The Quantum Mass Spectrum of the Kerr Black Hole

In this paper, the merger rate of black holes in a cluster of primordial black holes (PBHs) is investigated. The clusters have characteristics close to those of typical globular star clusters. A cluster that has a wide mass spectrum ranging from 10−2 to 10M⊙ (Solar mass) and contains a massive central black hole of the mass M•=103M⊙ is considered. It is shown that in the process of the evolution of cluster, the merger rate changed significantly, and by now, the PBH clusters have passed the stage of active merging of the black holes inside them.

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Influence of the geometric configuration of accretion flow on the black hole spin dependence of relativistic acoustic geometry

International Journal of Modern Physics D ◽

10.1142/s0218271818500232 ◽

2018 ◽

Vol 27 (03) ◽

pp. 1850023 ◽

Cited By ~ 2

Author(s):

Pratik Tarafdar ◽

Tapas K. Das

Keyword(s):

Black Hole ◽

Kerr Black Hole ◽

Geometric Configuration ◽

Surface Gravity ◽

Linear Perturbation ◽

Flow Profile ◽

White Hole ◽

Accretion Flow ◽

Black Hole Spin ◽

General Relativistic

Linear perturbation of general relativistic accretion of low angular momentum hydrodynamic fluid onto a Kerr black hole leads to the formation of curved acoustic geometry embedded within the background flow. Characteristic features of such sonic geometry depend on the black hole spin. Such dependence can be probed by studying the correlation of the acoustic surface gravity [Formula: see text] with the Kerr parameter [Formula: see text]. The [Formula: see text]–[Formula: see text] relationship further gets influenced by the geometric configuration of the accretion flow structure. In this work, such influence has been studied for multitransonic shocked accretion where linear perturbation of general relativistic flow profile leads to the formation of two analogue black hole-type horizons formed at the sonic points and one analogue white hole-type horizon which is formed at the shock location producing divergent acoustic surface gravity. Dependence of the [Formula: see text]–[Formula: see text] relationship on the geometric configuration has also been studied for monotransonic accretion, over the entire span of the Kerr parameter including retrograde flow. For accreting astrophysical black holes, the present work thus investigates how the salient features of the embedded relativistic sonic geometry may be determined not only by the background spacetime, but also by the flow configuration of the embedding matter.

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