UHECR acceleration by magnetic reconnection in relativistic jets and the origin of very high energy emission

Discussion timeslot (ZOOM-Meeting): 20. July 2021 - 18:00
ZOOM-Meeting URL: https://desy.zoom.us/j/92210078166
ZOOM-Meeting ID: 92210078166
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/11-UHECR-Acceleration-CRI/83
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-03/4

Abstract:
'Relativistic jets are believed to be born magnetically dominated. Very and ultra-high energy cosmic rays can be efficiently accelerated by magnetic reconnection in these sources. We here demonstrate this by means of three-dimensional relativistic magnetohydrodynamical (3D-RMHD) simulations, injecting thousands of low-energy particles in the transition region of the relativistic jet from magnetically to kinetically dominated, where its magnetization parameter sigma ~1. In this region, there is efficient magnetic energy dissipation by fast magnetic reconnection which is naturally driven by kink instabilities (KI) in the initial helical magnetic fields of the jet. We find that the particles are accelerated up to energies E ~10^{18}$ eV for background magnetic fields B ~ 0.1 G, and E ~ 10^{20} eV for B ~ 10 G. We have also derived directly from the simulations the acceleration rate due to magnetic reconnection which has a dependence on the particles energy, r_{acc} ~ E^{-0.1}. The energy spectrum of the accelerated particles develops a power-law tail with spectral index p ~ -1.2. Our results can explain observed variable emission patterns, specially at very high energies as well as the associated neutrino emission recently detected in blazars. Successful applications of our results to the blazars MRK 421 and TXS 0506+056 are also discussed.'

Authors: Elisabete de Gouveia Dal Pino | Tania Medina-Torrejon | Luis Kadowaki | G. Kowal
Collaboration: CTA

Indico-ID: 220
Proceeding URL: https://pos.sissa.it/395/454