The Synchrotron Low-energy Spectrum Arising from the Cooling of Electrons in Gamma-Ray Bursts

Abstract This work is a continuation of previous effort (Panaitescu) to study the cooling relativistic electrons through radiation (synchrotron and self-Compton) emission adiabatic losses, with application spectra light curves synchrotron gamma-ray burst (GRB) produced by such electrons. Here, we derive low-energy slope β LE GRB pulse- integrated spectrum quantify implications measured distribution . Radiative processes that produce soft can accommodate harder slopes CGRO/BATSE Fermi/GBM only if magnetic field lifetime t B shorter than time during which typical cool radiate below 1–10 keV, less (at most) 10 radiative timescales rad electron. In this case, there one-to-one correspondence between To account for > −3/4, electron-cooling requires similar restriction on diversity arises mostly from how electron-injection rate varies (temporal power-law injection rates yield spectra) not timescale.