Theoretical implications of thermal emission from gamma-ray bursts

Asaf Pe'er, Felix Ryde

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

1 Scopus citations


Recent analysis show evidence for a thermal emission component that accompanies the non-thermal emission during the prompt phase of GRBs. We show that this component is naturally explained by considering emission from the photosphere. The photosphere of a relativistically expanding plasma wind strongly depends on the angle to the line of sight, θ. As a result, thermal emission can be seen after tens of seconds. Using probability density function P(r, θ) to describe photon escape at radius r and angle θ, we show that the thermal flux is expected to decay at late times as F BB̃ t-2 , and the observed temperature decays as T ̃ t-a, with a ̃ 1/2 - 2/3. We discuss the relation between thermal emission and high energy, non-thermal spectra observed by FERMI. We show how thermal emission can be used to directly measure the Lorentz factor of the flow and the initial radius of the jet.

Original languageEnglish
Title of host publicationGamma-Ray Burst - 6th Huntsville Symposium
Number of pages6
StatePublished - 2009
Externally publishedYes
Event6th Huntsville Symposium on Gamma-Ray Bursts - Huntsville, AL, United States
Duration: 20 Oct 200823 Oct 2008

Publication series

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


Conference6th Huntsville Symposium on Gamma-Ray Bursts
Country/TerritoryUnited States
CityHuntsville, AL


  • Gamma rays:bursts
  • Plasmas
  • Radiation mechanism:Non-thermal
  • Radiation mechanism:Thermal
  • Scattering


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