Talk Details

Wednesday, December 3, 2008 - 3:15pm

Steffen Brinkmann (LSW):

"Accretion discs and blackholes"

Abstract. Accreting systems pose numerous questions concerning the details of accretion and ejection of matter. Angular momentum was found to be transported outwards by magnetorotational instability. Yet the global structure of the accretion flow close to the central object remains unclear, as well as and the processes that lead to jets and their properties. Applying the well-tested finite-volume-code PLUTO, we simulate the innermost region of a black hole accretion disc. By performing global, direct numerical MHD simulations with different initial magnetic configurations, we examine the widely accepted assumption, that the accreting matter "forgets" its original magnetic state. Also, we investigate the launching mechanisms of slow and fast winds and their properties. The results indicates that depending on the initial magnetic field, the actual accretion process does differ significantly. Also winds are launched at different timescales and show different mass loss rates. Jet rotation is found for each of the investigated scenarios. Remarkably, the fast winds show a periodic pattern of retrograde rotation.