Constraining the Intergalactic Magnetic Field Through Its Imprint on Gamma Ray Data from Distant Sources PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Constraining the Intergalactic Magnetic Field Through Its Imprint on Gamma Ray Data from Distant Sources PDF full book. Access full book title Constraining the Intergalactic Magnetic Field Through Its Imprint on Gamma Ray Data from Distant Sources by Timothy Christian Arlen. Download full books in PDF and EPUB format.
Author: Timothy Christian Arlen
Publisher:
ISBN:
Category :
Languages : en
Pages : 210
Get Book Here
Book Description
Gamma ray photons, with energies>TeV propagating cosmological distances will be attenuated by pair production with diffuse extragalactic background photon fields-both the cosmic microwave background (CMB) radiation and the UV - far-IR extragalactic background light (EBL). The produced electron/positron pairs will subsequently inverse Compton scatter background photons up to GeV - TeV energies, and some of these upscattered photons may also initiate pair production in the formation of an electromagnetic cascade. If an intergalactic magnetic field (IGMF) exists on cosmological length scales of relevance to the cascade, it will deflect the electrons and positrons and will leave an imprint on the resulting spectral, angular, and temporal properties of the cascade radiation. The primary goal of this study was to constrain the properties of the IGMF using data from known sources of TeV gamma-rays. This thesis describes the construction of a high precision, 3-dimensional, particle-tracking Monte Carlo simulation code to model the intergalactic electromagnetic cascade, and uses it to systematically explore the effects of the IGMF on the cascades in multiple observational domains. We then compare the simulations with gamma-ray data from current generation ground-based gamma-ray instruments such as VERITAS, HESS, and MAGIC, sensitive to TeV-scale energies, as well as the Fermi satellite, sensitive to the GeV-scale. This novel technique of constraining the IGMF has rapidly emerged over the last decade as gamma-ray instruments have become more sensitive and as theoretical understanding of the cascade process has progressed. This emerging field has proven to be richly complex and we find that the data from current generation gamma-ray instruments do not allow for an unambiguous upper or lower limit to be placed on the IGMF at present. We do find it likely that the next generation ground based gamma-ray observatory, the Cherenkov Telescope Array (CTA) will be able to detect unambiguous signatures of gamma-ray cascading if the IGMF magnitude is within a certain range, and thus provide a robust constraint on IGMF properties.
Author: Timothy Christian Arlen
Publisher:
ISBN:
Category :
Languages : en
Pages : 210
Get Book Here
Book Description
Gamma ray photons, with energies>TeV propagating cosmological distances will be attenuated by pair production with diffuse extragalactic background photon fields-both the cosmic microwave background (CMB) radiation and the UV - far-IR extragalactic background light (EBL). The produced electron/positron pairs will subsequently inverse Compton scatter background photons up to GeV - TeV energies, and some of these upscattered photons may also initiate pair production in the formation of an electromagnetic cascade. If an intergalactic magnetic field (IGMF) exists on cosmological length scales of relevance to the cascade, it will deflect the electrons and positrons and will leave an imprint on the resulting spectral, angular, and temporal properties of the cascade radiation. The primary goal of this study was to constrain the properties of the IGMF using data from known sources of TeV gamma-rays. This thesis describes the construction of a high precision, 3-dimensional, particle-tracking Monte Carlo simulation code to model the intergalactic electromagnetic cascade, and uses it to systematically explore the effects of the IGMF on the cascades in multiple observational domains. We then compare the simulations with gamma-ray data from current generation ground-based gamma-ray instruments such as VERITAS, HESS, and MAGIC, sensitive to TeV-scale energies, as well as the Fermi satellite, sensitive to the GeV-scale. This novel technique of constraining the IGMF has rapidly emerged over the last decade as gamma-ray instruments have become more sensitive and as theoretical understanding of the cascade process has progressed. This emerging field has proven to be richly complex and we find that the data from current generation gamma-ray instruments do not allow for an unambiguous upper or lower limit to be placed on the IGMF at present. We do find it likely that the next generation ground based gamma-ray observatory, the Cherenkov Telescope Array (CTA) will be able to detect unambiguous signatures of gamma-ray cascading if the IGMF magnitude is within a certain range, and thus provide a robust constraint on IGMF properties.
![Probing Intergalactic Magnetic Fields from [gamma]-ray Observations PDF](https://books.google.com/books/content/images/frontcover/Y1BinQAACAAJ?fife=w80-h100)
Author: Wenlei Chen
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 171
Get Book Here
Book Description
The large-scaled magnetic fields in intergalactic space may contain detailed information of the primordial magnetic fields produced in the early Universe. The generation of the cosmological matter-antimatter asymmetry may produce helical magnetic fields via CP (charge conjugation and parity) violating interactions during matter-genesis. Thus, the study of the intergalactic magnetic field (IGMF) could provide a new window on early-Universe cosmology. IGMFs deflect the electron-positron pairs produced by TeV gamma-rays from blazars, resulting in broadened beams of cascade GeV gamma-rays known as pair halos. In the presence of helical IGMFs, cascade GeV gamma-rays at different energies from a distant source fall into patterns in the observation plane in the GeV gamma-ray sky that have a similar chirality. These signatures of the IGMF on the gamma-ray emission from extragalactic sources, i.e. pair halos and helical patterns, can be observed using data from the Fermi Large Area Telescope (Fermi-LAT). In this dissertation, I describe methods for probing the IGMF using gamma-ray observations. I report on the results of a search for gamma-ray pair halos with a stacking analysis of low-redshift blazars using data from Fermi-LAT. For this analysis we used a number of a priori selection criteria, including the spatial and spectral properties of the Fermi sources. The angular distribution of ~1 GeV photons around 24 stacked isolated high-synchrotron-peaked BL Lacs with redshift z 0.5 shows an excess over that of point-like sources. A frequentist test yields a p-value of p ~0.01 for the extended emission against the point-source hypothesis. A Bayesian estimation provides the common logarithm of Bayes factors 2, consistent with expectations for pair halos produced in the IGMF with strength of ~10−17 to 10−15 Gauss. In addition, I present a search for parity violating signatures of helical IGMFs in the GeV gamma-ray sky. In this study, the IGMF helicity is examined by evaluating a parity-odd statistic using gamma-ray data obtained from Fermi-LAT observations at high galactic latitudes. The resulting negative values of the parity-odd statistic imply that there is an excess of left-handed spirals in the gamma-ray sky, indicating a left-handed helicity consistent with a helical magnetic field with strength of ~10−14 Gauss on ~10 Mpc scales.
