Dr Carole Haswell (Open University)
15th January 2003
Accretion Flows and Black Hole Masses
Observations of Black Hole X-ray transients have led to a firm empirical case for the existence of black holes. This empirical case rests on observations of the mass donor stars in quiescence. In persistently-accreting X-ray binaries the accretion light itself dominates. Consequently in general there are few reliable ways to determine the mass of an accreting object, and these work only for a subset of neutron star accretors. I will describe observations of time-dependent accretion flows in superhumping CVs, and compare these with semi-analytic numerical models and SPH simulations. We find that time-dependent emission is associated with spiral density waves, tidal stressing in the bulk of the disc, and the dissipation at the convergence of the disc and stream flows. We use the kinematics of the model flows to simulate trailed spectrograms of superhumping discs. Our results suggest possible new methods of determining system parameters from photometry and spectroscopy of the accretion flow.

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