The propagation of acoustic waves and quasi-periodic oscillations in accretion disc boundary layers.
We provide one-dimensional time-dependent calculations of optically thick and geometrically thin accretion disc boundary layers in catalysmic variables (CVs), by using the Chebyshev spectral method. Our numberical calculations show that the properties of quasi-periodic oscillations (QPOs) are characteristic of acoustic waves propagating in the inner region of accretion discs for low values of @. Moreover, the observations provide significant evidance in support of the acoustic nature of the QPOs. The relative amplitudes of the QPOs (as observed in the optical and the X-ray), the autocorrelation function of their light curve, and the relation between the QPO periods and their decay times are all characteristic of acoustic waves.
|Main Author:||Godon, Patrick.|