It has recently been suggested that gravitomagnetic precession of the inner part of the accretion disk , possibly driven by radiation torques , may be responsible for some of the quasi-periodic X-ray brightness oscillations ( QPOs ) and other spectral features with frequencies between 20 and 300 Hz observed in the power spectra of some low-mass binary systems containing accreting neutron stars and black hole candidates .
We have explored the free and driven normal modes of geometrically thin disks in the presence of gravitomagnetic and radiation warping torques .

We have found a family of low-frequency gravitomagnetic ( LFGM ) modes with precession frequencies that range from the lowest frequency allowed by the size of the disk up to a certain critical frequency \omega _ { crit } , which is \sim 1 Hz for a compact object of solar mass .
The lowest-frequency ( lowest-order ) LFGM modes are similar to the previously known radiation warping modes , extend over much of the disk , and have damping rates \gtrsim 10 times their precession frequencies .
The highest-frequency LFGM modes are tightly wound spiral corrugations of the disk that extend to \sim 10 times its inner radius and have damping rates \gtrsim 10 ^ { 3 } times their precession frequencies .
A radiation warping torque can cause a few of the lowest-frequency LFGM modes to grow with time , but even a strong radiation warping torque has essentially no effect on the LFGM modes with frequencies \gtrsim 10 ^ { -4 } Hz .

We have also discovered a second family of high-frequency gravitomagnetic ( HFGM ) modes with precession frequencies that range from \omega _ { crit } up to slightly less than the gravitomagnetic precession frequency \omega _ { gm,i } of a particle at the inner edge of the disk , which is 30 Hz if the disk extends inward to the innermost stable circular orbit around a 2 M _ { \odot } compact object with dimensionless angular momentum cJ / GM ^ { 2 } = 0.2 .
The lowest-frequency HFGM modes are very strongly damped and have warp functions and precession frequencies very similar to those of the highest-frequency LFGM modes .
In contrast , the highest-frequency ( lowest-order ) HFGM modes are very localized spiral corrugations of the inner disk and are weakly damped , with Q values \sim 2–50 .

We discuss the implications of our results for the observability of Lense-Thirring precession in X-ray binaries .