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;