Blustin, AJ;
Band, D;
Barthelmy, S;
Boyd, P;
Capalbi, M;
Holland, ST;
Marshall, FE;
... White, NE; + view all
(2006)
Swift panchromatic observations of the bright gamma-ray burst GRB 050525a.
ASTROPHYS J
, 637
(2)
901 - 913.
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Abstract
The bright gamma- ray burst GRB 050525a has been detected with the Swift observatory, providing unique multiwavelength coverage from the very earliest phases of the burst. The X- ray and optical / UV afterglow decay light curves both exhibit a steeper slope similar to 0.15 days after the burst, indicative of a jet break. This jet break time combined with the total gamma- ray energy of the burst constrains the opening angle of the jet to be 3 degrees.2. We derive an empirical `` timelag'' redshift from the BAT data of (z) over bar z 0: 69 +/- 0: 02, in good agreement with the spectroscopic redshift of 0.61. Prior to the jet break, the X- ray data can be modeled by a simple power law with index alpha = - 1: 2. However, after 300 s the X- ray flux brightens by about 30% compared to the power- law fit. The optical / UV data have a more complex decay, with evidence of a rapidly falling reverse shock component that dominates in the first minute or so, giving way to a flatter forward shock component at later times. The multiwavelength X- ray/ UV/ optical spectrum of the afterglow shows evidence for migration of the electron cooling frequency through the optical range within 25,000 s. The measured temporal decay and spectral indexes in the X- ray and optical/ UV regimes compare favorably with the standard fireball model for gamma- ray bursts assuming expansion into a constant- density interstellar medium.
| Type: | Article |
|---|---|
| Title: | Swift panchromatic observations of the bright gamma-ray burst GRB 050525a |
| Open access status: | An open access version is available from UCL Discovery |
| Keywords: | astrometry, galaxies : distances and redshifts, gamma rays : bursts, shock waves, X-rays : individual (GRB 050525a), AFTERGLOW LIGHT CURVES, OPTICAL AFTERGLOWS, PEAK LUMINOSITY, REVERSE-SHOCK, GRB 050525A, ENERGY, GRB-021211, SPECTRA, MODEL, GRB-990123 |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/9229 |
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