High‐Energy Gamma‐Ray Emission from Galactic Kerr‐Newman Black Holes. I. The Central Engine

Abstract

A model of the central engine of the unidentiÐed high-latitude galactic hard c-ray (EGRET) sources based on black hole electrodynamics is presented. The c-ray emission is produced in a bipolar outÑow from a charged, rotating black hole (a Kerr-Newman black hole) in a low-density region of the Galaxy, the details of which are provided in a companion paper. The model proposed in this article and its companion is a synthesis of pair creation scenarios for pulsars, the theory of black hole magnetospheres and synchrotron self-Compton large-scale jets. This article describes the physics of the putative central engine. Kerr-Newman black holes are plausible endpoints of the catastrophic gravitational collapse of the most massive magnetized rotating stars. In the following, the ability of a Kerr-Newman black hole to drive a magnetically dominated plasma wind in the charge-starved limit is explored for the Ðrst time. Although there are important analogies to magnetohydrodynamic (MHD) wind theory of Kerr (uncharged rotating) black holes, there are also enormous distinctions. However, previous experience with the MHD Kerr case is exploited to render this more complicated problem tractable. The most important parameter for quantifying the wind energy is the magnetic Ðeld line angular velocity, (and)