Determination of black hole masses

We analyze 17 transition episodes from eight BH sources observed with Rossi X-Ray Timing Explorer. Our scaling technique for BH mass determination uses a correlation between the spectral index and quasi-periodic oscillation (QPO) frequency.

In addition, we use a correlation between the index and the normalization of the disk "seed" component to cross-check the BH mass determination and estimate the distance to the source. We use GRO J1655-40 as a primary reference source for which the BH mass, distance, and inclination angle are evaluated by dynamical measurements with unprecedented precision among other Galactic BH sources. We apply our scaling technique to determine BH masses and distances for Cygnus X-1, GX 339-4, 4U 1543-47, XTE J1550-564, XTE J1650-500, H 1743-322, and XTE J1859-226.