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We report the results of Swift X-Ray Telescope (XRT) observations of GRB 050318. This event triggered the Burst Alert Telescope (BAT) aboard Swift and was followed-up with XRT and UVOT for 11 consecutive orbits starting from 54 minutes after the trigger. A previously unknown fading X-ray source was detected and accurately monitored. The source was found to decrease in intensity with time and a clear temporal break occurring at ~18000 s after the trigger was observed. The X-ray light curve was found to be consistent with a broken power-law with decay indices -1.17 +/- 0.08 and -2.10 (+0.22) (-0.24) before and after the break. The spectrum of the X-ray afterglow was well described by a photoelectrically absorbed power-law with energy index of -1.09 +/-0.09. No evidence of spectral evolution was found. We compare these results with those obtained with UVOT and separately reported and refine the data analysis of BAT. We discuss our results in the framework of a collimated fireball model and a synchrotron radiation emission mechanism. Assuming the GRB redshift derived from the farthest optical absorption complex (z = 1.44), the event is fully consistent with the E_p-E_iso correlation.
The Swift Gamma-Ray Burst Explorer, launched on 2004 November 20, is a multiwavelength, autonomous, rapid-slewing observatory for gamma-ray burst (GRB) astronomy. On 2004 December 23, during the activation phase of the mission, the Swift X-Ray Telesc
(Abridged) The Swift X-Ray Telescope (XRT) reveals some interesting features of early X-ray afterglows, including a distinct rapidly decaying component preceding the conventional afterglow component in many sources, a shallow decay component before t
The Swift XRT has been observing GRB afterglows since December 23, 2004. Three-quarters of these observations begin within 300 s of the burst onset, providing an unprecendented look at the behavior of X-ray emission from GRB afterglows in the first f
We present observations of GRB 050318 by the Ultra-Violet and Optical Telescope (UVOT) on-board the Swift observatory. The data are the first detections of a Gamma Ray Burst (GRB) afterglow decay by the UVOT instrument, launched specifically to open
The unique capability of the Swift satellite to perform a prompt and autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the discovery of interesting new properties of GRB X-ray afterglows, such as the steep early lightcurve decay a