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تسجيل مستخدم جديدJet Breaks in Short Gamma-Ray Bursts. I: The Uncollimated Afterglow of GRB 050724
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تأليف
D. Grupe
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We report the results of the chandra observations of the swift-discovered short Gamma-Ray Burst GRB 050724. chandra observed this burst twice, about two days after the burst and a second time three weeks later. The first chandra pointing occurred at the end of a strong late-time flare. About 150 photons were detected during this 49.3 ks observation in the 0.4-10.0 keV range. The spectral fit is in good agreement with spectral analysis of earlier swift XRT data. In the second chandra pointing the afterglow was clearly detected with 8 background-subtracted photons in 44.6 ks. From the combined swift XRT and chandra-ACIS-S light curve we find significant flaring superposed on an underlying power-law decay slope of $alpha$=0.98$^{+0.11}_{-0.09}$. There is no evidence for a break between about 1 ks after the burst and the last chandra pointing about three weeks after the burst. The non-detection of a jet break places a lower limit of 25$^{circ}$ on the jet opening angle, indicating that the outflow is less strongly collimated than most previously-reported long GRBs. This implies that the beaming corrected energy of GRB 050724 is at least $4times 10^{49}$ ergs.
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We report the best evidence to date of a jet break in a short Gamma-Ray Burst (GRB) afterglow, using Chandra and Swift XRT observations of the X-ray afterglow of GRB 051221A. The combined X-ray light curve, which has three breaks, is similar to those
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