Download or read book Very High Energy Gamma Rays from Binary Systems written by Hugh John Dickinson and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a study of the very high energy (VHE) gamma-ray emission from X-ray binary systems using the H.E.S.S. imaging atmospheric Cherenkov array. The historical background and basic principles of ground-based gamma-ray astronomy are briefly reviewed and an overview of the design and capabilities of the H.E.S.S. telescope system is presented. The broadband observational properties of X-ray binary systems and their relevance in a broader astrophysical context is also discussed. A review of the radiative emission mechanisms which relate to VHE gamma-ray emission in X-ray binaries is presented, with emphasis given to the leptonic emission processes of synchrotron radiation and inverse-Compton scattering. Intrinsic absorption processes which act to attenuate the emitted flux of VHE gamma-rays are also discussed. Three computer models are introduced which simulate aspects of the gamma-ray emission and absorption in X-ray binary systems. A detailed analysis of the VHE gamma-ray emission from the X-ray binary LS 5039 is presented and the relevant procedures for data selection, gamma-hadron separation and background estimation are discussed in some detail. Methods for the determination of detection significance and the calculation of gamma-ray fluxes are also reviewed and results are derived which apply specifically to LS 5039. A detailed temporal analysis of the gamma-ray signal from LS 5039 is presented, applying tests for secular, excess and periodic variability. Strong evidence is found for modulation of the observed gamma-ray flux on the orbital period of ~3.9 days. Following a brief discussion of the procedures required for spectral analysis of VHE gamma-ray data, results are presented for LS 5039 which reveal evidence for spectral variability which is correlated with the observed gamma-ray flux and therefore, the orbital phase of the binary system. The spectral and temporal characteristics of LS 5039 are then compared with the predictions of theoretical models in an attempt to explain the observed behaviour. Contemporaneous X-ray and VHE gamma-ray observations of three galactic microquasars using the Rossi X-ray Timing Explorer and H.E.S.S. are presented. Although no gamma-ray detections are reported, the observations permit the derivation of upper limits to the VHE gamma-ray flux which correspond to episodes of known X-ray behaviour. The X-ray characteristics of each target are compared with pre-existing observational data to infer the presence or otherwise of relativistic outflows at the H.E.S.S. observation epochs. The implications of the gamma-ray non-detections are then discussed in the context of these inferred system properties. The results of a survey of the VHE gamma-ray emission associated with the positions of 125 known X-ray binaries are presented. Although no conclusive detections were obtained, tentative indications were found for a population of faint, spectrally hard gamma-ray sources associated with high-mass X-ray binary systems. The inferred characteristics of the indicated population show broad agreement with the measured properties of known gamma-ray-emitting X-ray binary systems like LS 5039.
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 A Search for Very High Energy Gamma Rays from Hercules X 1 written by Patrick Olson Slane and published by . This book was released on 1988 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Point Sources of Ultra high Energy Gamma Rays with an Emphasis on the Binary System Cygnus X 3 written by Hans Albert Krimm and published by . This book was released on 1991 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Very High Energy Gamma Ray Emission from Cygnus X 3 written by Andrew Harold Szentgyorgyi and published by . This book was released on 1986 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very High Energy Gamma Ray Astronomy written by K.E. Turver and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Advanced Research Workshop on Very High Energy Gamma Ray Astronomy and Related Topics was held at Durham, England during August 11-15 1986. The meeting was sponsored by the Scientific Affairs Division of NATO and the University of Durham. It is four years since the first Workshop dedicated to High Energy Gamma Ray Astronomy was held at Ootacamund, India. At that meeting the developments in Very High Energy Gamma Ray Astronomy over a period of more than 20 years were reported and the methodology, limitations, improvements and prospects for further progess were discussed. The possible requirement for a follow-up meeting was clear if the optimistic future foreseen for the field at the Ooty meeting was correct. The Durham meeting was suggested to fill this role. Although the arrangements for the Durham meeting were discussed as long ago as 1983 with possible dates in 1984 or 1986, the eventual date in 1986 has proved admirable and has coincided with a time when further advances have been reported. An important feature of the proposal for the Durham meeting was the emphasis on a series of Workshop sessions, the conclusions of each to be summarized by a Rapporteur. The purpose of these sessions was to provide a consensus view of many of the important areas in the field at a time of increasing interest by the rest of the astrophysics community.
