Shadow from a rotating black hole in an extended gravity

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040060
Author(s):  
Vjacheslav Prokopov ◽  
Stanislav Alexeyev
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Rotating Black Hole ◽  
Extended Gravity ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories

We focus on the consequences of that the Event Horizon Telescope obtained images of the black hole shadow in the center of the M87 galaxy. We show that to test extended theories of gravity the improving of the resolution by 3 orders is necessary. In addition it is demonstrated that the rotation distorts the shape of the shadow and corrections from the extended gravity may affect on this distortion.

On embeddings of the Kerr geometry

1981 ◽  
Vol 59 (5) ◽  
pp. 688-692 ◽  
Author(s):  
Nigel A. Sharp
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Equatorial Plane ◽  
Kerr Metric ◽  
Intrinsic Structure ◽  
Kerr Geometry ◽  
Rotating Black Hole ◽  
Isometric Embeddings

The use of isometric embeddings of curved geometries reveals their intrinsic structure in a way that is readily appreciated. This is done for 3 two-surfaces sliced from the Kerr metric which describes a rotating black hole: the equatorial plane, the event horizon, and the ergosurface.

scholarly journals Quantum-Gravitational Trans-Planckian Energy of a Time-Dependent Black Hole

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1303
Author(s):  
A. J. Nurmagambetov ◽  
I. Y. Park
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Black Hole Solution ◽  
Energy Analysis ◽  
Scaling Behavior ◽  
Time Dependent ◽  
Higgs Potential ◽  
Rotating Black Hole ◽  
Basic Features

We continue our recent endeavor in which a time-dependent black hole solution of a one-loop quantum-corrected Einstein-scalar system was obtained and its near-horizon behavior was analyzed. The energy analysis led to a trans-Planckian scaling behavior near the event horizon. In the present work, the analysis is extended to a rotating black hole solution of an Einstein–Maxwell-scalar system with a Higgs potential. Although the analysis becomes much more complex compared to that of the previous, we observe the same basic features, including the quantum-gravitational trans-Planckian energy near the horizon.

scholarly journals Estimate of the superradiance spectrum in dispersive media

2020 ◽  
Vol 378 (2177) ◽  
pp. 20190236 ◽  
Author(s):  
Theo Torres
Keyword(s):  
Black Hole ◽  
Reflection Coefficient ◽  
Event Horizon ◽  
Vortex Flow ◽  
Theoretical Description ◽  
Dispersive Media ◽  
Next Generation ◽  
Rotating Black Hole ◽  
Analogue Gravity ◽  
The Many

In 2016, the Nottingham group detected the rotational superradiance effect. While this experiment demonstrated the robustness of the superradiance process, it still lacks a complete theoretical description due to the many effects at stage in the experiment. In this paper, we shine new light on this experiment by deriving an estimate of the reflection coefficient in the dispersive regime by means of a Wentzel–Kramers–Brillouin analysis. This estimate is used to evaluate the reflection coefficient spectrum of counter-rotating modes in the Nottingham experiment. Our finding suggests that the vortex flow in the superradiance experiment was not purely absorbing, contrary to the event horizon of a rotating black hole. While this result increases the gap between this experimental vortex flow and a rotating black hole, it is argued that it is in fact this gap that is the source of novel ideas. This article is part of a discussion meeting issue ‘The next generation of analogue gravity experiments’.

Sign in / Sign up

Export Citation Format

Share Document