High-Frequency Quasi-Periodic Oscillations in black-hole binaries. (arXiv:1207.2311v1 [astro-ph.HE])

High-Frequency Quasi-Periodic Oscillations in black-hole binaries. (arXiv:1207.2311v1 [astro-ph.HE]):
We present the results of the analysis of a large database of X-ray
observations of 22 galactic black-hole transients with the Rossi X-Ray timing
explorer throughout its operative life for a total exposure time of ~12 Ms. We
excluded persistent systems and the peculiar source GRS 1915+105, as well as
the most recently discovered sources. The semi-automatic homogeneous analysis
was aimed at the detection of high-frequency (100-1000 Hz) quasi-periodic
oscillations (QPO), of which several cases were previously reported in the
literature. After taking into account the number of independent trials, we
obtained 11 detections from two sources only: XTE J1550-564 and GRO J1655-40.
For the former, the detected frequencies are clustered around 180 Hz and 280
Hz, as previously found. For the latter, the previously-reported dichotomy
300-450 Hz is found to be less sharp. We discuss our results in comparison with
kHz QPO in neutron-star X-ray binaries and the prospects for future timing
X-ray missions.