Implications of the Visible and X-Ray Counterparts to GRB970228

Abstract

The gamma-ray burst source GRB970228 has been observed after a delay of 8--12 hours in X-rays and after one day in visible and near infrared light. This marks the first detection of emission at lower frequencies following the gamma-ray observation of a GRB and the first detection of any visible counterpart to a GRB. We consider possible delayed visible and X-ray emission mechanisms, and conclude that the intrinsic gamma-ray activity continued at a much reduced intensity for at least a day. There are hints of such continued activity in other GRB, and future observations can decide if this is true of GRB in general. The observed multi-band spectrum of GRB970228 agrees with the predictions of relativistic shock theory when the flux is integrated over a time longer than that required for a radiating electron to lose its energy.

5 pp., tex, 1 figure

References in corpus (4)

• Discovery of the X-Ray Afterglow of the Gamma-Ray Burst of February 28 1997
• Variability in GRBs - A Clue
• Yet Another Model of Gamma-Ray Bursts
• Possible Evidence for Relativistic Shocks in Gamma-Ray Bursts

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