On the Enhanced X-ray Emission from SGR 1900+14 after the August 27 Giant Flare

Abstract

We show that the giant flares of soft-gamma ray repeaters (E~10^44 ergs) can push the inner regions of a fall-back disk out to larger radii by radiation pressure, while matter remains bound to the system for plausible parameters. The subsequent relaxation of this pushed-back matter can account for the observed enhanced X-ray emission after the August 27 giant flare of SGR 1900+14. Based on the results of our models, we estimate that the ratio of the fluences of the enhanced X-ray emissions to that of the preceding bursts remains constant for a particular SGR with similar preburst inner disk conditions, which is consistent with the four different burst observations of SGR 1900+14.