Related papers: Transonic properties of the accretion disk around …
We explore the global structure of the accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. The accretion flow is optically thin and advection dominated. Synchrotron radiation is…
Here we furnish a pseudo-Newtonion potential for accretion disk modeling around rotating central objects having hard sueface. That means, the potential may be useful to describe the accretion disk around rotating neutron stars and strange…
These notes introduce and review some of the physical principles underlying the theory of astrophysical accretion, emphasizing the central roles of angular momentum transport, angular momentum loss, and radiative cooling in determining the…
(abridged) Accretion from disks onto young stars is thought to follow magnetic field lines from the inner disk edge to the stellar surface. The accretion flow thus depends on the geometry of the magnetic field. This paper extends previous…
We present global solutions that describe advection-dominated accretion flows around black holes. The solutions are obtained by numerically solving a set of coupled ordinary differential equations corresponding to a steady axisymmetric…
Nonlinear time-dependent calculations have been carried out in order to study the evolution of the thermal instability for optically thick, transonic, slim accretion discs around black holes. In the present calculations we have investigated…
Matter falling onto a black hole is trans-relativistic, transonic, and close to the horizon it is sub-Keplerian. Such a flow shows the existence of multiple critical point, shocks etc. Employing relativistic equation of state and realistic…
Accretion onto a compact object must occur through a disc when the material has some initial angular momentum. Thin discs and the thicker low radiative efficiency accretion flows are solutions to this problem that have been widely studied…
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…
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during which the angular momentum of the disk at large scales is…
A number of `modified' Newtonian potentials of various forms are available in the literature which accurately approximate some general relativistic effects important for studying accretion discs around a Schwarzschild black hole. Such…
Transonic accretion onto astrophysical objects is a unique example of analogue black hole realized in nature. In the framework of acoustic geometry we study axially symmetric accretion and wind of a rotating astrophysical black hole or of a…
We study the general relativistic transonic accretion flow around the primary black hole, which forms the circumprimary disc (CPD), within a binary black hole (BBH) system. The BBH spacetime is characterized by the mass ratio ($q$) and the…
The secular evolution of the purely general relativistic low angular momentum accretion flow around a spinning black hole is shown to exhibit hysteresis effects. This confirms that a stationary shock is an integral part of such an accretion…
We provide complete and global solutions of transonic flows around black holes, in presence of advection, rotation, heating and cooling. We show that for any degree of advection, there may exist two critical viscosity parameters…
We give the formulation and the general analysis of the rotational accretion problem on $D$-dimensional spherical spacetime and investigate sonic points and critical points. First, we construct the simple two-dimensional rotating accretion…
We use three dimensional magnetohydrodynamic simulations, in a pseudo-Newtonian potential, to study geometrically thin accretion disc flows crossing the marginally stable circular orbit around black holes. We concentrate on vertically…
We present a set of new characteristic frequencies associated with accretion disks around compact objects. These frequencies arise from persistent rotating patterns in the disk that are finite in radial extent and driven purely by the…
Theoretical models have long predicted the existence of shocks in multi-transonic accretion flows onto a black hole, yet their fate under realistic general relativistic simulations has not been fully tested. In this study, we present…
We study nucleosynthesis in low accretion rate hot advective flows around black holes. We find that matter is generally photo-dissociated into protons and neutrons inside the disk. These neutrons stay around black holes for longer time…