Abstract Details

Name: Ritaban Chatterjee
Affiliation: Presidency University Kolkata
Conference ID: ASI2021_397
Title : Blazar Variability: A Study of Non-stationarity and the Flux-RMS Relation
Authors and Co-Authors : Ritaban Chatterjee (Presidency U.), Souradip Bhattacharyya (Presidency U.), Ritesh Ghosh (Visva-Bharati U.), Nabanita Das (Presidency U.)
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : We have analyzed the X-ray light curves of the blazars Mrk 421, PKS 2155-304, and 3C 273 using observations by AstroSat and archival XMM-Newton data. We use light curves of length 30-90 ks each from 3-4 epochs for all three blazars. In this talk, we shall show that the power spectral density (PSD) of the X-ray variability of the individual blazars are consistent within uncertainties across the epochs. This implies that the construction of broadband PSD using light curves from different epochs is accurate. However, using certain properties of the variance of the light curves and its segments, we show that the blazars exhibit hints of non-stationarity beyond that due to their characteristic red noise nature in some of those observations. We shall also demonstrate that there is a linear relationship between the root-mean-squared amplitude of variability at shorter timescales and the mean flux level at longer timescales for light curves of Mrk 421 across epochs separated by decades as well as light curves spanning 5 days and 10 years. The presence of flux-rms relation over very different timescales may imply that, similar to the X-ray binaries and Seyfert galaxies, longer and shorter timescale variability are connected in blazars. This work has been published in the Astrophysical Journal in 2020 (“Blazar Variability: A Study of Non-stationarity and the Flux-RMS Relation”, Bhattacharyya, Souradip; Ghosh, Ritesh; Chatterjee, Ritaban & Das, Nabanita 2020, ApJ, 897, 25. arXiv: 2005.05230). The submitted abstract is from that paper.