Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2010-11-23
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
6 pages, 8 figs, submit
Scientific paper
We investigate the recently published data for the coherence of twin kHz quasi-period oscillations (QPOs) in the neutron star (NS) low-mass X-ray binaries (LMXBs) in a holistic way. We find that: (1) The quality factors of upper kHz QPOs are low ($2 \sim 20$ in general) and increase with the frequencies. The data point tracks in $Q-\nu$ plane are roughly similar for Z and atoll sources. (2) There are significant differences in $Q-\nu$ diagram for the lower kHz QPOs between Z and atoll sources. The quality factors ($Q_1$ usually lower than 15) of most Z sources rise steadily with the frequencies, except for Sco X-1 with an abrupt drop at frequency 750 Hz, while that of atoll sources are very high (from 2 to 200). A rising part, a maximum and an abrupt drop present in the $Q_1-\nu_1$ diagram for most atoll sources. (3) There are three atoll sources (4U 1728-34, 4U 1636-53 and 4U 1608-52) that display very high quality factors ($Q_1$) for lower kHz QPOs. The spin frequencies and sidebands between the twin kHz QPOs are detected for all three sources. The source with higher spin frequency presents a higher maximum quality factor and lower sideband frequency. (4) The $Q-\nu$ tracks also present specialities for individual source in each type, and the implications are discussed. Furthermore, motivated by the similarity between Sco X-1 and atoll sources for the lower $Q-\nu$ tracks, we try to present a holistic scenario for the evolution between atoll and Z sources. The revelations for the mechanisms of kHz QPOs in NS LMXBs are discussed.
Qu Jin Lu
Wang Jeffrey
Zhang Cheng-Min
No associations
LandOfFree
Holistic Analysis for the Coherence of kHz QPOs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Holistic Analysis for the Coherence of kHz QPOs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Holistic Analysis for the Coherence of kHz QPOs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-587915