X-ray observations of gamma-ray burst counterparts with ASCA

X-ray counterpart searches of GRBs are of key importance in solving the mystery of their origin. Possible X-ray counterparts of the May 1, 1992 and the Nov. 19, 1978 GRBs were observed with ASCA. In this report, we mention only GRB920501. Its 0.5–10.0 keV spectrum with ASCA appears hard and was heavily absorbed at low energies. The amount of low-energy absorption is consistent with the galactic value in this direction. This suggests that the X-ray source is quite distant, and cannot be a field star or a supernova remnantin the galactic disk.