Non-uniform particle injection into black hole jets by radiative magnetic reconnection

TL;DR

This paper investigates how non-uniform electron-positron pair production via magnetic reconnection near black holes supplies plasma to jets, explaining observed emissions and the influence of black hole spin.

Contribution

It introduces a model of pair production distribution in black hole jets considering photon anisotropy and black hole spin effects, based on GRMHD simulations and ray tracing.

Findings

Sufficient plasma can be supplied to explain M87 jet emission.

Black hole spin significantly influences pair distribution and jet properties.

Photon anisotropy affects the spatial distribution of pairs.

Abstract

Active galactic nuclei often exhibit highly collimated relativistic plasma outflows launched from the vicinity of their central black holes. One of the key theoretical challenges in understanding black hole jet formation is the origin of the plasma that feeds the jet, which remains poorly understood, particularly in explaining the observed jet emission. In this study, we focus on electron positron pair production generated by high energy photons from non axisymmetric magnetic reconnection near the black hole, as suggested by recent three dimensional general relativistic magnetohydrodynamics simulations. By employing general relativistic ray tracing, we calculate the spatial distribution of the pair production rate in the jet, taking into account photon propagation and collision angles in curved spacetime. We find that our scenario can naturally supply a sufficient amount of plasma to explain the observed radio emission from the M87 jet, even when photon anisotropy is considered. Furthermore, we show that a spinning black hole plays a crucial role in shaping the spartial dsitribution of the pairs, which in turn affects jet acceleration and very high energy emission from the jet base.