diversity of signals (across electromagnetic wavebands, and of non-em carriers). It is timely for the astronomy community to debate the meaning of balance in the NASA astrophysics program as the “Statement of Task” (SoT) that defines the goals and process of the 2020 Astrophysics Decadal review are now being formulated.Here I propose some ways in which the Astro2020 SoT could be made more specific in order to make balance more evident and so avoid the tendency for a single science question, and a single mission to answer that question, to dominate the program. As an example of an alternative ambitious approach, I present a proof-of-principle program of 6, mostly “probe-class” missions, that would fit the nominal funding profile for the 2025-2035 NASA Astrophysics Program, while being more diverse in ambitious science goals and in wavelength coverage.

Spectroscopics database for warm Xenon and Iron in Astrophysics and Laboratory Astrophysics conditions

Science.gov (United States)

Busquet, Michel; Klapisch, Marcel; Bar-Shalom, Avi; Oreg, Josse

2010-11-01

The main contribution to spectral properties of astrophysics mixtures come often from Iron. On the other hand, in the so-called domain of ``Laboratory Astrophysics,'' where astrophysics phenomena are scaled down to the laboratory, Xenon (and Argon) are commonly used gases. At so called ``warm'' temperatures (T=5-50eV), L-shell Iron and M-shell Xenon present a very large number of spectral lines, originating from billions of levels. More often than not, Local Thermodynamical Equilibrium is assumed, leading to noticeable simplification of the computation. Nevertheless, complex and powerful atomic structure codes are required. We take benefit of powerful statistics and numerics, included in our atomic structure codes, STA[1] and HULLAC[2], to generate the required spectra. Recent improvements in both fields (statistics, numerics and convergence control) allow obtaining large databases (ro x T grid of > 200x200 points, and > 10000 frequencies) for temperature down to a few eV. We plan to port these improvements in the NLTE code SCROLL[3]. [1] A.Bar-Shalom, et al, Phys. Rev. A 40, 3183 (1989) [2] M.Busquet,et al, J.Phys. IV France 133, 973-975 (2006); A.Bar-Shalom, M.Klapisch, J.Oreg, J.Oreg, JQSRT 71, 169, (2001) [3] A.Bar-Shalom, et al, Phys. Rev. E 56, R70 (1997)

Nuclear astrophysics at DRAGON

International Nuclear Information System (INIS)

Hager, U.

2014-01-01

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

Massive magnetic monopoles in cosmology and astrophysics

International Nuclear Information System (INIS)

Kolb, E.W.

1984-01-01

The astrophysical and cosmological consequences of magnetic monopoles are discussed. The production of monopoles during phase transition in the early universe is addressed, and proposals which have been made to alleviate the monopole problem are summarized. Astrophysical limits on galactic magnetic monopoles are discussed along with experimental efforts to detect monopoles. Finally, monopole-induced proton decay is addressed. 48 references

Rounding Up the Astrophysical Weeds

Science.gov (United States)

McMillan, James P.

2016-09-01

New instruments used for astronomy such as ALMA, Herschel, and SOFIA have greatly increased the quality of available astrophysical data. These improved data contain spectral lines and features which are not accounted for in the quantum mechanical (QM) catalogs. A class of molecules has been identified as being particularly problematic, the so-called "weeds". These molecules have numerous transitions, of non-trivial intensity, which are difficult to model due to highly perturbed low lying vibrational states. The inability to properly describe the complete contribution of these weeds to the astrophysical data has led directly to the misidentification of other target molecules. Ohio State's Microwave Laboratory has developed an alternative approach to this problem. Rather than relying on complex QM calculations, we have developed a temperature dependent approach to laboratory based terahertz spectroscopy. We have developed a set of simple packages, in addition to traditional line list catalogs, that enable astronomers to successfully remove the weed signals from their data. This dissertation will detail my laboratory work and analysis of three keys weeds: methanol, methyl formate and methyl cyanide. Also, discussed will be the analytical technique I used to apply these laboratory results to astrophysical data.

FOREWORD: Nuclear Physics in Astrophysics V

Science.gov (United States)

Auerbach, Naftali; Hass, Michael; Paul, Michael

2012-02-01

the conference dinner banquet at the Dan hotel. An excursion to the 'Red Canyon' in the Eilat Mountains on Wednesday afternoon was one of the social highlights of the conference. A total number of 140 scientists attended NPA5 and about 30 accompanying persons; about 25% of these were young participants (less than 36 years old). 23 participants were from Israel, and 27 were from outside of Europe (including two from Africa). The subjects covered at the conference in Eilat concentrated mainly on the spirit of the original idea - to probe experimental and theoretical activity in nuclear structure and reactions that is directly related to the physics of the Universe. There were also sessions of general interest in astrophysics, as well as a poster session on Tuesday evening featuring 40 posters. The topics included: Nuclear Structure - Theory and Experiment Big-Bang Nucleosynthesis and Formation of First Stars Stellar Reactions and Solar Neutrinos Explosive Nucleosynthesis, Radioactive Beams and Exotic Nuclei-New Facilities and Future Possibilities for Astrophysics Neutrino Physics - the Low and High-Energy Frontiers Rare events, Dark Matter, Double beta-decay, Symmetries The conference started with an excellent exposé of the progress made in the discovery of super-heavy elements and the study of their properties. The progress in this field is enormous, and this subject should be communicated to more general audiences. The role of the nuclear equation of state and of the precise determination of nuclear masses in nucleosynthesis was emphasized in several talks. The role of neutrinos in astrophysics was discussed extensively in several sessions. One of the highlights of this was the presentation about the IceCube and DeepCore detectors operating deep in the Antarctic ice. These facilities are able to detect cosmogenic neutrinos in a wide energy range, from 10 GeV to 1010 GeV. The subject of solar neutrinos was discussed in a number of talks. Topics related to properties

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.

Astrophysical Russian Dolls

OpenAIRE

Loeb, Abraham; Imara, Nia

2017-01-01

Are there examples of "astrophysical Russian dolls," and what could we learn from their similarities? In this article, we list a few such examples, including disks, filaments, and clusters. We suggest that forging connections across disciplinary borders enhances our perception of beauty, while simultaneously leading to a more comprehensive understanding of the Universe.

Nuclear Data and Reaction Rate Databases in Nuclear Astrophysics

Science.gov (United States)

Lippuner, Jonas

2018-06-01

Astrophysical simulations and models require a large variety of micro-physics data, such as equation of state tables, atomic opacities, properties of nuclei, and nuclear reaction rates. Some of the required data is experimentally accessible, but the extreme conditions present in many astrophysical scenarios cannot be reproduced in the laboratory and thus theoretical models are needed to supplement the empirical data. Collecting data from various sources and making them available as a database in a unified format is a formidable task. I will provide an overview of the data requirements in astrophysics with an emphasis on nuclear astrophysics. I will then discuss some of the existing databases, the science they enable, and their limitations. Finally, I will offer some thoughts on how to design a useful database.

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

Science.gov (United States)

2010-03-22

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... of the Astrophysics Subcommittee of the NASA Advisory Council (NAC). This Subcommittee reports to the...: The agenda for the meeting includes the following topics: --Astrophysics Division Update. --Kepler...

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

Science.gov (United States)

2011-01-31

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics... contacting Marian Norris. The agenda for the meeting includes the following topics: --Astrophysics Division...

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

Science.gov (United States)

2012-01-27

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics... topics: --Astrophysics Division Update --Update on Balloons Return to Flight Changes --James Webb Space...

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

Science.gov (United States)

2012-06-26

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics...: --Astrophysics Division Update --James Webb Space Telescope Update --Wide-Field Infrared Survey Telescope Report...

Building better optical model potentials for nuclear astrophysics applications

International Nuclear Information System (INIS)

Bauge, Eric; Dupuis, Marc

2004-01-01

In nuclear astrophysics, optical model potentials play an important role, both in the nucleosynthesis models, and in the interpretation of astrophysics related nuclear physics measurements. The challenge of nuclear astrophysics resides in the fact that it involves many nuclei far from the stability line, implying than very few (if any) experimental results are available for these nuclei. The answer to this challenge is a heavy reliance on microscopic optical models with solid microscopic physics foundations that can predict the relevant physical quantities with good accuracy. This use of microscopic information limits the likelihood of the model failing spectacularly (except if some essential physics was omitted in the modeling) when extrapolating away from the stability line, in opposition to phenomenological models which are only suited for interpolation between measured data points and not for extrapolating towards unexplored areas of the chart of the nuclides.We will show how these microscopic optical models are built, how they link to our present knowledge of nuclear structure, and how they affect predictions of nuclear astrophysics models and the interpretation of some key nuclear physics measurements for astrophysics

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

Science.gov (United States)

2013-04-04

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics... password [email protected] The agenda for the meeting includes the following topics: --Astrophysics Division...

Astrophysical relevance of γ transition energies

International Nuclear Information System (INIS)

Rauscher, Thomas

2008-01-01

The relevant γ energy range is explicitly identified where additional γ strength must be located to have an impact on astrophysically relevant reactions. It is shown that folding the energy dependences of the transmission coefficients and the level density leads to maximal contributions for γ energies of 2≤E γ ≤4 unless quantum selection rules allow isolated states to contribute. Under this condition, electric dipole transitions dominate. These findings allow us to more accurately judge the relevance of modifications of the γ strength for astrophysics

Astronomy and astrophysics in the new millennium: Panel reports

National Research Council Canada - National Science Library

Astronomy and Astrophysics Survey Committee, Board on Physics and Astronomy, Space Studies Board, National Research Council

2001-01-01

In preparing the report, Astronomy and Astrophysics in the New Millenium , the AASC made use of a series of panel reports that address various aspects of ground- and space-based astronomy and astrophysic...

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

Science.gov (United States)

2011-03-15

... Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics...: --Astrophysics Division Update. It is imperative that the meeting be held on these dates to accommodate the...

Excitation of compound states in the subsystems as indirect tool in nuclear astrophysics

Directory of Open Access Journals (Sweden)

Tribble R.E.

2010-03-01

Full Text Available Astrophysical reactions proceeding through compound states represent one of the crucial part of nuclear astrophysics. However, due to the presence of the Coulomb barrier, it is often very difficult or even impossible to obtain the astrophysical S (E factor from measurements in the laboratory at astrophysically relevant energies. The Trojan Horse method (THM provides a unique tool to obtain the information about resonant astrophysical reactions at astrophysically relevant energies. Here the theory and application of the THM for the resonant reactions is addressed.

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.

β-delayed α decay of {sup 16}N and the {sup 12}C(α,γ){sup 16}O cross section at astrophysical energies: A new experimental approach

Energy Technology Data Exchange (ETDEWEB)

Sanfilippo, S., E-mail: simone.sanfilippo@studium.unict.it [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via S.Sofia 64, 95123 Catania (Italy); Cherubini, S.; Lattuada, M.; Spitaleri, C. [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via S.Sofia 64, 95123 Catania, Italy and INFN - Laboratori Nazionali del Sud, Catania (Italy); Hayakawa, S.; Di Pietro, A.; Figuera, P.; La Cognata, M. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Gulino, M. [INFN - Laboratori Nazionali del Sud, Catania, Italy and Università Kore, Enna (Italy); Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study, University of Tokyo, Wako Branch, Saitama (Japan); Kubono, S.; Wakabayashi, Y. [RIKEN Nishina Center, Wako, Saitama (Japan); Hashimoto, T. [RCNP, Osaka University, Osaka (Japan); Iwasa, N.; Okoda, Y.; Ushio, K. [Department of Physics, Tohoku University, Sendai (Japan); Teranishi, T. [Department of Physics, Kyushu University, Fukuoka (Japan); Mazzocco, M. [Dipartimento di Fisica e Astronomia, Università di Padova and INFN-Sez. Padova, Padova (Italy); and others

2015-02-24

The {sup 12}C(α,γ){sup 16}O reaction at energies corresponding to the quiescent helium burning in massive stars is regarded as one of the most important processes in nuclear astrophysics. Although this process has being studied for over four decades, our knowledge of its cross section at the energies of interest for astrophysics is still widely unsatisfactory. Indeed, no experimental data are available around 300 keV and in the energy region of astrophysical interest extrapolations are performed using some theoretical approaches, usually R-matrix calculations. Consequently, the published astrophysical factors range from 1 to 288 keVb for S{sub E1}(300) and 7 to 120 keVb for S{sub E2}(300), especially because of the unknown contribution coming from subthreshold resonances. To improve the reliability of these extrapolations, data from complementary experiments, such as elastic and quasi- elastic α scattering on {sup 12}C, α-transfer reactions to {sup 16}O, and {sup 16}N decay are usually included in the analysis. Here the β-delayed α decay of {sup 16}N is used to infer information on the {sup 12}C(α,γ){sup 16}O reaction and a new experimental technique is suggested.

NASA Astrophysics EPO Resources For Engaging Girls in Science

Science.gov (United States)

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

2011-09-01

A new collaboration among the NASA Science Mission Directorate (SMD) Astrophysics EPO community is to engage girls in science who do not self-select as being interested in science, through the library setting. The collaboration seeks to (i) improve how girls view themselves as someone who knows about, uses, and sometimes contributes to science, and (ii) increase the capacity of EPO practitioners and librarians (both school and public) to engage girls in science. As part of this collaboration, we are collating the research on audience needs and best practices, and SMD EPO resources, activities and projects that focus on or can be recast toward engaging girls in science. This ASP article highlights several available resources and individual projects, such as: (i) Afterschool Universe, an out-of-school hands-on astronomy curriculum targeted at middle school students and an approved Great Science for Girls curriculum; (ii) Big Explosions and Strong Gravity, a Girl Scout patch-earning event for middle school aged girls to learn astronomy through hands-on activities and interaction with actual astronomers; and (iii) the JWST-NIRCAM Train the Trainer workshops and activities for Girl Scouts of USA leaders; etc. The NASA Astrophysics EPO community welcomes the broader EPO community to discuss with us how best to engage non-science-attentive girls in science, technology, engineering, and mathematics (STEM), and to explore further collaborations on this theme.

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.

Shape: A 3D Modeling Tool for Astrophysics.

Science.gov (United States)

Steffen, Wolfgang; Koning, Nicholas; Wenger, Stephan; Morisset, Christophe; Magnor, Marcus

2011-04-01

We present a flexible interactive 3D morpho-kinematical modeling application for astrophysics. Compared to other systems, our application reduces the restrictions on the physical assumptions, data type, and amount that is required for a reconstruction of an object's morphology. It is one of the first publicly available tools to apply interactive graphics to astrophysical modeling. The tool allows astrophysicists to provide a priori knowledge about the object by interactively defining 3D structural elements. By direct comparison of model prediction with observational data, model parameters can then be automatically optimized to fit the observation. The tool has already been successfully used in a number of astrophysical research projects.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Since 1977, papers in Astrophysics and Astronomy appeared as a special section in Pramana. ... The journal publishes original research papers on all aspects of astrophysics and ... Articles are also visible in Web of Science immediately.

