CORRELATED SPECTRAL AND TEMPORAL BEHAVIOR OF LATE-TIME AFTERGLOWS OF GAMMA-RAY BURSTS
- Physics Department, Technion, Haifa 32000 (Israel)
The cannonball (CB) model of gamma-ray bursts (GRBs) predicts that the asymptotic behavior of the spectral energy density of GRB afterglows is a power law in time and in frequency, and the difference between the temporal and spectral power-law indices, {alpha}{sub X} - {beta}{sub X}, is restricted to the values 0, 1/2, and 1. Here we report the distributions of the values {alpha}{sub X} and {beta}{sub X}, and their difference for a sample of 315 Swift GRBs. This sample includes all Swift GRBs that were detected before 2012 August 1, whose X-ray afterglow extended well beyond 1 day and the estimated error in {alpha}{sub X} - {beta}{sub X} was {<=}0.25. The values of {alpha}{sub X} were extracted from the CB-model fits to the entire light curves of their X-ray afterglow while the spectral index was extracted by the Swift team from the time-integrated X-ray afterglow of these GRBs. We found that the distribution of the difference {alpha}{sub X} - {beta}{sub X} for these 315 Swift GRBs has three narrow peaks around 0, 1/2, and 1 whose widths are consistent with being due to the measurement errors, in agreement with the CB-model prediction.
- OSTI ID:
- 22139980
- Journal Information:
- Astrophysical Journal, Vol. 761, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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