Optical and Infrared Observations of Black Hole Binaries and Related Systems

Yale University, New Haven CT

Investigators

Abstract

"Optical and Infrared Observations of Black Hole Binaries and Related Systems" AST- 0098421 Optical and infrared observations of X-ray sources with soft X-ray transients will be carried out. These objects are binary star systems, which consist of an accreting compact object and a less massive companion star that is the donor. Optical and infrared observations show that the compact object is possibly a black hole in many cases although the results are controversial. In quiescence, the optical light is dominated by that of the companion star and orbital parameters can be measured which indicate that, in most cases, the mass of the compact object is above the 3 solar mass upper limit for a neutron star. At the times of X-ray outburst, the optical and infrared radiation is dominated by that from the accretion flow and from X-ray irradiation of the secondary star and surrounding material. Simultaneous optical and X-ray observations are needed to describe the geometry and physics of these objects which are presently providing some of the strongest evidence for the existence of black holes.