Swift observations of the prompt X-ray emission and afterglow from GRB050126 and GRB050219A
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چکیده
We report on the temporal and spectral characteristics of the early X-ray emission from the Gamma Ray Bursts GRB050126 and GRB050219A as observed by Swift. The X-ray light-curves of these 2 bursts both show remarkably steep early decays (F(t) ∝ t−3), breaking to flatter slopes on timescales of a few hundred seconds. For GRB050126 the burst shows no evidence of spectral evolution in the 20–150 keV band, and the spectral index of the γ-ray and X-ray afterglows are significantly different suggesting a separate origin. By contrast the BAT spectrum of GRB050219A displays significant spectral evolution, becoming softer at later times, with Γ evolving toward the XRT photon index seen in the early X-ray afterglow phase. For both bursts, the 0.2–10 keV spectral index preand post-break in the X-ray decay light-curve are consistent with no spectral evolution. We suggest that the steep early decline in the X-ray decay light-curve is either the curvature tail of the prompt emission; X-ray flaring activity; or external forward shock emission from a jet with high density regions of small angular size (>Γ−1). The late slope we associate with the forward external shock.
منابع مشابه
Swift observations of the prompt X - ray emission and afterglow from GRB 050126 & GRB 050219 A
We report on the temporal and spectral characteristics of the early X-ray emission from the Gamma Ray Bursts GRB050126 and GRB050219A as observed by Swift. The X-ray light-curves of these 2 bursts both show remarkably steep early decays (F(t) ∝ t−3), breaking to flatter slopes on timescales of a few hundred seconds. For GRB050126 the burst shows no evidence of spectral evolution in the 20-150 k...
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