GRB 090510: Early LAT emission is not from external shock

Hao Ning He, Xue Feng Wu, Kenji Toma, Peter Mészáros, Xiang Yu Wang

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

Abstract

Long-lived high-energy (> 100MeV) emission, a common feature of most Fermi-LAT detected gamma-ray burst, is detected up to ∼ 102 s in the short GRB 090510. We study the origin of this long-lived high-energy emission, using broad-band observations including X-ray and optical data. We confirm that the late > 100 MeV, X-ray and optical emission can be naturally explained via synchrotron emission from an adiabatic forward shock propagating into a homogeneous ambient medium with low number density under significant Klein-Nishina effects. Under the constraints from the low-energy observations, the adiabatic forward shock synchrotron emission is consistent with the later-time (t > 2s) high-energy emission, but falls below the early-time (t < 2s) high energy emission. Thus we argue that an extra high energy component is needed at early times. A standard reverse shock origin is found to be inconsistent with this extra component. Therefore, we attribute the early part of the high-energy emission (t < 2s) to the prompt component, and the long-lived high energy emission (t > 2s) to the adiabatic forward shock synchrotron afterglow radiation. This avoids the requirement for an extremely high initial Lorentz factor.

Original languageEnglish
Title of host publicationGamma Ray Bursts 2010, GRB 2010
Pages191-194
Number of pages4
DOIs
Publication statusPublished - 2011 Sep 12
Externally publishedYes
EventGamma Ray Bursts 2010, GRB 2010 - Annapolis, MD, United States
Duration: 2010 Nov 12010 Nov 4

Publication series

NameAIP Conference Proceedings
Volume1358
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

ConferenceGamma Ray Bursts 2010, GRB 2010
Country/TerritoryUnited States
CityAnnapolis, MD
Period10/11/110/11/4

Keywords

  • Burst
  • Gamma-rays
  • Non-thermal
  • Radiation mechanism

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science
  • Physics and Astronomy(all)
  • Nature and Landscape Conservation

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