Nuclear astrophysics and nuclei far from stability

International Nuclear Information System (INIS)

Schatz, H.

2003-01-01

Unstable nuclei play a critical role in a number of astrophysical scenarios and are important for our understanding of the origin of the elements. Among the most important scenarios are the r-process (Supernovae), Novae, X-ray bursters, and Superbursters. For these astrophysical events I review the open questions, recent developments in astronomy, and how nuclear physics, in particular experiments with radioactive beams, needs to contribute to find the answers. (orig.)

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

Spherical Panoramas for Astrophysical Data Visualization

Science.gov (United States)

Kent, Brian R.

2017-05-01

Data immersion has advantages in astrophysical visualization. Complex multi-dimensional data and phase spaces can be explored in a seamless and interactive viewing environment. Putting the user in the data is a first step toward immersive data analysis. We present a technique for creating 360° spherical panoramas with astrophysical data. The three-dimensional software package Blender and the Google Spatial Media module are used together to immerse users in data exploration. Several examples employing these methods exhibit how the technique works using different types of astronomical data.

Nuclear astrophysics with DRAGON at ISAC: the 21Na(p, γ)22Mg reaction

International Nuclear Information System (INIS)

D'Auria, J.M.

2003-01-01

The DRAGON facility at the new intense radioactive beams facility, ISAC, is now operational. It was built to perform studies of radiative alpha and proton capture reactions involving radioactive reactants, and of interest to nuclear astrophysics. The rate of the 21 Na(p, γ) 22 Mg reaction has been measured using inverse kinematics. Resonance strengths have been measured for states of importance for novae explosions. This report will summarize aspects of this study and its impact. (orig.)

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.

Extensive Air Showers High Energy Phenomena and Astrophysical Aspects - A Tutorial, Reference Manual and Data Book

CERN Document Server

Grieder, Peter K.F

2010-01-01

Extensive air showers are a very unique phenomenon. In the more than six decades since their discovery by Auger et al. we have learned a great deal about these extremely energetic events and gained deep insights into high-energy phenomena, particle physics and astrophysics. In this Tutorial, Reference Manual and Data Book Peter K. F. Grieder provides the reader with a comprehensive view of the phenomenology and facts of the various types of interactions and cascades, theoretical background, experimental methods, data evaluation and interpretation, and air shower simulation. He discusses astrophysical aspects of the primary radiation and addresses the questions that continue to puzzle researchers. The book is divided into two parts, each in its own separate volume: Part I in Volume I deals mainly with the basic theoretical framework of the processes that determine an air shower and ends with a summary of ways to extract information on the primary radiation from air shower observations. It also presents a compi...

Nuclear information needs for the astrophysical s-process

Energy Technology Data Exchange (ETDEWEB)

Mathews, G.J.; Howard, W.M.; Takahashi, K.; Ward, R.A.

1986-01-01

The astrophysical s-process is a sequence of neutron-capture and beta-decay reactions on a slow time scale compared to beta-decay lifetimes near the line of stability. This detailed sequence of neutron capture, continuum and bound-state beta decay, positron decay, and electron-capture reactions that comprise the s-process has been studied for a broad range of astrophysical environments. The results are then compared with the solar-system abundancies of heavy elements to determine the range of physical conditions responsible for their nucleosynthesis. The nuclear data needs are extensive but have begun to be precise enough to allow for a consistent interpretation of the astrophysical site for the s-process.

Nuclear information needs for the astrophysical s-process

Energy Technology Data Exchange (ETDEWEB)

Mathews, G.J.; Howard, W.M.; Takahashi, K.; Ward, R.A.

1985-05-01

The astrophysical s-process is a sequence of neutron-capture and beta-decay reactions on a slow time scale compared to beta-decay lifetimes near the line of stability. We systematically study this detailed sequence of neutron capture, continuum and bound-state beta decay, positron decay, and electron-capture reactions that comprise the s-process for a broad range of astrophysical environments. Our results are then compared with the solar-system abundances of heavy elements to determine the range of physical conditions responsible for their nucleosynthesis. The nuclear data needs are extensive but have begun to be precise enough to allow for a consistent interpretation of the astrophysical site for the s-process.

VI School on Cosmic Rays and Astrophysics

International Nuclear Information System (INIS)

2017-01-01

VI School on Cosmic Rays and Astrophysics 17-25 November 2015, Chiapas, Mexico The VI School on Cosmic Rays and Astrophysics was held at the MCTP, at the Autonomous University of Chiapas (UNACH), Tuxtla Gutiérrez, Chiapas, Mexico thanks to the Science for Development ICTP-UNACH-UNESCO Regional Seminar, 17-25 November 2015 (http://mctp.mx/e-VI-School-on-Cosmic-Rays-and-Astrophysics.html). The School series started in La Paz, Bolivia in 2004 and it has been, since then, hosted by several Latin American countires: 1.- La Paz, Bolivia (August, 2004), 2.- Puebla, Mexico (September, 2006), 3.- Arequipa, Peru (September, 2008), 4.- Santo André, Brazil (September, 2010), 5.- La Paz, Bolivia (August, 2012). It aims to promote Cosmic Ray (CR) Physics and Astrophysics in the Latin American community and to provide a general overview of theoretical and experimental issues on these topics. It is directed to undergraduates, postgraduates and active researchers in the field. The lectures introduce fundamental Cosmic Ray Physics and Astrophysics with a review of standards of the field. It is expected the school continues happening during the next years following a tradition. In this edition, the list of seminars included topics such as experimental techniques of CR detection, development of CR showers and hadronic interactions, composition and energy spectrum of primary CR, Gamma-Ray Bursts (GRBs), neutrino Astrophysics, spacecraft detectors, simulations, solar modulation, and the current state of development and results of several astroparticle physics experiments such as The Pierre Auger Observatory in Argentina, HAWC in Mexico, KASCADE and KASCADE Grande, HESS, IceCube, JEM-EUSO, Fermi-LAT, and others. This time the school has been complemented with the ICTP-UNACH-UNESCO Seminar of theory on Particle and Astroparticle Physics. The organization was done by MCTP, the Mesoamerican Centre for Theoretical Physics. The school had 46 participants, 30 students from Honduras, Brazil

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Sravani Vaddi. 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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Abudusaimaitijiang Yisikandeer. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 3 September 2016 pp 22 Research Article. Velocity Distributions of Runaway Stars Produced by Supernovae in the Galaxy · Abudusaimaitijiang Yisikandeer ...

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

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...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Abhishek Shukla. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 1 March 2017 pp 7 Research Article. Benford's Distribution in Extrasolar World: Do the Exoplanets Follow Benford's Distribution? Abhishek Shukla Ankit Kumar Pandey ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Siddhartha Bhattacharyya. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 37 Review. Fast Transients with the Square Kilometre Array and its Pathfinders: An Indian Perspective · Yashwant Gupta Poonam Chandra ...

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. Stefano Ciroi. Articles written in Journal of Astrophysics and Astronomy. Volume 36 Issue 4 December 2015 pp 447-455 Review. Optical Counterparts of Undetermined Type -Ray Active Galactic Nuclei with Blazar-Like Spectral Energy Distributions.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Corot team. 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 for ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Jordan Vannitsen. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 4 December 2017 pp 70 Research Article. A Satellite Data Analysis and CubeSat Instrument Simulator Tool for Simultaneous Multi-spacecraft Measurements of Solar ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Ankit Kumar Pandey. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 1 March 2017 pp 7 Research Article. Benford's Distribution in Extrasolar World: Do the Exoplanets Follow Benford's Distribution? Abhishek Shukla Ankit Kumar Pandey ...

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...

Mass-23 nuclei in astrophysics

International Nuclear Information System (INIS)

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

2015-01-01

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

Positron astrophysics and areas of relation to low-energy positron physics

International Nuclear Information System (INIS)

Guessoum, N.

2014-01-01

I briefly review our general knowledge of positron astrophysics, focusing mostly on the theoretical and modelling aspects. The experimental/observational aspects of the topic have recently been reviewed elsewhere [E. Churazov et al., Mon. Nat. R. Astron. Soc. 411, 1727 (2011); N. Prantazos et al., Rev. Mod. Phys. 83, 1001 (2011)]. In particular, I highlight the interactions and cross sections of the reactions that the positrons undergo in various cosmic media. Indeed, these must be of high interest to both the positron astrophysics community and the low-energy positron physics community in trying to find common areas of potential collaboration for the future or areas of research that will help the astrophysics community make further progress on the problem. The processes undergone by positrons from the moments of their birth to their annihilation (in the interstellar medium or other locations) are thus examined. The physics of the positron interactions with gases and solids (dust grains) and the physical conditions and characteristics of the environments where the processes of energy loss, positronium formation, and annihilation take place, are briefly reviewed. An explanation is given about how all the relevant physical information is taken into account in order to calculate annihilation rates and spectra of the 511 keV emission in the ISM; special attention is paid to positron interactions with dust and with polycyclic aromatic hydrocarbons. In particular, an attempt is made to show to what extent the interactions between positrons and interstellar dust grains are similar to laboratory experiments in which beams of low-energy positrons impinge upon solids and surfaces. Sample results are shown for the effect of dust grains on positron annihilation spectra in some phases of the ISM which, together with high resolution spectra measured by satellites, can be used to infer useful knowledge about the environment where the annihilation is predominantly taking place

TESS Objects of Interest

Science.gov (United States)

Guerrero, Natalia; Glidden, Ana; Fausnaugh, Michael; TESS Team

2018-01-01

We describe the search for TESS Objects of Interest (TOIs), led by the MIT branch of the TESS Science Office (TSO). TSO has developed a tool called TESS Exoplanet Vetter (TEV) to facilitate this process. Individuals independently examine data validation products for each target and assign a category to the object: planet candidate, eclipsing binary, other astrophysical, stellar variability, or instrument noise/systematic. TEV assigns a preliminary follow-up priority designation to each object and allows for modification when final dispositions are decided on in a group setting. When all targets are vetted, TEV exports a catalogue of TOIs which is delivered to the TESS Follow-Up Observing Program (TFOP), working with ExoFOP-TESS, and made publicly available on the official TESS website and the Mikulski Archive for Space Telescopes (MAST).

RX emission of thin astrophysical plasma: interstellar medium and intra-cluster medium

International Nuclear Information System (INIS)

Arnaud, Monique

1984-01-01

As previous publications presented an important discrepancy of ionisation rates in astrophysical plasmas, this research thesis first reports a systematic study (by isoelectric sequence) of ionisation cross sections, based on measurements performed by mono-energetic beams, and on quantum assessments. The author proposes simple analytic fits for ionisation rates, for direct ionisation and for excitation-self-ionisation of ions of interest in astrophysics. He reports a critical review of recombination rates published in the literature, and the calculation of radiative recombination rates for different ions (hydrogen-like, helium-like, and lithium-like). Software have then been developed to determine the ionisation rate at the equilibrium and out of it for thin plasma, and to obtain ion fraction tables for different ions (H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni). Then, a software integrating recent data on collisional excitation rates has been used to calculate the emission spectrum of a thin plasma with respect to temperature. These results are then used for the study of the interstellar medium and of supernovae remnants, and finally for the study of the intra-cluster medium [fr

Automated Detection of Short Optical Transients of Astrophysical Origin in Real Time

Directory of Open Access Journals (Sweden)

Marcin Sokołowski

2010-01-01

Full Text Available The detection of short optical transients of astrophysical origin in real time is an important task for existing robotic telescopes. The faster a new optical transient is detected, the earlier follow-up observations can be started. The sooner the object is identified, the more data can be collected before the source fades away, particularly in the most interesting early period of the transient. In this the real-time pipeline designed for identification of optical flashes with the “Pi of the Sky” project will be presented in detail together with solutions used by other experiments.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. N. Kameswara Rao. Articles written in Journal of Astrophysics and Astronomy. Volume 26 Issue 2-3 June-September 2005 pp 331-338. High Resolution Stellar Spectroscopy with VBT Echelle Spectrometer · N. Kameswara Rao S. Sriram K. Jayakumar F. Gabriel.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Subhashis Roy. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 30 Review. Explosive and Radio-Selected Transients: Transient Astronomy with Square Kilometre Array and its Precursors · Poonam Chandra G. C. ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Pantea Davoudifar. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 3 September 2011 pp 359-370. Extragalactic Gamma Ray Excess from Coma Supercluster Direction · Pantea Davoudifar S. Jalil Fatemi · More Details Abstract Fulltext ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Niruj M. Ramanujam. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 37 Review. Fast Transients with the Square Kilometre Array and its Pathfinders: An Indian Perspective · Yashwant Gupta Poonam Chandra Manjari ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Sushan Konar. 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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Nathalie Degenaar. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 3 September 2017 pp 49 Review Article. Cooling of Accretion-Heated Neutron Stars · Rudy Wijnands Nathalie Degenaar Dany Page · More Details Abstract Fulltext PDF.

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. 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 ...

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. Kalpana Duorah. Articles written in Journal of Astrophysics and Astronomy. Volume 30 Issue 3-4 September-December 2009 pp 165-175. Rapid Neutron Capture Process in Supernovae and Chemical Element Formation · Rulee Baruah Kalpana ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. H. L. Duorah. Articles written in Journal of Astrophysics and Astronomy. Volume 30 Issue 3-4 September-December 2009 pp 165-175. Rapid Neutron Capture Process in Supernovae and Chemical Element Formation · Rulee Baruah Kalpana Duorah H. L. Duorah.

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. Avinash A. Deshpande. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 37 Review. Fast Transients with the Square Kilometre Array and its Pathfinders: An Indian Perspective · Yashwant Gupta ...

Astrophysics is easy! an introduction for the amateur astronomer

CERN Document Server

Inglis, Michael

2015-01-01

Astrophysics is often –with some justification – regarded as incomprehensible without the use of higher mathematics. Consequently, many amateur astronomers miss out on some of the most fascinating aspects of the subject. Astrophysics Is Easy! cuts through the difficult mathematics and explains the basics of astrophysics in accessible terms. Using nothing more than plain arithmetic and simple examples, the workings of the universe are outlined in a straightforward yet detailed and easy-to-grasp manner.   The original edition of the book was written over eight years ago, and in that time, advances in observational astronomy have led to new and significant changes to the theories of astrophysics. The new theories will be reflected in both the new and expanded chapters.   A unique aspect of this book is that, for each topic under discussion, an observing list is included so that observers can actually see for themselves the concepts presented –stars of the spectral sequence, nebulae, galaxies, even black ...

