Testing the Metric-Affine Gravity Using Particle Dynamics and Photon Motion

TL;DR

This paper investigates the optical properties of black holes within metric-affine gravity, analyzing how dilation, spin, and shear charges influence phenomena like shadows, lensing, and photon orbits.

Contribution

It introduces a detailed analysis of black hole optical features in metric-affine gravity considering dilation, spin, and shear charges, highlighting their effects on observable phenomena.

Findings

Dilation, spin, and shear charges significantly affect black hole shadows.

Photon sphere radius varies with different charge parameters.

Gravitational lensing and image magnification are influenced by the charges.

Abstract

This work mainly focuses to unveil the optical features of a black hole. For this objective, we utilize the metric-affine black hole geometry with the inclusion of dilation, spin, and shear charge. The Lagrangian coefficients $f_1$ and $d_1$ are the main parameters, where $f_1<0$, which differentiate the solutions by $d_1=8f_1,\;d_1=-8f_1,\;\&\;d_1=\pm8f_1$. Based on these parameters, we carry out this work in two cases, i.e., $d_1=8f_1,\;\&\;d_1=-8f_1$. We forecast the detailed impact of dilation, spin, and shear charges on the optical properties of the black holes in both cases. To unreveal the optical features, we calculate horizon radius, inner stable circular orbit, photon sphere radius, BH shadows, quasi-periodic oscillations, the red-blue shift of photon particles, effective force, weak gravitational lensing, and image magnification by using metric-affine gravity black hole geometry.