Download or read book A Search for Gamma Ray Emission from Supernova Remnants and Its Relation to the Origin of Cosmic Rays written by Thomas Clifford May and published by . This book was released on 1968 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shock Cloud Interaction in RX J1713 7 3946 written by Hidetoshi Sano and published by Springer. This book was released on 2016-11-14 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a study of the young supernova remnant RX J1713.7-3946 in order to reveal the origin of cosmic rays in our galaxy. The study focuses on the X-ray and gamma radiation from the cosmic ray electrons and protons in the supernova remnant as well as the emission from the surrounding interstellar gas measured by the NANTEN2 4-m radio telescope at Nagoya University. The gamma rays show a good spatial correspondence with the interstellar gas, which for the first time provides strong evidence of the acceleration of cosmic ray protons. Additionally, the author determines that an interaction between the supernova shockwaves and interstellar gas, referred to as “shock-cloud interaction,” promotes the efficient acceleration of cosmic ray electrons in the supernova remnant. The book reveals that the interstellar gas plays an essential role in producing the high-energy radiation and cosmic rays, offering vital new insights into the origin and behavior of galactic cosmic rays.
Download or read book Gamma ray and Neutrino Signatures of Galactic Cosmic ray Accelerators written by Silvia Celli and published by Springer Nature. This book was released on 2019-12-17 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses three “hot” topics concerning the general problem of the origin of Galactic cosmic rays, namely (1) the acceleration, propagation, and radiation of particles in supernova remnants; (2) very high energy neutrinos from the Galactic Center; and (3) the potential held by the next-generation gamma-ray and neutrino detectors CTA and KM3NeT for studying extended non-thermal sources in the Galaxy. The topics are intrinsically connected to determining the nature (“hadronic or leptonic?”) of gamma-ray emissions from young and middle-aged supernova remnants and the search for cosmic-ray PeVatrons. The results and conclusions provided here are based on extensive analytical and numerical simulations, which are formulated and presented in a straightforward format that can be readily used in the interpretations of gamma-ray and neutrino observations, as well as for confident predictions for future measurements.
Download or read book Gamma ray Studies of the Young Shell type SNR RX J1713 7 3946 written by and published by . This book was released on 2014 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most significant current discussions in Astrophysics relates to the origin of high-energy cosmic rays. According to our current knowledge, the abundance distribution of the elements in cosmic rays at their point of origin indicates, within plausible error limits, that they were initially formed by nuclear processes in the interiors of stars. It is also believed that their energy distribution up to 1018 eV has Galactic origins. But even though the knowledge about potential sources of cosmic rays is quite poor above " 1015 eV, that is the "knee" of the cosmic-ray spectrum, up to the knee there seems to be a wide consensus that supernova remnants are the most likely candidates. Evidence of this comes from observations of non-thermal X-ray radiation, requiring synchrotron electrons with energies up to 1014 eV, exactly in the remnant of supernovae. To date, however, there is not conclusive evidence that they produce nuclei, the dominant component of cosmic rays, in addition to electrons. In light of this dearth of evidence, [gamma]-ray observations from supernova remnants can offer the most promising direct way to confirm whether or not these astrophysical objects are indeed the main source of cosmic-ray nuclei below the knee. Recent observations with space- and ground-based observatories have established shell-type supernova remnants as GeV-to- TeV [gamma]-ray sources. The interpretation of these observations is however complicated by the different radiation processes, leptonic and hadronic, that can produce similar fluxes in this energy band rendering ambiguous the nature of the emission itself. The aim of this work is to develop a deeper understanding of these radiation processes from a particular shell-type supernova remnant, namely RX J1713.7-3946, using observations of the LAT instrument onboard the Fermi Gamma-Ray Space Telescope. Furthermore, to obtain accurate spectra and morphology maps of the emission associated with this supernova remnant, an improved model of the diffuse Galactic [gamma]-ray emission background is developed. The analyses of RX J1713.7-3946 carried out with this improved background show that the hard Fermi-LAT spectrum cannot be ascribed to the hadronic emission, leading thus to the conclusion that the leptonic scenario is instead the most natural picture for the high-energy [gamma]-ray emission of RX J1713.7-3946. The leptonic scenario however does not rule out the possibility that cosmic-ray nuclei are accelerated in this supernova remnant, but it suggests that the ambient density may not be high enough to produce a significant hadronic [gamma]-ray emission. Further investigations involving other supernova remnants using the improved back- ground developed in this work could allow compelling population studies, and hence prove or disprove the origin of Galactic cosmic-ray nuclei in these astrophysical objects. A break- through regarding the identification of the radiation mechanisms could be lastly achieved with a new generation of instruments such as CTA.
