Publication date: Feb 2013
Abstract:
Using known frequencies of the twin peak high-frequency quasiperiodic
oscillations (HF QPOs) and known mass M of the central black hole, the
black-hole dimensionless spin a can be determined assuming a concrete
version of the resonance model. However, large range of observationally
limited values of the black hole mass implies a low precision of the
spin estimates. We discuss the possibility of higher precision of the
black hole spin a measurements in the framework of multi-resonance model
inspired by observations of more than two HF QPOs in some black hole
sources. We determine the spin and mass dependence of the twin peak
frequencies with a general rational ratio n:m assuming a non-linear
resonance of oscillations with the epicyclic and Keplerian frequencies
or their combinations. In the multi-resonant model, the twin peak
resonances are combined properly to give the observed frequency set. We
focus on the special case of duplex frequencies, when the top, bottom,
or mixed frequency is common at two different radii where the resonances
occur giving triple frequency sets.
Authors:
Stuchlík, Zdeněk; Kotrlová, Andrea; Török, Gabriel;