Recurrent burst activity from the soft γ-ray repeater SGR 1900+14

Abstract

Of the one thousand or so detected sources of cosmic γ-ray bursts (GRBs), only three are known to have exhibited recurrent activity1-4. These events differ from the majority of GRBs in that they are of much shorter duration and have relatively soft spectra5. The recurrent sources can thus be considered as a distinct class of objects - the soft gamma repeaters (SGRs). The embryonic distribution of the SGRs suggests that they are of galactic origin4, whereas the distribution6 of GRBs seems to be inconsistent with any known galactic source population. Here we report the detection by the Burst and Transient Source Experiment (BATSE) 7 of three short, very soft transient events from a location consistent with that of the 'old' repeater SGR 1900 + 14 (ref. 8). Our results suggest that the SGR active phase lasts at least 13 years, which, in conjunction with the arguments for a galactic origin, lends support to suggestions4,5 that SGRs are neutron stars. © 1993 Nature Publishing Group