Variability of the X-ray Broad Iron Spectral Features in Active Galactic Nuclei and Black-hole Binaries
Abstract
The "broad iron spectral features" are often seen in X-ray spectra of Active Galactic Nuclei (AGN) and black-hole binaries (BHB). These features may be explained either by the "relativistic disc reflection" scenario or the "partial covering" scenario: It is hardly possible to determine which model is valid from time-averaged spectral analysis. Thus, X-ray spectral variability has been investigated to constrain spectral models. To that end, it is crucial to study iron structure of BHBs in detail at short time-scales, which is, for the first time, made possible with the Parallel-sum clocking (P-sum) mode of XIS detectors on board Suzaku. This observational mode has a time-resolution of 7.8~ms as well as a CCD energy-resolution. We have carried out systematic calibration of the P-sum mode, and investigated spectral variability of the BHB GRS 1915+105. Consequently, we found that the spectral variability of GRS 1915+105 does not show iron features at sub-seconds. This is totally different from variability of AGN such as 1H0707--495, where the variation amplitude significantly drops at the iron K-energy band. This difference can be naturally explained in the framework of the "partial covering" scenario.
Keywords
Cite
@article{arxiv.1510.08189,
title = {Variability of the X-ray Broad Iron Spectral Features in Active Galactic Nuclei and Black-hole Binaries},
author = {Misaki Mizumoto and Ken Ebisawa and Masahiro Tsujimoto and Hajime Inoue},
journal= {arXiv preprint arXiv:1510.08189},
year = {2016}
}
Comments
5 pages, 7 figures, Accepted for publication in Astronomische Nachrichten (Proceedings of "The Extremes of Black Hole Accretion" workshop, held at ESAC, Madrid, in June 2015)