Study of energy extraction and epicyclic frequencies in Kerr-MOG (modified gravity) black hole

The mass-energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and the expression for the irreducible mass of a static black hole. It is shown that the efficiency of energy extraction process during the formation of the black hole is linked in an essential way to the gravitational binding energy, the formation of the horizon and the reduction of the kinetic energy of implosion. Here a maximum efficiency of 50% in the extraction of the mass energy is shown to be generally attainable in the collapse of a spherically symmetric shell: surprisingly this result holds as well in the two limiting cases of the Schwarzschild and extreme Reissner–Nordström space–times. Moreover, the analytic expression recently found for the implosion of a spherical shell to an already formed black hole leads to a new exact analytic expression for the energy extraction which results in an efficiency strictly less than 100% for any physical implementable process. There appears to be no incompatibility between General Relativity and Thermodynamics at this classical level.

Download Full-text

Neutral Particle Motion around a Schwarzschild Black Hole in Modified Gravity

Journal of Experimental and Theoretical Physics ◽

10.1134/s1063776118090182 ◽

2018 ◽

Vol 127 (3) ◽

pp. 491-502 ◽

Cited By ~ 3

Author(s):

M. Sharif ◽

Misbah Shahzadi

Keyword(s):

Black Hole ◽

Particle Motion ◽

Modified Gravity ◽

Neutral Particle ◽

Schwarzschild Black Hole

Download Full-text

An exact solution for a rotating black hole in modified gravity

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2018/01/033 ◽

2018 ◽

Vol 2018 (01) ◽

pp. 033-033 ◽

Cited By ~ 12

Author(s):

Francesco Filippini ◽

Gianmassimo Tasinato

Keyword(s):

Exact Solution ◽

Black Hole ◽

Modified Gravity ◽

Rotating Black Hole

Download Full-text

Evidence of Spin and Energy Extraction in a Galactic Black Hole Candidate: The [ITAL]XMM-Newton[/ITAL]/EPIC-[CLC]pn[/CLC] Spectrum of XTE J1650−500

The Astrophysical Journal ◽

10.1086/341099 ◽

2002 ◽

Vol 570 (2) ◽

pp. L69-L73 ◽

Cited By ~ 147

Author(s):

J. M. Miller ◽

A. C. Fabian ◽

R. Wijnands ◽

C. S. Reynolds ◽

M. Ehle ◽

...

Keyword(s):

Black Hole ◽

Energy Extraction ◽

Black Hole Candidate ◽

Galactic Black Hole

Download Full-text

Physics of black hole binaries: Geodesics, relaxation modes, and energy extraction

Physical Review D ◽

10.1103/physrevd.100.044002 ◽

2019 ◽

Vol 100 (4) ◽

Cited By ~ 8

Author(s):

Laura Bernard ◽

Vitor Cardoso ◽

Taishi Ikeda ◽

Miguel Zilhão

Keyword(s):

Black Hole ◽

Energy Extraction ◽

Black Hole Binaries ◽

Relaxation Modes

Download Full-text

Effect of charge and deformation parameter on energy extraction in charged non-Kerr black holes

International Journal of Modern Physics D ◽

10.1142/s021827182040012x ◽

2019 ◽

Vol 28 (16) ◽

pp. 2040012

Author(s):

Rehana Rahim ◽

Khalid Saifullah

Keyword(s):

Black Holes ◽

Black Hole ◽

Deformation Parameter ◽

High Efficiency ◽

Process Efficiency ◽

Energy Extraction ◽

Penrose Process ◽

Kerr Black Holes ◽

Very High

We analyze the charged Johannsen–Psaltis black hole for energy extraction via the Penrose process. Efficiency of the Penrose process is found to be dependent on the deformation parameter of the metric and charge. Doing the calculations numerically, we find that, in the nonextremal limit, presence of charge leads to lesser efficiency than the Kerr. In the extremal cases with negative deformation parameter, charge leads to a very high efficiency, higher than that of the Kerr and Johannsen–Psaltis black holes.

Download Full-text