Download or read book Study of Non thermal Emission from Supernova Remnants and Cosmic Ray Injection in the Milky Way Using the Fermi Large Area Telescope written by Shiu Hang Lee and published by Stanford University. This book was released on 2011 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supernova remnants (SNRs) are the only class of sources known in our Galaxy capable of providing the energy necessary to power the bulk of the Galactic cosmic-rays (CRs) below the `knee' (~ 3 PeV). They are observable across the entire frequency spectrum from radio to TeV gamma-rays, and are known to exhibit a rich variety of complex morphologies in multi-wavelength. Non-thermal emissions from SNRs in X-ray and gamma-ray arise from interaction between particles accelerated by the SNR blast wave and the surrounding medium, and are hence one of the most useful probe for the Galactic CR production process. In this thesis, we will try to obtain a fuller understanding of the origin of Galactic CRs through studying non-thermal emissions from SNRs and modelling CR injection from their astrophysical accelerators. In the first part of the thesis, we will develop a robust tool to simulate time and space-resolved broadband emission from young shell-type SNRs using coupled hydrodynamic and diffusive shock acceleration (DSA) calculations. Usually, the DSA process is expected to be highly non-linear for young SNRs due to a number of postulated coupling phenomena, which leads to the inter-correlation of the emission spectra and morphology at different wavelengths. Therefore, to gain the full picture, it is important to combine multi-wavelength observations and the relevant physical processes into a self-consistent and flexible calculation framework. By taking into account particle transport, escape, interaction and various radiative processes, our tool can predict photon emissivity in full three-dimension and multi-wavelength for any given SNR model and surrounding environment, such as in the presence of a nearby molecular cloud. Through illustrations using a few typical models for Type Ia SNR, we will demonstrate its capability of calculating results directly comparable to observations, as well as to pinpoint the gamma-ray emission mechanism, namely the leptonic and hadronic scenarios. In the second part, we will study the gamma-ray emission from a middle-aged SNR IC 443 (G189.1+3.0) using the Fermi Large Area Telescope (LAT). IC 443 has been extensively studied in the past few decades through radio to TeV gamma-ray, but high quality data in the sub-GeV to sub-TeV band, the most crucial window for constraining the origin of the high-energy emission, has still been missing. We will fill in this gap by analyzing LAT data from 200 MeV to 50 GeV using the 1st year of LAT data. Equipped with the high photon statistics available, and the excellent resolution, sensitivity and low background rate of LAT, we are able to probe the gamma-ray emission from IC 443 with minimal confusion with the backgrounds. We discovered spatially extended emission from IC 443 in the 1 - 50 GeV band for the first time, which eliminates the pulsar wind nebula (PWN) as the dominating gamma-ray emitter. We found good spatial correlation of the GeV mission with the TeV source recently detected by VERITAS, as well as a known group of ambient and shocked molecular clouds (MC). The sub-GeV to TeV broadband spectrum can be described by a power-law with a smooth break at a few GeV, the same feature also observed from several other LAT-detected middle-aged SNRs interacting with MCs. We will argue that the gamma-ray emission is most naturally explained by a neutral pion decay dominated origin, and the leptonic scenarios are disfavored. Finally, we will also discuss the major discoveries from LAT observations of other gamma-ray bright Galactic SNRs during the first 2 years of operation of Fermi. In the last part, we will construct a model of Galactic CR injection using constraints from most recent GeV and TeV observation data and CR measurements, which can provide a natural explanation for the enhanced positron flux above 10 GeV recently observed by PAMELA as compared to previous measurements. Without making speculation on `additional' positron contribution from any special nearby objects or resorting to exotic phenomena, we will look at a steady-state picture of our Galaxy in which the ensembles of SNRs and PWNe steadily inject CRs into the interstellar space. Using the GALPROP CR propagation code, the CR spectra and ratios at Earth are calculated and compared with data. Without tweaking the model parameters specifically to fit the positron data other than using observation and astrophysics-based assumptions, we will show that this steady-state model can satisfactorily reproduce the positron enhancement and other CR measurement results. Assisted by recent observations of middle-aged SNRs interacting with MCs by Fermi LAT, we are also able to set an upper-limit on the total number of these systems residing in our Galaxy. Finally, using this consistent model, we will estimate the energy budgets of the major species of Galactic CRs.
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 Handbook of X ray and Gamma ray Astrophysics written by Cosimo Bambi and published by Springer Nature. This book was released on with total page 5912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non thermal Emission from Supernova Remnants Observed with Suzaku and Its Implications for Cosmic ray Acceleration written by Takaaki Tanaka and published by . This book was released on 2007 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fermi Large Area Telescope Observations of the Supernova Remnant G8 7 0 1 written by and published by . This book was released on 2012 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 ± 0.6 (stat) ± 1.2 (sys) GeV, and photon indices of 2.10 ± 0.06 (stat) ± 0.10 (sys) below the break and 2.70 ± 0.12 (stat) ± 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.
Download or read book Physics and Evolution of Supernova Remnants written by Jacco Vink and published by Springer Nature. This book was released on 2020-11-10 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by a leading expert, this monograph presents recent developments on supernova remnants, with the inclusion of results from various satellites and ground-based instruments. The book details the physics and evolution of supernova remnants, as well as provides an up-to-date account of recent multiwavelength results. Supernova remnants provide vital clues about the actual supernova explosions from X-ray spectroscopy of the supernova material, or from the imprints the progenitors had on the ambient medium supernova remnants are interacting with - all of which the author discusses in great detail. The way in which supernova remnants are classified, is reviewed and explained early on. A chapter is devoted to the related topic of pulsar wind nebulae, and neutron stars associated with supernova remnants. The book also includes an extended part on radiative processes, collisionless shock physics and cosmic-ray acceleration, making this book applicable to a wide variety of astronomical sub-disciplines. With its coverage of fundamental physics and careful review of the state of the field, the book serves as both textbook for advanced students and as reference for researchers in the field.
