The Nature of Stable Soft X-Ray Emissions in Several Types of Active Galactic Nuclei Observed by Suzaku
Abstract
To constrain the origin of the soft X-ray excess phenomenon seen in many active galactic nuclei, the intensity-correlated spectral analysis, developed by Noda et al. (2011, PASJ, 63, S925) for Markarian 509, was applied to wide-band (0.5-45 keV) Suzaku data of five representative objects with a relatively weak reflection signature. They are the typical bare-nucleus type 1 Seyfert Fairall 9, the bright and typical type 1.5 Seyfert MCG -2-58-22, 3C 382, which is one of the X-ray brightest broad line radio galaxies, the typical Seyfert-like radio loud quasar 4C +74.26, and the X-ray brightest radio quiet quasar MR 2251-178. In all of them, soft X-ray intensities in energies below 3 keV were tightly correlated with that in 3-10 keV, but with significant positive offsets. These offsets, when calculated in finer energy bands, define a stable soft component in 0.5-3 keV. In each object, this component successfully explained the soft excess above a power-law fit. These components were interpreted in several alternative ways, including a thermal Comptonization component that is independent of the dominant power-law emission. This interpretation, considered physically most reasonable, is discussed from a viewpoint of Multi-Zone Comptonization, which was proposed for the black hole binary Cygnus X-1 (Makishima et al. 2008, PASJ, 60, 585).
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- February 2013
- DOI:
- 10.1093/pasj/65.1.4
- arXiv:
- arXiv:1208.3536
- Bibcode:
- 2013PASJ...65....4N
- Keywords:
-
- galaxies: active;
- galaxies: individual (Fairall 9;
- MCG -2-58-22;
- 3C 382;
- 4C + 74.26;
- MR 2251-178);
- galaxies: Seyfert galaxy;
- Radio galaxy;
- Radio loud quasar;
- Radio quiet quasar;
- X-rays: galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 18 pages, 12 figures, 7 tables