Weak gravitational lensing and shadow cast by rotating black holes in axionic Chern-Simons theory
Abstract
We investigate the impact of the axionic coupling parameter on the bending angle of light and the shadow cast by slowly rotating black holes in Chern-Simons modified gravity. We utilize the Ishihara \etal method to derive the deflection angle of light for an observer and source located at finite distances from a lens object in an asymptotically flat spacetime, using the Gauss-Bonnet theorem. The deflection angle exhibits an increasing trend up to a certain point, followed by a decrease as a function of the impact parameter, with the presence of the axion matter field causing the observed increase. Additionally, we calculate the Einstein ring radius as a direct application of the weak deflection angle. We also investigate the effect of the axion matter field on the time delay of light and analyze its impact on the shadow cast by slowly rotating black holes. Our findings reveal a significant effect of the axionic coupling parameter on the black hole's shadow.
Keywords
Cite
@article{arxiv.2305.09157,
title = {Weak gravitational lensing and shadow cast by rotating black holes in axionic Chern-Simons theory},
author = {Nashiba Parbin and Dhruba Jyoti Gogoi and Umananda Dev Goswami},
journal= {arXiv preprint arXiv:2305.09157},
year = {2023}
}
Comments
18 pages and 9 figures. Published in Physics of the Dark Universe