Astrophysics is easy! an introduction for the amateur astronomer

CERN Document Server

Inglis, Mike

2007-01-01

With some justification, many amateur astronomers believe astrophysics is a very difficult subject, requiring at least degree-level mathematics to understand it properly. This isn’t necessarily the case. Mike Inglis' quantitative approach to the subject explains all aspects of astrophysics in simple terms and cuts through the incomprehensible mathematics with which this fascinating subject is all too often associated. Astrophysics is Easy! begins by looking at the H-R diagram and other basic tools of astrophysics, then ranges across the universe, from a first look at the interstellar medium and nebulae, through the birth, evolution and death of stars, to the physics of galaxies and clusters of galaxies. A unique feature of this book is the way that Dr. Inglis lists example objects for practical observation at every stage, so that practical astronomers can go and look at the object or objects under discussion – using only easily-available commercial amateur equipment.

Dusty plasmas in application to astrophysics

International Nuclear Information System (INIS)

Verheest, F.

1999-01-01

Highly charged and massive dust grains have much smaller characteristic frequencies than electrons and ions and lead to interesting modifications of existing modes and to exciting new possibilities for modes and instabilities at the lower frequency end of the spectrum. Space observations of planets and comets have shown wave-like behaviour which can only be explained by the presence of charged dust grains. Two typical solar system applications are spokes and braids in the rings of Saturn and the influence of charged dust on the pickup process of ions of cometary origin by the solar wind. As dust is ubiquitous in the universe, the Jeans instability in astrophysics is modified by incorporating plasma and charged dust and treating electromagnetic and self-gravitational aspects together. Besides the usual mechanism based upon thermal agitation, other ways of countering gravitational contraction are via excitation of electrostatic dust-acoustic modes or via Alfven-Jeans instabilities for perpendicular magnetosonic waves. The unstable wavelengths tend to be much larger, due to the dominance of plasma and magnetic pressures in inhibiting gravitational collapse. (author)

Cosmology and particle astrophysics. 2. ed.

International Nuclear Information System (INIS)

Bergstroem, L.; Goobar, A.

2006-01-01

Beginning with some basic facts about the observable universe the authors consider in successive chapters the complete range of topics that make up a degree course in cosmology and particle astrophysics. The outstanding feature of this book is that it is self-contained, in that no specialised knowledge is required on the part of the reader, apart from basic undergraduate mathematics and physics. This paperback edition will again target students of physics, astrophysics and cosmology at the advanced undergraduate level or early graduate level. One of the book's biggest strong points is that the authors rapidly involve students in the most exciting of today's developments in the field in a simple and self-contained manner, relegating the more technical aspects to appendices. The worked examples throughout the book, and summaries at the end of each chapter, which were expanded in the second edition, have been very well received by students. This book offers advanced undergraduate level and beginning graduate level students a highly readable, yet comprehensive review of particle astrophysics. Competing books cover this topic at too advanced a level for this readership. (orig.)

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. K. Anilkumar. 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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. ABHILASH R. SARWADE. Articles written in Journal of Astrophysics and Astronomy. Volume 39 Issue 1 February 2018 pp 11 Review. Study of X-ray transients with Scanning Sky Monitor (SSM) onboard AstroSat · M. C. RAMADEVI B. T. RAVISHANKAR ABHILASH R.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. BLESSY ELIZABETH BABY. Articles written in Journal of Astrophysics and Astronomy. Volume 39 Issue 1 February 2018 pp 11 Review. Study of X-ray transients with Scanning Sky Monitor (SSM) onboard AstroSat · M. C. RAMADEVI B. T. RAVISHANKAR ABHILASH ...

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. Monica Trasatti. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 589-598. LOFAR: Recent Imaging Results and Future Prospects · George Heald Michael R. Bell Andreas Horneffer André R. Offringa ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. SANTABRATA DAS. Articles written in Journal of Astrophysics and Astronomy. Volume 23 Issue 1-2 March-June 2002 pp 143-147. Standing Shocks around Black Holes and Estimation of Outflow Rates · Santabrata Das Sandip K. Chakrabarti · More Details Abstract ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. G. Maheswar. 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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Gireesh C. Joshi. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 4 December 2017 pp 72 Research Article. Identification of Stellar Sequences in Various Stellar Systems: ESO65-SC03, Teutsch 106, Turner 6 · Gireesh C. Joshi.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Rajesh Mondal. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 29 Review. Modelling the 21-cm Signal from the Epoch of Reionization and Cosmic Dawn · T. Roy Choudhury Kanan Datta Suman Majumdar ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Surya Ratna Prakash Dumpa. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 35 Review Article. Planning and Scheduling of Payloads of AstroSat During Initial and Normal Phase Observations · R. Pandiyan S. V. ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Surajit Paul. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 533-536. Double Relics in the Outskirts of A3376: Accretion Flows Meet Merger Shocks? Ruta Kale K. S. Dwarakanath Joydeep Bagchi Surajit Paul.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. T. Roy Choudhury. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 27 Review. Probing Individual Sources during Reionization and Cosmic Dawn using Square Kilometre Array HI 21-cm Observations · Kanan K. Datta ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. MOHAMMED HASAN. Articles written in Journal of Astrophysics and Astronomy. Volume 39 Issue 1 February 2018 pp 11 Review. Study of X-ray transients with Scanning Sky Monitor (SSM) onboard AstroSat · M. C. RAMADEVI B. T. RAVISHANKAR ABHILASH R.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Samir Choudhuri. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 35 Review. Prospects of Measuring the Angular Power Spectrum of the Diffuse Galactic Synchrotron Emission with SKA1 Low · Sk. Saiyad Ali Somnath ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. PATRICK DAS GUPTA. Articles written in Journal of Astrophysics and Astronomy. Volume 39 Issue 1 February 2018 pp 14 Review. Collapsing supra-massive magnetars: FRBs, the repeating FRB121102 and GRBs · PATRICK DAS GUPTA NIDHI SAINI · More Details ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

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. Sujan Sengupta. Articles written in Journal of Astrophysics and Astronomy. Volume 34 Issue 2 June 2013 pp 151-155. Spectro-Polarimetry of Self-Luminous Extrasolar Planets · Sujan Sengupta · More Details Abstract Fulltext PDF. Planets which are ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. VIVEK KUMAR AGARWAL. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 32 Review Article. Early In-orbit Performance of Scanning Sky Monitor Onboard AstroSat · M. C. Ramadevi B. T. Ravishankar N. Sitaramamurthy G.

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. N. Kumar. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 3 September 2017 pp 57. Classical Orbital Paramagnetism in Non-equilibrium Steady State · Avinash A. Deshpande N. Kumar · More Details Abstract Fulltext PDF.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Prateek Sharma. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 31 Review. Clusters of Galaxies and the Cosmic Web with Square Kilometre Array · Ruta Kale K. S. Dwarakanath Dharam Vir Lal Joydeep Bagchi ...

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.

The new astrophysics

International Nuclear Information System (INIS)

Longair, M.

1993-01-01

The various themes developed are: radioastronomy, X-ray and gamma-ray astronomy, cosmic ray, ultraviolet, neutral hydrogen and molecular line astronomy, optical and theoretical astronomy; the large scale distribution of matter and radiation in the universe, the galaxies, stars and stellar evolution, the interstellar medium (gas, dust) and star formation, galaxies and clusters of galaxies, active galaxies and quasars, astrophysical cosmology, the astronomy of the future. 86 figs., 60 refs

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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. A. K. Singh. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 29 Review Article. Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance · K. P. Singh G. C. Stewart N. J. Westergaard S.

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. 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 ...

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. John McKean. Articles written in Journal of Astrophysics and Astronomy. Volume 32 Issue 4 December 2011 pp 557-566. LOFAR and APERTIF Surveys of the Radio Sky: Probing Shocks and Magnetic Fields in Galaxy Clusters · Huub Röttgering ...

Nuclear Astrophysics from View Point of Few-Body Problems

International Nuclear Information System (INIS)

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

2013-01-01

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

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Zhao Wen-juan. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 21 Research Article. Classification of Stellar Spectra with Fuzzy Minimum Within-Class Support Vector Machine · Liu Zhong-bao Song Wen-ai Zhang Jing ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. V. Navalkar. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 29 Review Article. Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance · K. P. Singh G. C. Stewart N. J. Westergaard S.

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. B. N. Dwivedi. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 3-4 September-December 2000 pp 397-401 Session X – Cycle Variation in the Quiet Corona & Coronal Holes. The EUV Spectrum of Sunspot Plumes ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. K. H. Navalgund. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 29 Review Article. Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance · K. P. Singh G. C. Stewart N. J. Westergaard S.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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. ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Viral Parekh. Articles written in Journal of Astrophysics and Astronomy. Volume 37 Issue 4 December 2016 pp 31 Review. Clusters of Galaxies and the Cosmic Web with Square Kilometre Array · Ruta Kale K. S. Dwarakanath Dharam Vir Lal Joydeep Bagchi Surajit ...

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. 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.

E1-forbidden transition rates in ions of astrophysical interest

International Nuclear Information System (INIS)

Träbert, E

2014-01-01

Transition rates in atomic systems may appear to be of little importance in steady-state plasmas that are observed at great distances from Earth. However, some of the transition rates compete with collision rates, and in these cases certain line intensity ratios are affected and can serve as remote indicators of density. In the low-density environments of stellar coronae and planetary nebulae, the transition rates of interest are mostly spin-forbidden E1 decays, higher-multipole order transitions (M1, E2, M2, M3), and hyperfine-induced transitions. On Earth, measurements of the long upper level lifetimes of these atomic systems require the use of ion traps. A fair number of test cases with lifetimes in the range from nanoseconds to many seconds have been treated successfully, and the evolution of calculations along with the experimental progress is notable. A new generation of cold ion traps is expected to extend the atomic lifetime measurements on multiply charged ions into the range of many minutes. (paper)

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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 ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Essy Samuel. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Ruta Kale. 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 Abstract ...

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.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. V. Girish. Articles written in Journal of Astrophysics and Astronomy. Volume 26 Issue 2-3 June-September 2005 pp 203-211. HD 12098 and Other Results from Nainital–Cape Survey · V. Girish · More Details Abstract Fulltext PDF. Nainital;Cape Survey was started ...

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. 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. ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. N. Vagshette. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

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. 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.

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. M. Ferricha-Alami. Articles written in Journal of Astrophysics and Astronomy. Volume 36 Issue 2 June 2015 pp 269-280. Tree Level Potential on Brane after Planck and BICEP2 · M. Ferricha-Alami A. Safsafi L. Lahlou H. Chakir M. Bennai.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Sergey V. Ershkov. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 1 March 2017 pp 5 Research Article. Forbidden Zones for Circular Regular Orbits of the Moons in Solar System, R3BP · Sergey V. Ershkov · More Details Abstract Fulltext ...

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. T. Sivarani. Articles written in Journal of Astrophysics and Astronomy. Volume 34 Issue 1 March 2013 pp 5-17 Review Articles. Stellar Relics from the Early Galaxy · T. Sivarani · More Details Abstract Fulltext PDF. We reviewed the recent progress in ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

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. One of ...

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. 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.

Nuclear Data for Astrophysics: Resources, Challenges, Strategies, and Software Solutions

International Nuclear Information System (INIS)

Smith, Michael Scott; Lingerfelt, Eric J.; Nesaraja, Caroline D.; Hix, William Raphael; Roberts, Luke F.; Koura, Hiroyuki; Fuller, George M.; Tytler, David

2008-01-01

One of the most exciting utilizations of nuclear data is to help unlock the mysteries of the Cosmos -- the creation of the chemical elements, the evolution and explosion of stars, and the origin and fate of the Universe. There are now many nuclear data sets, tools, and other resources online to help address these important questions. However, numerous serious challenges make it important to develop strategies now to ensure a sustainable future for this work. A number of strategies are advocated, including: enlisting additional manpower to evaluate the newest data; devising ways to streamline evaluation activities; and improving communication and coordination between existing efforts. Software projects are central to some of these strategies. Examples include: creating a virtual 'pipeline' leading from the nuclear laboratory to astrophysics simulations; improving data visualization and management to get the most science out of the existing datasets; and creating a nuclear astrophysics data virtual (online) community. Recent examples will be detailed, including the development of two first-generation software pipelines, the Computational Infrastructure for Nuclear Astrophysics for stellar astrophysics and the bigbangonline suite of codes for cosmology, and the coupling of nuclear data to sensitivity studies with astrophysical simulation codes to guide future research.

Bibliometric indicators of young authors in astrophysics

DEFF Research Database (Denmark)

Havemann, Frank; Larsen, Birger

2015-01-01

We test 16 bibliometric indicators with respect to their validity at the level of the individual researcher by estimating their power to predict later successful researchers. We compare the indicators of a sample of astrophysics researchers who later co-authored highly cited papers before...... 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...

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

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. A. A. Hakobyan. 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. ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. K. S. Dwarakanath. Articles written in Journal of Astrophysics and Astronomy. Volume 24 Issue 1-2 March-June 2003 pp 37-43. GMRT Detection of HI 21cm Associated Absorption towards the = 1.2 Red Quasar 3C 190 · C. H. Ishwara-Chandra K. S. Dwarakanath ...

New Features in the Computational Infrastructure for Nuclear Astrophysics

International Nuclear Information System (INIS)

Smith, Michael Scott; Lingerfelt, Eric; Scott, J. P.; Nesaraja, Caroline D; Chae, Kyung YuK.; Koura, Hiroyuki; Roberts, Luke F.; Hix, William Raphael; Bardayan, Daniel W.; Blackmon, Jeff C.

2006-01-01

A Computational Infrastructure for Nuclear Astrophysics has been developed to streamline the inclusion of the latest nuclear physics data in astrophysics simulations. The infrastructure consists of a platform-independent suite of computer codes that are freely available online at http://nucastrodata.org. The newest features of, and future plans for, this software suite are given

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. M. M. Lame'e. Articles written in Journal of Astrophysics and Astronomy. Volume 31 Issue 2 June 2010 pp 97-104. Photometric Observation and Light Curve Analysis of Binary System ER-Orionis · M. M. Lame'e B. Javanmardi N. Riazi · More Details ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. S. V. Vadawale. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

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.

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. 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 ...

