Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: General relativistic rotational energy extraction from black
  holes-accretion disk systems   We constrain the BHs spin with the evaluation of the dimensionless parameter
\xi, the total rotational energy extracted versus the BH mass. 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 corotating and counter-rotating tori orbiting one
central Kerr SMBH, associating \xi to the accretion processes characteristics.
We relate the regions of tori parameters to the energy extraction processes,
binding \xi to properties of light surfaces by using the bundles, 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 the BH--accretion disk system observational characteristics.
The analysis points relevant BH spins a\approx0.94M, a\approx 0.7M and
a\approx0.3M. We show the relation between the rotational law of the tori, the
bundle characteristic frequency and the relativistic velocity defining the von
Zeipel surfaces. The inferior limit on the formation of corotating is
\ell/a\geq2, for counter-rotating tori \ell/a\leq -22/5 (\ell is the fluids
specific angular momentum).

21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn