20-200 keV observations of binary X-ray sources with a balloon-borne payload

Abstract

The spectral information in the hard X-ray energy region above 30 keV is available only for a small number of X-ray objects even though hard X-ray flux has been observed from about 80 of the 200,000 X-ray sources cataloged so far. We have attempted spectral observations of binary X-ray sources in the 20-200 keV band using a newly developed balloon-borne large area scintillation counter telescope. In this paper we present the hard X-ray spectra of some of these sources obtained during various experiments.