Talk detail

Participant	Molla, Aslam Ali
Institution	Indian Centre for Space Physics - 43, Chalantika, Garia st. road - Kolkata - West Bengal - India

Session	AC1	Accepted		Order		Time
Talk	Oral abstract	Title	Timing and Spectral properties of transient Black Hole candidate MAXI J1659-152 during its 2010 outburst
Coauthors	Chakrabarti, Sandip K.; Debnath, D.; Mondal, S.; Jana, A.; Chatterjee, D.
Abstract	One of the great interesting features of transient black hole candidates (BHCs) is their outburst profile, because they show rapid spectral and timing variability in a very short time scale. A systematic detailed study on the Spectral and the Timing properties on a daily basis is necessary to understand the accretion physics around these BHCs. We make a detailed study of the evolution of spectral properties of newly discovered Galactic transient BHC MAXI J1659-152 during its very first (2010) outburst after its discovery on 2010 Sept. 25 by MAXI/GSC using Chakrabarti-Titarchuk two-component advective flow (TCAF) model as an additive table model in XSPEC. Accretion flow parameters (Keplerian disk and sub-Keplerian halo rates, shock location and shock strength) are extracted from our spectral fits with TCAF. We studied the variation of these fitted parameters during the entire outburst as it passed through three spectral classes: hard, hard-intermediate, and soft-intermediate. More interestingly, no soft state is observed, which may be due to the lack of matter from thermally cool Keplerian disk. So in that context, we can call this outburst as a 'failed' outburst. Mass of the BHC was predicted in between 5-8 Solar mass.
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Session	HE3	Accepted	No	Order	10	Time	18:10	15'
Talk	Oral abstract	Title	Mass prediction of steller massive black hole candidates from Spectral study using TCAF model with ASTROSAT data
Coauthors	Chakrabarti, Sandip K.; Debnath, D.; Mondal, S.; Jana, A.; Chatterjee, D.
Abstract	There are many black hole candidates(BHCs), mainly transients, whose masses are not known via dynamical methods. So it is the most challenging task to predict mass of these BHCs via indirect methods. One of such method is Titarchuk and his collaborators photon index vs. QPO frequency relations. Recently, after the inclusion of two-component advective flow (TCAF) model into NASA's spectral analysis software package XSPEC as local model, we have found that model normalization becomes constant (as it depends only on mass and distance of the source) throughout the entire outburst for a particular range of BH mass values. Recently we studied two newly discovered transient BHCs (MAXI J1659-152, and MAXI J1836-194), whose masses are not determined dynamically, with TCAF using RXTE PCA data to find constant normalization. Our TCAF model fits suggest that masses of MAXI J1659-152, and MAXI J1836-194 should lie in the range of 5-8, and 8-11 Solar masses respectively. We hope that Indian first multi-wavelength satellite ASTROSAT (will be launch into its orbit in the last quarter of 2015) will be very useful to study accretion flow dynamics of transient BHCs during their outbursts with TCAF, as well as to predict mass of unknown BHCs.
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