Mass and Spin Estimates OT Two NearExtreme Kerr Black Hole Candidates GRS 1915+105 and XTE J1650500 from the Extended Orbital Resonance Model for HighFrequency Qpos
Abstract
Humpy profile of the LNRFrelated orbital velocity was found for accretion discs orbiting rapidly rotating Kerr black holes with a spin a > 0.9953 (Keplerian discs) and a > 0.99979 (marginally stable thick discs). Maximal positive rate of change of the orbital velocity in terms of the proper radial distance is used to define a local frequency characterising possible physical processes in the disc connected with the velocity hump. Comparing the "humpy frequency" related to distant observers with epicyclic frequencies of perturbed orbital motion, it was shown that in Keplerian discs orbiting nearextreme Kerr black holes (a > 0.998) the the ratio of radial epicyclic frequency and humpy frequency (both evaluated at the same radius) is in terms of small integers asymptotically going to the ratio 3:2 for a → 1. The Extended Orbital Resonance Model with nonlinear humpinduced oscillations was applied to two Xray variable sources GRS 1915+105 and XTE J1650500. In the case of GRS 1915+105, the model is able to address the whole set of reported QPOs, giving the mass and spin of the central black hole: a = 0.9998; M = 14:8M_{⊙}. For XTE J1650500, similar ideas give values a = 0.9982; M = 5:1M_{⊙}.
 Publication:

Twelfth Marcel Grossmann Meeting on General Relativity
 Pub Date:
 2012
 DOI:
 10.1142/9789814374552_0098
 Bibcode:
 2012mgm..conf..934S