Query : 2021A&A...650A.163C

2021A&A...650A.163C - Astronomy and Astrophysics, volume 650A, 163-163 (2021/6-1)

Synthetic gamma-ray light curves of Kerr black hole magnetospheric activity from particle-in-cell simulations.


Abstract (from CDS):

Context. The origin of ultra-rapid flares of very high-energy radiation from active galactic nuclei remains elusive. Magnetospheric processes, occurring in the close vicinity of the central black hole, could account for these flares.
Aims. Our aim is to bridge the gap between simulations and observations by synthesizing gamma-ray light curves in order to characterize the activity of a black hole magnetosphere, using kinetic simulations.
Methods. We performed global axisymmetric 2D general-relativistic particle-in-cell simulations of a Kerr black hole magnetosphere. We included a self-consistent treatment of radiative processes and plasma supply, as well as a realistic magnetic configuration, with a large-scale equatorial current sheet. We coupled our particle-in-cell code with a ray-tracing algorithm in order to produce synthetic light curves.
Results. These simulations show a highly dynamic magnetosphere, as well as very efficient dissipation of the magnetic energy. An external supply of magnetic flux is found to maintain the magnetosphere in a dynamic state, otherwise the magnetosphere settles in a quasi-steady Wald-like configuration. The dissipated energy is mostly converted to gamma-ray photons. The light curves at low viewing angle (face-on) mainly trace the spark gap activity and exhibit high variability. On the other hand, no significant variability is found at high viewing angle (edge-on), where the main contribution comes from the reconnecting current sheet.
Conclusions. We observe that black hole magnetospheres with a current sheet are characterized by a very high radiative efficiency. The typical amplitude of the flares in our simulations is lower than is detected in active galactic nuclei. These flares could result from the variation in parameters external to the black hole.

Abstract Copyright: © B. Crinquand et al. 2021

Journal keyword(s): black hole physics - magnetic fields - acceleration of particles - plasmas - radiation mechanisms: non-thermal - methods: numerical

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 M 87 AGN 12 30 49.42338414 +12 23 28.0436859 10.16 9.59 8.63   7.49 ~ 7068 3
2 NAME Centaurus A Sy2 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4421 3
3 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 14048 0
4 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4260 3
5 QSO B2155-304 BLL 21 58 52.0652249880 -30 13 32.118447792   13.36 13.09 12.62   ~ 1708 1

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