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    Extended orbital resonance model with hump-induced oscillations

    Zdeněk Stuchlík · Únor 01, 2008 · Fyzika · 0 comments
    0

    Publication date: Feb 2008

    Abstract:
    Change of sign of the LNRF-velocity gradient has been found for
    accretion discs orbiting rapidly rotating Kerr black holes with spin a
    > 0.9953 for Keplerian discs and a > 0.99979 for marginally stable
    thick discs. Such a "humpy" LNRF-velocity profiles occur just above the
    marginally stable circular geodesic and could be related to oscillations
    of accretion discs. The frequency of such "hump"-induced oscillations
    can be identified with the maximal rate of change of the orbital
    velocity within the "humpy" profile. Therefore, we introduce an extended
    orbital resonance model (EXORM) of quasiperiodic oscillations (QPOs)
    assuming non-linear resonant phenomena between oscillations with the
    orbital epicyclic frequencies and the humpy frequency defined in a fully
    general relativistic way. The EXORM is developed for both Keplerian
    discs and perfect-fluid tori where the approximation of oscillations
    with epicyclic frequencies is acceptable. Clearly, the EXORM could be
    applied to the near-extreme Kerr black hole systems exhibiting
    relatively complex QPO frequency patterns. Assuming a Keplerian disc, it
    can be shown that in the framework of the EXORM, all the QPOs observed
    in the microquasar GRS 1915+105 could be explained, while it is not
    possible in the case of QPOs observed in the Galactic Centre source Sgr
    A*.

    Authors:
    Stuchlik, Zdenek; Slany, Petr; Torok, Gabriel;

    http://adsabs.harvard.edu/abs/2008arXiv0802.3844S

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