Download or read book High Energy Radiation from Black Holes written by Charles Dermer and published by Princeton University Press. This book was released on 2009-10-11 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with Einstein's special and general theories of relativity, the authors give a detailed mathematical description of fundamental astrophysical radiation processes, including Compton scattering of electrons and photons, synchrotron radiation of particles in magnetic fields, and much more.
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 Science With The Cherenkov Telescope Array written by The Cta Consortium and published by World Scientific. This book was released on 2018-12-31 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the science to be carried out by the upcoming Cherenkov Telescope Array, a major ground-based gamma-ray observatory that will be constructed over the next six to eight years. The major scientific themes, as well as core program of key science projects, have been developed by the CTA Consortium, a collaboration of scientists from many institutions worldwide.CTA will be the major facility in high-energy and very high-energy photon astronomy over the next decade and beyond. CTA will have capabilities well beyond past and present observatories. Thus, CTA's science program is expected to be rich and broad and will complement other major multiwavelength and multimessenger facilities. This book is intended to be the primary resource for the science case for CTA and it thus will be of great interest to the broader physics and astronomy communities. The electronic version (e-book) is available in open access.
Download or read book Origin of Cosmic Rays written by Vitaliĭ Lazarevich Ginzburg and published by . This book was released on 1969 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Particle Physics Reference Library written by Stephen Myers and published by Springer Nature. This book was released on 2020-01-01 with total page 867 pages. Available in PDF, EPUB and Kindle. Book excerpt: This third open access volume of the handbook series deals with accelerator physics, design, technology and operations, as well as with beam optics, dynamics and diagnostics. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A,B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1993 with total page 1146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmic Magnetism written by Percy Seymour and published by CRC Press. This book was released on 1986 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of extraterrestrial magnetic fields is a relatively new one, confirmation of the existance of the first such field (that of our Sun) having come a s late as 1908. In the past 30 years a great ammount of knowledge has been accumulated on Cosmic Magnetism, which has turned out to be a truly fascinating topic for study. Percy Seymour's book is the first to deal with the topic in a non-mathematical way, and he offers a fine introduction to his subject. The first three chapters consolidate our knowledge on magnetism in general and the magnetic field of the Earth, as well as discussing the reasons for studying astronomy and cosmic magnetism in particular. The remainder of the book is devoted to the main areas of cosmic magnetism - solar, plantetary and interplanetary fields, fields in stars and pulsars, fields of the milky way and fields in other galaxies. Cosmic Magnetism in an ideal book for sixth-formers and undergraduates studying physics or astronomy and will also appeal to amateur astronomers. as previous work on this topic has been 'hidden' in specialised academic journals.
Download or read book Nonlinear Cosmic Ray Diffusion Theories written by Andreas Shalchi and published by Springer Science & Business Media. This book was released on 2009-06-04 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: If charged particles move through the interplanetary or interstellar medium, they interact with a large-scale magnetic ?eld such as the magnetic ?eld of the Sun or the Galactic magnetic ?eld. As these background ?elds are usually nearly constant in time and space, they can be approximated by a homogeneous ?eld. If there are no additional ?elds, the particle trajectory is a perfect helix along which the par- cle moves at a constant speed. In reality, however, there are turbulent electric and magnetic?elds dueto the interstellaror solar wind plasma. These ?elds lead to sc- tering of the cosmic rays parallel and perpendicular to the background ?eld. These scattering effects, which usually are of diffusive nature, can be described by s- tial diffusion coef?cients or, alternatively, by mean free paths. The knowledge of these parameters is essential for describing cosmic ray propagation as well as d- fusive shock acceleration. The latter process is responsible for the high cosmic ray energies that have been observed. The layout of this book is as follows. In Chap. 1, the general physical scenario is presented. We discuss fundamental processes such as cosmic ray propagation and acceleration in different systems such as the solar system or the interst- lar space. These processes are a consequence of the interaction between charged cosmic particles and an astrophysical plasma (turbulence). The properties of such plasmas are therefore the subject of Chap. 2.
Download or read book Cosmic Rays and Particle Physics written by Thomas K. Gaisser and published by Cambridge University Press. This book was released on 1990 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over recent years there has been marked growth in interest in the study of techniques of cosmic ray physics by astrophysicists and particle physicists. Cosmic radiation is important for the astrophysicist because in the farther reaches of the universe. For particle physicists, it provides the opportunity to study neutrinos and very high energy particles of galactic origin. More importantly, cosmic rays constitue the background, and in some cases possibly the signal, for the more exotic unconfirmed hypothesized particles such as monopoles and sparticles. Concentrating on the highest energy cosmic rays, this book describes where they originate, acquire energy, and interact, in accreting neutron stars, supernova remnants, in large-scale shock waves. It also describes their interactions in the atmosphere and in the earth, how they are studied in surface and very large underground detectors, and what they tell us.
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 Historical Supernovae and Their Remnants written by Francis Richard Stephenson and published by Oxford University Press on Demand. This book was released on 2002 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text, written by two leading experts, reviews the historical observations of supernova explosions in our Galaxy over the past two thousand years and discusses modern observations of the remnants of these explosions at radio and other wavelengths.