Download or read book Experimental Tests of the Supernovae Origin of Cosmic Rays written by Carl E. Fichtel and published by . This book was released on 1968 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very High Energy Cosmic Gamma Radiation written by Felix A. Aharonian and published by World Scientific. This book was released on 2004 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma ray astronomy, the branch of high energy astrophysics that studies the sky in energetic ?-ray photons, is destined to play a crucial role in the exploration of nonthermal phenomena in the Universe in their most extreme and violent forms. The great potential of this discipline offers impressive coverage of many OC hot topicsOCO of modern astrophysics and cosmology, such as the origin of galactic and extragalactic cosmic rays, particle acceleration and radiation processes under extreme astrophysical conditions, and the search for dark matter."
Download or read book Very High Energy Cosmic Gamma Radiation A Crucial Window On The Extreme Universe written by Felix A Aharonian and published by World Scientific. This book was released on 2004-07-19 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma ray astronomy, the branch of high energy astrophysics that studies the sky in energetic γ-ray photons, is destined to play a crucial role in the exploration of nonthermal phenomena in the Universe in their most extreme and violent forms. The great potential of this discipline offers impressive coverage of many “hot topics” of modern astrophysics and cosmology, such as the origin of galactic and extragalactic cosmic rays, particle acceleration and radiation processes under extreme astrophysical conditions, and the search for dark matter. The recent observational results and exciting theoretical predictions provide a strong rationale for a deep study of cosmic radiation with forthcoming satellite-borne and ground-based detectors in the so-called very high energy domain of the electromagnetic spectrum above 1010 eV.This invaluable book presents the motivations and highlights the principal objectives of the field, as well as demonstrates its intrinsic links to other branches of high energy astrophysics. Preference is given to three topical areas: (i) origin of cosmic rays; (ii) physics and astrophysics of relativistic jets; (iii) observational gamma ray cosmology. Also, an essential part of the book is devoted to the discussion of the principal mechanisms of production and absorption of energetic γ-rays in different astrophysical environments, as well as to the description of the detection methods of high energy cosmic γ-radiation.
Download or read book Search for Gamma ray Emission from Bow Shocks of Runaway Stars written by and published by . This book was released on 2014 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mystery of the origin of cosmic rays has been tackled for more than hundred years and is still not solved. Cosmic rays are detected with energies spanning more than 10 orders of magnitude and reaching energies up to ~1021 eV, far higher than any man-made accelerator can reach. Different theories on the astrophysical objects and processes creating such highly energetic particles have been proposed. A very prominent explanation for a process producing highly energetic particles is shock acceleration. The observation of high-energy gamma rays from supernova remnants, some of them revealing a shell like structure, is clear evidence that particles are accelerated to ultrarelativistic energies in the shocks of these objects. The environments of supernova remnants are complex and challenge detailed modelling of the processes leading to high-energy gamma-ray emission. The study of shock acceleration at bow shocks, created by the supersonic movement of individual stars through the interstellar medium, offers a unique possibility to d...zeige mehr
Download or read book The Astrophysics of Galactic Cosmic Rays written by Roland Diehl and published by Springer Science & Business Media. This book was released on 2002-02-28 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings from two ISSI workshops, 18-22 October 1999 and 15-19 May 2000, Bern, Switzerland
Download or read book Composition and Origin of Cosmic Rays written by M.M. Shapiro and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute, Ettore Majorana Centre, Erice, Sicily, Italy, June 20-30, 1982
Download or read book Study of the Extreme Gamma ray Emission from Supernova Remnants and the Crab Pulsar written by Daniel Galindo Fernández and published by . This book was released on 2018 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: In our Galaxy, supernova remnants and pulsars are the two most numerous populations of non-thermal objects. The goal of this thesis is to study the extreme gamma-ray emission from these two astrophysical objects with Fermi -LAT and MAGIC. In particular, supernova remnants Cassiopeia A and SNR G24.7+0.6 and the Crab pulsar. Cassiopeia A, one of the historical supernova remnants and the prime candidate of its class to be a PeVatron accelerator, has been discarded as so since we provided the first measurement of a turn-off in the gamma-ray spectrum at 3 TeV, implying the emission observed is produced by the decay of neutral pions, produced in proton- proton interactions of a parent population of accelerated protons with an energy cut-off at about 10TeV. Such a maximum energy of accelerated cosmic rays in Cassiopeia A falls short to explain the high energy end ( PeV) of the Galactic cosmic ray spectrum. Considering that Cassiopeia A was the main PeVatron candidate, the results obtained in this work challenge the existence of supernova remnants as galactic Pevatrons and therefore the popular conviction that supernova remnants are the main source of Galactic cosmic ray up to the knee. In the case of SNR G24.7+0.6, the remnant is evolving in a dense medium and might be interacting with the CO-rich surrounding. The observations performed allowed us to detect for the first time the counterpart of the radio emission, MAGIC J1835–069, from 60MeV