Recent Results on Extragalactic Cosmic X-Ray Sources from Rocket and Balloon Flights

Abstract

Two experiments carried out recently at M.I.T. gave results which bear on the problems of extragalactic X-ray sources. One of these is the work of a group under the direction of Hale Bradt (Bradt et al., 1967), who used an attitude-controlled Aerobee rocket to scan a portion of the sky which included the radio galaxy M 87 (Virgo A). Among their detectors were two banks of argon-filled, 2 mil beryllium window proportional counters, each with an effective area of 350 cm² and a mechanical collimator giving a 2°×20° FWHM field of view. The fields of view were crossed

so that their long directions made an angle of 60° with one another. Aspect was determined to within 5 min of arc by star photography.

This work was supported in part by the National Aeronautics and Space Administration under Contracts NSR22-009-129 and NsG-386, and in part by the U.S. Atomic Energy Commission under contract AT(30-l)-2098.