Testing Symmergent gravity through the shadow image and weak field photon deflection by a rotating black hole using the M87$^*$ and Sgr. A$^*$ results

Abstract

Motivated by recent work on the Symmergent black hole [Phys. Dark Univ. 10.1016/j.dark.2021.100900, 2021, here we study spinning black holes in Symmergent gravity, with spin parameter a. The goal is to uncover the deviations caused by the Symmergent gravity parameters relative to the known Kerr solution. To this aim, we first investigate the deviations in the photon sphere and shadow size. The EHT data was used to find constraints to cO that fit well in M87* within ±1σ than in Sgr. A*. We also found that depending on the sign of the quadratic curvature coefficient cO, the increase in photon radius results in a decrease in shadow radius. Exploring the Symmergent effects on the geodesics of time-like particles, we find that these are more sensitive to the effects than null particles. To broaden the scope of the study, we also analyzed the weak field limit of the deflection angles, where we used the Gauss-Bonnet theorem with the consideration of the finite distance of the source and the receiver to the lensing object. We have shown how the Symmergent gravity parameter cO, which is proportional to the number difference between fermions and bosons affects the deflection angle. Remarkably, the distance of the receiver (or source) greatly affects the angle. Finally, we also analyze the Symmergent gravity effects on the rotating black hole as it acts as a particle accelerator.

Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

“…Werner then improved this method for rotating spacetimes such as Kerr black hole [78]. Afterwards, this method was applied to various asymptotically flat spacetimes and was also extended to non-asymptotically flat spacetimes [39][40][41][42][43][44][45][46][47][48][79][80][81][82][83][84][85][86][87][88][89][90][91][92].…”

Poincaré Breaking and Gauge Invariance: A Road to Emergent Gravity and New Particles

“…One such effect is the Starobinsky inflation, and seems to require n b − n f ≈ 10 13 [54]. One other effect concerns the black holes, which put limits [55,56,57] on c O and the vacuum energy V (µ) through the EHT observations [58].…”

Gauge and Poincaré properties of the UV cutoff and UV completion in quantum field theory

“…In addition, symmergent gravity itself may realize a quantum cosmology phase [91]. One other effect concerns the black holes, which put limits [92][93][94][95] on c O and the vacuum energy V (µ) through the EHT observations [96]. Effects of c O on stellar structure and wormhole dynamics can also be significant.…”