395 citations · 1.7k across the 42 of their papers we have counts for
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Distribution of kilohertz QPO frequencies and their ratios in the atoll source 4U 1636-53
Gabriel Torok, Marek A. Abramowicz, Pavel Bakala +5
A recently published study on long term evolution of the frequencies of the kilohertz quasi-periodic oscillations (QPOs) in the atoll source 4U 1636-53 concluded that there is no p…
On the origin of clustering of frequency ratios in the atoll source 4U 1636-53
Gabriel Torok, Michal Bursa, Jiri Horak +4
A long discussion has been devoted to the issue of clustering of the kHz QPO frequency ratios in the neutron star sources. While the distribution of ratios inferred from an occurre…
The correlations and anticorrelations in QPO data
M. A. Abramowicz, D. Barret, M. Bursa +4
Double peak kHz QPO frequencies in neutron star sources varies in time by a factor of hundreds Hz while in microquasar sources the frequencies are fixed and located at the line ν_2…
Global oscillations of a fluid torus as a modulation mechanism for black-hole high-frequency QPOs
Michal Bursa
We study strong-gravity effects on modulation of radiation emerging from accreting compact objects as a possible mechanism for flux modulation in QPOs. We construct a toy model of…
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…
Evidence for a 2:3 resonance in Sco X-1 kHz QPOs
M. A. Abramowicz, T. Bulik, M. Bursa +1
We find evidence that the two high frequency QPOs in Sco X-1 are, more often than not, approximately in the 2:3 frequency ratio familiar from studies of black hole candidates (e.g.…