SwiftObservations of the X‐Ray–Bright GRB 050315

Abstract

This paper discusses Swift observations of the γ-ray burst GRB 050315 (z=1.949) from 80 s to 10 days after the onset of the burst. The X-ray light curve displayed a steep early decay (t −5 ) for ∼ 200 s and several breaks. However, both the prompt hard X-ray/γ-ray emission (observed by the BAT) and the first ∼ 300 s of X-ray emission (observed by the XRT) can be explained by exponential decays, with similar decay constants. Extrapolating the BAT light curve into the XRT band suggests the rapidly decaying, early X-ray emission was simply a continuation of the fading prompt emission; this strong similarity between the prompt γ-ray and early X-ray emission may be related to the simple temporal and spectral character of this X-ray rich GRB. The prompt (BAT) spectrum was a steep down to ∼ 15 keV, and appeared to continue through the XRT bandpass, implying a low peak energy, inconsistent with the Amati relation. Following the initial steep decline the X-ray afterglow did not fade for ∼ 1.2×10 4 s, after which time it decayed with a temporal index of α ≈ 0.7, followed by a second break at ∼ 2.5 × 10 5 s to a slope of α ∼ 2. The apparent 'plateau' in the X-ray light curve, after the early rapid decay, makes this one of the most extreme examples of the steep-flat-steep X-ray light curves revealed by Swift. If the second afterglow break is identified with a jet break then the jet opening angle was θ 0 ∼ 5 • , and implying E γ ∼ > 10 50 erg.

Swift monitoring of the new accreting millisecond X-ray pulsar IGR J17511-3057 in outburst

“…Ancillary response files, accounting for different extraction regions, vignetting, and PSF corrections, were generated by using the xrtmkarf task. All PC data were affected by a strong pile-up, and corrected according to the technique developed by Vaughan (2006). We used the xrtlccorr task to account for this correction in the background-subtracted light curves.…”

Constraining the properties of neutron star crusts with the transient low-mass X-ray binary Aql X-1

“…For observations with count rates of >150 c s −1 (WT) and >0.6 c s −1 (PC), pile-up corrections were applied by exercising as many inner pixels as needed for the count rate to drop below these limiting values (Vaughan et al 2006;Romano et al 2006). For creating count rate light curves, corrections for losses due to pile-up and dead zones on the CCD (hot pixels and bad columns) were applied by simulating the complete (i.e., unaffected) and partial (i.e., affected) PSFs for each interval, the ratio of which gives the required correction factor (Evans et al 2007).…”

Giant outburst from the supergiant fast X-ray transient IGR J17544−2619: accretion from a transient disc?

“…The XRT data were processed and filtered with xrtpipeline (v0.13.1). Pileup was corrected for (ObsID 00614903000 only) by adopting standard procedures (Romano et al 2006;Vaughan et al 2006): source events were extracted from annuli (inner/outer radii of 4/20 pix for windowed-timing (WT), 5/30 pix for photon-counting (PC); 1 pixel ∼2.36 ). Light curves were corrected for point spread function losses, vignetting and were background subtracted.…”