![A Study of the Intergalactic Magnetic Field Using Extra-galactic Ultra High Energy [gamma]-ray Sources PDF](https://books.google.com/books/content/images/frontcover/VK2GuAAACAAJ?fife=w80-h100)
Author: M. Honda
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Get Book Here
Book Description
Author: Thomas Raymond Weisgarber
Publisher:
ISBN: 9781267438843
Category :
Languages : en
Pages : 152
Get Book Here
Book Description
In this work, I develop a new method for accurately quantifying the extended gamma-ray halo that arises due to the influence of the EGMF on the extragalactic cascades. This method is sensitive to EGMF strengths between 3 × 10 –17 and 10–14 Gauss. I compare the predictions from a Monte Carlo simulation to combined data from ground-based imaging atmospheric Cherenkov telescopes and the Fermi Gamma-Ray Space Telescope in an attempt to measure or constrain the properties of the EGMF. Depending on certain assumptions about the source lifetime, I interpret the absence of any detectable gamma-ray halo around the blazars RGB J0710+591 and 1ES 0229+200 as evidence for an EGMF with a strength greater than 3 × 10 –15 Gauss. This represents the strongest firm lower limit on the EGMF strength at the present time.
Author: Roland Diehl
Publisher: Springer Science & Business Media
ISBN: 3642126979
Category : Science
Languages : en
Pages : 577
Get Book Here
Book Description
This book introduces the reader to the field of nuclear astrophysics, i.e. the acquisition and reading of measurements on unstable isotopes in different parts of the universe. The authors explain the role of radioactivities in astrophysics, discuss specific sources of cosmic isotopes and in which special regions they can be observed. More specifically, the authors address stars of different types, stellar explosions which terminate stellar evolutions, and other explosions triggered by mass transfers and instabilities in binary stars. They also address nuclear reactions and transport processes in interstellar space, in the contexts of cosmic rays and of chemical evolution. A special chapter is dedicated to the solar system which even provides material samples. The book also contains a description of key tools which astrophysicists employ in those particular studies and a glossary of key terms in astronomy with radioactivities.
Author: B. Bertotti
Publisher: Cambridge University Press
ISBN: 9780521372138
Category : Science
Languages : en
Pages : 460
Get Book Here
Book Description
Modern cosmology aims to determine the origin, evolution, and ultimate fate of the Universe. This is an area of modern science that has engendered fierce debates which have captured public interest. This book recounts the development of modern cosmology, in chapters contributed by many of the leading protagonists. It is a fascinating account of physical and observational cosmology, the great cosmological debates, important observations and the riddle of dark matter. The enormous controversy surrounding the Big Bang theory is retold in personal recollections from H. Bondi, W. McCrea, and Fred Hoyle. This is followed by chapters on the discovery of cosmic radio waves and the contributions made by radio astronomers to current cosmology. The book concludes with a tribute to some of the pioneers of cosmology.
Author: Ronaldo Bellazzini
Publisher: Cambridge University Press
ISBN: 9780521191845
Category : Science
Languages : en
Pages : 384
Get Book Here
Book Description
Due to the advent of a new generation of detectors, X-ray polarimetry promises to join X-ray imaging, spectroscopy and timing as one of the main observational techniques in high energy astrophysics. This has renewed interest in the field, and indeed several polarimetric missions have recently been proposed. This volume provides a complete and up-to-date view of the subject for researchers in astrophysics. The contributors discuss the present status and perspectives of instruments, review current theoretical models, and examine future missions. As well as detailed papers, the book contains broad reviews that can be easily understood by astrophysicists new to the field.
Author: Richard Wielebinski
Publisher: Springer Science & Business Media
ISBN: 9783540241751
Category : Science
Languages : en
Pages : 306
Get Book Here
Book Description
While magnetic fields permeate the universe on all scales, the present book is dedicated to their investigation on the largest scales and affords a balanced account of both theoretical and observational aspects. Written as a set of advanced lectures and tutorial reviews that lead up to the forefront of research, this book offers both a modern source of reference for the experienced researchers as well as a high-level introductory text for postgraduate students and nonspecialist researchers working in related areas.
Author: Gabriele Ghisellini
Publisher: Springer
ISBN: 3319006126
Category : Science
Languages : en
Pages : 152
Get Book Here
Book Description
This book grew out of the author’s notes from his course on Radiative Processes in High Energy Astrophysics. The course provides fundamental definitions of radiative processes and serves as a brief introduction to Bremsstrahlung and black body emission, relativistic beaming, synchrotron emission and absorption, Compton scattering, synchrotron self-compton emission, pair creation and emission. The final chapter discusses the observed features of Active Galactic Nuclei and their interpretation based on the radiative processes presented in the book. Written in an informal style, this book will guide students through their first encounter with high-energy astrophysics.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309157994
Category : Science
Languages : en
Pages : 324
Get Book Here
Book Description
Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
