摘要:

In this talk I will review some of the highlights of three decades of x‐ray astronomy. That leaves me with an average of 90 sec per year which is highly insufficient to do justice to the many exciting milestones. The choice I have made obviously reflects my own perceptions and biases. The following text is a somewhat edited version of my 45‐min talk. To meet the page limit in these proceedings, I had to delete 15 of my 20 figures. However, all are referenced in the text so that the reader can look them up if (s)he so desires. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45979

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The gathering of a wealth of precise quantitative observational data on x‐ray binaries and recycled radio pulsars during the last decades has allowed the testing of many theoretical ideas on the physics, formation, and evolution of neutron stars and black holes, which could never have been tested on single compact objects. Also, new observations often have led to new theories and models which again can be tested observationally. In this talk I give a personal view of this development over the past thirty years. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.46006

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

I was fortunate to have been actively involved in x‐ray astronomy from its inception. As is frequently the case, the discoveries did not always proceed as neatly as the journal articles would lead one to believe. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45978

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Although various observational properties have been suggested as indicators of a black hole in a binary system (e.g., rapid x‐ray fluctuations, ultra‐soft x‐ray spectra, etc.), the most certain way to determine the mass is to measure it dynamically, using observed radial velocities of the companion star. This paper discusses the x‐ray binaries for which such observational evidence for a stellar black hole is presently available. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45987

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

The x‐ray spectra of accreting black holes in x‐ray binaries show anultrasoft/ultrahardspectral combination that is distinct amongst the galactic population of x‐ray binaries. This spectral signature is used to identify new black hole candidates, BHC. A total of 23 BHC are listed (including six that have been well established from optical radial velocity measurements). In 20 BHC systems the binary companion star is late type, and of these 15 are transient systems. Only 3 BHC are associated with early type companions. The galactic distribution of these black hole candidates, BHC, is compared with that of the entire population of low mass and high mass x‐ray binaries. The transient BHC are not strongly clustered at the galactic center, nor have any been found in a globular cluster. This suggests the transient BHC systems are population I. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45935

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Observations of Galactic black hole candidates performed with the ART‐P telescope aboardGranatin 1990–1992 focused our attention on studying of the sources spectral variability vs the accretion rate. We show that in contrast with the current scenario of disk accretion onto a black hole the hard spectral state of the sources always occurs at smaller accretion rate than the soft state. The arguments are presented that hard x‐rays detected during the ‘‘very high’’ and ‘‘low’’ states of black hole candidates have a distinct origin. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45949

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We have collected data from the literature of the past two decades, and are carrying out for the first time a systematic, statistical study of all the documented long‐term x‐ray and optical light curves of x‐ray nova outbursts. This study can yield information which is critical to our understanding of these systems, as well as provide us with the necessary empirical ingredients for detailed theoretical modeling efforts. In this paper we discuss the basic properties of the light curves. Some distinguished features not well known before are also identified and briefly discussed. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45956

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Low‐mass stars in close orbits around supermassive black holes in active galactic nuclei (AGN) may provide an important signature for testing the existence of supermassive black holes. Here we discuss how such systems can form by being ‘‘ground down’’ by their interaction with an AGN accretion disk and discuss the peculiarities of such binaries with extreme mass ratios. In particular, we show that, in the case of a low‐mass main‐sequence companion, the orbit has to be circularized to avoid tidal disruption. If the companion is filling its Roche lobe, mass loss will occur through the outer Lagrangian point rather than the inner because of irradiation effects (this may also be important for some binary pulsars like PSR 1957+20). Finally, we discuss possible signatures of such systems. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45957

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.45991

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Many of the recently‐discovered soft x‐ray transients are also black hole candidates; I explore the possibility that magnetic braking, a plausible driving mechanism of mass transfer in these systems, may naturally lead black hole systems to become transients. I show that, regardless of the details, magnetic braking leads to a lower accretion rate for black hole primary with masses substantially greater than 1.4 M⊙than for neutron star binaries. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.45992

出版商:AIP    

年代:1994

数据来源: AIP