Preface: Eighth European Summer School on Experimental Nuclear Astrophysics

International Nuclear Information System (INIS)

Claudio, Spitaleri; Livio, Lamia; Gianluca, Pizzone Rosario

2016-01-01

often quoted statement of Carl Sagan, “We are all star stuff,” is exhaustively describing one of the great discoveries of the 20th century as well as the main aim of nuclear astrophysics. The present theory of stellar nucleosynthesis (based on the famous paper B 2 FH) predicts chemical evolution of the Universe, which is testable by looking at stellar spectral lines, meteorites, pre-solar grains or other means of investigation. Quantum mechanics explains why different atoms emit light at characteristic wavelengths, and so by studying the light emitted from different stars, one may infer the atmospheric composition of individual stars. However, upon undertaking such a task, observations indicate a strong correlation between a star’s heavy element content (metallicity) and its age (red shift). Big bang nucleosynthesis tells us that the early universe consisted of only the light elements, and so one expects the first stars to be composed of hydrogen, helium, and lithium, the three lightest elements. The recent achievements of WMAP and Planck missions, with the precise measurement of many cosmological parameters, have re-ignited the interest on the primordial nucleosynthesis, especially for the still unclear Lithium primordial abundance. Stellar structure and the H-R diagram indicate that the lifetime of a star depends greatly on its initial mass and chemical composition, so that massive stars are very short-lived, and less massive stars are longer-lived. As a star dies, nuclear astrophysics argues that it will enrich the interstellar medium with “heavy elements” (in this case all elements heavier than lithium, the third element), from which new stars are formed. This account is consistent with the observed correlation between stellar metallicity and red shift. The theory of stellar nucleosynthesis would not be very convincing if reliable nuclear physics inputs are adopted. By carefully scrutinizing the table of nuclides, nuclear astrophysicists were able to

First advanced research workshop: Gravity, astrophysics and strings at the Black Sea. Proceedings

International Nuclear Information System (INIS)

Fiziev, P.; Todorov, M.

2002-01-01

The aim of the First Advanced Workshop ‘Gravity, Astrophysics, and Strings’ was: 1)Bringing together scientists from various branches of gravitational physics, astrophysics and string theory gave an opportunity for interdisciplinary exchange of views and enhanced possible collaborations; 2)Provided a unique opportunity to scientists from various countries to communicate with colleagues on the hottest topics of gravitational physics, astrophysics, and string theory; 3) Opened new venue to young talented scientists to communicate and work with major research groups on the topics of the conference. The workshop covered wide aspects of gravity, astrophysics, and string theory concerning the topics: Astrophysics; Mathematical Modeling and Numerical Simulations in Relativity; Astrophysics, and Strings; Relativistic Gravity; (Super)Strings. About 40 participants from Europe, America and Asia gave 30 invited talks and contributed presentations. The full text of 17 of them are included in this book

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.

Research in nuclear astrophysics

International Nuclear Information System (INIS)

Lattimer, J.M.; Yahil, A.

1989-01-01

The interaction between nuclear theory and some outstanding problems in astrophysics is examined. We are actively researching both the astrophysics of gravitational collapse, neutron star birth, and the emission of neutrinos from supernovae, on the one hand, and the nuclear physics of the equation of state of hot, dense matter on the other hand. There is close coupling between nuclear theory and the supernova phenomenon; in fact, nuclear matter properties, especially at supernuclear densities, might be best delineated by astrophysical considerations. Our research has also focused on the neutrinos emitted from supernovae, since they are the only available observables of the internal supernova mechanism. The recent observations of neutrinos from SN 1987A proved to be in remarkable agreement with models we pioneered in the one and one half years prior to its explosion in February 1987. We have also developed a novel hydrodynamical code in which shocks are treated via Riemann resolution rather than with artificial viscosity. We propose to modify it to use implicit differencing and to include multi-group neutrino diffusion and General Relativity. In parallel, we are extending calculations of the birth of a neutron star to include convection and mass accretion, by incorporating a hydrodynamic envelope onto a hydrostatic core. In view of the possible recent discovery of a pulsar in SN1987A, we are including the effects of rotation. We are undertaking a detailed comparison of current equations of state, focusing on disagreements regarding the nuclear incompressibly, symmetry energy and specific heat. Especially important is the symmetry energy, which below nuclear density controls free proton fractions and weak interaction rates and above this density critically influences the neutron star maximum mass and binding energy. 60 refs

Theory of magnetostatic equilibria and applications in astrophysics

International Nuclear Information System (INIS)

Amari, T.

1988-04-01

Magnetohydrostatic equations are used to study the properties of magnetic configurations of astrophysical interest, particularly in solar physics. Results on force-free solutions with singularities (with current sheets) and on solutions which take into account current sheets and gravitational fields are obtained. A general method to construct an infinite class of non-y-symmetric models of protuberances when the magnetic field of the support is assumed to be potential is outlined. The general integral properties of current sheets of arbitrary geometry plunged into a nonlinear force-free magnetic field are established. It is shown that for a given mass, the equilibrium height of the protuberance increases with the shear of the force-free field. The case where the current sheet is reduced to a filament is examined. It is also shown that there exists a critical pressure beyond which no equilibrium is possible [fr

Extrasolar Planets Swiss Society for Astrophysics and Astronomy

CERN Document Server

Cassen, Patrick; Quirrenbach, Andreas

2006-01-01

Research on extrasolar planets is one of the most exciting fields of activity in astrophysics. In a decade only, a huge step forward has been made from the early speculations on the existence of planets orbiting "other stars" to the first discoveries and to the characterization of extrasolar planets. This breakthrough is the result of a growing interest of a large community of researchers as well as the development of a wide range of new observational techniques and facilities. Based on their lectures given at the 31st Saas-Fee Advanced Course, Andreas Quirrenbach, Tristan Guillot and Pat Cassen have written up up-to-date comprehensive lecture notes on the "Detection and Characterization of Extrasolar Planets", "Physics of Substellar Objects Interiors, Atmospheres, Evolution" and "Protostellar Disks and Planet Formation". This book will serve graduate students, lecturers and scientists entering the field of extrasolar planets as detailed and comprehensive introduction.

Gamma-ray bursts: astrophysical puzzle of the century

International Nuclear Information System (INIS)

Hudec, R.

1998-01-01

An overview is given of the problems of gamma-ray bursts /GRB/. As GRB became one of the greatest mysteries in modern astrophysics, this field of astrophysics is a subject of intensive research. The article covers some topical aspects of experiments related to the indentification of gamma-ray bursts. The preparation and results of experiments in the Astronomical Institute of the Academy of Sciences of the Czech Republic are described. (Z.J.)

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. S. Seetha. Articles written in Journal of Astrophysics and Astronomy. Volume 21 Issue 1-2 June 2000 pp 29-38. X-ray Observation of XTE J2012+381 during the 1998 Outburst · S. Naik P. C. Agrawal B. Paul A. R. Rao S. Seetha Κ. Kasturirangan · More Details Abstract ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. P. Priya. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna A. P. K. ...

Statistical learning methods in high-energy and astrophysics analysis

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, J. [Forschungszentrum Juelich GmbH, Zentrallabor fuer Elektronik, 52425 Juelich (Germany) and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)]. E-mail: zimmerm@mppmu.mpg.de; Kiesling, C. [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

2004-11-21

We discuss several popular statistical learning methods used in high-energy- and astro-physics analysis. After a short motivation for statistical learning we present the most popular algorithms and discuss several examples from current research in particle- and astro-physics. The statistical learning methods are compared with each other and with standard methods for the respective application.

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. 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.

Statistical learning methods in high-energy and astrophysics analysis

International Nuclear Information System (INIS)

Zimmermann, J.; Kiesling, C.

2004-01-01

We discuss several popular statistical learning methods used in high-energy- and astro-physics analysis. After a short motivation for statistical learning we present the most popular algorithms and discuss several examples from current research in particle- and astro-physics. The statistical learning methods are compared with each other and with standard methods for the respective application

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. S. Kalita. 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 ...

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.

Astrophysical cosmology

International Nuclear Information System (INIS)

Bardeen, J.M.

1986-01-01

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

Evaluation of the implementation of the R-matrix formalism with reference to the astrophysically important {sup 18}F(p,α){sup 15}O reaction

Energy Technology Data Exchange (ETDEWEB)

Mountford, D.J., E-mail: d.j.mountford86@gmail.com [SUPA, School of Physics and Astronomy, University of Edinburgh, EH9 3JZ (United Kingdom); Boer, R.J. de [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Descouvemont, P. [Physique Nucléaire Théorique et Physique Mathématique, C.P. 229, Université Libre de Bruxelles (ULB), B 1050 Brussels (Belgium); Murphy, A. St. J. [SUPA, School of Physics and Astronomy, University of Edinburgh, EH9 3JZ (United Kingdom); Uberseder, E.; Wiescher, M. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-12-11

Background. The R-Matrix formalism is a crucial tool in the study of nuclear astrophysics reactions, and many codes have been written to implement the relevant mathematics. One such code makes use of Visual Basic macros. A further open-source code, AZURE, written in the FORTRAN programming language is available from the JINA collaboration and a C++ version, AZURE2, has recently become available. Purpose The detailed mathematics and extensive programming required to implement broadly applicable R-Matrix codes make comparisons between different codes highly desirable in order to check for errors. This paper presents a comparison of the three codes based around data and recent results of the astrophysically important {sup 18}F(p,α){sup 15}O reaction. Methods Using the same analysis techniques as in the work of Mountford et al. parameters are extracted from the two JINA codes, and the resulting cross-sections are compared. This includes both refitting data with each code and making low-energy extrapolations. Results All extracted parameters are shown to be broadly consistent between the three codes and the resulting calculations are in good agreement barring a known low-energy problem in the original AZURE code. Conclusion The three codes are shown to be broadly consistent with each other and equally valid in the study of astrophysical reactions, although one must be careful when considering low lying, narrow resonances which can be problematic when integrating.

Nuclear and Particle Physics, Astrophysics and Cosmology : T-2 : LANL

Science.gov (United States)

linked in Search T-2, Nuclear and Particle Physics, Astrophysics and Cosmology T-2 Home T Division Focus Areas Nuclear Information Service Nuclear Physics Particle Physics Astrophysics Cosmology CONTACTS Group fundamental and applied theoretical research in applied and fundamental nuclear physics, particle physics

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 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.

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.

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.

Distance correlation methods for discovering associations in large astrophysical databases

International Nuclear Information System (INIS)

Martínez-Gómez, Elizabeth; Richards, Mercedes T.; Richards, Donald St. P.

2014-01-01

High-dimensional, large-sample astrophysical databases of galaxy clusters, such as the Chandra Deep Field South COMBO-17 database, provide measurements on many variables for thousands of galaxies and a range of redshifts. Current understanding of galaxy formation and evolution rests sensitively on relationships between different astrophysical variables; hence an ability to detect and verify associations or correlations between variables is important in astrophysical research. In this paper, we apply a recently defined statistical measure called the distance correlation coefficient, which can be used to identify new associations and correlations between astrophysical variables. The distance correlation coefficient applies to variables of any dimension, can be used to determine smaller sets of variables that provide equivalent astrophysical information, is zero only when variables are independent, and is capable of detecting nonlinear associations that are undetectable by the classical Pearson correlation coefficient. Hence, the distance correlation coefficient provides more information than the Pearson coefficient. We analyze numerous pairs of variables in the COMBO-17 database with the distance correlation method and with the maximal information coefficient. We show that the Pearson coefficient can be estimated with higher accuracy from the corresponding distance correlation coefficient than from the maximal information coefficient. For given values of the Pearson coefficient, the distance correlation method has a greater ability than the maximal information coefficient to resolve astrophysical data into highly concentrated horseshoe- or V-shapes, which enhances classification and pattern identification. These results are observed over a range of redshifts beyond the local universe and for galaxies from elliptical to spiral.

Thermonuclear Reaction Rate Libraries and Software Tools for Nuclear Astrophysics Research

International Nuclear Information System (INIS)

Smith, Michael S.; Cyburt, Richard; Schatz, Hendrik; Smith, Karl; Warren, Scott; Ferguson, Ryan; Wiescher, Michael; Lingerfelt, Eric; Buckner, Kim; Nesaraja, Caroline D.

2008-01-01

Thermonuclear reaction rates are a crucial input for simulating a wide variety of astrophysical environments. A new collaboration has been formed to ensure that astrophysical modelers have access to reaction rates based on the most recent experimental and theoretical nuclear physics information. To reach this goal, a new version of the REACLIB library has been created by the Joint Institute for Nuclear Astrophysics (JINA), now available online at http://www.nscl.msu.edu/~nero/db. A complementary effort is the development of software tools in the Computational Infrastructure for Nuclear Astrophysics, online at nucastrodata.org, to streamline, manage, and access the workflow of the reaction evaluations from their initiation to peer review to incorporation into the library. Details of these new projects will be described

Nuclear data for astrophysics: resources, challenges, strategies, and software solutions

International Nuclear Information System (INIS)

Smith, M.S.; Lingerfelt, E.J.; Nesaraja, C.D.; Raphael Hix, W.; Roberts, L.F.; Hiroyuki, Koura; Fuller, G.M.; Tytler, D.

2008-01-01

One of the most exciting utilizations of nuclear data is to help unlock the mysteries of the Cosmos - the creation of the chemical elements, the evolution and explosion of stars, and the origin and fate of the Universe. There are now many nuclear data sets, tools, and other resources online to help address these important questions. However, numerous serious challenges make it important to develop strategies now to ensure a sustainable future for this work. A number of strategies are advocated, including: enlisting additional manpower to evaluate the newest data; devising ways to streamline evaluation activities; and improving communication and coordination between existing efforts. Software projects are central to some of these strategies. Examples include: creating a virtual - pipeline - leading from the nuclear laboratory to astrophysics simulations; improving data visualization and management to get the most science out of the existing datasets; and creating a nuclear astrophysics data virtual (online) community. Recent examples will be detailed, including the development of two first-generation software pipelines, the Computational Infrastructure for Nuclear Astrophysics for stellar astrophysics and the Bigbangonline suite of codes for cosmology, and the coupling of nuclear data to sensitivity studies with astrophysical simulation codes to guide future research. (authors)

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...

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.

Particles in astrophysics and cosmology: a dark connection

International Nuclear Information System (INIS)

Fornengo, Nicolao

2010-01-01

The particle physics interpretation of the missing-mass, or dark-matter, problem of cosmological and astrophysical nature is going to be posed under deep scrutiny in the next years. From the particle physics side, accelerators will deeply test theoretical ideas of new physics beyond the Standard Model, where particle candidates of dark matter are predicted. From the astrophysical side, many probes are already providing a great deal of independent information on the foreseen signals which can be produced by the galactic or extra-galactic dark matter. The ultimate hope is in fact the emergence of dark matter signals from the various sources of backgrounds and the rise of a coherent picture of new physics from the accelerator physics, astrophysics and cosmology sides. A very ambitious and far-reaching project, which will bring to a deeper level our understanding of the fundamental laws which rule the Universe.

