Accretion of the Vlasov gas on Reissner-Nordström black holes (original) (raw)
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Accretion of the relativistic Vlasov gas in the equatorial plane of the Kerr black hole
Physical Review D
We investigate stationary accretion of the collisionless Vlasov gas onto the Kerr black hole, occurring in the equatorial plane. The solution is specified by imposing asymptotic boundary conditions: at infinity the gas obeys the Maxwell-Jüttner distribution, restricted to the equatorial plane (both in positions and momenta). In the vicinity of the black hole, the motion of the gas is governed by the spacetime geometry. We compute accretion rates of the rest-mass, the energy, and the angular momentum, as well as the particle number surface density, focusing on the dependence of these quantities on the asymptotic temperature of the gas and the black hole spin. The rest-mass and energy accretion rates, normalized by the black hole mass and appropriate asymptotic surface densities of the gas, increase with increasing asymptotic temperature. The accretion slows down the rotation of the black hole.
Physical Review D, 2021
The accretion of a spherically symmetric, collisionless kinetic gas cloud onto a Schwarzschild black hole is analyzed. Whereas previous studies have treated this problem by specifying boundary conditions at infinity, here the properties of the gas are given at a sphere of finite radius. The corresponding steady-state solutions are computed using four different models with an increasing level of sophistication, starting with the purely radial infall of Newtonian particles and culminating with a fully general relativistic calculation in which individual particles have angular momentum. The resulting mass accretion rates are analyzed and compared with previous models, including the standard Bondi model for a hydrodynamic flow. We apply our models to the supermassive black holes Sgr A* and M87*, and we discuss how their low luminosity could be partially explained by a kinetic description involving angular momentum. Furthermore, we get results consistent with previous model-dependent bounds for the accretion rate imposed by rotation measures of the polarized light coming from Sgr A* and with estimations of the accretion rate of M87* from the Event Horizon Telescope collaboration. Our methods and results could serve as a first approximation for more realistic black hole accretion models in various astrophysical scenarios in which the accreted material is expected to be nearly collisionless.
Relativistic Accretion into a Reissner-Nordström Black Hole Revisited
Journal of Thermodynamics, 2012
The accretion of relativistic and nonrelativistic fluids into a Reissner-Nordström black hole is revisited. The position of the critical point, the flow velocity at this point, and the accretion rate are only slightly affected with respect to the Schwarzschild case when the fluid is nonrelativistic. On the contrary, relativistic fluids cross the critical point always subsonically. In this case, the sonic point is located near the event horizon, which is crossed by the fluid with a velocity less than the light speed. The accretion rate of relativistic fluids by a Reissner-Nordström black hole is reduced with respect to those estimated for uncharged black holes, being about 60% less for the extreme case (charge-to-mass ratio equal to one).
Radial accretion flows on static spherically symmetric black holes
Classical and Quantum Gravity, 2015
We analyze the steady radial accretion of matter into a nonrotating black hole. Neglecting the selfgravity of the accreting matter, we consider a rather general class of static, spherically symmetric and asymptotically flat background spacetimes with a regular horizon. In addition to the Schwarzschild metric, this class contains certain deformation of it which could arise in alternative gravity theories or from solutions of the classical Einstein equations in the presence of external matter fields. Modeling the ambient matter surrounding the black hole by a relativistic perfect fluid, we reformulate the accretion problem as a dynamical system, and under rather general assumptions on the fluid equation of state, we determine the local and global qualitative behavior of its phase flow. Based on our analysis and generalizing previous work by Michel, we prove that for any given positive particle density number at infinity, there exists a unique radial, steady-state accretion flow which is regular at the horizon. We determine the physical parameters of the flow, including its accretion and compression rates, and discuss their dependency on the background metric.
Thermodynamic Analysis of Non-Linear Reissner-Nordström Black Holes
Universe, 2015
In the present article we study the Inverse Electrodynamics Model. This model is a gauge and parity invariant non-linear Electrodynamics theory, which respects the conformal invariance of standard Electrodynamics. This modified Electrodynamics model, when minimally coupled to General Relativity, is compatible with static and spherically symmetric Reissner-Nordström-like black-hole solutions. However, these black-hole solutions present more complex thermodynamic properties than their Reissner-Nordström black-hole solutions counterparts in standard Electrodynamics. In particular, in the Inverse Model a new stability region, with both the heat capacity and the free energy negative, arises. Moreover, unlike the scenario in standard Electrodynamics, a sole transition phase is possible for a suitable choice in the set of parameters of these solutions.
