Testing dynamical torsion effects on the charged black hole's shadow, deflection angle and greybody with M87*and Sgr. A* from EHT

Poincare Gauge's theory of gravity is the most noteworthy alter-native extension of general relativity that has a correspondence between spin and spacetime geometry. In this paper, we use Reissner-Nordstrom-de Sitter and anti-de Sitter solutions, where torsion Tau is added as an independent field, to analyze the weak deflection angles alpha circumflex accent of massive and null particles in finite distance regime. We then apply alpha circumflex accent to determine the Einstein ring formation in M87* and Sgr. A* and determine that relative to Earth's location from these black holes, massive torsion effects can provide considerable deviation, while the cosmological con-stant's effect remains negligible. Furthermore, we also explore how the torsion parameter affects the shadow radius perceived by both static and co-moving (with cosmic expansion) observers in a Universe dominated by dark energy, matter, and radiation. Our findings indicate that torsion and cosmological constant parameters affect the shadow radius differently between ob-servers in static and co-moving states. We also show how the torsion parameter affects the luminosity of the photonsphere by studying the shadow with infalling accretion. The calculation of the quasinormal modes, greybody bounds, and high-energy ab-sorption cross-section are also affected by the torsion parameter considerably.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this paper, the Poincare Gauge theory of gravity is used to analyze the effects of torsion on black holes by studying the deflection angles and shadow radius. The study also explores the impact of torsion on the luminosity of the photonsphere and other properties of black holes. The findings suggest that the torsion parameter plays a significant role in these phenomena.