X Ray Imaging And Spectroscopy Of Cosmic Hot Plasmas

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.

The present decade is opening new frontiers in high-energy astrophysics. After the X-ray satellites in the 1980's, including Einstein, Tenma, EXOSAT and Ginga, several satellites are, or will soon be, simultaneously in orbit offering spectacular advances in X-ray imaging at low energies (ROSATj Yohkoh) as well as at high energies (GRANAT), in spectroscopy with increased bandwidth (ASCAj SAX), and in timing (XTE). While these satellites allow us to study atomic radiation from hot plasmas or energetic electrons, other satellites study nuclear radiation at gamma-ray energies (CGRO) associated with radioactivity or spallation reactions. These experiments show that the whole universe is emitting radiation at high energies, hence we call it the "hot universe. " The hot universe, preferentially emitting X- and gamma-rays, provides us with many surprises and much information. A symposium "The Hot Universe" was held in conjunction with the XXIIIrd General Assembly of the International Astronomical Union, at Kyoto on August 26-30 in 1997. The proceedings are organized as follows. Synthetic view of "the hot universe" is discussed in Section 1, "Plasma and Fresh Nucleosynthesis Phenomena". Timely discussions on the strategy for future missions "Future Space Program" are found in Section 2. Then the contents are divided into two major subjects: the compact objects and thin hot diffuse plasmas. Section 3 is devoted to the category of compact objects which includes white dwarfs, neutron stars, and gravitationally collapsed objects: stellar mass black holes or active galactic nuclei.

Since its launch in 1991, the Yohkoh satellite has been returning unprecedented observations of solar flares and the dynamic solar corona. This book is a collection of papers presented at a meeting held in: Yoyogi, Tokyo, on the occasion of Yohkoh's fifth anniversary of operation. The papers constitute a summary of observations and results over the five years, including contributions based on data from Yohkoh's hard and soft X-ray telescopes and its spectrometer experiments. The five years of data, covering approximately one-half of a solar cycle, reveal a fresh perspective on solar science, with a new picture of solar flares and the active Sun emerging. Also, for the first time there are extensive results from Yohkoh observations of the Sun during the solar minimum period. This wide-ranging volume will be of interest to workers in solar physics and X-ray astronomy. It also contains material appropriate for supplemental reading for graduate students in solar physics.

Space experiments have opened practically all electromagnetic windows on the Universe. A discussion of the most important results obtained with multi-frequency photonic astrophysics experiments will provide new input to advance our knowledge of physics, very often in its more extreme conditions. A multitude of high quality data across the whole electromagnetic spectrum came at the scientific community's disposal a few years after the beginning of the Space Era. With these data we are attempting to explain the physics governing the Universe and its origin, which continues to be a matter of the greatest curiosity for humanity. In this book we describe the latest steps of the investigations born with the advent of space experiments. We highlight the most important results, identify unsolved problems, and comment on perspectives we can reasonably expect. This book aims to provide a useful tool for the reader who is not specialized in space astrophysics and for students. Therefore, the book is written in the form of a review with a still reasonable length, taking into account the complexity of the arguments discussed. We do not claim to present a complete picture of the physics governing the Universe, but have rather selected particular topics for a more thorough discussion. A cross section of essays on historical, modern, and philosophical topics is offered and combined with personal views into tricks of the space astrophysics trade.

A thorough introduction to solar physics based on recent spacecraft observations. The author introduces the solar corona and sets it in the context of basic plasma physics before moving on to discuss plasma instabilities and plasma heating processes. The latest results on coronal heating and radiation are presented. Spectacular phenomena such as solar flares and coronal mass ejections are described in detail, together with their potential effects on the Earth.