Download or read book A Search for Ultra High Energy Gamma Ray Emission from Binary X ray Systems written by Philip Gregory Edwards and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Searching for TeV Gamma ray Emission from Compact Binaries with the HAWC Observatory written by Chang Dong Rho and published by . This book was released on 2019 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Astrophysical sources of very-high-energy (VHE) gamma-ray radiation provide unique information about astrophysical particle acceleration and cosmic-ray production. In particular, compact binary systems, composed of a compact object (a neutron star or black hole) in orbit with a massive stellar companion, provide an ideal environment for VHE gamma-ray production. They are not only powerful particle accelerators, but they also exhibit periodic emission that makes them excellent astrophysical laboratories. However, only a handful of binary systems have ever been observed in VHE gamma rays. Partly, this is because VHE gamma-ray binaries appear to be very rare, and part is due to observational bias. Most instruments operating at TeV are pointed and must allocate time to observing many kinds of objects. The High Altitude Water Cherenkov (HAWC) Observatory, on the other hand, has high uptime (duty cycle >95%) and a wide field of view (2 sr), making it well-suited for observing transient and time-varying sources such as binaries. HAWC is also currently the only detector that is sensitive to gamma-ray photons above 10 TeV. Collected HAWC data spanning33 months between November 2014 and January 2018 are used to analyze the known and candidate VHE gamma-ray binary systems in this work. "Microquasars" are a special subclass of X-ray binaries that are also candidate VHE gamma-ray sources. Unlike other types of binaries, compact objects in microquasars accrete matter from their companion star. This process forms an accretion disk around the compact object and relativistic jets of particles are released perpendicular to the accretion disk. This feature is very similar to active galactic nuclei (AGN), only smaller in size. Given the fact that direct observation of particle acceleration in distant AGN is very challenging, microquasars grant the valuable opportunity to model similar processes using nearby objects in our own Galaxy. SS 433 is a known microquasar that has two jets ("east" and "west") terminating in radio lobes of a surrounding supernova remnant, W 50. The recent observation of SS 433 with HAWC marked the first direct evidence of gamma-ray emission from the jets of a microquasar. Using HAWC data, we have measured a VHE flux of [formula not rendered] at the jet interaction region e1 in the east lobe and [formula not rendered] in the west lobe with a combined post-trial statistical significance of 5:4. The systematic studies used to confirm the VHE gamma-ray emission at 20 TeV from the SS 433 jet interaction regions is discussed in this work, along with a brief description of the theoretical interpretation associated with the observation. The HAWC data were also used to search for gamma rays from the known VHE binaries HESS J0632+057 and LS 5039. No emission was observed from HESS J0632+057, so we compute upper limits on its flux. Emission at low statistical significance is observed from LS 5039, which is located in a crowded region of the Galactic plane and is contaminated by gamma rays from nearby extended sources. A multiple-source analysis of the region surrounding LS 5039, as well as a time-series analysis of the light curve from LS 5039, are presented. At this time, data from HAWC are not significant enough to support multi-TeV emission from LS 5039"--Pages xi-xiii.
Download or read book Gamma Ray Bursts written by Gilbert Vedrenne and published by Springer Science & Business Media. This book was released on 2009-03-20 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since their discovery was first announced in 1973, gamma-ray bursts (GRBs) have been among the most fascination objects in the universe. While the initial mystery has gone, the fascination continues, sustained by the close connection linking GRBs with some of the most fundamental topics in modern astrophysics and cosmology. Both authors have been active in GRB observations for over two decades and have produced an outstanding account on both the history and the perspectives of GRB research.