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.

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

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. D. Anish Roshi. Articles written in Journal of Astrophysics and Astronomy. Volume 28 Issue 1 March 2007 pp 41-53. GMRT and VLA Observations at 49 cm and 20 cm of the HII Region near = 24.8°, = 0.1° · N. G. Kantharia W. M. Goss D. Anish ...

Theoretical nuclear structure and astrophysics at FAIR

International Nuclear Information System (INIS)

Rodríguez, Tomás R

2014-01-01

Next generation of radioactive ion beam facilities like FAIR will open a bright future for nuclear structure and nuclear astrophysics research. In particular, very exotic nuclei (mainly neutron rich) isotopes will be produced and a lot of new exciting experimental data will help to test and improve the current nuclear models. In addition, these data (masses, reaction cross sections, beta decay half-lives, etc.) combined with the development of better theoretical approaches will be used as the nuclear physics input for astrophysical simulations. In this presentation I will review some of the state-of-the-art nuclear structure methods and their applications.

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.

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

Science.gov (United States)

Swinbank, Elizabeth

1997-01-01

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

Relativistic kinetic theory with applications in astrophysics and cosmology

CERN Document Server

Vereshchagin, Gregory V

2017-01-01

Relativistic kinetic theory has widespread application in astrophysics and cosmology. The interest has grown in recent years as experimentalists are now able to make reliable measurements on physical systems where relativistic effects are no longer negligible. This ambitious monograph is divided into three parts. It presents the basic ideas and concepts of this theory, equations and methods, including derivation of kinetic equations from the relativistic BBGKY hierarchy and discussion of the relation between kinetic and hydrodynamic levels of description. The second part introduces elements of computational physics with special emphasis on numerical integration of Boltzmann equations and related approaches, as well as multi-component hydrodynamics. The third part presents an overview of applications ranging from covariant theory of plasma response, thermalization of relativistic plasma, comptonization in static and moving media to kinetics of self-gravitating systems, cosmological structure formation and neut...

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

International Nuclear Information System (INIS)

Liu, Shengjin; Sakurai, Makoto; Sagara, Kenshi; Teranishi, Takashi; Fujita, Kunihiro; Yamaguchi, Hiroyuki; Matsuda, Sayaka; Mitsuzumi, Tatsuki; Iwazaki, Makoto; Rosary, Mariya T.; Kato, Daiji; Tolstikhina, I.Yu.

2014-01-01

In astrophysics, 4 He( 12 C, 16 O)γ reaction places an important role. At Kyushu University Tandem accelerator Laboratory (KUTL), the measurement of 4 He( 12 C, 16 O)γ cross section is in progress in the energy range of astrophysical nuclear reaction. Since the charge state of product 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 16 O ions passing through the He gas target precisely. Here, we report the charge state distribution of the 16 O recoils both experimentally and theoretically. Experimentally, we measured the equilibrium charge state distribution of 16 O ions in the windowless helium gas target with the beam energy of primary 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 created via 4 He( 12 C, 16 O)γ reaction

A plasma deflagration accelerator as a platform for laboratory astrophysics

Science.gov (United States)

Underwood, Thomas C.; Loebner, Keith T. K.; Cappelli, Mark A.

2017-06-01

The replication of astrophysical flows in the laboratory is critical for isolating particular phenomena and dynamics that appear in complex, highly-coupled natural systems. In particular, plasma jets are observed in astrophysical contexts at a variety of scales, typically at high magnetic Reynolds number and driven by internal currents. In this paper, we present detailed measurements of the plasma parameters within deflagration-produced plasma jets, the scaling of these parameters against both machine operating conditions and the corresponding astrophysical phenomena. Using optical and spectroscopic diagnostics, including Schlieren cinematography, we demonstrate the production of current-driven plasma jets of ∼100 km/s and magnetic Reynolds numbers of ∼100, and discuss the dynamics of their acceleration into vacuum. The results of this study will contribute to the reproduction of various types of astrophysical jets in the laboratory and indicate the ability to further probe active research areas such as jet collimation, stability, and interaction.

Positron astrophysics and areas of relation to low-energy positron physics

Science.gov (United States)

Guessoum, Nidhal

2014-05-01

I briefly review our general knowledge of positron astrophysics, focusing mostly on the theoretical and modelling aspects. The experimental/observational aspects of the topic have recently been reviewed elsewhere [E. Churazov et al., Mon. Nat. R. Astron. Soc. 411, 1727 (2011); N. Prantazos et al., Rev. Mod. Phys. 83, 1001 (2011)]. In particular, I highlight the interactions and cross sections of the reactions that the positrons undergo in various cosmic media. Indeed, these must be of high interest to both the positron astrophysics community and the low-energy positron physics community in trying to find common areas of potential collaboration for the future or areas of research that will help the astrophysics community make further progress on the problem. The processes undergone by positrons from the moments of their birth to their annihilation (in the interstellar medium or other locations) are thus examined. The physics of the positron interactions with gases and solids (dust grains) and the physical conditions and characteristics of the environments where the processes of energy loss, positronium formation, and annihilation take place, are briefly reviewed. An explanation is given about how all the relevant physical information is taken into account in order to calculate annihilation rates and spectra of the 511 keV emission in the ISM; special attention is paid to positron interactions with dust and with polycyclic aromatic hydrocarbons. In particular, an attempt is made to show to what extent the interactions between positrons and interstellar dust grains are similar to laboratory experiments in which beams of low-energy positrons impinge upon solids and surfaces. Sample results are shown for the effect of dust grains on positron annihilation spectra in some phases of the ISM which, together with high resolution spectra measured by satellites, can be used to infer useful knowledge about the environment where the annihilation is predominantly taking place

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.

Journal of Astrophysics and Astronomy

Indian Academy of Sciences (India)

27

Indian Institute of Astrophysics, Koramangala 2nd Block, Bangalore. 560034, India .... the hydrogen rich thermosphere so significantly that the internal energy of the gas becomes greater than the gravitational potential energy. This leads ... way greenhouse, water vapor would reach the stratosphere where it would.

An introduction to nuclear astrophysics

International Nuclear Information System (INIS)

Norman, E.B.

1987-09-01

The role of nuclear reactions in astrophysics is described. Stellar energy generation and heavy element nucleosynthesis is explained in terms of specific sequences of charged-particle and neutron induced reactions. The evolution and final states of stars are examined. 20 refs. 11 figs., 2 tabs

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.

The Neutrino: A Better Understanding Through Astrophysics: Final Report

International Nuclear Information System (INIS)

Kneller, James P.

2016-01-01

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.

Computational Astrophysics Towards Exascale Computing and Big Data

Science.gov (United States)

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

2016-06-01

Traditionally, Armenia has a leading position both within the computer science and Information Technology and Astronomy and Astrophysics sectors in the South Caucasus region and beyond. For instance recent years Information Technology (IT) became one of the fastest growing industries of the Armenian economy (EIF 2013). The main objective of this article is to highlight the key activities that will spur Armenia to strengthen its computational astrophysics capacity thanks to the analysis made of the current trends of e-Infrastructures worldwide.

Karl Schwarzschild and the professionalization of astrophysics. (German Title: Karl Schwarzschild und die Professionalisierung der Astrophysik)

Science.gov (United States)

Schmidt-Kaler, Theodor

Professionalization is characteristic for physics and astronomy since 1830, and forms the basis for their rapid evolution in the 20th century. Karl Schwarzschild's contributions to professionalization of astronomy are presented: the introduction of course lectures in a repeating cycle, a permanent astrophysical laboratory, a tight connection between teaching and research, simulations and suggestions for astronomy at high schools and for the training of high school teachers, an interest in international organisation, and the initiative and planning of a southern observatory.

Nuclear data needs in nuclear astrophysics: Charged-particle reactions

International Nuclear Information System (INIS)

Smith, Michael S.

2001-01-01

Progress in understanding a diverse range of astrophysical phenomena - such as the Big Bang, the Sun, the evolution of stars, and stellar explosions - can be significantly aided by improved compilation, evaluation, and dissemination of charged-particle nuclear reaction data. A summary of the charged-particle reaction data needs in these and other astrophysical scenarios is presented, along with recommended future nuclear data projects. (author)

Coulomb disintegration as an information source for relevant processes in nuclear astrophysics

International Nuclear Information System (INIS)

Bertulani, C.A.

1989-01-01

The possibility of obtaining the photodisintegration cross section using the equivalent-photon number method first deduced and employed for the Coulomb disintegration processes has been suggested. This is very interesting because there exist radioactive capture processes, related to the photodisintegration through time reversal, that are relevant in astrophysics. In this paper, the recent results of the Karlsruhe and the Texas A and M groups on the Coulomb disintegration of 6 Li and 7 Li and the problems of the method are discussed. The ideas developed in a previous paper (Nucl. Phys. A458 (1986) 188) are confirmed qualitatively. To understand the process quantitatively it is necessary to use a quantum treatment that would imply the introduction of Coulomb excitation effects of higher orders. The Coulomb disintegration of exotic secondary beams is also studied. It is particularly interesting the question about what kind of nuclear structure information, as binding energies of momentum distributions, may be obtained. (Author) [es

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.

AstroBlend: An astrophysical visualization package for Blender

Science.gov (United States)

Naiman, J. P.

2016-04-01

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 datasets. Here, I present AstroBlend, an open-source Python library for use within the three dimensional modeling software, Blender. While Blender has been a popular open-source software among animators and visual effects artists, in recent years it has also become a tool for visualizing astrophysical datasets. AstroBlend combines the three dimensional capabilities of Blender with the analysis tools of the widely used astrophysical toolset, yt, to afford both computational and observational astrophysicists the ability to simultaneously analyze their data and create informative and appealing visualizations. The introduction of this package includes a description of features, work flow, and various example visualizations. A website - www.astroblend.com - has been developed which includes tutorials, and a gallery of example images and movies, along with links to downloadable data, three dimensional artistic models, and various other resources.

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...

Considerations about the apparent 'superluminal expansions' in astrophysics

International Nuclear Information System (INIS)

Recami, E.; Castellino, A.; Maccarrone, G.D.; Rodono, M.

1984-01-01

The orthodox models devised to explain the apparent 'superluminal expansions' observed in astrophysics - and here briefly summarized and discussed together with the experimental data - do not seem to be too much succesful. Especially when confronted with the most recent observations, suggesting complicated expansion patterns, even with possible accelerations. At this point it may be, therefore, of some interest to explore the possible alternative models in which actual Superluminal motions take place. The ground is prepared starting from a variational principle, introducing the elements of a tachyon mechanics within special relativity, and arguing about the expected behaviour of tachyonic objects when interacting (gravitationally, for instance) among themselves or with ordinary matter. Then the simplest 'Superluminal models' are reviewed and developed, paying particular attention to the observations which they would give rise to. Itis concluded that some of them appear to be physically acceptable and are statistically favoured with respect to the orthodox ones. (Author) [pt

TeV Particle Astrophysics 2010, Booklet of abstracts

International Nuclear Information System (INIS)

None, C.; Davide Ferella, A.; Pato, M.; Catena, R.; Salucci, P.; Rielage, K.; Kobayashi, K.; Degunda, U.; Estrada, J.; Yue, Q.; Benbow, W.; Maestro, P.; Berghaus, P.; Benzvi, S.; Gallant, Y.; Coniglione, R.; Frey, R.; Besson, D.; Odrowski, S.; Ernenwein, J.P.; Dios Zornosa, J. de; Colnard, C.; Cavalcante de Souza, J.; Fraija, N.; Cerdeno, D.; Moroi, T.; Kumar, J.; Slatyer, T.; Yaguna, C.; Thomson, G.; Tameda, Y.; Taylor, A.; Giacinti, G.; Calvez, A.; Kotera, K.; Shinozaki, K.; Aharonian, F.; Essey, W.; Ahlers, M.; Fargion, D.; Canadas, B.; Boehm, C.; Palomares-Ruiz, S.; Panci, P.; Sanchez-Conde, M.A.; Hensley, B.; Vivier, M.; Hooper, D.; Finkbeiner, D.; Dobler, G.; Malyshev, D.; Mertsch, P.; Giannios, D.; Dalton, M.; Casandijan, J.M.; Mukherjee, R.; Morlino, G.; Ando, S.; Gilmore, R.; Medina, C.; Weitzel, Q.; Caprioli, D.; Vovk, I.; Vincent, S.; Delahaye, T.; Lavalle, J.; Galli, S.; Crocker, R.; Catena, R.; Cholis, I.; Sandick, P.; Rydberg, C.E.; Hulss, J.P.; Danninger, M.; Tran, D.; Spolyar, D.; Belanger, G.; Ronga, F.; Montanino, D.; Fornasa, M.; Regoes, E.; Caprioli, D.; Morlino, G.; Ostapchenko, S.; Kawanaka, N.; Kalli, S.; Whitehorn, N.; Boutayeb, B.; Casanellas, J.; Lopes, I.

2012-01-01

The aim of the conference is to bring together theorists and experimentalists working in the fields of Particle Physics, Astrophysics and Cosmology, with a shared interest in physical processes at the TeV energy scale. After decades of theoretical speculation, the exploration of the TeV energy frontier has now in fact begun, with the results provided by ground-based and space-born observatories of gamma-rays (Fermi, HESS, Magic, Veritas, Cangaroo, Milagro), anti-matter (PAMELA, ATIC, HESS and soon AMS-02) and neutrinos (IceCube, Antares), with a large number of ongoing direct Dark Matter search experiments exploiting different detection techniques, and with the TeV particle accelerators Tevatron and the Large Hadron Collider. The physics underlying these experiments involves many intertwined issues, such as the nature of Dark Matter, Physics beyond the Standard Model, the origin of Cosmic Rays and the distribution of Dark and visible matter in the Universe. This document gathers only the abstracts of the papers. (authors)

Considerations about the apparent superluminal expansions in astrophysics

International Nuclear Information System (INIS)

Recami, E.; Castellino, A.; Maccarrone, G. D.; Rodono, M.

