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.