Download or read book Discovery and Characterization of the Binary System LSI 61 303 in Very High Energy Gamma rays with MAGIC written by Núria Sidro Martín and published by . This book was released on 2008 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very High Energy Gamma Ray Astronomy and Non pulsating Low Mass X ray Binaries written by Alberto Carraminana and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Quasars to Gamma Ray Bursts written by Bergman and published by . This book was released on 2023-12-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrophysics has always been a captivating field, delving into the mysteries of the universe and providing glimpses into the workings of celestial objects. However, it is in the realm of high-energy astrophysics that the universe truly reveals its most extreme phenomena. From quasars to gamma-ray bursts, this subchapter explores the historical milestones that have unraveled the mysteries of high-energy astrophysics. In the early 20th century, the study of astrophysics was primarily focused on the visible light emitted by stars and galaxies. It wasn't until 1932 that the first cosmic rays, highly energetic particles from space, were discovered by physicist Victor Hess. This groundbreaking observation hinted at the existence of high-energy phenomena beyond the reach of traditional telescopes. The discovery of the first X-ray source outside our solar system in 1962 marked a turning point in high-energy astrophysics. Astronomers soon realized that X-rays and gamma-rays, with their much higher energies than visible light, could provide vital information about the most energetic processes in the universe. Exploratory missions, such as the Uhuru satellite launched in 1970, opened a new window for studying high-energy astrophysics. The birth of X-ray astronomy gave rise to incredible findings. In 1967, the first X-ray pulsar, a rapidly rotating neutron star, was discovered. This revelation paved the way for understanding the behavior of matter under extreme gravitational forces. Subsequently, in 1974, the discovery of the first X-ray binary system, where a compact object accretes matter from a companion star, provided further insights into the dynamics of high-energy processes. The 1990s marked a new era with the launch of the Compton Gamma Ray Observatory. This satellite enabled astronomers to observe gamma-ray bursts, the most energetic events in the universe, for the first time. These fleeting bursts of gamma-rays, lasting only a few seconds, puzzled scientists and sparked a race to understand their origins. It wasn't until 1997 that the first optical afterglow of a gamma-ray burst was detected, leading to the realization that these cataclysmic events were associated with the explosive deaths of massive stars. With the advent of space-based observatories like the Chandra X-ray Observatory and the Fermi Gamma-ray Space Telescope, high-energy astrophysics has continued to push the boundaries of our knowledge. These observatories have revealed the existence of supermassive black holes at the centers of galaxies, shedding light on their role in the evolution of cosmic structures.
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 Detection of Very High Energy Gamma Rays from the Binary X ray Source Hercules X 1 written by Robert J. Williams and published by . This book was released on 1986 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gamma Ray Emissions from Pulsar Binaries written by Chun-Kwan Leung and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Gamma-ray Emissions From Pulsar Binaries" by Chun-kwan, Leung, 梁晉堃, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The launch of the Fermi Gamma-ray Space Telescope marked a new era in observing gamma-rays from astrophysical sources. Fermi's high sensitivity in the 0.1-300GeV energy range opens an important window in the observation of the gamma-ray emissions from pulsar binaries, which emit most of their radiation energy in the gamma-ray range. We can now observe the gamma-ray emissions from pulsar binaries at an unprecedented accuracy, and investigate their origin in detail. In this thesis, we present the studies on two systems of pulsar binary of two distinct classes. The gamma-ray emissions from the high-mass gamma-ray binary LS 5039 were studied using the latest data from Fermi. The emission is modulated according to the 3.9 hr orbital period of the system. The results can be explained by the contribution of three components: the pulsar magnetospheric emission, the pulsar wind emission and the emissions from the shock formed from the interaction between the pulsar wind and companion's stellar wind. The results were compared with observed data from Fermi and also in X-ray and TeV. In addition, the emissions from the millisecond pulsar PSR J1023+0038 and its low mass binary companion were also studied. This system recently went through a transition from the rotation-powered state to the accretion state, after going the opposite way in 2007. This state transition, discovered through the disappearance of radio pulsation, was accompanied by the brightening in GeV, X-ray and UV fluxes. A detailed Fermi observation was performed, supplemented by multi-wavelength observations. It was found that the emission from this system can also be described by the emissions from the pulsar magnetosphere, the pulsar wind and its shock. These two systems, although of distinct classes of pulsar binaries, provide complementary cases for the study of high-energy radiation processes in pulsar binaries. DOI: 10.5353/th_b5317064 Subjects: Gamma ray astronomy Pulsars
Download or read book High Energy Radiation from Magnetized Neutron Stars written by Peter Mészáros and published by University of Chicago Press. This book was released on 1992-06 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron stars, the most extreme state of matter yet confirmed, are responsible for much of the high-energy radiation detected in the universe. Mèszàros provides a general overview of the physics of magnetized neutron stars, discusses in detail the radiation processes and transport properties relevant to the production and propagation of high-energy radiation in the outer layers of these objects, and reviews the observational properties and theoretical models of various types of neutron star sources.
