Publication date: Dec 2007
Abstract:
The "Extended Orbital Resonance Model", i.e., the idea of oscillations
induced by the hump of the orbital velocity profile (related to the
locally non-rotating frames – LNRF), which are proposed to excite the
oscillations of Keplerian discs around near-extreme Kerr black holes
with epicyclic frequencies, is used to estimate the mass and spin of
three near-extreme Kerr black hole candidates GRS 1915+105, XTE
J1650-500, and NGC 5408 X-1. The hump-induced oscillations are
characterized by the so-called "humpy frequency", and a non-linear
resonant coupling between these and epicyclic oscillations is expected.
It it shown that the quasiperiodic variability (QPOs) observed in these
sources can be matched with the proposals of the model, giving for the
mass and spin of their black holes values consistent with the other
observationally-established estimates.
Authors:
Slaný, Petr; Stuchlík, Zdeněk;