Late-time X-ray flares during GRB afterglows: Extended internal engine activity

A. D. Falcone, D. N. Burrows, P. Romano, S. Kobayashi, D. Lazzati, B. Zhang, S. Campana, G. Chincarini, G. Cusumano, N. Gehrels, P. Giommi, M. R. Goad, O. Godet, J. E. Hill, J. A. Kennea, P. Mészáros, D. Morris, J. A. Nousek, P. T. O'Brien, J. P. OsborneC. Pagani, K. Page, G. Tagliaferri

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


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.

Original languageEnglish (US)
Title of host publicationGAMMA-RAY BURSTS IN THE SWIFT ERA
Subtitle of host publicationSixteenth Maryland Astrophysics Conference
Number of pages6
StatePublished - May 19 2006
EventGAMMA-RAY BURSTS IN THE SWIFT ERA: 16th Maryland Astrophysics Conference - Washington, D.C., United States
Duration: Nov 29 2005Dec 2 2005

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


OtherGAMMA-RAY BURSTS IN THE SWIFT ERA: 16th Maryland Astrophysics Conference
Country/TerritoryUnited States
CityWashington, D.C.

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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