General relativistic rotational energy extraction from black holes-accretion disk systems

Abstract

The determination of mass and spin parameters of the black holes (BHs) is crucial in the analysis of the merger of BHs and BHs formation and evolution, including accretion. Here we constrain the BH spin with the evaluation of the dimensionless parameter ξ representing the total rotational energy extracted versus the mass of the BH, following procedure introduced by Daly (2009 Astrophys. J. 691 L72–6) that is independent from the details of the specific extraction process. The energy extraction can power an outflow which can be then observed. We relate the energy extraction to the accreting configurations and the accretion processes occurring in a cluster of agglomerate corotating and counter-rotating tori orbiting one central Kerr SMBH, associating ξ to the characteristics of the accretion processes. We relate the regions of tori parameters to features of the energy extraction processes, binding ξ to properties of light surfaces by using the bundles developed by Pugliese and Quevedo (2019 Eur. Phys. J. C 79 209), relating measures in different regions of the spacetimes. We evaluate properties of the BH accretions disks, and correlate spacetimes prior and after their transition due to the energy extraction. Light surfaces are related to the generators of Killing horizons, proving limiting frequency of the stationary observers of the geometries. We consider the photon limiting curves of the stationary observers as constraints for various processes regulated by these frequencies, to relate different BH states, prior and after the energy extraction, investigating regions close to the BH horizons and rotational axis. From methodological view-point we used a naked singularity—BH correspondence defined with metric bundles to predict observational characteristics of the BH—accretion disk system. The analysis points relevant BH spins a ≈ 0.94M, a ≈ 0.7M and a ≈ 0.3M. We show the relation between the rotational law of the tori, the characteristic frequency of the bundle and the relativistic velocity defining the von Zeipel surfaces. The inferior limit on the formation of corotating tori is ℓ/a ⩾ 2, for counter-rotating tori ℓ/a ⩽ −22/5 (ℓ is the fluids specific angular momentum).

Limiting effects in tori clusters

“…Evaluation of these quantities defined in Table (1) are in Figs 2 as functions of the BH dimensionless rotational energy for different models, fixed according to selected values of the fluid specific angular momentum (fixing the cusp location and the center of maximum density) and the K s ∈]K × , 1[, fixing the flow thickness at the cusp 34 .…”

“…Thee BH dimensionless spin is a In Figs 2 and Figs 3 the tori aggregates energetic characteristics at the state 0, prior a possible process involving the BH and its environment, are related to the BH rotational energy. The energetic parameter ξ and the angular relativistic velocity of the BH determine the BH state prior the transition- [34][35][36] . This analysis turns particularly relevant for the RAD model which, because of its inner discrete structure, can be characterized by phases of enhanced accretion rates.…”

Extracting information on black hole horizons

“…Such photon orbits are shown to exist especially in regions close to the BH rotational axis. We interpret the results in the more general framework of metric bundles (MBs), introduced in [14,15,16,17,18,19,4] and connected to the structures considered in [9,10,12,8], and [5,20] and [13,21,22].…”

Analysis of accretion disk around a black hole in dRGT massive gravity

“…The other studies can be found in the Refs. [36][37][38][39][40][41] This way, we look at different aspects of this issue. Gamma ray bursts (GRBs) are outbursts of huge energy in order of 1% of the solar mass, while this energy only lasts seconds [42,43].…”