Bright X-ray flares in XRF 050406 and GRB 050502B provide evidence for extended central engine activity

Preprint
Publisher Website
Google Scholar
  • 13 June 2005
Abstract
Gamma-ray bursts (GRBs) are the most powerful explosions since the Big Bang, with typical energies around 10**51 ergs. Long GRBs (duration > 2 s) are thought to signal the creation of black holes, most likely by collapse of massive stars. The detected signals from the resulting highly relativistic fireball consist of prompt gamma-ray emission (from internal shocks in the fireball) lasting for several seconds to minutes, followed by afterglow emission (from external shocks as the fireball encounters surrounding material) covering a broad range of frequencies from radio through X-rays. Because of the time needed to determine the GRB position, most afterglow measurements have been made hours after the burst, and little is known about the characteristics of afterglows in the minutes following a burst, when the afterglow emission is actively responding to inhomogeneities in both the fireball and the circumburst environment. Here we report our discovery of two bright X-ray flares peaking a few minutes after the burst. These amazingly strong, rapid X-ray flares imply that the central engines of the bursts are active at much later times than previously thought, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

This publication has 0 references indexed in Scilit: