Testing the relativistic precession model using low frequency and kHz quasi-periodic oscillations in neutron star low mass X-ray binaries with known spin

Understand

We analyze all available RXTE data on a sample of 13 low mass X-ray binaries with known neutron star spin that are not persistent pulsars.

• We carefully measure the correlations between the centroid frequencies of the quasi-periodic oscillations (QPOs).
• We compare these correlations to the prediction of the relativistic precession model (RPM) that, due to frame dragging, a QPO will occur at the Lense-Thirring precession frequency $\nu_{LT}$ of a test particle orbit whose orbital frequency is the upper kHz QPO frequency $\nu_u$.
• Contrary to the most prominent previous studies, we find two different oscillations in the range predicted for $\nu_{LT}$ that are simultaneously present over a wide range of $\nu_u$.