1985-01-01

The ortodox models devised to explain the apparent ''superluminal expansions'' observed in astrophysics, and here briefly summarized and discussed together with th experimental data, do not seem to be to much successful. Especially when confronted with the most recent observations, suggesting complicated expansion patterns, even with possible accelerations. At this point it may be, therefore, of some interest to explore the possible alternative models in which actual superluminal motion take place. To prepare the ground one starts from a variational principle, introduces the elements of a tachyon mechanics within special relativity, and argues about the expected behaviour of tachyonic objects when interacting (gravitationally, for instance) among themselves or with ordinary matter. Then the simplest ''superluminal models'', paying particular attention to the observations which they would give rise to are revie wed and developed. It is concluded that some of them appear to be physically acceptable and are statistically favoured with respect to the ortodox ones

75 FR 61778 - NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting

Science.gov (United States)

2010-10-06

... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: (10-118)] NASA Advisory Council; Science Committee; Astrophysics Subcommittee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration (NASA) announces a meeting of the Astrophysics...

New astrophysical S factor for the 15N(p,γ)16O reaction via the asymptotic normalization coefficient (ANC) method

International Nuclear Information System (INIS)

Mukhamedzhanov, A. M.; Gagliardi, C. A.; Goldberg, V. Z.; Plunkett, A.; Trache, L.; Tribble, R. E.; Bem, P.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Novak, J.; Piskor, S.; Simeckova, E.; Vesely, F.; Vincour, J.; La Cognata, M.; Pizzone, R. G.; Romano, S.; Spitaleri, C.

2008-01-01

The 15 N(p,γ) 16 O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong J π =1 - resonances at E R =312 and 962 keV and direct capture to the ground state. Asymptotic normalization coefficients (ANCs) for the ground and seven excited states in 16 O were extracted from the comparison of experimental differential cross sections for the 15 N( 3 He,d) 16 O reaction with distorted-wave Born approximation calculations. Using these ANCs and proton and α resonance widths determined from an R-matrix fit to the data from the 15 N(p,α) 12 C reaction, we carried out an R-matrix calculation to obtain the astrophysical factor for the 15 N(p,γ) 16 O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0)=36.0±6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200±300 cycles of the main CN cycle one CN catalyst is lost due to this reaction

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

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...

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.

Nonlocal astrophysics dark matter, dark energy and physical vacuum

CERN Document Server

Alexeev, Boris V

2017-01-01

Non-Local Astrophysics: Dark Matter, Dark Energy and Physical Vacuum highlights the most significant features of non-local theory, a highly effective tool for solving many physical problems in areas where classical local theory runs into difficulties. The book provides the fundamental science behind new non-local astrophysics, discussing non-local kinetic and generalized hydrodynamic equations, non-local parameters in several physical systems, dark matter, dark energy, black holes and gravitational waves. Devoted to the solution of astrophysical problems from the position of non-local physics Provides a solution for dark matter and dark energy Discusses cosmological aspects of the theory of non-local physics Includes a solution for the problem of the Hubble Universe expansion, and of the dependence of the orbital velocity from the center of gravity

Astronomy and astrophysics for the 1970's. Volume 2. Reports of the panels

International Nuclear Information System (INIS)

1973-01-01

Specific panel reports include: radio astronomy, optical astronomy, infrared astronomy, space astronomy, solar astronomy, theoretical astrophysics, dynamical astronomy, astrophysics and relativity, and statistics. These provide guidance as to the major trends anticipated in astronomical and astrophysical research. They also list instrumental facilities, auxiliary equipment, and programs of theoretical research and offer numerous recommendations

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.

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.

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

Science.gov (United States)

2012-10-15

... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice 12-081] Meeting of Astrophysics Subcommittee... Astrophysics Subcommittee of the NASA Advisory Council (NAC) Science Committee. This Subcommittee reports to...: The agenda for the meeting includes the following topics: --Astrophysics Division Update --Proposed...

Astronomy & Astrophysics: an international journal

Science.gov (United States)

Bertout, C.

2011-07-01

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

Journal of Astrophysics and Astronomy

Indian Academy of Sciences (India)

65

Northern IMF as simulated by PIC code in parallel with MHD model-Journal of Astrophysics ... The global structure of the collisionless bow shock was inves- tigated by ..... international research community, access to modern space science simulations. ...... LaTeX Font Info: Redeclaring math alphabet \\mathbf on input line 29.

77 FR 67677 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

Science.gov (United States)

2012-11-13

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting...) on issues [[Page 67678

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.

From dripline to dripline: Nuclear astrophysics in the laboratory

International Nuclear Information System (INIS)

Meisel, Zach

2016-01-01

For the better part of a century the field of nuclear astrophysics has aimed to answer fundamental questions about nature, such as the origin of the elements and the behavior of high-density, low-temperature matter. Sustained and concerted efforts in nuclear experiment have been key to achieving progress in these areas and will continue to be so. Here I will briefly review recent accomplishments and open questions in experimental nuclear astrophysics. (paper)

Astrophysical dark matter: candidates from particle physics and detection possibilities

International Nuclear Information System (INIS)

Freese, K.

1989-01-01

In this talk, I will discuss the arguments that 50% to 90% of the matter in galaxies, including our own, is made of an unknown type of dark matter. I will review the reason why cosmologists believe Ω = 1 and illustrate the contrast with the limits on the amount of baryonic matter from element abundances in Big Bang Nucleosynthesis. Other arguments for nonbaryonic dark matter will also be discussed. Candidates for the dark matter from particle physics will be presented. I will focus on cold dark matter candidates known as WIMPs, weakly interacting massive (O(GeV)) particles. I will try to illustrate why these particles are interesting for astrophysics and outline ideas for cornering them. Detection possibilities for these particles include indirect detection, which takes advantage of the annihilation products of these particles in the galactic halo, the sun, or the earth. Direct detection via newly proposed cryogenic detectors must be sensitive to <∼ keV energy deposits. Annual modulation of the dark matter signal can be used as a signature for these halo particles. I hope to motivate the interest in these particles and discuss ideas for finding them

Trojan Horse Method: A tool to explore electron screening effect

Energy Technology Data Exchange (ETDEWEB)

Pizzone, R G; Spitaleri, C; Cherubini, S; Cognata, M La; Lamia, L; Romano, S; Sergi, M L [Laboratori Nazionali del Sud-INFN, Catania (Italy) and Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Rolfs, C; Strieder, F [Ruhr Universitaet Bochum (Germany); Burjan, V; Kroha, V; Mrazek, J [Cyclotron Institute, Academy of Science, Rez (Czech Republic); Li, C; Wen, Q; Zhou, S [CIAE, Beijing (China); Tumino, A, E-mail: rgpizzone@lns.infn.i [Universita Kore, Erma (Italy)

2010-01-01

Owing the presence of the Coulomb barrier at astrophysically relevant energies, it is very difficult, or sometimes impossible to measure reaction rates for charged particle induced reactions. Moreover due to the presence of the electron screening effect in direct measurements, the relevant nuclear input for astrophysics, i.e. the bare nucleus S(E)-factor, can hardly be extracted. This is why different indirect techniques are being used along with direct measurements. The THM is an unique: indirect technique which allows one to measure reactions cross sections of astrophysical interest down the thermal energies typical of the different scenarios. The basic principle and a review of the main applications of the Trojan Horse Method are given. The applications aiming at the extraction of the bare S{sub b}(E) astrophysical factor and electron screening potentials U{sub e} for several two body processes are discussed.

Carbon dioxide and climate: an astrophysical perspective

Energy Technology Data Exchange (ETDEWEB)

Kandel, R S

1979-01-01

In this survey the earth is viewed from the astrophysical perspective, i.e. using global mean values of environmental parameters. The role of carbon dioxide is described in the processes of energy transfer from the earth's surface to space, which determine global climate as measured by the mean surface temperature. Analogies and differences between the problems of the terrestrial atmosphere and those of the solar and stellar atmospheres are examined, both in the computation of model atmospheres and in remote sensing of atmospheric temperature and composition. Subsequently, the temporal astrophysical perspective, with a review of the evolution of CO/sub 2/ abundance and climate on astrophysical or geological time scales, on earth as an Venus (the runaway greenhouse) and on Mars is introduced. Variation of CO/sub 2/ may have been critical to the maintenance of an environment in which life could originate and evolve, and may itself have been affected by life. On human time scales, the recent and continuing increase in atmospheric CO/sub 2/ raises new problems, which are briefly surveyed. It is argued, that the differential greenhouse effect of increased CO/sub 2/ in the earth's atmosphere is essentially identifical to the blanketing effect of spectral lines on the temperature structure of stellar atmospheres. The methods used by astrophysicists in such studies are reviewed and compared with those used to evaluate the differential greenhouse effect of CO/sub 2/ in radiative-convective models of the earth's atmosphere. The latter methods remain relatively crude, but recent results by different authors are in reasonably good agreement; however, the astrophysical perspective, i.e. the use of one-dimensional global mean models, remains a gross simplification of the real complexity of the earth's climate system, which is also true in stellar atmospheres.

Indirect Techniques in Nuclear Astrophysics. Asymptotic Normalization Coefficient and Trojan Horse

International Nuclear Information System (INIS)

Mukhamedzhanov, A.M.; Blokhintsev, L.D.; Brown, S.

2007-01-01

We address two important indirect techniques, the asymptotic normalization coefficient (ANC) and the Trojan Horse (TH) methods. We discuss the application of the ANC technique to determine the astrophysical factor for the 13 C(α, n) 16 O reaction which is one of the neutron generators for the s processes in AGB stars. The TH method is a unique indirect technique allowing one to measure astrophysical S factors for rearrangement reactions down to astrophysically relevant energies. We derive equations connecting the cross sections for the binary direct and resonant reactions determined from the indirect TH reactions to direct cross sections measurements

Hot topics of X-ray Astrophysics from past and future missions

International Nuclear Information System (INIS)

Costa, Enrico

2013-01-01

50 years after the first discovery, X-ray Astrophysics is a well-established discipline, with a continuous development of detection/observation techniques. These can find application on both large observatories and thematic space missions. I will recall the main milestones of X-ray Astrophysics and review some of the hottest topics of High Energy Astrophysics, included some open problems of Fundamental Physics, that can be addressed with measurements in the X-ray band. I will show which proposed missions and which concepts of new missions could be more attractive for a future development of this discipline

XXII SLAC summer institute on particle physics: Proceedings. Particle physics, astrophysics and cosmology

Energy Technology Data Exchange (ETDEWEB)

Chan, J; DePorcel, L [eds.

1996-02-01

The seven-day school portion of the Institute revolved around the question of dark matter: where is it and what is it? Reviews were given of microlensing searches for baryonic dark matter, of dark matter candidates in the form of neutrinos and exotic particles, and of low-noise detection techniques used to search for the latter. The history of the universe, from the Big Bang to the role of dark matter in the formation of large-scale structure, was also covered. Other lecture series described the astrophysics that might be done with x-ray timing experiments and through the detection of gravitational radiation. As in past years, the lectures each morning were followed by stimulating afternoon discussion sessions, in which students could pursue with the lecturers the topics that most interested them. The Institute concluded with a three-day topical conference covering recent developments in theory and experiment. Highlights from the astrophysical and cosmological arenas included observations of anisotropy in the cosmic microwave background, and of the mysterious gamma-ray bursters. From terrestrial accelerators came tantalizing hints of the top quark and marked improvements in precision electroweak measurements, among many other results. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

XXII SLAC summer institute on particle physics: Proceedings. Particle physics, astrophysics and cosmology

International Nuclear Information System (INIS)

Chan, J.; DePorcel, L.

1996-02-01

The seven-day school portion of the Institute revolved around the question of dark matter: where is it and what is it? Reviews were given of microlensing searches for baryonic dark matter, of dark matter candidates in the form of neutrinos and exotic particles, and of low-noise detection techniques used to search for the latter. The history of the universe, from the Big Bang to the role of dark matter in the formation of large-scale structure, was also covered. Other lecture series described the astrophysics that might be done with x-ray timing experiments and through the detection of gravitational radiation. As in past years, the lectures each morning were followed by stimulating afternoon discussion sessions, in which students could pursue with the lecturers the topics that most interested them. The Institute concluded with a three-day topical conference covering recent developments in theory and experiment. Highlights from the astrophysical and cosmological arenas included observations of anisotropy in the cosmic microwave background, and of the mysterious gamma-ray bursters. From terrestrial accelerators came tantalizing hints of the top quark and marked improvements in precision electroweak measurements, among many other results. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

Astrophysics in 1999

OpenAIRE

Trimble, V; Aschwanden, MJ

2000-01-01

The year 1999 saw the arrival of a star with three planets, a universe with three parameters, and a solar corona that could be heated at least three ways. In addition, there were at least three papers on every question that has ever been asked in astrophysics, from "Will the Universe expand forever?" to "Does mantle convection occur in one or two layers?" The answers generally were, "Yes," "No," and "None of the above," to each of the questions. The authors have done their best to organize th...

Isometric embeddings in cosmology and astrophysics

Indian Academy of Sciences (India)

embedding theory, a given spacetime (or 'brane') is embedded in a higher- ..... If one recalls that the motivation (at least in part) for non-compact extra ... to successfully embed (apparently perfect fluid) astrophysical models, we typically need to.

The proceedings of the 1st international workshop on laboratory astrophysics experiments with large lasers

International Nuclear Information System (INIS)

Remington, B.A.; Goldstein, W.H.

1996-01-01

The world has stood witness to the development of a number of highly sophisticated and flexible, high power laser facilities (energies up to 50 kJ and powers up to 50 TW), driven largely by the world-wide effort in inertial confinement fusion (ICF). The charter of diagnosing implosions with detailed, quantitative measurements has driven the ICF laser facilities to be exceedingly versatile and well equipped with diagnostics. Interestingly, there is considerable overlap in the physics of ICF and astrophysics. Both typically involve compressible radiative hydrodynamics, radiation transport, complex opacities, and equations of state of dense matter. Surprisingly, however, there has been little communication between these two communities to date. With the recent declassification of ICF in the USA, and the approval to commence with construction of the next generation ''superlasers'', the 2 MJ National Ignition Facility in the US, and its equivalent, the LMJ laser in France, the situation is ripe for change. . Given the physics similarities that exist between ICF and astrophysics, one strongly suspects that there should exist regions of overlap where supporting research on the large lasers could be beneficial to the astrophysics community. As a catalyst for discussions to this end, Lawrence Livermore National Laboratory sponsored this workshop. Approximately 100 scientists attended from around the world, representing eight countries: the USA, Canada, UK, France, Germany, Russia, Japan, and Israel. A total of 30 technical papers were presented. The two day workshop was divided into four sessions, focusing on nonlinear hydrodynamics, radiative hydrodynamics, radiation transport, and atomic physics-opacities. Copies of the presentations are contained in these proceedings

The proceedings of the 1st international workshop on laboratory astrophysics experiments with large lasers

Energy Technology Data Exchange (ETDEWEB)

Remington, B.A.; Goldstein, W.H. [eds.

