Perturbation of mass accretion rate, associated acoustic geometry and stability analysis

Bollimpalli, D. A.; Bhattacharya, Sourav; Das, Tapas K.

doi:10.1016/j.newast.2016.09.001

Cited by 23 publications

(30 citation statements)

References 41 publications

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“…Moreover, we did not address this question from the point of view of an analytical stability analysis. Such analysis was provided by Moncrief (1980) for the spherical accretion onto non-rotating black hole and quite recently by Bollimpalli et al (2017) for low angular momentum flow with standing shocks, who also report the stability of the solution.…”

Section: Discussionmentioning

confidence: 96%

Shocks in the relativistic transonic accretion with low angular momentum

Suková

Charzyński

Janiuk

2017

Monthly Notices of the Royal Astronomical Society

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We perform 1D/2D/3D relativistic hydrodynamical simulations of accretion flows with low angular momentum, filling the gap between spherically symmetric Bondi accretion and disc-like accretion flows. Scenarios with different directional distributions of angular momentum of falling matter and varying values of key parameters such as spin of central black hole, energy and angular momentum of matter are considered. In some of the scenarios the shock front is formed. We identify ranges of parameters for which the shock after formation moves towards or outwards the central black hole or the long lasting oscillating shock is observed. The frequencies of oscillations of shock positions which can cause flaring in mass accretion rate are extracted. The results are scalable with mass of central black hole and can be compared to the quasi-periodic oscillations of selected microquasars (such as GRS 1915+105, XTE J1550-564 or IGR J17091-3624), as well as to the supermassive black holes in the centres of weakly active galaxies, such as Sgr A * .

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Section: Discussionmentioning

confidence: 96%

Shocks in the relativistic transonic accretion with low angular momentum

Suková

Charzyński

Janiuk

2017

Monthly Notices of the Royal Astronomical Society

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“…where H θ is the characteristic angular scale of the flow. Thus the continuity equation for vertically averaged axially symmetric accretion can be written as [15,17,65] ∂ t (ρv t −gH θ ) + ∂ r (ρv r −gH θ ) = 0 (13) whereg is the value of g, the determinant of the background metric g µν , on the equatorial plane. For Kerr metric g = − sin 2 θA 2 and thusg = −r 4 .…”

Section: Disc Structurementioning

confidence: 99%

“…For simplicity, therefore, we will write H θ simply as H 0 . Further details on different flow geometries can be found in [13,15,17]. From now on all the equations will be derived by assuming the flow to be vertically averaged and the variables have values equal to that in the equatorial plane.…”

Section: Disc Structurementioning

confidence: 99%

Relativistic sonic geometry for isothermal accretion in the Kerr metric

Shaikh

2018

Class. Quantum Grav.

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We linearly perturb advective isothermal transonic accretion onto rotating astrophysical black holes to study the emergence of the relativistic acoustic spacetime and to investigate how the salient features of such spacetime get influenced by the spin angular momentum of the black hole. We have perturbed three different quantities -the velocity potential, the mass accretion rate and the relativistic Bernoulli's constant to show that the acoustic metric obtained for these three cases are same up to a conformal factor . By constructing the required causal structures, it has been demonstrated that the acoustic black holes are formed at the transonic points of the flow and acoustic white holes are formed at the shock location. The corresponding acoustic surface gravity has been computed in terms of the relevant accretion variables and the background metric elements. The linear stability analysis of the background stationary flow has been performed.

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“…Now the perturbation on the stationary flow is done by following standard linear perturbation analysis [10,11,45,46] where acoustic space-time metric for conical flow was derived. Time-dependent accretion variables, like the components of four velocity and pressure are written as small time-dependent linear perturbations added their stationary values.…”

Section: Derivation Of Acoustic Metric From Linear Perturbation Of Fl...mentioning

confidence: 99%

Carter-Penrose diagrams for emergent spacetime in axisymmetrically accreting black hole systems

Maity,

Shaikh,

Tarafdar

et al. 2021

Preprint

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For general relativistic, inviscid, axisymmetric flow around Kerr black hole, one may choose different flow thickness. The stationary flow equations can be solved using methods of dynamical system to get transonic accretion flows, i.e, flow infalling in the black hole that turns supersonic from subsonic with decreasing radial distance, or vice versa. These transonic flows are obtained by choosing the particular flow passing through critical points of the phase portrait. For certain flow thickness like the one maintaining conical shape, the sonic point coincides with the critical point. But there are certain flows maintaining hydrostatic equilibrium, such as the one described by Novikov-Thorne, where the sonic point is not the same as the critical point. We perturb the flow for both kind of flow and study the behaviour of linear perturbation which behaves like a massless scalar field in some curved spacetime, known as analogue space-time. We draw the compactified causal structure, i.e, Penrose Carter diagram for both kind of analogue metric and prove that for both cases critical points are the acoustic horizons, whereas in the case where sonic points do not coincide with critical points, the sonic points are not the acoustic horizon, as one may expect from the definition of sound speed.

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Perturbation of mass accretion rate, associated acoustic geometry and stability analysis

Cited by 23 publications

References 41 publications

Shocks in the relativistic transonic accretion with low angular momentum

Shocks in the relativistic transonic accretion with low angular momentum

Relativistic sonic geometry for isothermal accretion in the Kerr metric

Carter-Penrose diagrams for emergent spacetime in axisymmetrically accreting black hole systems

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