2005/04/30 by Asaf Pe’er, Asaf Pe'er, Peter Mészáros +2 · 102 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Compton scattering #Dissipation #Electron #Gamma-ray bursts and supernovae #Laser-Plasma Interactions and Diagnostics #Lorentz factor #Lorentz transformation #Photon #Scattering #Shock (circulatory) #Thermal #astro-ph
paper · pdf · doi:10.1086/497360
published in The Astrophysical Journal 635(1), 476-480 (IOP Publishing) · Extended explanations about the electron energy balance; Refine figures; Accepted for publication in Ap.J
arxiv created 2005/09/12 · openalex publication_date 2005/12/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We study the properties of plasmas containing a low-energy thermal photon component at comoving temperatures of θ ≡ kT '/ m e c 2 ~ 10 -5 to 10 -2 interacting with an energetic electron component characteristic of, e.g., the dissipation phase of relativistic outflows in gamma-ray bursts (GRBs), X-ray flashes, and blazars. We show that for scattering optical depths larger than a few, the balance between Compton and inverse Compton scattering leads to the accumulation of electrons at values of γβ ~ 0.1-0.3. For optical depths larger than ~100, this leads to a peak in the comoving photon spectrum at 1-10 keV that is very weakly dependent on the values of the free parameters. In particular, these results are applicable to the internal shock model of GRBs, as well as to slow dissipation models, e.g., as might be expected from reconnection, if the dissipation occurs at a subphotospheric radii. For GRB bulk Lorentz factors of ~100, this results in observed spectral peaks clustering in the 0.1-1 MeV range, with conversion efficiencies of electrons into photon energy in the BATSE range of ~30%.