Distribution of twin kHz QPOs in LMXBs
Abstract
With kilohertz quasi-periodic oscillation (kHz QPO) sources in neutron star low mass X-ray binaries (NS-LMXBs) published up to now, we analyze the centroid frequency (ν) distribution of twin kHz QPOs. We find that Atoll and Z sources show the similar distributions of ν1 and ν2, which indicate that twin kHz QPOs may be the common property of NS-LXMBs and have the similar physical origins. The mean values of ν1 and ν2 in Atoll sources are higher than those in Z sources, and we consider that this may because the QPO signals are sheltered by the thicken accretion disk or corona in Z sources. The maximums of ν2 in both Atoll and Z sources are the same order as the Keplerian orbital frequency of the NS surface, so kHz QPOs could occur near the NS surface.
- Publication:
-
Feeding Compact Objects: Accretion on All Scales
- Pub Date:
- February 2013
- DOI:
- 10.1017/S1743921312020248
- Bibcode:
- 2013IAUS..290..327W
- Keywords:
-
- X-rays: binaries;
- stars: neutron;
- accretion;
- accretion disks