Lower twin peak quasiperiodic oscillation coherence across luminosity and the tidal stretching time-scale

Abstract

In this manuscript we pursue tidal disruption of magnetically confined clumps of matter as candidate to interpret the twin peak high-frequency quasiperiodic oscillations (HF QPOs) seen in low-mass x-ray binaries (LMXBs). In previews works we have proposed the upper HF QPO seen in neutron star (NS) LMXBs be linked to the energy released during tidal circularization of relativistic orbits. The lower HF QPO instead might come from the energy released during spiraling and tidal stretching of the clump. The observed behavior of the coherence \(Q\) of the lower HF QPO was related to both the tidal stretching time-scale of the clump along the orbit and the number of turns clumps make before reaching the innermost stable bound orbit. In this paper we focus on the maximum value of \(Q\) across LMXBs spanning two orders of magnitudes in luminosity. We show the \(Q_{max}\) behavior of the lower HF QPO seen across LMXBs luminosity might be related to tidal stretching time-scale as well, giving an estimate of the magnetic field in the plasma.