Abstract Details

Name:	Nazma husain
Affiliation:	Jamia Millia Islamia University
Conference ID :	ASI2024_309
Title :	Broadband spectroscopy of 4U 1543-47 with hints of disk-wind absorption
Authors :	Nazma Husain Yash Bhargava Akash Garg Sneha Prakash Mudambi Ranjeev Misra Somasri Sen
Authors Affiliation:	Department of Physics, Jamia Millia Islamia, New Delhi-110025, India Tata Institute of Fundamental Research, Mumbai-400005, India Inter-University Centre for Astronomy and Astrophysics, Pune-411007, India CHRIST (Deemed to be University), Bengaluru-560029, India Inter-University Centre for Astronomy and Astrophysics, Pune-411007, India Department of Physics, Jamia Millia Islamia, New Delhi-110025, India
Mode of Presentation:	Oral
Abstract Category :	High Energy Phenomena, Fundamental Physics and Astronomy
Abstract :	After two decades of inactivity, 4U 1543-47 went into an outburst in 2021 becoming the brightest outburst ever observed for a black hole binary system. During the outburst decay, AstroSat carried out nine observations of the source spanning from July 1st to September 26th, 2021. This report presents a comprehensive spectral analysis of the source during its High/Soft state throughout the observation period. The source spectra was dominated by the presence of thermal emission, accompanied by a faint high-energy tail (with a power-law index of ≥ 2.5) and a high inner disk temperature of ~ 0.84 keV. When modeling the disk continuum using both non-relativistic and relativistic models, we found that the inner radius was considerably truncated (>10 Rg). Alternatively, in order to understand the spectral evolution by assuming the inner disk to be at the Innermost Stable Circular Orbit, variations in the spectral hardening within the range of approximately 1.5-1.9, was required. There are also clear indications of blurred reflection in the spectra particularly the prominent dip observed in the energy range of 7.0–11.0 keV, which could be associated with the disk-wind absorption.