X-ray astronomy from space

Abstract

The growth of X-ray astronomy since its beginning in 1962 is briefly discussed. Different types of X-ray s0.urces are described and a detailed discussion of the characteristics of X-ray binaries is presented. Present international status of research m the studl~ of the X~ray binaries is summarized with special reference to the results from current satellite missions. Re.cent ~iscovery of quasi-periodic oscillations with frequency in the range of about SOO-1200Hz from several low mass X-ray binaries and their origin are discussed. Some of the Important results from the X-ray spectroscopic observations with the ASCA satellite are highhghted. Indian research groups have contnbuted significantly to the temporal studies of X-ray binaries earlier with the balloon-borne instruments and now With the Indian X-ray Astronomy Experiment (lXAE) on the IRS-P3 satellite launched on March 21, 1996. Details of the lXAE are presented and important results ~btamed with it so far are described in some detail with reference to the black hole binary source CygX-1 and GRS 1915 -t- 105. The recent discovery of regular X-ray bursts with the lXAE from GRS 1915 + 105. which have the unique characteristics of slow rise and fast decay, IS descnbed in detail and it is shown that this is a possible indication of matter disappearing into the event honzon of the black hole.