X-ray observations of the 5 March 1979 γ-burst field

On 5 March 1979, an extremely intense burst of hard X rays and γ rays was recorded by the nine interplanetary spacecraft of the burst sensor network and localised by time-of-flight determinations to a position coincident with the supernova remnant N49 in the Large Magellanic Cloud^1-3. Several times, both before and after the γ-ray event, we observed this region of the sky with the soft X-ray imaging instruments aboard the Einstein Observatory. Coupled with optical plate material, the soft X-ray data are used here to place severe constraints on models for the origin of this remarkable transient phenomenon.