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The correlations between the twin kHz QPO frequencies of LMXBs

C. M. Zhang·H. X. Yin·Y. H. Zhao·F. Zhang·L. M. Song
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Abstract

We analyzed the recently published kHz QPO data in the neutron star low-mass X-ray binaries (LMXBs), in order to investigate the different correlations of the twin peak kilohertz quasi-eriodic oscillations (kHz QPOs) in bright Z sources and in the less luminous Atoll sources. We find that a power-law relation $\no\sim\nt^{b}$ between the upper and the lower kHz QPOs with different indices: $b\simeq$1.5 for the Atoll source 4U 1728-34 and $b\simeq$1.9 for the Z source Sco X-1. The implications of our results for the theoretical models for kHz QPOs are discussed.

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C. M. Zhang, H. X. Yin, Y. H. Zhao, F. Zhang, L. M. Song. 2006-01-16. The correlations between the twin kHz QPO frequencies of LMXBs. https://doi.org/10.1111/j.1365-2966.2006.09920.x

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