2017/08/27 by Siyao Xu, Bing Zhang · 39 citations
Physics and Astronomy · #Acceleration #Adiabatic process #Astrophysics and Cosmic Phenomena #Cutoff #Electron #Fermi acceleration #Gamma-ray bursts and supernovae #Magnetohydrodynamic turbulence #Particle acceleration #Pulsars and Gravitational Waves Research #Synchrotron #Synchrotron radiation #astro-ph.HE #hep-th #physics.plasm-ph
paper · pdf · doi:10.3847/2041-8213/aa88b1
published in The Astrophysical Journal Letters 846(2), L28 (IOP Publishing) · 5 pages, 2 figures; accepted for publication in ApJL
arxiv created 2017/08/27 · openalex publication_date 2017/09/08 · openalex created_date 2017/09/15 · arxiv updated 2017/09/20 · openalex updated_date 2026/08/06
Abstract We introduce a non-resonant acceleration mechanism arising from the second adiabatic invariant in magnetic turbulence and apply it to study the prompt emission spectra of gamma-ray bursts (GRBs). The mechanism contains both the first- and second-order Fermi acceleration, originating from the interacting turbulent reconnection and dynamo processes. It leads to a hard electron energy distribution up to a cutoff energy at the balance between the acceleration and synchrotron cooling. The sufficient acceleration rate ensures a rapid hardening of any initial energy distribution to a power-law distribution with the index , which naturally produces a low-energy photon index via the synchrotron radiation. For typical GRB parameters, the synchrotron emission can extend to a characteristic photon energy on the order of ∼100 keV.