Zielona Gora University and
Copernicus Center, Poland
QPOs, resonance and non-linear
oscillations in accretion disks.
Quasi-periodic variability has been detected in the X-ray
emissions of
accreting white dwarfs, neutron stars and black holes. I will review the
evidence that in all three types of these binary systems the
highest-frequency variability is caused by oscillations of the accretion
disk.
In some cases direct evidence of a non-linear resonance is present.
An overview of the status of a mathematical model of 3:2 resonance
in rotating fluid tori oscillating in the strong gravity of the Kerr
metric
will also be given.