Study of Einstein-bumblebee gravity with Kerr-Sen-like solution in the presence of a dispersive medium

TL;DR

This paper investigates the effects of Lorentz violation and plasma on photon trajectories, energy emission, and gravitational lensing around a Kerr-Sen-like black hole in Einstein-bumblebee gravity, with implications for observational constraints.

Contribution

It introduces a Kerr-Sen-like black hole solution with Lorentz violation in Einstein-bumblebee gravity and analyzes photon orbits, energy emission, and deflection angles in a dispersive medium.

Findings

Lorentz violation and plasma significantly affect photon orbits and deflection angles.

Constraints on Lorentz violation parameters are derived from EHT observations.

Energy emission rates are influenced by both Lorentz violation and plasma parameters.

Abstract

A Kerr-Sen-like black hole solution appears in the Einstein-bumblebee theory of gravity. The solution contains contains a Lorentz violating parameter in an explicit manner. We study the null geodesics in the background of this Kerr-Sen-like black hole surrounded by a dispersive medium like plasma. We investigate the effect of the charge of the black hole, the Lorentz violation parameter, and the plasma parameter on the photon orbits with the evaluation of the effective potential in the presence of both the Lorentz violation parameter and the plasma parameter. We also study the influence of the Lorentz violation parameter and plasma parameter on the emission of energy from the black hole due to thermal radiation. Besides, we compute the angle of deflection of massless particles with weak-field approximation in this generalized situation and examine how it varies with the Lorentz violation parameter in presence of plasma. Constraining the parameters of this Lorentz violating Kerr-Sen-like black hole is also attempted here with the result obtained from the observations of the Event Horizon Telescope (EHT) collaboration.