Stability of generalrelativistic accretion disks
Abstract
Selfgravitating relativistic disks around black holes can form as transient structures in a number of astrophysical scenarios such as binary neutron star and black holeneutron star coalescences, as well as the core collapse of massive stars. We explore the stability of such disks against runaway and nonaxisymmetric instabilities using threedimensional hydrodynamics simulations in full general relativity using the Thor code. We model the disk matter using the ideal fluid approximation with a Γlaw equation of state with Γ=4/3. We explore three disk models around nonrotating black holes with disktoblack hole mass ratios of 0.24, 0.17, and 0.11. Because of metric blending in our initial data, all of our initial models contain an initial axisymmetric perturbation which induces radial disk oscillations. Despite these oscillations, our models do not develop the runaway instability during the first several orbital periods. Instead, all of the models develop unstable nonaxisymmetric modes on a dynamical time scale. We observe two distinct types of instabilities: the PapaloizouPringle and the socalled intermediate type instabilities. The development of the nonaxisymmetric mode with azimuthal number m=1 is accompanied by an outspiraling motion of the black hole, which significantly amplifies the growth rate of the m=1 mode in some cases. Overall, our simulations show that the properties of the unstable nonaxisymmetric modes in our disk models are qualitatively similar to those in the Newtonian theory.
 Publication:

Physical Review D
 Pub Date:
 February 2011
 DOI:
 10.1103/PhysRevD.83.043007
 arXiv:
 arXiv:1011.3010
 Bibcode:
 2011PhRvD..83d3007K
 Keywords:

 98.70.Rz;
 04.25.dg;
 04.30.Db;
 gammaray sources;
 gammaray bursts;
 Numerical studies of black holes and blackhole binaries;
 Wave generation and sources;
 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 30 pages, 21 figures