Testing Born–Infeld f(T) teleparallel gravity through Sgr $$\hbox {A}^\star $$ observations

Abstract

We use observational data from the S2 star orbiting around the Galactic Center to constrain a black hole solution of extended teleparallel gravity models. Subsequently, we construct the shadow images of Sgr $$\hbox {A}^{\star }$$ A ⋆ black hole. In particular, we constrain the parameter $$\alpha =1/\lambda $$ α = 1 / λ which appears in the Born–Infeld f(T) model. In the strong gravity regime we find that the shadow radius increases with the increase of the parameter $$\alpha $$ α . Specifically, from the S2 star observations, we find within $$1\sigma $$ 1 σ that the parameter must lie between $$0 \le \alpha /M^2 \le 6 \times 10^{-4}$$ 0 ≤ α / M 2 ≤ 6 × 10 - 4 . Consequently, we used the best fit parameters to model the shadow images of Sgr $$\hbox {A}^{\star }$$ A ⋆ black hole and then using the Gauss-Bonnet theorem we analysed the deflection angle for leading order expansions of the parameter $$\alpha $$ α . It is found that within the parameter range, these observables are very close to the Schwarzschild case. Furthermore, using the best fit parameters for the Born–Infeld f(T) model we show that the angular diameter is consistent with recent observations for the Sgr $$\hbox {A}^{\star }$$ A ⋆ with angular diameter $$(51.8 \pm 2.3) \mu $$ ( 51.8 ± 2.3 ) μ arcsec and difficult to be distinguished from the GR. For the deflection angle of light, in leading order terms, we find that the deflection angle expressed in the ADM mass coincides with the GR, but the ADM mass in the Born–Infeld f(T) gravity increases with the increase of $$\alpha $$ α and the overall deflection angle is expected to me greater in f(T) gravity. As a consequence of this fact, we have shown that the electromagnetic intensity observed in shadow images is smaller compared to GR.

Black hole shadow and chaos bound violation in f(T) teleparallel gravity

“…In principle, such a a violation of MSS bound in f (T ) teleparallel gravity could be tested in forthcoming BH shadow and GW detections. Phenomenology and possible matching with observational data, see for example [31], will be the argument of a forthcoming study.…”

“…1 See Refs. [25][26][27][28][29][30][31][32][33] for several recent works on BH shadow and QNMs beyond GR.…”

Quantum effects on the black hole shadow and deflection angle in the presence of plasma*

“…Further, we aim to evalute the effect of the plasma medium on the optical images of the RGI BH. To achieve this goal, we use the backward raytracing technique [50,[63][64][65][66][67][68]. In this technique, for the given image, one has to compute the specific intensity, , observed at some distance from the BH [64] {γ, Ω} Fig.…”

“…[35][36][37][38][39][40][41][42][43][44][45][46][47][48]. More recently, new observations made by the EHT team on the shadow of the Sgr A BH [49] have also spurred interest in further analytical studies on BH and wormhole shadow models [50][51][52][53][54][55][56].…”

Dark matter spike around Bumblebee black holes

“…BHs can be characterized by various features, including a photon sphere radius consisting of orbiting light rays. Additionally, light rays can be categorized as unstable or stable based on whether they can fall or escape to infinity, respectively [11,12]. The astronomical survey carried out by the Event Horizon Telescope (EHT) team revealed that the bright accretion disk encircling the SMBH M87 appears distorted, which is believed to be caused by the phenomenon of GL.…”