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    QPOs in Microquasars: the Spin Problem

    Zdeněk Stuchlík · Srpen 01, 2007 · Fyzika · 0 comments
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    Publication date: Aug 2007

    Abstract:
    In Galactic microquasars with double-peak kHz quasi-periodic
    oscillations (QPOs), the ratio of the two frequencies is 3:2. This
    supports the suggestion that double-peak kHz QPOs are due to a non-
    linear resonance between two modes of accretion disk oscillations. For
    the microquasars with known mass, we briefly compare the black hole spin
    estimates based on the orbital resonance model with the recently
    reported spin predictions obtained by fitting the spectral continua.
    Results of these two approaches are not in good agreement. We stress
    that if the spectral fit estimates are accurate and can be taken as
    referential (which is still questionable), the disagreement between the
    predicted and referential values would represent a rather generic
    problem for any relativistic QPO model, as no spin influence would
    appear in the observed 1/M scaling of the QPO frequencies. The epicyclic
    frequencies relevant in these models are often considered to be equal to
    those of a test particle motion. However modifications of the
    frequencies due to disc pressure or other non-geodesic effects may play
    an important role, and the inaccuracy introduced in the spin estimates
    by the test particle approximation could be crucial.

    Authors:
    Török, Gabriel; Abramowicz, Marek A.; Stuchlík, Zdeněk; Šrámková, Eva;

    https://ui.adsabs.harvard.edu/abs/2007IAUS..240..724T

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