Kerr-Newman Black Holes in Weyl-Cartan Theory: Shadows and EHT constraints

TL;DR

This paper investigates Kerr-Newman black holes within Weyl-Cartan theory by analyzing their shadows and EHT constraints, aiming to distinguish this theory from general relativity and understand black hole evolution.

Contribution

It introduces a novel analysis of Kerr-Newman black holes in Weyl-Cartan theory using shadow observations and emission rates, providing new constraints on the theory's parameters.

Findings

Shadow sizes consistent with EHT observations for certain parameters

Model parameters influence particle emission rates

Black hole lifetime estimates within Weyl-Cartan theory

Abstract

With the recent release of the black hole image of Sgr A* alongside the earlier image of M87*, one can achieve an in-depth understanding of gravitational physics at the horizon scale. According to the Event Horizon Telescope (EHT) collaboration, the observed image is consistent with the expected appearance of a Kerr black hole. In the present work, we consider Kerr-Newman black holes in Weyl-Cartan theory as a supermassive black hole (BH) and evaluate the parameters of the model with shadow size estimates done by the observations of M87* and Sgr A* from EHT. Such a study can be a possible way to distinguish Weyl-Cartan theory from general relativity and ensure the validity of the idea. Besides, we calculate the energy emission rate for the corresponding BH and discuss how the model's parameters affect the emission of particles around the black hole. With this investigation, we are able to examine the time evolution and lifetime of the black hole in such a theory of gravity.