Very early optical and near infrared (IR) emission was discovered accompanying the long gamma-ray burst (GRB) 041219a. We show that the optical/IR flash tracking the gamma-ray lightcurve during the prompt emission could be understood as emission from neutron-rich internal shocks, as has been suggested by Fan & Wei. The early K_s-band afterglow lightcurve after the prompt phase could be well-modeled as the superposition of a reverse shock and a forward shock component. The radio data also support the reverse shock interpretation.
@article{arxiv.astro-ph/0504165,
title = {Early optical-IR emission from GRB 041219a: neutron-rich internal shocks and a mildly magnetized external reverse shock},
author = {Y. Z. Fan and Bing Zhang and D. M. Wei},
journal= {arXiv preprint arXiv:astro-ph/0504165},
year = {2009}
}
Comments
4 pages, including 2 figures, accepted for publication in ApJL (shortened to match the page limit)