Name: Sneha Prakash Mudambi
Affiliation: CHRIST (Deemed to be University)
Conference ID : ASI2022_318
Title : Multi mission view of the black hole binary candidate 4U1957+115
Authors : M. Sneha Prakash (1), S. B. Gudennavar (1), R. Misra (2) and S. G. Bubbly (1) (1) Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore Central Campus, Bengaluru-560029, India. (2) Inter-University Centre for Astronomy and Astrophysics, Ganeshkind, Pune-411007, India
Abstract Type: Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : 4U1957+115, a persistently active, low mass black hole binary was first discovered in 1973. Despite being studied in Optical and X-rays for over four decades proper consensus on the black hole mass, spin and source distance are yet to be achieved. We present here the results of comprehensive broadband (0.3-50.0 keV) studies using AstroSat, SWIFT and NuSTAR data. Thermal spectra were well represented by multicolour blackbody emission, relativistic reflection and non-thermal components. Modelling the spectra with diskbb model revealed the presence of a hot disc (1.35-1.59 keV) close to the accretor (norm=10). We found a positive correlation between the disc temperature and total un-absorbed flux. Asymptotic power-law index was estimated to be ~2.62. We then studied the variation of spin for a wide range of distance, inclination and black hole masses. Our findings suggest that a high mass (M_{BH}=16 M_sun) and maximally rotating black hole (a=0.99) with high disc inclination (i=77.6 degrees) best describes the binary.