摘要:

We present the conclusions of a panel discussion held on the final day of the workshop. The major themes discussed by the panel involved increasing standardization, sharing information, improving access to space, and the changing role of the Principal Investigator. We have not attempted to construct a verbatim transcript of the event, but will rather present a summary of the debate and draw some conclusions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302215

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The systematic study of the properties of the structure and evolution of hot white dwarfs owes a tremendous debt to space borne astronomy. At the temperature and densities found in these stars, observations in visible light generally only reveal evidence of the most abundant photospheric elements, hydrogen or helium. Access to spectral windows ranging from the far UV, through the EUV and into the soft X-ray band reveals a much more complex picture of trace heavy element opacity in the stellar atmospheres and interstellar absorption than could ever have been deduced from ground-based measurements alone. Moreover, many of the spacecraft responsible for these results would fall within the ‘Small Mission’ category. This review discusses the legacy ofIUE, theROSATWide Field Camera andEUVE, among others, outlining the need for small and medium Explorer Class missions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302216

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The concept of using a pinhole camera as wide field-of-view detector for an X-ray all-sky monitor was first proposed by S. Holt and W. Priedhorsky in 1987 [1]. The hardware for such a monitor is ready to be launched. Here we discuss scientific tasks for such an experiment, its main parameters, and possibilities to install it on platforms/satellites of different types. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302217

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The cosmological origin of gamma-ray bursts (GRBs) has now been established with reasonable certainty. Many more bursts will need to be studied to establish the typical distance scale, and to map out the large variability in properties, which have been indicated by the first handful of events. We are proposing BALLERINA, a small satellite to provide accurate gamma burst positions at a rate an order of magnitude larger than from Beppo-SAX. On the experimental side, it remains a challenge to ensure the earliest detection of the X-ray afterglow. The mission proposed here allows for the first time systematic studies of the soft X-ray emission in the time interval from only a few minutes after the onset of the burst to a few hours later. In addition to positions of GRBs with accuracy better than 1’reported to the ground within a few minutes of the burst, essential for follow-up work, BALLERINA will on its own provide observations in an uncharted region of parameter space. Secondary objectives of the BALLERINA mission includes observations of the earliest phases of the outbursts of X-ray novae and other X-ray transients. BALLERINA is one of four missions currently under study for the Danish Small Satellite Program. The selection will be announced in 1999 for a planned launch in 2002–2003. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302218

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Large collecting area is the domain of large missions, but high resolution x-ray images can be captured with small instruments in small missions. We discuss techniques for achieving high resolution x-ray images including high resolution telescopes and interferometry. We discuss the likely limitations within the confines of small spacecraft. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302219

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

I present an overview of some of the recent advances in our understanding of the distribution and evolution of the ordinary, baryonic matter in the universe. Two observations that strongly suggest that most of the baryons seen at high redshift(z⩾2)have turned into some forms yet undetected atz=0are highlighted. With the aid of large-scale cosmological hydrodynamic simulations, it is shown that most of the baryons today are in a gaseous form with a temperature of105–107&hthinsp;Klevin—the “warm/hot gas”, shock heated during the gravitational collapse and formation of the large-scale structure at low redshift. Primarily line emissions from this warm/hot gas may account for a large fraction of the residual (after removal of identifiable discrete sources) soft X-ray background athv<1.0&hthinsp;keV.How this warm/hot gas may be detected by the next generation of EUV and soft X-ray instruments is indicated. Detection or non-detection of this warm/hot gas will have profound implications for cosmology. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302220

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The physical properties of hard-radiation emitting astrophysical objects (X-ray binaries pulsars, active galactic nuclei) can be studied in detail using compact instruments on-board small spacecraft. The polarization and spectroscopic measurements are of particular interest. The search and study of emission lines in hard radiation of X-ray binaries, black hole candidates as well as in diffuse gamma-radiation from Galactic Center and star formation regions, are the main goals of spectroscopic observations. It seems that for further progress of spectrometric measurements, detectors based on pure or enriched germanium should be used. As for polarization measurements, searching and measurements of polarization of hard radiation of pulsars and black hole candidates are of great interest. If the exposure time of the same X-ray source will be about several years, it allows us to search the electromagnetic radiation component, caused by the interaction of high-frequency gravitational radiation of the neutron star with its magnetic field. Such observational data will be unique because until the present time continuous long measurements of X-ray polarization and its time variations have not been performed. These data allow to solve some problems of fundamental physics of the X-ray binaries and to estimate the upper limit of high frequency gravitational radiation intensity. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302221

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

The Crab and other pulsars suffer sudden and permanent increases in their spin-down rates, suggesting that the torques upon them grow in steps. Torque changes could come about as a consequence ofstarquakesoccurring as the star spins down and its rigid crust becomes less oblate. We study the evolution of strain in the crust, the initiation of starquakes, the effects on the magnetic field structure and the observable consequences for neutron star spin down. We find that the stellar crust begins breaking at the rotational equator, forming a fault along which matter flows to reduce the equatorial circumference. Magnetic stresses favor fault lines inclined at an angle to the equator and directed toward the magnetic poles. The resulting asymmetric matter redistribution produces a misalignment of the angular momentum and spin axes. Subsequently, damped precession to a new rotational state increases the angle between rotation and magnetic axes. The change in this angle could increase the external torque, producing a permanent increase in the spin-down rate. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302222

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

An overview is given of the Robotic Optical Transient Search Experiment, a ground-based observational astronomy project intended to detect visible radiation from gamma-ray bursts. The major result of the project was the detection of an early bright optical transient from a GRB. (AIP) ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302223

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

It is remarkable that a small space satellite mission can be created that has, potentially, the capability of detection of the dark matter of the universe, and in particular, detection of the intergalactic medium. I describe the approach for such a sample mission, and I also briefly comment on, andillustrate, black holes; black holes represent another candidate for the “missing” baryonic dark matter in the Universe. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1302224

出版商:AIP    

年代:1999

数据来源: AIP