Work

Spectral evolution and the onset of the X-ray GRB afterglow

Year: 2011

Type: article

Abstract: Based on light curves from the Swift Burst Analyser, we investigate whether a ‘dip’ feature commonly seen in the early‐time hardness ratios of Swift‐XRT data could arise from the juxtaposition of the decaying prompt emission and rising afterglow. We are able to model the dip as such a feature, assuming the afterglow rises as predicted by Sari and Piran [1]. Using this model we measure the initial bulk Lorentz factor of the fireball. For a sample of 23 GRBs we find a median value of Γ[subscript: 0] = 225, assuming a constant‐density circumburst medium; or Γ[subscript: 0] = 93 if we assume a wind‐like medium.

Source: Figshare

Authors: P. A. Evans (7582265), J. P. Osborne (7602755), R. Willingale (7603352), P. T. O'Brien (7604567)

Institution: University of Leicester

Language: English

Topic: Gamma-ray bursts and supernovae

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

OpenAlex ID: W3125164665

FWCI: 0.127

Cites: 6

Cited by: 3

Related to: 10