Spectral Analysis Of Ultraluminous X Ray Sources Using The Chandra Xray Observatory
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Spectral Analysis Of Ultraluminous X Ray Sources Using The Chandra Xray Observatory
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Author : Akram Chandrajit Singha, A Senorita Devi
language : en
Publisher: Sankalp Publication
Release Date :
Spectral Analysis Of Ultraluminous X Ray Sources Using The Chandra Xray Observatory written by Akram Chandrajit Singha, A Senorita Devi and has been published by Sankalp Publication this book supported file pdf, txt, epub, kindle and other format this book has been release on with Education categories.
This book is a comprehensive introduction to the data analysis of ultraluminous X-ray sources. This book will provide the readers with a familiar environment in data analysis methods and the different software used in high energy astrophysical data analysis.
High Resolution X Ray Spectroscopy
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Author : Cosimo Bambi
language : en
Publisher: Springer Nature
Release Date : 2023-09-01
High Resolution X Ray Spectroscopy written by Cosimo Bambi and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-09-01 with Science categories.
NASA's Chandra X-ray Observatory and ESA's XMM-Newton Observatory have been the pioneering satellites for studying the Universe with X-rays and the cornerstone of X-ray spectroscopy since their launches more than 20 years ago. The onboard gratings provide us a unique opportunity to distinguish individual spectral lines from different atoms thanks to their high energy resolutions. Enormous discoveries have been achieved by these two missions when observing a variety of X-ray-emitting astronomical objects, such as black holes, supernova remnants, clusters of galaxies, and stars. However, the data are limited to fairly bright X-ray sources. The recent JAXA's mission Hitomi opened a new window of high-resolution X-ray spectroscopy thanks to its onboard X-ray calorimeter. Although this mission was shortly terminated due to a mishap, Hitomi left behind a few sets of observations awaiting more data mining. The first half of this book introduces the history of high-resolution X-ray spectroscopy and different generations of X-ray spectrometers. A tutorial guide on how to reduce, analyze, and understand the astronomical data from Chandra, XMM-Newton, and Hitomi is also included. The second half of the book reviews past results obtained by the high-resolution spectrometers on these missions on multiple topics and discusses possible discoveries by upcoming missions in the next decade.
Optical X Ray Studies Of Ultraluminous X Ray Sources
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Author : Jeanette Claire Gladstone
language : en
Publisher:
Release Date : 2009
Optical X Ray Studies Of Ultraluminous X Ray Sources written by Jeanette Claire Gladstone and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with X-ray sources, Galactic categories.
Ultraluminous X-ray Sources (ULXs) are point like X-ray sources situated external to the nucleus of their host galaxy, with inferred X-ray luminosities in excess of 10 {39} erg s {?1} . Although?rst observed? 30 years ago, these sources are yet to be fully understood. Some have suggested that these fascinating objects may contain intermediate mass black holes, whilst others have proposed they are stellar mass black holes residing in a new extreme accretion state. This thesis works towards the conclusion of this debate, by developing our understanding of these systems and their environments. This work begins with a photometric survey of the optical counterparts of ULXs. The main aim of this survey is to?nd plausible candidates to gain radial velocity measurements and therefore mass functions of these systems. However, the collation of this sample also provides the opportunity to classify the stellar objects held within these systems. From this work, we?nd seven good candidates for optical spectroscopic follow-up. Our results also show that many of our sample are consistent with OB type stars, while some contain later type bright giants/supergiants. Possibly our best chance to gain precise measurements of M_{BH}, and settling the debate over the nature of these systems, is by using radial velocity curves of their optical counterparts to calculate a mass function of ULXs. We are currently undertaking a programme to pursue mass function measurements for these systems. To date, we have received the pilot spectra of three optical counterparts. We discuss the progress of this programme to date and perform analysis on both the absorption/emission features and the continuum of these spectra. Initial analysis reveals the presence of the He ii 4686 A line in two of our pilot spectra. This line may be associated with the accretion disc of these systems, and could therefore be used in our pursuit of the mass function. We also?nd the presence of both low and high ionization lines, with some evidence for shock ionisation, and electron temperature of 7,000? 