Neutron Stars And Pulsars

Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only reviews the progress made since the early days of pulsar astronomy, but especially focuses on questions such as: "What have we learned about the subject and how did we learn it?", "What are the most important open questions in this area?" and "What new tools, telescopes, observations, and calculations are needed to answer these questions?". All authors who have contributed to this book have devoted a significant part of their scientific careers to exploring the nature of neutron stars and understanding pulsars. Everyone has paid special attention to writing educational comprehensive review articles with the needs of beginners, students and young scientists as potential readers in mind. This book will be a valuable source of information for these groups.

This book is a collation of the contributions presented at a major conference on isolated neutron stars held in London in April 2006. Forty years after the discovery of radio pulsars it presents an up-to-date description of the new vision of isolated neutron stars that has emerged in recent years. The great variety of isolated neutron stars, from pulsars to magnetars, is well covered by descriptions of recent observational results and presentations of the latest theoretical interpretation of these data.

IAU Symposium 291 features a rich harvest of recent scientific discoveries and looks forward to the many exciting avenues for future neutron-star research. The volume starts with general, lively, comprehensive introductions to three main themes that successfully communicate the excitement of current pulsar research. The subsequent reviews and contributions on hot topics cover: ongoing searches for pulsars, both radio and gamma-ray; neutron star formation and properties; binary pulsars; pulsar timing and tests of gravitational theories; magnetars; radio transients; radio, X-ray and gamma-ray pulse properties and emission mechanisms; and future facilities. This range of topics clearly illustrates the diverse nature and wide application of neutron-star research. Through a combination of introductory reviews and practically complete coverage of current results from across the electromagnetic spectrum, IAU S291 is the perfect reference for neutron-star researchers and also provides an excellent read for advanced undergraduate and starting graduate students.

This book is an introduction to pulsars, a key area in high energy astrophysics with continuing potential for fundamental discoveries. Throughout the book runs the unifying thread of the evolutionary link between rotation-powered pulsars and accretion-powered pulsars ? a milestone of modern astrophysics. Early textbooks on pulsars dealt almost entirely with rotation-powered ones, while accounts of pulsars in volumes on X-ray binaries focused almost exclusively on accretion-powered ones. This is the first textbook to treat these two kinds of pulsars simultaneously with equal importance, stressing the fact that both are rotating, magnetic neutron stars, operating under different conditions during different parts of their lives. It describes the observational properties of both kinds of pulsars, summarizes our physical understanding of these properties, and pays detailed attention to the physics of superdense matter which neutron stars are composed of, as well as to the superfluidity which is expected to occur in neutron stars. Evolution from rotation-power to accretion-power, and vice versa, are carefully described. The effects of the strong magnetic fields of neutron stars on themselves, their emission properties, and their environments are discussed, as are the origin and evolution of such magnetic fields. Also treated is the superbly accurate verification of Einstein's theory of general relativity through timing studies of binary pulsars, which led to the award of the Nobel Prize to Hulse and Taylor in 1993. On each topic, the book starts with simple, basic physical concepts, and builds up the exposition to the point where the latest and most exciting developments become accessible to the reader.

Neutron stars hold a central place in astrophysics, not only because they are made up of the most extreme states of the condensed matter, but also because they are, along with white dwarfs and black holes, one of the stable configurations that stars reach at the end of stellar evolution. Neutron stars posses the highest rotation rates and strongest magnetic fields among all stars. They radiate prolifically, in high energy electromagnetic radiation and in the radio band. This book is devoted to the selected lectures presented in the 6th NATO-ASI series entitled "The Electromagnetic Spectrum of Neutron Stars" in Marmaris, Turkey, on 7-18 June 2004. This ASI is devoted to the spectral properties of neutron stars. Spectral observations of neutron stars help us to understand the magnetospheric emission processes of isolated radio pulsars and the emission processes of accreting neutron stars. This volume includes spectral information from the neutron stars in broadest sense, namely neutrino and gravitational radiation along with the electromagnetic spectrum. We believe that this volume can serve as graduate level of text including the broad range of properties of neutron stars.

Some twenty-three years after the discovery of pulsars and their identification as rotating neutron stars, neutron star physics may be regarded as comingofage. Pul sars and accreting neutron stars have now been studied at every wavelength, from the initial radio observations, through optical, X-, and "{-ray, up to the very recent observations in the TeV region, while theorists have studied in some detail relevant physical processes both outside and inside neutron stars. As a result, comparisonof theory with observation provides a test ofour theoretical ideas in fields as diverse as neutron and nuclear matter, superfluidity and superconductivity, the acceleration of high energy particles, and the generation and maintenance of intense magnetic fields. For example, through observations of glitches and post glitch behavior of pulsars, it has become possible to establish the presence ofsuperfluid neutron mat ter in the inner crust of neutron stars, and to determine some of its properties, while neutron stars in compact binary systems offer one ofthe most efficient energy generation mechanisms known. It is in fact the interactive interpretation of these ,diverse pieces of information that can lead to major advances in our understanding of the physics of these exotic objects, and justifies the characterization of neutron stars as hadron physics laboratories.

This volume is the documentation of the second Course on 'Neutron Stars, Active Galactic Nuclei and Jets', held at Erice in September 1988. This second Course was devoted to our knowledge about neutron-star sources. The poster spoke of: pulsars, accreting X-ray sources and jet englnes, perhaps also UHE pulsars, X ra~' bursters and black-hole candidat.es. Neutron stars have even been proposed as the primary cosmic-ray boosters. Most of theil' properties are stil1 controversial, such as their birth mechanism (neutrino versus magnetic piston), internal structure (neutrons, quarks, strange particles), magnetic, thermal and spin histories, wind generation (hydrogen versus pair plasma, radiation versus centrifugal pressure), magnetospheric structure and accretion modes (along field lines versus quasi-Keplerian). The listed controversies have largely survived through the Course and entered into the proceedings. Several lecturers speak of 'magnetic-field decay' in neutron stars, of the 'recycling' of old pulsars, and of 'accretion-induced collapse' of white dwarfs as though such processes were textbook knowledge. Terms and abbreviations like RPSR (=recycled pulsar), spinup line, AIC, and ADC (=accretion disk corona) help to foster the assumptions. It is not clear to me at this time whether any of these notions has an application to reality.