Probing the accretion disc structure by the twin kHz QPOs and spins of neutron stars in LMXBs

We analyse the relation between the emission radii of twin kilohertz quasi-periodic oscillations (kHz QPOs) and the co-rotation radii of the 12 neutron star low-mass X-ray binaries (NS-LMXBs), which are simultaneously detected with the twin kHz QPOs and NS spins. We find that the average co-rotation radius of these sources is 〈rco〉 ∼ 32 km, and all the emission positions of twin kHz QPOs lie insid...