Publication date: Nov 2006
Kilohertz Quasi-Periodic Oscillations (QPOs) have been detected in many
accreting X-ray binaries. It has been suggested that the highest QPO
frequencies observed in the modulation of the X-ray flux reflect a
non-linear resonance between two modes of accreting disk oscillation.
This hypothesis implies certain very general predictions, several of
which have been borne out by observations. Some of these follow from
properties of non-linear oscillators, while the others are specific to
oscillations of fluid in strong gravity. A 3:2 resonant ratio of
frequencies can be clearly recognized in the black-hole as well as in
the neutron-star QPO data.
Török, Gabriel; Abramowicz, Marek; Kluźniak, Włodek; Stuchlík, Zdeněk;