Browsing by Subject "X-ray binary stars"

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    QPOs in cataclysmic variables and in X-ray binaries
    (2005) Kluźniak, W; Lasota, J-P; Abramowicz, M A; Warner, B
    Recent observations, reported by Warner and Woudt, of Dwarf Nova Oscillations (DNOs) exhibiting frequency drift, period doubling, and 1:2:3 harmonic structure, can be understood as disc oscillations that are excited by perturbations at the spin frequency of the white dwarf or of its equatorial layers. Similar quasi-periodic disc oscillations in black hole low-mass X-ray binary (LMXB) transients in a 2:3 frequency ratio show no evidence of frequency drift and correspond to two separate modes of disc oscillation excited by an internal resonance. Just as no effects of general relativity play a role in white dwarf DNOs, no stellar surface or magnetic field effects need be invoked to explain the black hole QPOs.
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    Open Access
    Unveiling the nature of INTEGRAL objects through optical spectroscopy: III. Observations of seven southern sources
    (2006) Masetti, N; Pretorius, M L; Palazzi, E; Bassani, L; Bazzano, A; Bird, A J; Charles, P A; Dean, A J; Malizia, A; Nkundabakura, P; Stephen, J B; Ubertini, P
    . The detection, thanks to the