An external-shock origin of the E_p-E_gamma relation for Gamma-Ray Bursts
arXiv:0811.2163 · doi:10.1111/j.1365-2966.2008.14240.x
Abstract
We investigate the possibility that the E_p propto E_gamma^{1/2} relation between the peak energy E_p of the nuF_nu spectrum and energy output E_gamma for long-duration GRBs arises from the external shock produced by the interaction of a relativistic outflow with the ambient medium. To that aim, we take into account the dependence of all parameters which determine E_p and E_gamma on the radial distribution of the ambient medium density and find that the E_p-E_gamma relation can be explained if the medium around GRBs has a universal radial stratification. For various combinations of GRB radiative process (synchrotron or inverse-Compton) and dissipation mechanism (reverse or forward shock), we find that the circumburst medium must have a particle density with a radial distribution different than the R^{-2} expected for constant mass-loss rate and terminal speed.
6 pages, to appear in MNRAS
References in corpus (7)
- The Ep,i - Eiso correlation in GRBs: updated observational status, re-analysis and main implications
- The early X-ray emission from GRBs
- Testing the standard fireball model of GRBs using late X-ray afterglows measured by Swift
- The Epeak-Eiso plane of long Gamma Ray Bursts and selection effects
- Global Properties of X-Ray Flashes and X-Ray-Rich Gamma-Ray Bursts Observed by Swift
- Peak energy of the prompt emission of long Gamma Ray Bursts vs their fluence and peak flux
- Electron acceleration in relativistic GRB shocks
Cited by in corpus (7)
- A complete sample of bright Swift Long Gamma Ray Bursts: testing the spectral-energy correlations
- Spectral-Luminosity relation within individual Fermi GRBs
- The faster the narrower: characteristic bulk velocities and jet opening angles of Gamma Ray Bursts
- Gamma Ray Burst Prompt correlations
- The impact of selection biases on the Ep-Liso correlation of Gamma Ray Bursts
- Spectral evolution of Fermi/GBM short Gamma-Ray Bursts
- Comptonization signatures in the prompt emission of Gamma Ray Bursts