Discovery of Two Cosmic X-Ray Bursts in 1970

Two bursts of high-energy photons have been discovered during analysis of 2 1/2 years of data from NRL's solar X-ray detector on OSO-6. Both bursts were simultaneously observed by the OGO-5 hard X-ray spectrometer (Kane, 1975). The bursts occurred at about 18 087 s UT on 25 January, 1970, and about 56 532 s UT on 1 October, 1970. The October event was also observed by Vela 5A; however, none of the Vela detectors observed the January event which had an intensity of about 2×10^‑5 ergs cm^‑2. Based on these new data, the number of bursts with intensities above about 10^‑5 ergs cm^‑2 appears to be about 50% higher than the Vela data alone would indicate.