P. Godon, THE PROPAGATION OF ACOUSTIC-WAVES AND QUASI-PERIODIC OSCILLATIONS IN ACCRETION DISC BOUNDARY-LAYERS, Monthly Notices of the Royal Astronomical Society, 274(1), 1995, pp. 61-74
We provide one-dimensional time-dependent calculations of optically th
ick and geometrically thin accretion disc boundary layers in cataclysm
ic variables (CVs), by using the Chebyshev spectral method. Our numeri
cal calculations show that the properties of quasi-periodic oscillatio
ns (QPOs) are characteristic of acoustic waves propagating in the inne
r region of accretion discs for low values of alpha. Moreover, the obs
ervations provide significant evidence in support of the acoustic natu
re of the QPOs. The relative amplitudes of the QPOs (as observed in th
e 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.