314 citations · 5.3k across the 121 of their papers we have counts for
7 papers · 1 filter
On the high coherence of kilo-Hz Quasi-Periodic Oscillations
D. Barret, W. Kluzniak, J. F. Olive +2
We have carried out a systematic study of the properties of the kilo-Hertz quasi-periodic oscillations (QPO) observed in the X-ray emission of the neutron star low-mass X-ray binar…
Epicyclic frequencies derived from the effective potential: simple and practical formulae
M. A. Abramowicz, W. Kluzniak
We present and discuss a short and simple derivation of orbital epicyclic frequencies for circular geodesic orbits in stationary and axially symmetric spacetimes. Such spacetimes i…
The upper kHz QPO: a gravitationally lensed vertical oscillation
M. Bursa, M. A. Abramowicz, V. Karas +1
We show that a luminous torus in the Schwarzschild metric oscillating along its own axis gives rise to a periodically varying flux of radiation, even though the source of radiation…
Resonance in Forced Oscillations of an Accretion Disk and Kilohertz Quasi Periodic Oscillations
William H. Lee, Marek A. Abramowicz, Wlodek Kluzniak
We have performed numerical simulations of a radially perturbed "accretion" torus around a black hole or neutron star and find that the torus performs radial and vertical motions a…
High-frequency QPOs as a problem in physics: non-linear resonance
Wlodek Kluzniak, Marek A. Abramowicz, William H. Lee
The presence of a kHz frequency in LMXBs has been expected from scaling laws, by analogy with the QPO phenomenon in HMXB X-ray pulsars. Interpretation of the two kHz frequencies, o…
The importance of discovering a 3:2 twin-peak QPO in a ULX or how to solve the puzzle of intermediate mass black holes
Marek A. Abramowicz, Wlodek Kluzniak, Jeffrey E. McClintock +1
Recently, twin-peak QPOs have been observed in a 3:2 ratio for three Galactic black-hole microquasars with frequencies that have been shown to scale as 1/M, as expected for general…
The orbital resonance model for twin peak kHz QPOs
Marek A. Abramowicz, Wlodek Kluzniak, Zdenek Stuchlik +1
Many Galactic black hole and neutron star sources in low X-ray mass binaries show QPOs (quasi periodic oscillations) in their observed X-ray fluxes, i.e. peaks in the Fourier varia…