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.

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.

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.

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.

The IAU Symposium No. 55 on 'X-Ray and Gamma-Ray Astronomy' has occurred, not entirely by coincidence, at an important moment in the development of these new branches of observational astronomy. In X-ray astronomy the data from the first X-ray observatory UHURU have contributed to a new view of the X-ray sky and a new conception of the nature and properties of galactic and extragalactic X-ray sources. In gamma-ray astronomy the exciting and often controversial nature of the results underlines the importance of the forthcoming launch of SAS-B, the first orbiting y-ray observatory. As Bruno Rossi reminds us (p. I), the Symposium occurred almost exactly ten years after the first detection of the X-ray star Sco X-I. During this time we have moved from the detection of a handful of the nearest and brightest sources to the detailed study of the nature of stellar sources in the farthest reaches of our own galaxy and in external galaxies of the local group. The detection of pulsating X-ray sources in bi nary systems permits the measurement of pulsation periods, and orbital parameters with precisions comparable to any yet achieved with traditional observational techniques. The strong indications that most X-ray sources are extremely compact objects give us confidence that X-ray astronomy will playa significant and possibly decisive role in the study of stars near the end point of stellar evolution.

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.

This book provides a comprehensive introduction to X-ray and gamma-ray astronomy. The first part discusses the basic theoretical and observational topics related to black hole astrophysics; the optics and the detectors employed in X-ray and gamma-ray astronomy; and past, present, and future X-ray and gamma-ray missions. The second part then describes data reduction and analysis, the statistics used in X-ray and gamma-ray astronomy, and demonstrates how to write a successful proposal and a scientific paper. Data reduction in connection with specific X-ray and gamma-ray missions is covered in the appendices. Presenting the state of the art in X-ray and gamma-ray astronomy, this is both a valuable textbook for students and an important reference resource for researchers in the field.