# Gamma‐ray burst efficiency and possible physical processes shaping the early afterglow

@article{Fan2006GammarayBE,
title={Gamma‐ray burst efficiency and possible physical processes shaping the early afterglow},
author={Yizhong Fan and Tsvi Piran},
journal={Monthly Notices of the Royal Astronomical Society},
year={2006},
volume={369},
pages={197-206}
}
• Published 4 January 2006
• Physics
• Monthly Notices of the Royal Astronomical Society
The discovery by Swift that a good fraction of gamma-ray bursts (GRBs) have a slowly decaying X-ray afterglow phase led to the suggestion that energy injection into the blast wave takes place several hundred seconds after the burst. This implies that right after the burst the kinetic energy of the blast wave was very low and in turn the efficiency of production of gamma-rays during the burst was extremely high, rendering the internal shocks model unlikely. We re-examine the estimates of kinetic…
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## References

SHOWING 1-10 OF 70 REFERENCES
Prompt γ-ray and early afterglow emission in the external shock model
• Physics
• 2004
We describe our attempt to determine if γ-ray burst (GRB) and afterglow emissions could both arise in external shocks for simple GRBs – bursts consisting of just a few peaks in their light curves. We
Impulsive and Varying Injection in Gamma-Ray Burst Afterglows
• Physics
The Astrophysical journal
• 2000
This work reanalyzes the refreshed shock scenario, in which slower material catches up with the decelerating ejecta and reenergizes it, and shows that during this time the overall spectral peak is found at the characteristic frequency of the reverse shock.
The Case for Anisotropic Afterglow Efficiency within Gamma-Ray Burst Jets
• Physics
• 2006
Early X-ray afterglows recently detected by Swift frequently show a phase of very shallow flux decay lasting from ~102.5 up to ~104 s, followed by a steeper, more familiar decay. We suggest that the
A unified treatment of the gamma-ray burst 021211 and its afterglow
• Physics
• 2003
The gamma-ray burst (GRB) 021211 had a simple light curve, containing only one peak and the expected Poisson fluctuations. Such a burst may be attributed to an external shock, offering the best
Analysis of two scenarios for the early optical emission of the gamma‐ray burst afterglows 990123 and 021211
• Physics
• 2004
The optical light curves of gamma-ray burst (GRB) afterglows 990123 and 021211 exhibit a steep decay at 100‐600 s after the burst, the decay becoming slower after about 10 min. We investigate two
A Study of the Afterglows of Four Gamma-Ray Bursts: Constraining the Explosion and Fireball Model
• Physics
• 2003
We employ a fireball model of the gamma-ray burst (GRB) explosion to constrain intrinsic and environmental parameters of four events with good broadband afterglow data: GRB 970508, GRB 980329, GRB
Gamma-Ray Bursts with Continuous Energy Injection and Their Afterglow Signature
• Physics
• 2002
We consider generically the problem of a gamma-ray burst (GRB) fireball with an additional energy injection, either in the form of a Poynting-flux-dominated outflow or a kinetic-energy-dominated
The Distribution of Burst Energy and Shock Parameters for Gamma-Ray Bursts
We calculate the luminosity function for gamma-ray burst afterglows in some fixed observed frequency band and at some fixed elapsed time in observer frame (tobs) in two models—one in which the