Variabiity of the X‐ray broad iron spectral features in active galactic nuclei and black‐hole binaries. Issue 4 (May 2016)

• Record Type: Journal Article
• Authors: Mizumoto, M.; Ebisawa, K.; Tsujimoto, M.; Inoue, H.
• Is Part Of: Astronomische Nachrichten. Volume 337:Issue 4-5(2016)
• Page Start: 507
• Page End: 511
• Publication Date: 2016-05
• Subjects: accretion, accretion disks -- black hole physics -- galaxies: active -- galaxies: nuclei -- X‐rays: binaries; Astronomy -- Periodicals; 520.5
• DOI: 10.1002/asna.201612338
• Languages: English
• ISSNs: 0004-6337

Abstract

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 of Suzaku. This observational mode has a time‐resolution of 7.8 ms as well as a CCD energyresolution. 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. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)