Hard X Rays from the Region of Aquila XR-1

WE have previously presented experimental results on the hard X-ray spectrum of Her X-1 obtained from a balloon-borne instrument flown from Hyderabad, South India, on March 9, 1973 (ref. 1). During that flight the orientated X-ray telescope floated at a ceiling altitude of 4 g cm^-2 between 2230 and 0530 UT and was exposed to several Uhuru sources² besides Her X-1. Here we report what we believe to be the first evidence for hard X-ray emission from AQL XR-1 or the region close to it, and give the spectral results in the energy range 14-50 keV. The experimental details and the method of analysis are given in ref. 1.