Monthly Notices of the Royal Astronomical Society, 2002
The equations governing general relativistic, spherically symmetric, hydrodynamic accretion of polytropic fluid on to black holes are solved in the Schwarzschild metric to investigate some of the transonic properties of the flow. Only stationary solutions are discussed. For such accretion, it has been shown that real physical sonic points may form even for flow with g , 4=3 or g. 5=3. The behaviour of some flow variables in the close vicinity of the event horizon is studied as a function of specific energy and the polytropic index of the flow.
Discharge of a Reissner-Nordström black hole within the event horizon
Physical Review D, 1994
ABSTRACT A simple model is constructed to illustrate candidate interior geometries for charged spherical black holes. The new feature of this model is the explicit consideration of the evolution of the electromagnetic field and charge distribution in the black-hole interior. The model is constructed by joining the Reissner-Nordström and Schwarzschild geometries along a spacelike hypersurface at a constant radius lying between the inner and outer horizon radii of the Reissner-Nordström geometry. This model represents an idealization in which the Schwinger pair creation rate is approximated as zero below a critical electric field value E0 and as infinity above the critical field value. The spacelike hypersurface on which the geometries are joined represents a sheet of current caused by the created charged pairs. This current eliminates the interior electromagnetic field, resulting in a final state for the black-hole interior which contains no Cauchy horizons, naked singularities, or "tunnels to elsewhere."
Acta Physica Polonica B
In this paper, we study the relativistic, steady state, optically thin, advection-dominated accretion disks around the rotating black holes. We study axisymmetric and vertically averaged disks. For shear stress viscosity, the exact relations of the four-velocity with no approximation are derived. We effort to derive the general and analytic relation for density, relativistic enthalpy, temperature, pressure and inertial energy. We use the radial model for the radial component of four-velocity. In the radial model, the figures of density etc. are plotted. The influences of shear and bulk coefficients and spin of the black hole etc. are studied.
Monthly Notices of the Royal Astronomical Society, 2011
Based on the numerical solution of the time-dependent relativistic Euler equations onto a fixed Schwarzschild background space-time, we estimate the accretion rate of radial flow toward the horizon of a test perfect fluid obeying an ideal gas equation of state. We explore the accretion rate in terms of the initial density of the fluid for various values of the inflow velocity in order to investigate whether or not sufficiently arbitrary initial conditions allow a steady state accretion process depending on the values of the pressure. We extrapolate our results to the case where the fluid corresponds to dark matter and the black hole is a supermassive black hole seed. Then we estimate the equation of state parameters that provide a steady state accretion process. We found that when the pressure of the dark matter is zero, the black hole's mass grows up to values that are orders of magnitude above 10 9 M ⊙ during a lapse of 10Gyr, whereas in the case of the accretion of the ideal gas dark matter with non zero pressure the accreted mass can be of the order of ∼ 1M ⊙ /10Gyr for black holes of 10 6 M ⊙ . This would imply that if dark matter near a supermassive black hole acquires an equation of state with non trivial pressure, the contribution of accreted dark matter to the supermassive black hole growth could be small, even though only radial accretion is considered.
Accretion onto a higher dimensional black hole
Phys. Rev. D 88, 104005 (2013)
We examine the steady-state spherically symmetric accretion of relativistic fluids, with a polytropic equation of state, onto a higher dimensional Schwarzschild black hole. The mass accretion rate, critical radius, and flow parameters are determined and compared with results obtained in standard four dimensions. The accretion rate, M˙, is an explicit function of the black hole mass, M, as well as the gas boundary conditions and the dimensionality, D, of the spacetime. We also find the asymptotic compression ratios and temperature profiles below the accretion radius and at the event horizon. This analysis is a generalization of Michel's solution to higher dimensions and of the Newtonian expressions of Giddings and Mangano which considers the accretion of TeV black holes.