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Paper: Power Spectra of Disced and Discless Accretors
Volume: 157, Annapolis Workshop on Magnetic Cataclysmic Variables
Page: 15
Authors: Wickramasinghe, Dayal T.; Ferrario, Lilia
Abstract: We present a theoretical discussion on the signatures that are to be expected in the power spectra of intermediate polars which accrete via a disc or a stream. Disc-fed accretion is characterised by low radial velocity amplitudes ( 500-100 km s^{-1}). The dominant power in the optical continuum and line fluxes is at the spin frequency of the white dwarf (omega). In contrast, stream-fed accretion is characterised by high velocity amplitudes ( 500-1000 km s^{-1}), and the line and continuum radiation exhibits significant optical power at the sideband frequency 2(omega - Omega) if the field distribution has an up-down (above-orbital-plane-below-orbital-plane) symmetry, or at (omega-Omega) if this symmetry is broken. The characteristics of the power spectrum change with increasing magnetic field as the polarised cyclotron emission from the shocks make a significant contribution to the optical radiation.
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