Prospects for y-ray imaging telescopes

Abstract

Localized sources of y-radiation have been detected by both satellite and balloon-borne detectors but very few of these sources have been identified with known astronomical objects. Two of the objects listed in the second COS-B catalogue of y-ray sources (Swanenburg et al. 1981) have been linked with the Crab and Vela pulsars because of their characteristic variability, and one other has been fairly confidently associated with 3C273 (Swanenberg et al. 1978; Bignami et al. 1981). Another object is probably located in the p-Oph cloud complex (Mayer-Hasselwander et al. 1980; Bignami & Morfill 1980). Although the angular resolution of the COS-B telescope is typically + 5° for 100 MeV photons, more precise estimates of the most likely location of y-ray sources have been made by applying image processing techniques. Nevertheless, the best error boxes include of the order of 1000 stars having a magnitude m < 15 and a much higher angular resolution is therefore required to make a unique identification possible.