Observational optical constraints of regular black holes

Jafarzade, Khadije; Zangeneh, M. Kord

doi:10.1016/j.aop.2022.169126

Cited by 9 publications

(1 citation statement)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Simpson-Visser spacetime has an interesting feature, namely that the areal radii of the event horizon, the photon sphere, and the shadow are completely independent of parameter g, but the proper distance between these surfaces is g-dependent (Lima et al 2021). Several studies have been done on the observational features of Simpson-Visser black hole spacetime, namely gravitational lensing (Tsukamoto 2021;Ghosh & Bhattacharyya 2022), the black hole shadow (Jafarzade et al 2022;Lima et al 2021;Shaikh et al 2021), the optical appearance of a thin accretion disk (Guerrero et al 2021;Bambhaniya et al 2022), and quasi-periodic oscillations (Jiang et al 2021). Although, for a = 0, the black hole horizons disappear for g > g E = 2.0M, the prograde and retrograde photon orbits exist for g 3.0M and lead to a closed photon ring structure.…”

Section: Simpson-visser Spacetimementioning

confidence: 99%

Testing Rotating Regular Metrics with EHT Results of Sgr A*

Kumar

Ghosh

Maharaj

2022

ApJ

View full text Add to dashboard Cite

The Event Horizon Telescope (EHT) observation unveiled the first image of supermassive black hole Sgr A* showing a shadow of diameter θ sh = 48.7 ± 7 μas with fractional deviation from the Schwarzschild black hole shadow diameter δ = − 0.08 − 0.09 + 0.09 ( VLTI ) , − 0.04 − 0.10 + 0.09 ( Keck ) . The Sgr A* shadow size is within 10% of the Kerr predictions, providing us with another tool to investigate the nature of strong-field gravity. We use the Sgr A* shadow observables to constrain metrics of four independent and well-motivated, parametrically different from Kerr spacetime, rotating regular spacetimes and the corresponding no-horizon spacetimes. We present constraints on the deviation parameter g of rotating regular black holes. The shadow angular diameter θ sh within the 1σ region places bounds on the parameters a and g. Together with EHT bounds on the θ sh and δ of Sgr A*, our analysis concludes that the three rotating regular black holes, i.e., Bardeen, Hayward, and Simpson–Visser black holes, and corresponding no-horizon spacetimes agree with the EHT results of Sgr A*. Thus, these three rotating regular spacetimes and Kerr black holes are indiscernible in some parameter space, and one cannot rule out the possibility of the former being strong candidates to be astrophysical black holes.

show abstract