Bending Instability of an Accretion Disc Around a Black Hole
نویسندگان
چکیده
We demonstrate that generically an accretion disk around a compact object could have a new type of instability in that the accretion flow need not be symmetric with respect to the equatorial plane even when matter is supplied symmetrically farther out. We find that this behaviour is mainly due to interaction of outgoing matter bounced off the centrifugal barrier and the incoming accretion. We believe that X-ray variability could be developed by this instability. Subject headings: accretion, accretion disks — black hole physics — hydrodynamics — Instabilities — shock waves Accepted for publication in ApJ Letters
منابع مشابه
Stability of Accretion Disc around a Black Hole: effects of Bremsstrahlung and Synchrotron Cooling
We perform stability analysis of an accretion disc around a stellar mass black hole. The cooling of the accretion flow due to bremsstrahlung and synchrotron radiation processes are considered. The solutions with shock are perturbed at the shock location and the radial dependence of perturbation is obtained by solving the equations numerically using fourth-order Runge-Kutta method. The perturbat...
متن کاملThe Relativistic Shift of Spectral Lines from Black–Hole Accretion Discs
Abstract. We present a simple approximate analytical formulae describing relativistic shift of a spectral line, produced by a small bright spot on a thin accretion disc around a nonrotating black hole. For the redshift factor we employ similar approach as Zhang & Bao (1991), improved in terms of Beloborodov’s (2002) approximation for light bending. Another approximation is used also for calcula...
متن کاملFormation of massive stars and black holes in self-gravitating AGN discs, and gravitational waves in LISA band
We propose a scenario in which massive stars form at the outer edges of an AGN accretion disc. We analyze the dynamics of a disc forming around a supermassive black hole, in which the angular momentum is transported by turbulence induced by the disc’s self-gravity. We find that once the surface density of the disc exceeds a critical value, the disc fragments into dense clumps. We argue that the...
متن کاملThe runaway instability in general relativistic accretion discs
When an accretion disc falls prey to the runaway instability, a large portion of its mass is devoured by the black hole within a few dynamical times. Despite decades of effort, it is still unclear under what conditions such an instability can occur. The technically most advanced relativistic simulations to date were unable to find a clear sign for the onset of the instability. In this work, we ...
متن کاملThe runaway instability of thick discs around black holes . I . The constant angular momentum case
We present results from a numerical study of the runaway instability of thick discs around black holes. This instability is an important issue for most models of cosmic gamma-ray bursts, where the central engine responsible for the initial energy release is such a system consisting of a thick disc surrounding a black hole. We have carried out a comprehensive number of time-dependent simulations...
متن کامل