Part I. Talks

Section A. Space Missions and Observations



Title: The Next Generation of High-energy Astrophysics Observatories
Author: S. S. Holt
Affil: Goddard Space Flight Center, Code 600, Greenbelt MD 20771, U.S.A.
Abstract: The sky will soon be populated with a fleet of new X- and gamma-ray satellites with extraordinary capabilities. This paper is meant to introduce these new missions, Chandra, XMM, and Astro-E, which will provide a large fraction of our high energy ``space observatory'' functionality for the next decade.


Title: Particle Acceleration in Solar Flares and Coronal Mass Ejections
Author: R. P. Lin
Affil: University of California, Physics Department and Space Sciences Laboratory, Berkeley, CA 94720, U.S.A.
Abstract: The Sun accelerates ions up to tens of GeV and electrons up to 100s of MeV in solar flares and coronal mass ejections. The energy in the accelerated tens-of-keV electrons and possibly ~1 MeV ions constitutes a significant fraction of the total energy released in a flare, implying that the particle acceleration and flare energy release mechanisms are intimately related. The total rate of energy release in transients from flares down to microflares/nanoflares may be significant for heating the active solar corona.

Shock waves driven by fast CMEs appear to accelerate the high-energy particles in large solar energetic particle events detected at 1 AU. Smaller SEP events are dominated by ~1 to tens-of-keV electrons, with low fluxes of up to a few MeV/nucleon ions, typically enriched in [^3]He. The acceleration in gamma-ray flares appears to resemble that in these small electron--[^3]He SEP events.


Title: Recent Observations of X-ray Emission from Galactic Binary Neutron Stars
Author: J. Swank
Affil: NASA/Goddard Space Flight Center, Code 662, Greenbelt, MD 20771, U.S.A.
Abstract: Recent measurements of young, accreting binary neutron stars are determining more precise magnetic field and accretion parameters. A low magnetic field, accreting, millisecond pulsar has finally been found in a binary burster. At least 20 low-mass binaries have exhibited high frequency oscillations, 300--1200 hertz. The majority have, for some range of luminosity, the pair of quasiperiodic oscillations that have never been seen in a black hole candidate. Recent evidence from burst oscillations strengthens the case that the difference frequency of this pair is close to the spin frequency of the neutron star. These oscillations are correlated with the spectra, luminosity, and low frequency oscillations. Quasiperiodic oscillations are also seen sometimes in strong magnetic field pulsars, where their origin can be closely examined.


Title: Observation of Black Holes in X-ray Binaries
Author: Y. Tanaka
Affil: Max-Planck Institut fur Extraterrestrische Physik, D-85748 Garching, Germany
Abstract: Recent results of X-ray observations of Galactic X-ray binaries containing black holes are reviewed. So far, eleven X-ray binaries are confirmed to contain a black hole based on the mass determined from the optical mass functions. Study of these X-ray binaries shows that accreting black holes exhibit a characteristic X-ray spectrum that is distinct from that of accreting neutron stars. In total, about two dozen X-ray binaries show this characteristic spectrum and are believed to contain a black hole. Most of them are low-mass X-ray binaries and are transients. The statistics indicate the presence of several hundred or more black holes in quiescent X-ray binaries in our galaxy. The observed properties of accreting black holes are discussed, and other, related subjects are also presented.


Title: X-ray Emission Characteristics of Pulsars
Author: W. Becker
Affil: Max-Planck-Institut fur extraterrestrische Physik, Giessenbachstrasse 1, Postfach 1603, 85740 Garching, Germany
Abstract: Recent X-ray observatories such as ROSAT, ASCA, RXTE, BeppoSAX, and Chandra have achieved important progress in neutron star and pulsar astronomy. The identification of Geminga as a rotation-powered pulsar, the discovery of X-ray emission from millisecond pulsars, and the identification of cooling neutron stars are only a few of the fascinating results. In the following, I will give a brief review on the X-ray emission properties of rotation-powered pulsars and their wind nebulae.


Title: The Constellation X-ray Mission
Authors: N. E. White(1) and H. Tananbaum(2)
Affil: (1) NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771, U.S.A. (2) Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, U.S.A.
Abstract: The Constellation-X mission is a large collecting-area X-ray facility emphasizing observations at high spectral resolution (E/"Delta E" ~ 300--3000) while covering a broad energy band (0.25--40 keV). By increasing the telescope aperture and utilizing efficient spectrometers, the mission will achieve a factor of 100 increased sensitivity over current high-resolution X-ray spectroscopy missions. The use of focusing optics across the 10--40 keV band will provide a similar factor of 100 increased sensitivity in this band. When observations commence in ~2008, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe.


Title: X-Ray Emission as an Indicator of Cosmic Ray Acceleration in Supernova Remnants
Authors: R. Petre(1), G. E. Allen(2), U. Hwang(3), J. W. Keohane(4), E. V. Gotthelf(5)
Affil: (1) Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Greenbelt, MD 20771, U.S.A. (2) NASA / Chandra X-Ray Center, Massachusetts Institute of Technology, Cambridge MA, 02139, U.S.A. (3) Goddard Space Flight Center and University of Maryland, Greenbelt, MD 20771, U.S.A. (4) NASA / North Carolina School of Science and Mathematics, Durham, NC 27705, U.S.A. (5) Astronomy Department, Columbia University, New York, NY 10027, U.S.A.
Abstract: X-ray observations over the past several years have led to the discovery of nonthermal X-ray emission arising in the shells of many young supernova remnants, including SN 1006, Cas A, and Tycho. This emission is thought to be synchrotron emission from electrons that have been shock accelerated to hundreds of TeV, and thus represents strong evidence that cosmic rays are accelerated in SNR shocks. The X-ray observations are corroborated by detection of TeV gamma rays from two of these remnants. A systematic investigation of young, shell-like remnants suggests that the nonthermal X-ray emission from shock-accelerated electrons is a common, if not ubiquitous, feature. We review the status of the X-ray observations and describe how they can be used to provide insight into the shock acceleration process.


Title: Recent Satellite Observations of X-ray Emission from AGN
Author: H. Kunieda
Affil: Department of Physics, Nagoya University Furo-cho, Nagoya 464-8602, Japan
Abstract: Recent X-ray satellite observations provide plenty of spectral information with high resolution in a broad band. Major results from the spectral observations are related to the interaction of the power-law continuum flux with the ambient plasmas and accretion disks. The most prominent result is the broad iron-line feature from Seyfert I galaxies which is interpreted as the emission from the relativistic accretion disk. Doppler shift and boosting, as well as gravitational redshifts, are considerable at the distance of several Schwarzschild radii from the central black hole. Strong radiation from the central engine ionizes the ambient material of AGN. Edge structure found at around 0.8 keV is attributed to highly ionized oxygen of Ovii and Oviii}. Some iron emission lines from Seyfert II galaxies are emitted by highly photoionized plasmas. The study of fast temporal and spectral variability is the key approach to examine the emission mechanism and structure of the central vicinity of AGN. In 2000, two X-ray observatories (Chandra ) and XMM will be in orbit, and they will provide us with deeper insights of the physics around the black holes and of the physics of hot plasmas.