APT2 - Supermassive Black Holes |
Speaker_ |
Shaposhnikov, Nikolai |
Talk _ |
State transitions in Black Hole Sources. BH Mass Estimation in Cyg X-1. |
Abstract _ |
Correlation of spectral versus temporal propeties in Black Hole (BH) X-ray binaries during transitions between states provides an important information on the properties of the system. Recently, the saturation effect observed in photon index - quasi-periodic oscillation (QPO) frequency dependence has been proposed as a BH signature. Our analysis confirmed the saturation for BH source Cygnus X-1. The absence of saturation was established for at least one neutron star source 4U 1728-34. I will review these results and discuss an application of spectral index-OPQ correlation for BH mass determination in Cygnus X-1 using a correlation scaling method. We use GRO J1655-40 (for which the BH mass is known) as a reference source during our mass determination procedure. |