Late-Time X-ray Flares during GRB Afterglows: Extended Internal Engine Activity
Abstract
Observations of gamma ray bursts (GRBs) with Swift produced the initially surprising result that many bursts have large X-ray flares superimposed on the underlying afterglow. These flares were sometimes intense, rapid, and late relative to the nominal prompt phase. The most intense of these flares was observed by XRT with a flux >500 the afterglow. This burst then surprised observers by flaring again after >10000 s. The intense flare can be most easily understood within the context of the standard fireball model, if the internal engine that powers the prompt GRB emission is still active at late times. Recent observations indicate that X-ray flares are detected in ~1/3 of XRT detected afterglows. By studying the properties of the varieties of flares (such as rise/fall time, onset time, spectral variability, etc.) and relating them to overall burst properties, models of flare production and the GRB internal engine can be constrained.
Cite
@article{arxiv.astro-ph/0602135,
title = {Late-Time X-ray Flares during GRB Afterglows: Extended Internal Engine Activity},
author = {A. D. Falcone and D. N. Burrows and P. Romano and S. Kobayashi and D. Lazzati and B. Zhang and S. Campana and G. Chincarini and G. Cusumano and N. Gehrels and P. Giommi and M. R. Goad and O. Godet and J. E. Hill and J. A. Kennea and P. Meszaros and D. Morris and J. A. Nousek and P. T. O'Brien and J. P. Osborne and C. Pagani and K. Page and G. Tagliaferri and the Swift XRT Team},
journal= {arXiv preprint arXiv:astro-ph/0602135},
year = {2010}
}
Comments
To appear in the proceedings of the 16th Annual October Astrophysics Conference in Maryland "Gamma Ray Bursts in the Swift Era"