1996-08-09

The world has stood witness to the development of a number of highly sophisticated and flexible, high power laser facilities (energies up to 50 kJ and powers up to 50 TW), driven largely by the world-wide effort in inertial confinement fusion (ICF). The charter of diagnosing implosions with detailed, quantitative measurements has driven the ICF laser facilities to be exceedingly versatile and well equipped with diagnostics. Interestingly, there is considerable overlap in the physics of ICF and astrophysics. Both typically involve compressible radiative hydrodynamics, radiation transport, complex opacities, and equations of state of dense matter. Surprisingly, however, there has been little communication between these two communities to date. With the recent declassification of ICF in the USA, and the approval to commence with construction of the next generation ``superlasers``, the 2 MJ National Ignition Facility in the US, and its equivalent, the LMJ laser in France, the situation is ripe for change. . Given the physics similarities that exist between ICF and astrophysics, one strongly suspects that there should exist regions of overlap where supporting research on the large lasers could be beneficial to the astrophysics community. As a catalyst for discussions to this end, Lawrence Livermore National Laboratory sponsored this workshop. Approximately 100 scientists attended from around the world, representing eight countries: the USA, Canada, UK, France, Germany, Russia, Japan, and Israel. A total of 30 technical papers were presented. The two day workshop was divided into four sessions, focusing on nonlinear hydrodynamics, radiative hydrodynamics, radiation transport, and atomic physics-opacities. Copies of the presentations are contained in these proceedings.

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.

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…

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.

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.

Contributions to the study of astrophysical plasmas. From accretion-ejection flows to particle acceleration in shocks

International Nuclear Information System (INIS)

Casse, Fabien

2013-01-01

After having outlined that the study of turbulence is a point of convergence between mathematics and physics, and that magnetic turbulence is omnipresent in astrophysical plasmas and also present in the interstellar medium, in stars and in their environment, in accretion disks, at the vicinity of shocks, and so on, the author proposes an overview of his research works which started with a research thesis on magnetised accretion disks and transport of relativistic particles in a magnetic turbulence. So, in this report for an accreditation to supervise research (HDR), he first focuses on physics of systems in accretion, and particularly on magnetised accretion-ejection structures. He evokes his work on a stationary modelling of these structures, on magnetohydrodynamics digital simulation of these systems, and on some instabilities in accretion disks and their interest in astrophysics. In a second part, the author reports his works on numerical assessment of coefficients of spatial diffusion of cosmic rays in a magnetic turbulence, and the description of multi-scale environments such as supernovae debris or different regions of extra-galactic jets.

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.

CHOLLA: A NEW MASSIVELY PARALLEL HYDRODYNAMICS CODE FOR ASTROPHYSICAL SIMULATION

International Nuclear Information System (INIS)

Schneider, Evan E.; Robertson, Brant E.

2015-01-01

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 (≳256 3 ) 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

CHOLLA: A NEW MASSIVELY PARALLEL HYDRODYNAMICS CODE FOR ASTROPHYSICAL SIMULATION

Energy Technology Data Exchange (ETDEWEB)

Schneider, Evan E.; Robertson, Brant E. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2015-04-15

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 (≳256{sup 3}) 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.

A density spike on astrophysical scales from an N-field waterfall transition

Science.gov (United States)

Halpern, Illan F.; Hertzberg, Mark P.; Joss, Matthew A.; Sfakianakis, Evangelos I.

2015-09-01

Hybrid inflation models are especially interesting as they lead to a spike in the density power spectrum on small scales, compared to the CMB, while also satisfying current bounds on tensor modes. Here we study hybrid inflation with N waterfall fields sharing a global SO (N) symmetry. The inclusion of many waterfall fields has the obvious advantage of avoiding topologically stable defects for N > 3. We find that it also has another advantage: it is easier to engineer models that can simultaneously (i) be compatible with constraints on the primordial spectral index, which tends to otherwise disfavor hybrid models, and (ii) produce a spike on astrophysically large length scales. The latter may have significant consequences, possibly seeding the formation of astrophysically large black holes. We calculate correlation functions of the time-delay, a measure of density perturbations, produced by the waterfall fields, as a convergent power series in both 1 / N and the field's correlation function Δ (x). We show that for large N, the two-point function is ∝Δ2 (| x |) / N and the three-point function is ∝ Δ (| x - y |) Δ (| x |) Δ (| y |) /N2. In accordance with the central limit theorem, the density perturbations on the scale of the spike are Gaussian for large N and non-Gaussian for small N.

An overview of the Los Alamos Crestone Project : uses for astrophysical problems

Energy Technology Data Exchange (ETDEWEB)

Weaver, R. P. (Robert P.); Gittings, M. L. (Michael L.); Gisler, Galen R.; Coker, R. F. (Robert F.); New, K. C. (Kimberly C.); Hueckstaedt, R. M. (Robert M.)

2004-01-01

The Los Alamos Crestone Project is part of the Department of Energy's (DoE) Advanced Simulation and Computing (ASC) program. The main goal of this project is to investigate the use of continuous adaptive mesh refinement (CAMR) techniques for application to problems of interest to the Laboratory. An overview of the astrophysical simulations performed with the SAGE/RAGE codes will be shown here, including asteroid impacts in the deep-ocean, asteroid impacts on the continental shelf (e.g. - Chicxulub - the dinosaur killer), calculations of massive black holes at the galactic center, and calculations of supernova explosions. Examples of these simulations will be shown. We have shown that the SAGE and RAGE codes of the Crestone Project have been very successful products of the DoE's Advanced Simulation and Computing program. It is clear to those performing massively-parallel computations, that the use of thousands of processors in parallel is fundamentally changing the way we think about computer simulations. The Crestone Project codes are fully utilizing each new ASC supercomputer as they become available. The SAGE and RAGE codes are sophisticated Continuous Adaptive Mesh Refinement hydrodynamics codes for large parallel simulations. SAGE and RAGE are becoming useful tools for astrophysical applications. Further research is starting in a wider variety of areas, including cosmological studies with Mike Norman's group at UCSD.

Graphic-Card Cluster for Astrophysics (GraCCA) -- Performance Tests

OpenAIRE

Schive, Hsi-Yu; Chien, Chia-Hung; Wong, Shing-Kwong; Tsai, Yu-Chih; Chiueh, Tzihong

2007-01-01

In this paper, we describe the architecture and performance of the GraCCA system, a Graphic-Card Cluster for Astrophysics simulations. It consists of 16 nodes, with each node equipped with 2 modern graphic cards, the NVIDIA GeForce 8800 GTX. This computing cluster provides a theoretical performance of 16.2 TFLOPS. To demonstrate its performance in astrophysics computation, we have implemented a parallel direct N-body simulation program with shared time-step algorithm in this system. Our syste...

The usage of numerical code FLASH in plasma astrophysics

OpenAIRE

BROŽ, Jaroslav

2013-01-01

My diploma thesis is focused on the use of numerical computer codes for simulation in plasma astrophysics. They will learn the basic characteristics of the Sun, a closer focus on the solar corona and the solar corona heating problem. The following section is devoted to simulation software in plasma astrophysics, their installing and displaying the results using the visualization software. In the conclusion is demonstrated using this software on a model example and a simulation that performs s...

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.

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...

Determination by transfer reaction of alpha widths in fluorine for astrophysical interest; Determination par reaction de transfert de largeurs alpha dans le fluor 19. Applications a l'astrophysique

Energy Technology Data Exchange (ETDEWEB)

Oliveira Santos, F de

1995-04-15

The nucleosynthesis of fluorine is not known. Several astrophysical models predict the alpha radiative capture onto N{sup 15} as the main fluorine production reaction. In the expression of the reaction rate, one parameter is missing: the alpha width of the resonance on the E = 4.377 MeV level in fluorine. A direct measurement is excluded due to the very low cross-section expected. We have determined this alpha width using a transfer reaction followed by analyses with FR-DWBA (Finite Range Distorted Wave Born Approximation) in a simple cluster alpha model. This experiment was carried out with a Li{sup 7} beam with E = 28 MeV onto a N{sup 15} gas target. The 16 first levels were studied. Spectroscopic factors were extracted for most of them. Alpha widths for unbound levels were determined. Many alpha width were compared with known values from direct reaction and the differences lie within the uncertainty range (factor 2). The alpha width for the E = 4.377 MeV level was determined ({gamma}{sub {alpha}} = 1.5*10{sup -15} MeV), its value is about 60 times weaker than the used value. The influence of our new rate was studied in AGB (Asymptotic Giant Branch) stars during thermal pulses. In this model the alteration is sensitive. (author)

Particle physics-astrophysics working group

International Nuclear Information System (INIS)

Cronin, J.W.; Kolb, E.W.

1989-01-01

The working group met each afternoon and listened to mini-symposia on a broad range of subjects covering all aspects of particle physics---astrophysics both theoretical and experimental. This paper reports that as a result, a number of papers which follow were commissioned to reflect the present status and future prospects of the field

Astrophysics science operations - Near-term plans and vision

Science.gov (United States)

Riegler, Guenter R.

1991-01-01

Astrophysics science operations planned by the Science Operations branch of NASA Astrophysics Division for the 1990s for the purpose of gathering spaceborne astronomical data are described. The paper describes the near-future plans of the Science Operations in the areas of the preparation of the proposal; the planning and execution of spaceborne observations; the collection, processing, and analysis data; and the dissemination of results. Also presented are concepts planned for introduction at the beginning of the 20th century, including the concepts of open communications, transparent instrument and observatory operations, a spiral requirements development method, and an automated research assistant.

Extraction of interesting organic compounds from olive oil waste

Directory of Open Access Journals (Sweden)

Jiménez, Ana

2006-03-01

Full Text Available In the olive fruits there is a large amount of bioactive compounds and substances of high interest. Many of them are known by owing health beneficial properties that contribute to protective effect of the virgin olive oil. During olive oil processing, most of them remain in the olive oil wastes. Although, olive-mill wastewater (OMWW or “alpechin”, olive oil cake (OOC, and the new by-product, known as “alperujo” in Spain and generated by the two-phase extraction process, represent a major disposal and potentially severe pollution problem for the industry, they are also promising source of substances of high value. This review summarises the last knowledge on the utilisation of residual products, with more than 90 references including articles and patents, which are promising with regard to future application. All these investigations have been classified into two options, the recovery of valuable natural constituents and the bioconversion into useful products.Existe una gran cantidad de compuestos bioactivos y de alto interés presentes en la aceituna. Muchos de ellos se conocen por las cualidades beneficiosas que aportan al aceite de oliva virgen. La mayoría permanecen en mayor cantidad en el subproducto de la extracción del aceite. Aunque, el alpechín, el orujo y el nuevo subproducto de extracción del aceite en dos fases, alperujo, representan un problema potencial de vertido y contaminación, también son una prometedora fuente de compuestos de alto valor. Esta revisión resume lo último que se conoce sobre la utilización de estos residuos en el campo anteriormente mencionado, con más de 90 referencias que incluyen artículos y patentes. Todas estas investigaciones han sido clasificadas en cuanto a la recuperación de constituyentes naturalmente presentes o en cuanto a la bioconversión de los residuos en sustancias de interés.

Enhanced Starting Track Event Selection for Astrophysical Neutrinos in IceCube

Science.gov (United States)

Jero, Kyle; IceCube Collaboration

2017-09-01

IceCube’s measurements of the astrophysical neutrino flux have applied veto techniques to suppress atmospheric neutrinos and muons. All the vetos thus far have used the outer regions of the detector to identify and reject penetrating muon tracks, leaving the inner parts of the detector available to observe the astrophysical neutrino flux. Here we discuss a method that is optimized for muon neutrinos which have a charged-current interaction with a contained vertex. This analysis exploits the high quality directional information of muons to determine a veto on an event by event basis. The final sample will contain astrophysical neutrinos with good purity starting around 10 TeV.

Photoneutron strengths in 26Mg at energies of astrophysical interest

Science.gov (United States)

deBoer, R. J.; Best, A.; Görres, J.; Smith, K.; Tan, W.; Wiescher, M.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.

2014-05-01

Background: The 22Ne(α,n)25Mg reaction is an important source of neutrons for s-process nucleosynthesis. The neutron production from the reaction is quite sensitive to the low-energy cross section, which is dominated by narrow resonances. The high level density of the 26Mg compound nucleus above the α separation energy prevents simple extrapolations from higher energy and the high Coulomb barrier makes the direct measurements extremely difficult. For this reason, indirect methods must be employed to study the level properties of 26Mg. Purpose: The current measurement utilizes the reaction 26Mg(γ,n)25Mg to probe the level structure of the 26Mg compound nucleus from the neutron-separation energy at 11.093 MeV up to Ex≈ 12 MeV. Methods: The High-Intensity γ-ray Source of the Triangle Universities Nuclear Laboratory was used to bombard a ˜16 g sample of enriched 26Mg oxide and the resulting decay neutrons were detected with an array of nine liquid scintillator detectors. Neutron time-of-flight peaks with corresponding energies as low as ˜50 keV were detected. An efficiency measurement of the detectors was made at the University of Notre Dame's nuclear science laboratory to energies as low as 45 keV. Results: Five resonances were observed at Eγ = 11.150, 11.289, 11.329, 11.506, and 11.749 MeV and their strengths have been extracted. Conclusion:. The resulting strengths at Eγ = 11.289, 11.329, 11.506, and 11.749 MeV are in good agreement with previous measurements. The strength of the resonance at Eγ = 11.150 MeV is somewhat lower than previously measured but is in reasonable agreement when systematic uncertainties are considered. The results are also consistent with those of 25Mg(n,γ)26Mg studies where a comparison shows that many of the resonances observed here are the result of multiple unresolved narrow resonances.

Cosmological birefringence constraints from CMB and astrophysical polarization data

Energy Technology Data Exchange (ETDEWEB)

Galaverni, M. [Studio Teologico Interdiocesano, V.le Timavo 93, Reggio Emilia, 42121 Italy (Italy); Gubitosi, G. [Dipartimento di Fisica and sez. Roma1 INFN, Università di Roma ' La Sapienza' , P.le A. Moro 2, Rome, 00185 Italy (Italy); Paci, F. [SISSA, Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, Trieste, 34136 Italy (Italy); Finelli, F., E-mail: matteo.galaverni@gmail.com, E-mail: giulia.gubitosi@imperial.ac.uk, E-mail: fpaci@sissa.it, E-mail: finelli@iasfbo.inaf.it [INAF-IASF Bologna, via Gobetti 101, Bologna, I-40129 Italy (Italy)

2015-08-01

Cosmological birefringence is a rotation of the polarization plane of photons coming from sources of astrophysical and cosmological origin. The rotation can also depend on the energy of the photons and not only on the distance of the source and on the cosmological evolution of the underlying theoretical model. In this work, we constrain few selected models for cosmological birefringence, combining CMB and astrophysical data at radio, optical, X and γ wavelengths, taking into account the specific energy and distance dependences.

