X-ray and optical observations of the November 19, 1978 gamma-ray burst source region

The Nov. 19, 1978 gamma-ray burst (GRB) has a very well determined error box, 10 square arcmin (Cline et al., 1981). An 8000-sec IPC exposure with the Einstein Observatory detected, at a 3.4-sigma level, one low intensity (less than 3 x 10 to the -13th erg/sq cm per sec) X-ray source inside the error box. The probability of a serendipitous detection was 0.01. Inside the X-ray source error box there are two weak radio sources, one of them highly polarized (Hjellming and Ewald, 1981), and two 20-magnitude objects, not coincident with the radio sources visible in the ESO/SRC J and R plates. With the exception of N49, this is the first possible detection of X-ray emission inside a GRB box. Its low intensity justifies, in fact, the lack of detection for other events.