10,000 K. This Balmer decrement also indicates that the extinction can be highly variable across ULX?eld. This combination may suggest a?patchy? environment with separate shock and photoionisation emission regions. While the continuum emission of one of our sample can be explained by either the spectra of an OB star or of a standard accretion disc, the steep slopes of two of our sample indicates non-stellar origins that could represent the optical spectrum of a super-Eddington accretion disc. Finally, this work highlights the need for further observations of these sources in order to unlock their nature. We present results of X-ray spectral variability studies of the ULX population contained within NGC 4485 & 4490. We collate Chandra and XMM-Newton observations of the interacting galaxy pair, to analyse the emission from the six ULXs previously identified, and one additional source observed in the a recent exposure. This provides us with an opportunity to study variability on both short and longer time scales. The spectral variability is generally characterised by a hardening of the source spectra as their luminosities increase. The sources show a variety of long-term light curves; however, short-term (intra-observational) temporal variability is conspicuous by its absence. This survey also reveals the detection of a possible change in accretion state that could be used to gain crude mass estimates of the compact objects. Finally, we explore further the variability of these systems with the aid of two new proprietary observations. Finally, analysis of some of the best quality X-ray spectral data publicly available on these sources has provided the opportunity to explore the nature of these systems. We apply phenomenological models to characterise the spectra of these objects and more physically motivated models in order to explore the physical processes underlying these characteristics. Results show that the spectra of these sources are fundamentally different to that of Galactic X-ray binaries, whilst the application of physical models indicates a more extreme version of the highest known luminosity state, the very high state. We therefore speculate that in observing ULXs we are observing stellar mass black holes residing in a new?ultraluminous? state.
Fast Spectral Variability In The X Ray Emission Of Accreting Black Holes
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Author : Chris Skipper
language : en
Publisher: Springer
Release Date : 2014-09-04
Fast Spectral Variability In The X Ray Emission Of Accreting Black Holes written by Chris Skipper and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-09-04 with Science categories.
This thesis brings together the various techniques of X-ray spectral analysis in order to examine the properties of black holes that vary in mass by several orders of magnitude. In all these systems it is widely accepted that the X-ray emission is produced by Compton up-scattering of lower energy seed photons in a hot corona or accretion flow, and here these processes are examined through a study of the X-ray spectral variability of each source. A new technique is introduced, in which models are fitted to over 2 million X-ray spectra on time-scales as short as 16 ms, and subsequently it is shown that the nature of the correlation between intensity and spectral index is strongly dependent upon the spectral state of the black hole. Finally, the results of an extensive survey of nearby galactic nuclei using the Chandra X-ray telescope are presented in the form of images and spectra, and these results are used along with data from the literature to search for Compton-thick nuclei.
Handbook Of X Ray And Gamma Ray Astrophysics
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Author : Cosimo Bambi
language : en
Publisher: Springer Nature
Release Date :
Handbook Of X Ray And Gamma Ray Astrophysics written by Cosimo Bambi and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.
Spectral Analysis Of X Ray Emission Mechanisms In Local Astrophysical Environments
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Author : Bradford T Snios
language : en
Publisher:
Release Date : 2016
Spectral Analysis Of X Ray Emission Mechanisms In Local Astrophysical Environments written by Bradford T Snios and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Electronic dissertations categories.
