Abstract Details

Name: Akash Garg
Affiliation: Jamia Millia Islamia
Conference ID: ASI2021_279
Title : Modelling the energy dependent fractional rms and time lags in MAXI J1535-571 as observed by AstroSat
Authors and Co-Authors : Akash Garg (Department of Physics, Jamia Millia Islamia), Ranjeev Misra (Inter-University Center for Astronomy and Astrophysics), Somasri Sen (Department of Physics, Jamia Millia Islamia)
Abstract Type : Oral
Abstract Category : Stars, ISM and Galaxy
Abstract : Numerous timing studies in the past have shown that Blackhole X-ray binaries possess rapid X-ray variability during their outburst period. In Fourier space, such variations are seen as narrow peaks known as Quasi-periodic oscillations(QPOs) along with broadband noise component. There have been attempts to explain observed behavior either by geometric origin or by identifying radiative components that can give rise to them. For the latter one, it is needed to carry out the spectral analysis and determine spectral parameters which then needs to be translated into physical ones to obtain interpretation for accretion disk around black holes in the systems. The variations in these parameters can then be chosen numerically to produce the energy-dependent properties related to QPOs. Since LAXPC and SXT onboard AstroSat provides a broad energy range for spectral analysis along with better timing resolution of LAXPC, we chose AstroSat observations of low-frequency QPOs in MAXI J1535-571 and fitted the observed behaviour with the theoretical one. We found that variations in accretion rate, inner disk radius, coronal optical depth, and heating rate along with time delays between them can explain the variability.