Abstract Details

Name: Blessy Baby
Affiliation: U R Rao Satellite Centre, ISRO, Bangalore
Conference ID: ASI2021_466
Title : Swift J173.5-0127 : Understanding the accretion geometry through freqeuncy resolved spectroscopy
Authors and Co-Authors : 1. Blessy E. Baby (URSC, ISRO, Bengaluru; University of Calicut, Kerala). 2. M. C. Ramadevi (URSC, ISRO, Bengaluru).
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : The Black Hole Binary source Swift J175.5-0127 remained in outburst for ∼ 12 years from May 2005 to April 2017. For most part of the outburst the source remained in the Low Hard State (LHS) displaying transitions to softer states only towards the end of the outburst for short periods of time. A soft thermal component was required to model the spectrum in LHS which does not conform to the generally accepted disc truncation theory. Here, we attempt to obtain a clearer picture of the accretion disk geometry using frequency resolved spectroscopy on select observations. Type-C Quasi-Periodic Oscillations (QPO) are observed in the Power Density Spectrum (PDS). We obtain the QPO rms spectrum of the source during the bright-hard state and model it with physical components. We find that the QPO rms spectrum can be described only by a comptonization component with no contribution from the thermal disc. This indicates that the variability observed in the PDS originates in the comptonization component and the evolution of the QPOs can be attributed to physical changes in this component rather than disc truncation.