POYNTING-FLUX-DOMINATED JETS CHALLENGED BY THEIR PHOTOSPHERIC EMISSION
- 1 April 2015
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 802 (2)
- https://doi.org/10.1088/0004-637x/802/2/134
Abstract
One of the key open question in the study of jets, in general, and jets in gamma-ray bursts (GRBs), in particular, is the magnetization of the outflow. Here we consider the photospheric emission of Poynting-flux-dominated outflows, when the dynamics is mediated by magnetic reconnection. We show that thermal three-particle processes, responsible for the thermalization of the plasma, become inefficient at a radius of r(sup) similar to 10(9.5) cm, far below the photosphere, at similar to 10(11.5) cm. Conservation of the total photon number above r(sup) combined with Compton scattering below the photosphere enforces kinetic equilibrium between electrons and photons. This, in turn, leads to an increase in the observed photon temperature, which reaches. greater than or similar to 8 MeV (observed energy) when decoupling the plasma at the photosphere. This result is weakly dependent on the free model parameters. We show that in this case, the expected thermal luminosity is a few percent of the total luminosity, and could therefore be detected. The predicted peak energy is more than an order of magnitude higher than the observed peak energy of most GRBs, which puts strong constraints on the magnetization of these outflows.This publication has 51 references indexed in Scilit:
- PHOTOSPHERIC EMISSION AS THE DOMINANT RADIATION MECHANISM IN LONG-DURATION GAMMA-RAY BURSTSThe Astrophysical Journal, 2013
- REGULATION OF THE SPECTRAL PEAK IN GAMMA-RAY BURSTSThe Astrophysical Journal, 2013
- THE FERMI GBM GAMMA-RAY BURST SPECTRAL CATALOG: THE FIRST TWO YEARSThe Astrophysical Journal Supplement Series, 2012
- GeV EMISSION FROM COLLISIONAL MAGNETIZED GAMMA-RAY BURSTSThe Astrophysical Journal Letters, 2011
- Magnetohydrodynamic simulations of gamma-ray burst jets: Beyond the progenitor starNew Astronomy, 2010
- Self-similar force-free wind from an accretion discMonthly Notices of the Royal Astronomical Society, 2007
- The Ep,i-Eiso correlation in gamma-ray bursts: updated observational status, re-analysis and main implicationsMonthly Notices of the Royal Astronomical Society, 2006
- Gamma-ray burstsReports on Progress in Physics, 2006
- Spectra of black-hole binaries in the low/hard state: From radio to X-raysAstronomy & Astrophysics, 2005
- Double Compton emission in radiation dominated thermal plasmasThe Astrophysical Journal, 1981