Accretion discs around compact objects

Abstract

Accretion onto a compact object is the process that is thought to power unexpectedly intense radiation of some astrophysical objects like Active Galactic Nuclei and X-Ray Binaries. A similar process is known to exist in Cataclysmic Variables and Young Stellar Objects. When the accreting matter has enough angular momentum it forms a disc around the compact object (a black hole, neutron star or white dwarf) and this disc is called an accretion disc. In this thesis accretion discs around compact objects are studied both analytically and numerically. Simplifying hydrodynamic equations in their full generality by the assumptions of the standart accretion disc theory, both time-independent and time-dependent equations were solved analytically. Time-dependent solutions are supported by numerical results. In all solutions a viscosity prescription which is a little more generalized than the standart prescription is used. The solution of the time-dependent equations with the generalized viscosity belong to the same family with the earlier ones.