X-Ray Sky Surveys and the Rosat Mission

Abstract

The first X-ray source outside the solar system — Sco X-1 — was discovered in 1962 (Giacconi et al. 1962) and by the end of the 60’s a few dozen sources had been detected by numerous rocket and balloon experiments. The observational situation improved dramatically when Uhuru, the first X-ray astronomy satellite, was launched in 1970. Its instruments performed the first all sky survey in X-rays. Approximately half of the 400 sources discovered by Uhuru and its successor Ariel-5 are galactic objects: binary systems containing neutron stars and possibly blackholes, X-ray bursters, supernova remnants and transients. The extragalactic sources are mainly clusters of galaxies as well as Seyfert galaxies and BL Lac Objects. The identifications and follow-up studies of these sources have produced the main advances in X-ray astronomy in the first half of the 1970’s.