up to 5TeV. This very high energy emission results from proton-proton interactions between the runaway protons from the supernova remnant and a nearby molecular cloud. These observations of the field of view of SNR G24.7+0.6, also resulted in the detection of another new source, MAGIC J1837–073, that is likely to be associated with a stellar cluster as suggested by its localization in a region rich in molecular content and crowded of sources. The total energy obtained in accelerated protons can be explained assuming a quasi-continuous injection of cosmic rays during the cluster lifetime. The second part of this thesis is focused on the study and understanding of the Crab pulsar, the young and most energetic pulsar in our galaxy. Observations carried out with MAGIC resulted in the first ever detection of very energetic pulsed emission from a pulsar, reaching up to about 1.5 TeV. Moreover, the light curve of the Crab above 400 GeV shows two peaks synchronized with those measured at lower energies. Such extremely energetic pulsed emission has to be produced by electrons with very high Lorentz factor scattering low energy photons in the vicinity of the light cylinder, either inside or outside of it. Currently, none of the postulated models is yet capable of reproducing at the same time the light curve and the spectral shape for both peaks above 400 GeV.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book X ray Spectra of Supernova Remnants written by Andrew E. Szymkowiak and published by . This book was released on 1985 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray spectra were obtained from fields in three supernova remnants with the solid state spectrometer of the HEAO 2 satellite. These spectra, which contain lines from K-shell transitions of several abundant elements with atomic numbers between 10 and 22, were compared with various models, including some of spectra that would be produced by adiabatic phase remnants when the time-dependence of the ionization is considered.
Download or read book Cosmic Gamma Rays written by Floyd William Stecker and published by . This book was released on 1971 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic gamma ray production processes, galactic and extragalactic gamma rays, and cosmology.
Download or read book Search for Evidence of Cosmic Ray Acceleration by Supernova Remnant Kes 41 Using the Fermi LAT written by Timothy Robert Joubert and published by . This book was released on 2013 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis presented in this paper incorporated photon events received during the full run time of the Fermi Gamma Space Telescope (FGST) Large Area Telescope (LAT) to date. By studying the [gamma]y emission of the supernova remnant (SNR) Kes 41 for the energy range ~ 200MeV-200GeV, the [gamma]-ray morphology and spectrum were measured. These measurements required the use of reduced log likelihood statistics mediated by the Fermi Science Tools toolkit, developed for LAT analysis. The spatial analysis of the [gamma]-ray emission was measured at 5[sigma] for the area within and around the contours established during radio measurements [25]. It also resembles Kes 41's observed, centrally bright, X-ray emission [18, 25]. Spectral analysis was also carried out and the resulting [gamma]-ray spectrum was successfully fit to a power-law model of emission consistent with [pi]0-decay, a form of non-thermal emission caused by cosmic ray acceleration. An overall approximation of the [gamma]-ray luminosity was then measured as L[gamma] = 1.94 x 1035 erg/s using a measure of the total [gamma]-ray flux. A calculation also measured the particle density associated with material interacting with Kes 41 emission as n = 0.15 particles/cm-3. This value resembles that from other calculations involving SNR-Molecular cloud interaction [22]. This interaction serves to constrain [gamma]-ray emission to the [pi]0-decay channel, so evidence of a similar density value may be evidence that the significant [gamma]-ray emission observed, was due to the acceleration of cosmic rays.
Download or read book Gamma ray Emission from Crushed Clouds in Supernova Remnants written by and published by . This book was released on 2010 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of [pi]°-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.
Download or read book Are Supernova Remnants the Sources of Galactic Cosmic Rays written by Pierre Cristofari and published by . This book was released on 2013 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic rays have been discovered more than one century ago, but their orirign remains unknown. The most popular hypothesis is that supernova remnants are the source of Galactic cosmic rays. The observation of several remnants in gamma rays, which are indeed expected as the result of hadronic interactions between the cosmic rays accelerated at the remnant and the interstellar medium, is probably the strongest support to this idea. However, another mechanism, leptonic, can also account for the the observed gamma--ray émission, and in many cases the situtation remains ambiguous. Instead of relying on a case--by--case study, we adopt here a different approach and consider a population study using Monte Carlo simulations. We investigate the the number of supernova remnants that a given telescope can expect to detect, starting from the hypothesis that supernova remnant are the sources of Galactic cosmic rays. We find that our predictions are in aggrement with current observation results, such as the one of H.E.S.S, thus providing a novel consistency check for the supernova remnant paradigm for the origin of Galactic cosmic rays. The developed model can then be used to investigate the population of remnants that the next generation of telescope can expect to detect, such as the Cherenkov Telescope Array (CTA). Finally, we discuss on the hope of detection of neutrinos fron supernova remnants, which would testify that hadronic mechanisms are at stake, and could show unequivocally that supernova remnants are the sources of Galactic cosmic rays.
