Early afterglow and variability

Kunihito Ioka, Shiho Kobayashi, Bing Zhang, Toma Kenji, Ryo Yamazaki, Takashi Nakamura

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


We show that simple kinematic arguments can give limits on variabilities in gamma-ray burst (GRB) afterglows. These limits are violated by X-ray flares in the early afterglows recently identified by the Swift satellite. We discuss that a probable solution is that the central engine continues to eject an intermittent outflow for a very long timescale up to 1 day. This long-lived engine model may also explain the flat decay of early X-ray afterglows, while the gamma-ray efficiency of GRBs should be incredibly high (>75-90%) in this model. We suggest new possible models to evade this efficiency crisis and discuss implications for future observations.

Original languageEnglish
Title of host publicationGAMMA-RAY BURSTS IN THE SWIFT ERA
Subtitle of host publicationSixteenth Maryland Astrophysics Conference
Number of pages4
Publication statusPublished - 2006 May 19
EventGAMMA-RAY BURSTS IN THE SWIFT ERA: 16th Maryland Astrophysics Conference - Washington, D.C., United States
Duration: 2005 Nov 292005 Dec 2

Publication series

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


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


  • Gamma rays: bursts
  • Gamma rays: theory
  • Relativity


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