Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An analytic toy model for relativistic accretion in Kerr spacetime   We present a relativistic model for the stationary axisymmetric accretion
flow of a rotating cloud of non-interacting particles falling onto a Kerr black
hole. Based on a ballistic approximation, streamlines are described
analytically in terms of timelike geodesics, while a simple numerical scheme is
introduced for calculating the density field. A novel approach is presented for
describing all of the possible types of orbit by means of a single analytic
expression. This model is a useful tool for highlighting purely relativistic
signatures in the accretion flow dynamics coming from a strong gravitational
field with frame-dragging. In particular, we explore the coupling due to this
between the spin of the black hole and the angular momentum of the infalling
matter. Moreover, we demonstrate how this analytic solution may be used for
benchmarking general relativistic numerical hydrodynamics codes by comparing it
against results of smoothed particle hydrodynamics simulations for a
collapsar-like setup. These simulations are performed first for a ballistic
flow (with zero pressure) and then for a hydrodynamical one where we measure
the effects of pressure gradients on the infall, thus exploring the extent of
applicability of the ballistic approximation.

27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int