Estimation of the mass of the black hole candidate MAXI J1659-152 using TCAF and POS models

The Galactic transient black hole candidate (BHC) MAXI J1659-152 exhibited temporal and spectral evolution during its very first X-ray outburst (2010) after its discovery on 2010 September 25. Our recent studies of a few transient BHCs, including MAXI J1659-152, using the Chakrabarti-Titarchuk two-component advective flow (TCAF) solution as an additive table local model in the XSPEC software revealed details of the accretion-flow dynamics around the black holes. The TCAF model-fitted normalization (N) comes out to be almost constant throughout the entire outburst, consisting of several spectral states. We introduce two independent methods to determine the mass (M_BH) of the BHC: namely (i) keeping the TCAF fitted normalization parameter in a narrow range and (ii) studying the evolution of the quasi-periodic oscillation frequency (ν_QPO) with time, fitting with the propagating oscillatory shock (POS) model. The predicted mass ranges of the source with these two methods are 4.7-7.8 M_⊙ and 5.1-7.4 M_⊙, respectively. Combining the results of these two methods, we obtain a most probable mass range of the source of 4.7-7.8 M_⊙ or 6_-1.3^+1.8 M_⊙.