Gamma-Ray Emission from the Region of the Galactic Center

A combination nuclear-emulsion-spark-chamber y-ray (E > 100 MeV) telescope has been used to study the region of sky that includes the Galactic center. Ninety-five percent confidence upper limits on the flux from the reported sources Gy 2+3 and Sgr y-l were placed at 4.4 and 8.8 x 1O- photons 1, and a similar limit on the emission from the Galactic center as a point source (t0.75 ) was placed at 3.3 x 1O- photons 1, No enhanced emission was observed from the Galactic plane (I6 ), and an upper limit of 2 x 1O- photons cm-2 1 rad-1 was obtained. Three regions of enhanced emission were observed that had a combined Poisson probability of occurrence of less than S x 1O- . One of these is associated with a region of enhanced emission reported by other workers. The observations were made against an integral atmospheric background intensity of 1.4 I 0.4 photons cm-2 sterad-1 1 mb-1 that had a spectral index of 0.8 I 0.2 in the energy range from 0.1 to 2.5 GeY. Subject headings: Galaxy, The - gamma-rays