Energy of a photon emitted from a charged particle orbiting an extremely charged spherically symmetric black hole

Abstract

The radiation emitted by a charged particle moving in a charged black hole is examined in the present work. By treating the emitted radiation as photons along null geodesics we calculate the photon's energy shift which quantifies the photon's energy as it propagates from the vicinity of a charged black hole to an observer at infinity. This energy shift also includes the Doppler effects arising from the charged particle's motion. For an extreme case, where the black hole's charge Q is equal to its mass M, we find that the usual circular nature of the particle's orbit could be turned off for a specific values of the particle's charge-to-mass ratio ϵ.