Synchrotron spectra of GRB prompt emission and pulsar wind nebulae

Abstract

Particle acceleration is a fundamental process in many high-energy astrophysical environments and determines the spectral features of their synchrotron emission. We have studied the adiabatic stochastic acceleration (ASA) of electrons arising from the basic dynamics of magnetohydrodynamic (MHD) turbulence and found that the ASA acts to efficiently harden the injected electron energy spectrum. The dominance of the ASA at low energies and the dominance of synchrotron cooling at high energies result in a broken power-law shape of both electron energy spectrum and photon synchrotron spectrum. Furthermore, we have applied the ASA to studying the synchrotron spectra of the prompt emission of gamma-ray bursts (GRBs) and pulsar wind nebulae (PWNe). The good agreement between our theories and observations confirms that the stochastic particle acceleration is indispensable in explaining their synchrotron emission.

8 pages, 6 figures, conference proceedings paper for the 18th Annual International Astrophysics Conference (February 18-22, 2019, Pasadena, CA, USA)

References in corpus (5)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Turbulent dynamo in a conducting fluid and partially ionized gas
• Relativistic MHD simulations of collision-induced magnetic dissipation in Poynting-flux-dominated jets/outflows
• Adiabatic non-resonant acceleration in magnetic turbulence and hard spectra of gamma-ray bursts
• On the broad-band synchrotron spectra of pulsar wind nebulae