In order to establish contributions of different X-ray emission mechanisms from local astrophysical environments, we perform a theoretical analysis of observed cometary X-ray emission spectra. We develop a model from first principles that generates updated spectra of solar wind charge-exchange (CX) emissions together with accurate scattering and fluorescence spectra of solar X-rays by atoms, molecules, and dust/ice particles. This model also explores scattering and fluorescence spectra for different solar conditions, including spectra induced by solar X-ray flares of different classes and durations. We compare the modeled spectra with cometary and planetary observations from the Chandra X-Ray Observatory Advanced CCD Imaging Spectrometer (ACIS) and determine the primary emission mechanisms for both the 0.3–1.0 keV and 1.0–2.0 keV photon energy ranges. These comparisons establish upper limits on cometary dust/ice mass production rates and grain size distributions. Our results also demonstrate the utility of charge-exchange emissions as a remote diagnostics tool of both astrophysical plasma interaction and solar wind composition. In addition, we observe potential soft X-ray emissions via ACIS around 0.2 keV that are correlated in intensity to the hard X-ray emissions between 0.4-1.0 keV. We fit our CX model to these emissions, but our lack of a unique solution at low energies makes it impossible to conclude if they are cometary CX in origin. Finally, we discuss probable emission mechanism sources for these soft X-rays and explore new opportunities these findings present in understanding emission processes via Chandra.
Signals From Space
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Author : Robert Naeye
language : en
Publisher: Steck-Vaughn
Release Date : 2001
Signals From Space written by Robert Naeye and has been published by Steck-Vaughn this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with Juvenile Nonfiction categories.
The Chandra X-ray Observatory is the largest object ever carried into space by the Space Shuttle. Scientists and engineers faced many challenges before they completed the powerful new satellite. But their hard work paid off. The National Aeronautics and Space Administration (NASA) launched Chandra in July 1999. Today, this remarkable satellite sends vivid and astounding X-ray images back to Earth.
Observing The Universe In X Rays
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Author : Valerie Neal
language : en
Publisher:
Release Date : 1984
Observing The Universe In X Rays written by Valerie Neal and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1984 with Government publications categories.
"The Advanced X-Ray Astrophysics Facility (AXAF), an orbital observatory for detailed, longterm study of X-ray emissions and the phenomena that produce them. The AXAF is an essential step in our continuing quest to understand the universe."--P. 1.
X Ray Spectroscopy In Astrophysics
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Author : Jan van Paradijs
language : en
Publisher: Springer Science & Business Media
Release Date : 1999-02-17
X Ray Spectroscopy In Astrophysics written by Jan van Paradijs and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999-02-17 with Science categories.
This volume contains a comprehensive treatment of X-ray spectroscopy, as applied in astrophysics. It is presented in the form of extensive notes of lectures given by seven distinguished scientists at the Tenth Summer School of the European Astrophysics Doctoral Network. The subjects covered are: basic line and continuum radiation processes in X-ray and gamma-ray astronomy; atomic physics of collision- and radiation-dominated plasmas; X-ray spectroscopic observations with ASCA and BeppoSAX; future X-ray spectroscopy missions; X-ray optics, and X-ray spectroscopy instrumentation. The book, which will appeal to both researchers and graduate students, is timely in view of the scheduled launches of the big X-ray observatories AXAF and XMM in 1999.
High Resolution X Ray Spectroscopy Of Cosmic Plasmas
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Author : International Astronomical Union. Colloquium
language : en
Publisher: Cambridge University Press
Release Date : 1990-04-26
High Resolution X Ray Spectroscopy Of Cosmic Plasmas written by International Astronomical Union. Colloquium and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990-04-26 with Science categories.
This book gives an account of the proceedings of the International Astronomical Union Colloquium 115: High Resolution X-Ray Spectroscopy of Cosmic Plasmas. This was the first IAU meeting dedicated to high resolution X-ray spectroscopy of objects outside the solar system. A broad range of objects and astrophysical conditions are discussed. Results from the first generation of satellites with spectroscopic capability, i.e. the Einstein Observatory, EXOSAT, and Tenma, are reviewed from a perspective of a more precise interpretation allowed by improved theoretical models and plasma diagnostics. Laboratory and solar X-ray results that model or are relevant to conditions found in cosmic X-ray sources are also presented. The colloquium presents a forum for discussion of scientific objectives of new international missions in high resolution X-ray spectroscopy.