Swift Panchromatic Observations of the Bright Gamma-Ray Burst GRB 050525A

摘要

The Swift observatory discovered and observed GRB 050525A. The X-ray and optical/ultraviolet afterglow decay curves exhibit an achromatic break approximately 0.15 days after the burst. This break, and the total gamma-ray energy of the burst, implies a jet opening angle of 2.°5. Prior to the break the X-ray spectrum can be modelled by a power law with β_X = –1.2. A short X-ray flare occurred 300 s after the burst. The optical/ultraviolet data have a complex decay, with evidence of a reverse shock dominating in the first few minutes and a forward shock dominating at later times. The X-ray/ultraviolet/optical spectrum suggests that a cooling break moved through the optical between 800 and 25 000 s after the burst. The temporal decay and spectral indices agree with the standard fireball model, assuming a uniform interstellar medium.