Present status of hard X-ray astronomy

Abstract

The recent observational results obtained in the energy range of 15-150 keV from balloon and satellite borne instruments are reviewed. The detection of cyclotron line features in several X-ray binaries, hard X-ray spectra and variability of black hole candidates and the hard X-ray imaging of Galactic center region are discussed. The need for developing low background, good resolution, high sensitivity hard X-ray detectors is stressed and the developments carried out in this regard at Tata Institute of Fundamental Research (TIFR) and elsewhere are briefly outlined