Publication date: Feb 2013
Abstract:
The black hole mass and spin estimates assuming various specific models
of the 3 : 2 high frequency quasi-periodic oscillations (HF QPOs) have
been carried out in Török et al. (2005, 2011). Here we briefly summarize
some current points. Spectral fitting of the spin a ≡ cJ/GM 2
in the microquasar GRS 1915 + 105 reveals that this system can contain a
near extreme rotating black hole (e.g., McClintock et al., 2011).
Confirming the high value of the spin would have significant
consequences for the theory of the HF QPOs. The estimate of a > 0.9
is almost inconsistent with the relativistic precession (RP), tidal
disruption (TD), and the warped disc (WD) model. The epicyclic resonance
(Ep) and discoseismic models assuming the c- and g- modes are instead
favoured. However, consideration of all three microquasars that display
the 3 : 2 HF QPOs leads to a serious puzzle because the differences in
the individual spins, such as a = 0.9 compared to a = 0.7, represent a
generic problem almost for any unified orbital 3:2 QPO model.
Authors:
Kotrlová, Andrea; Török, Gabriel; Šrámková, Eva; Stuchlík, Zdeněk;