Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-11-15
ApJ 674 (2008) L65
Astronomy and Astrophysics
Astrophysics
5 pages, 1 fig, ApJL accepted version, minor changes-- add demonstration of gamma-ray emission radius, and comments on earlier
Scientific paper
10.1086/529042
The prompt gamma-ray emission in gamma-ray bursts is believed to be produced by internal shocks within a relativistic unsteady outflow. The recent detection of prompt optical emission accompanying the prompt gamma-ray emission appears to be inconsistent with this model since the out flowing plasma is expected to be highly optically thick to optical photons. We show here that fluctuations in flow properties on short, ~ 1 ms, time scale, which drive the gamma-ray producing collisions at small radii, are expected to lead to "residual" collisions at much larger radii, where the optical depth to optical photons is low. The late residual collisions naturally account for the relatively bright optical emission. The apparent simultaneity of gamma-ray and optical emission is due to the highly relativistic speed with which the plasma expands. Residual collisions may also account for the X-ray emission during the early "steep decline" phase, where the radius is inferred to be larger than the gamma-ray emission radius. Finally, we point out that inverse-Compton emission from residual collisions at large radii is expected to contribute significantly to the emission at high energy, and may therefore "smear" the pair production spectral cut-off.
Li Zhuo
Waxman Eli
No associations
LandOfFree
Prompt optical emission from residual collisions in GRB outflows does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Prompt optical emission from residual collisions in GRB outflows, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Prompt optical emission from residual collisions in GRB outflows will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-214915