Facilities at Indian Institute of Astrophysics and New Initiatives

Science.gov (United States)

Bhatt, Bhuwan Chandra

2018-04-01

The Indian Institute of Astrophysics is a premier national institute of India for the study of and research into topics pertaining to astronomy, astrophysics and related subjects. The Institute's main campus in Bangalore city in southern India houses the main administrative set up, library and computer center, photonics lab and state of art mechanical workshop. IIA has a network of laboratories and observatories located in various places in India, including Kodaikanal (Tamilnadu), Kavalur (Tamilnadu), Gauribidanur (Karnataka), Leh & Hanle (Jammu & Kashmir) and Hosakote (Karnataka).

Global kinetic theory of astrophysical jets

International Nuclear Information System (INIS)

Chang, T.

1989-01-01

We suggest that an astrophysical plasma stream flowing outward from a central object aling an open magnetic field line with decreasing field strength generally will have anisotropic velocity distributions. I particular, the electron distribution function of this type of plasma streams will contain a 'thermally populated' region and a stretche out high energy tail (or 'jet-like') region collimated in the utward direction of the magnetic field line. Our argument is based on a global, collisional, kinetic theory. Because the 'kinetic jets' are always pointed aling the outward direction of the field lines, thy are automatically collimated and will assume whatever the peculiar geometries dictated by the magnetic field. This result should be useful in the understanding of the basic structures of such diverse astrophysical objects as the extragalactic radio jets, stellar winds, the solar wind, planetary polar winds, and galactic jets. (author). 8 refs.; 2 figs

Sugar and Sugar Derivatives in Residues Produced from the UV Irradiation of Astrophysical Ice Analogs

Science.gov (United States)

Nuevo, M.; Sandford, S. A.; Cooper, G.

2016-01-01

A large variety and number of organic compounds of prebiotic interest are known to be present in carbonaceous chondrites. Among them, one sugar (dihydroxyacetone) as well as several sugar acids, sugar alcohols, and other sugar derivatives have been reported in the Murchison and Murray meteorites. Their presence, along with amino acids, amphiphiles, and nucleobases strongly suggests that molecules essential to life can form abiotically under astrophysical conditions. This hypothesis is supported by laboratory studies on the formation of complex organic molecules from the ultraviolet (UV) irradiation of simulated astrophysical ice mixtures consisting of H2O, CO, CO2, CH3OH, CH4, NH3, etc., at low temperature. In the past 15 years, these studies have shown that the organic residues recovered at room temperature contain amino acids, amphiphiles, nucleobases, as well as other complex organics. However, no systematic search for the presence of sugars and sugar derivatives in laboratory residues have been reported to date, despite the fact that those compounds are of primary prebiotic significance. Indeed, only small (up to 3 carbon atoms) sugar derivatives including glycerol and glyceric acid have been detected in residues so far.

Critical ionisation velocity effects in astrophysical plasmas

International Nuclear Information System (INIS)

Raadu, M.A.

1979-08-01

Critical ionisation velocity effects are relevant to astrophysical situations where neutral gas moves through a magnetised plasma. The experimental significance of the critical velocity is well established and the physical basis is now becoming clear. The underlying mechanism depends on the combined effects of electron impact ionisation and electron energisation by collective plasma interactions. For low density plasmas a theory based on a circular process involving electron heating through a modified two stream instability has been developed. Several applications of critical velocity effects to astrophysical plasmas have been discussed in the literature. The importance of the effect in any particular case may be determined from a detailed consideration of energy and momentum balance, using appropriate atomic rate coefficients and taking full account of collective plasma processes. (Auth.)

Status reports of supercomputing astrophysics in Japan

International Nuclear Information System (INIS)

Nakamura, Takashi; Nagasawa, Mikio

1990-01-01

The Workshop on Supercomputing Astrophysics was held at National Laboratory for High Energy Physics (KEK, Tsukuba) from August 31 to September 2, 1989. More than 40 participants of physicists, astronomers were attendant and discussed many topics in the informal atmosphere. The main purpose of this workshop was focused on the theoretical activities in computational astrophysics in Japan. It was also aimed to promote effective collaboration between the numerical experimentists working on supercomputing technique. The various subjects of the presented papers of hydrodynamics, plasma physics, gravitating systems, radiative transfer and general relativity are all stimulating. In fact, these numerical calculations become possible now in Japan owing to the power of Japanese supercomputer such as HITAC S820, Fujitsu VP400E and NEC SX-2. (J.P.N.)

Astrophysical data analysis with information field theory

International Nuclear Information System (INIS)

Enßlin, Torsten

2014-01-01

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

Astrophysical data analysis with information field theory

Science.gov (United States)

Enßlin, Torsten

2014-12-01

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

Astrophysical data analysis with information field theory

Energy Technology Data Exchange (ETDEWEB)

Enßlin, Torsten, E-mail: ensslin@mpa-garching.mpg.de [Max Planck Institut für Astrophysik, Karl-Schwarzschild-Straße 1, D-85748 Garching, Germany and Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, D-80539 München (Germany)

2014-12-05

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

NUMERICALLY DETERMINED TRANSPORT LAWS FOR FINGERING ('THERMOHALINE') CONVECTION IN ASTROPHYSICS

International Nuclear Information System (INIS)

Traxler, A.; Garaud, P.; Stellmach, S.

2011-01-01

We present the first three-dimensional simulations of fingering convection performed at parameter values approaching those relevant for astrophysics. Our simulations reveal the existence of simple asymptotic scaling laws for turbulent heat and compositional transport, which can be straightforwardly extrapolated from our numerically tractable values to the true astrophysical regime. Our investigation also indicates that thermo-compositional 'staircases', a key consequence of fingering convection in the ocean, cannot form spontaneously in the fingering regime in stellar interiors. Our proposed empirically determined transport laws thus provide simple prescriptions for mixing by fingering convection in a variety of astrophysical situations, and should, from here on, be used preferentially over older and less accurate parameterizations. They also establish that fingering convection does not provide sufficient extra-mixing to explain observed chemical abundances in red giant branch stars.

Astrophysics in a nutshell from the telescope to the sputnik

International Nuclear Information System (INIS)

Alfven, H.; Faelthammar, C.G.

1988-03-01

Progress in astrophysics - as well as in many other sciences - is not only due to new ideas but also to the introduction of new methods of observation. The 'Copernican revolution' was more due to the introduction of the telescope than to the heliocentric model which had been invented 2000 years earlier. Further, the decisive importance of electromagnetic effects in astrophysics originated from Langmuir's invention of the plasma probe and from Birkeland's terrella experiment and his observations of plasma in space (aurora). A similar revolution has now been introduced by space research which has made possible in situ measurements in cosmic plasmas and has opened the X-ray and γ-ray regions to observation. The result is a drastic revision of essential parts of astrophysics (including cosmology) leading to the 'Plasma Universe' model. (authors)

Nuclear astrophysics deep underground the case of the 15N(p,γ)16O reaction at LUNA

CERN Document Server

Mazzocchi, Chiara

2010-01-01

Measuring nuclear reactions of astrophysical interest at the relevant energies is not always possible on the Earth’s surface because of the cosmic-ray background that dominates the spectra. The LUNA collaboration exploits the lowbackground enviroment of Gran Sasso National Laboratory to study these reactions at or close to the Gamow peak. The latest experimental efforts included the measurement of the 15N(p,γ)16O at beam energies between 77 and 350 keV. The status of these measurements is summarised in this contribution.

Report on the workshop "Decay spectroscopy at CARIBU: advanced fuel cycle applications, nuclear structure and astrophysics". 14-16 April 2011, Argonne National Laboratory, USA.

Energy Technology Data Exchange (ETDEWEB)

Kondev, F.; Carpenter, M.P.; Chowdhury, P.; Clark, J.A.; Lister, C.J.; Nichols, A.L.; Swewryniak, D. (Nuclear Engineering Division); (Univ. of Massachusetts); (Univ. of Surrey)

2011-10-06

A workshop on 'Decay Spectroscopy at CARIBU: Advanced Fuel Cycle Applications, Nuclear Structure and Astrophysics' will be held at Argonne National Laboratory on April 14-16, 2011. The aim of the workshop is to discuss opportunities for decay studies at the Californium Rare Isotope Breeder Upgrade (CARIBU) of the ATLAS facility with emphasis on advanced fuel cycle (AFC) applications, nuclear structure and astrophysics research. The workshop will consist of review and contributed talks. Presentations by members of the local groups, outlining the status of relevant in-house projects and availabile equipment, will also be organized. time will also be set aside to discuss and develop working collaborations for future decay studies at CARIBU. Topics of interest include: (1) Decay data of relevance to AFC applications with emphasis on reactor decay heat; (2) Discrete high-resolution gamma-ray spectroscopy following radioactive decya and related topics; (3) Calorimetric studies of neutron-rich fission framgents using Total ABsorption Gamma-Ray Spectrometry (TAGS) technique; (4) Beta-delayed neutron emissions and related topics; and (5) Decay data needs for nuclear astrophysics.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry.

Science.gov (United States)

de Oliveira, Jonatas Rafael; de Castro, Vinicius Carlos; das Graças Figueiredo Vilela, Polyana; Camargo, Samira Esteves Afonso; Carvalho, Cláudio Antonio Talge; Jorge, Antonio Olavo Cardoso; de Oliveira, Luciane Dias

2013-08-15

With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7). Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA. In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg

Summary for astrophysics and non-accelerator physics

International Nuclear Information System (INIS)

Kahana, S.H.

1988-01-01

This paper summarizes the presentations at the astrophysics and non-accelerator physics conference. Discussed in this paper are: supernovae, neutrinos, x-rays, gamma rays, cosmic rays, monopoles and primordial nucleosynthesis. 15 refs

Positron-Electron Pairs in Astrophysics (Goddard Space Flight Center, 1983)

International Nuclear Information System (INIS)

Burns, M.L.; Harding, A.K.; Ramaty, R.

1983-01-01

A workshop on Position-Electron Pairs in Astrophysics was held in 1983 at the Goddard Space Flight Center. This workshop brought together observers and theorists actively engaged in the study of astrophysical sites, as well as physical processes therein where position-electron pairs have a profound influence on both the overall dynamics of the source region and the properties of the emitted radiation. This volume consists of the workshop proceedings

75 FR 1087 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

Science.gov (United States)

2010-01-08

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting... Administration (NASA) and the U.S. Department of Energy (DOE) on issues within the field of astronomy and [[Page...

75 FR 22863 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

Science.gov (United States)

2010-04-30

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following meeting: Name: Astronomy and Astrophysics Advisory Committee... Administration (NASA) and the U.S. Department of Energy (DOE) on issues within the field of astronomy and...

77 FR 2095 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

Science.gov (United States)

2012-01-13

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting... Administration (NASA) and the U.S. Department of Energy (DOE) on issues within the field of astronomy and...

76 FR 58049 - Astronomy and Astrophysics Advisory Committee #13883; Notice of Meeting

Science.gov (United States)

2011-09-19

... NATIONAL SCIENCE FOUNDATION Astronomy and Astrophysics Advisory Committee 13883; Notice of Meeting... Science Foundation announces the following Astronomy and Astrophysics Advisory Committee ( 13883) meeting... Administration (NASA) and the U.S. Department of Energy (DOE) on issues within the field of astronomy and...

The 2050 Decadal Survey of Astronomy and Astrophysics

Science.gov (United States)

Longair, Malcolm

2011-05-01

Astronomy, Astrophysics and Cosmology have changed out of all recognition over the last 40 years. The lecture will review some of the key scientific, technological and sociological changes which have contributed to that revolution and seek to understand the issues of maintaining that drive for discovery and understanding over the next 40 years. Some science objectives are well defined, but others may need new concepts, unexpected discoveries and quite a bit of good luck. A personal perspective will be presented on topics which the community should take seriously for the advance of astronomy and astrophysics and the role it can play for the betterment of society.

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.

Resolving astrophysical uncertainties in dark matter direct detection

CERN Document Server

Frandsen, Mads T; McCabe, Christopher; Sarkar, Subir; Schmidt-Hoberg, Kai

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 modulation fraction. However constraints from CDMS and XENON cannot be evaded by appealing to such astrophysical uncertainties alone.

Compressed Baryonic Matter of Astrophysics

OpenAIRE

Guo, Yanjun; Xu, Renxin

2013-01-01

Baryonic matter in the core of a massive and evolved star is compressed significantly to form a supra-nuclear object, and compressed baryonic matter (CBM) is then produced after supernova. The state of cold matter at a few nuclear density is pedagogically reviewed, with significant attention paid to a possible quark-cluster state conjectured from an astrophysical point of view.

Indirect methods in nuclear astrophysics

International Nuclear Information System (INIS)

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

2016-01-01

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

Solar astrophysics: ghettosis from, or symbiosis with, stellar and galactic astrophysics

Energy Technology Data Exchange (ETDEWEB)

Pecker, J C; Thomas, R N [Centre National de la Recherche Scientifique, 75 - Paris (France). Inst. d' Astrophysique

1976-07-01

The authors summarize how the solar-stellar symbiotic approach, an astrophysical research method, has led to the modeling of a star as a concentration of matter and energy. The observational aspect of the method is to discover an 'anomalous' feature, in either the Sun, where the feature is small, or in an unusual or exceptional star, where the feature is large. The theoretical aspect of the method is to discover some physical inconsistency in theoretical models of some phenomenon or in theoretical basis for some diagnostic method, and attempt to develop a better approach, guided by the observational application.

Neutrino Masses and Mixings and Astrophysics

Science.gov (United States)

Fuller, George M.

1998-10-01

Here we discuss the implications of light neutrino masses and neutrino flavor/type mixing for dark matter, big bang nucleosynthesis, and models of heavy element nucleosynthesis in super novae. We will also argue the other way and discuss possible constraints on neutrino physics from these astrophysical considerations.

Microphysics, cosmology, and high energy astrophysics

International Nuclear Information System (INIS)

Hoyle, F.

1974-01-01

The discussion of microphysics, cosmology, and high energy astrophysics includes particle motion in an electromagnetic field, conformal transformations, conformally invariant theory of gravitation, particle orbits, Friedman models with k = 0, +-1, the history and present status of steady-state cosmology, and the nature of mass. (U.S.)