High-energy X-ray observations of the galactic center region.

The authors present results from high-energy X-ray observations (18 - 250 keV) of the region within 5° of the galactic center on 1977 November 24 with a balloon-borne scintillation detector. The detector had a point source 3 σ detection threshold of 40 μJy (2 - 10 keV) for a Crab-like spectrum. The authors consider the known 2 - 10 keV sources to determine which are strongest above 200 keV and find an acceptable fit to their data using the bulge sources GX 3+1 and GX 5-1, the binary GX 1+4, the transient A1743-322, and A1742-294. More than one of these sources must vary to produce the variation in the γ-ray continuum slope and integrated flux (60 - 250 keV) observed 2 years later by HEAO 3.