A Variable Partial Covering Model for the Seyfert 1 Galaxy MCG-6-30-15

Abstract

We propose a simple spectral model for the Seyfert 1 Galaxy MCG-6-30-15 that can explain most of the 1 - 40 keV spectral variation by change of the partial covering fraction, similar to the one proposed by Miller et al. (2008). Our spectral model is composed of three continuum components; (1) a direct power-law component, (2) a heavily absorbed power-law component by mildly ionized intervening matter, and (3) a cold disk reflection component far from the black hole with moderate solid-angle (Ω/2π \approx 0.3) accompanying a narrow fluorescent iron line. The first two components are affected by the surrounding highly ionized thin absorber with N_H \approx 10^{23.4}cm-2 and log ξ \approx 3.4. The heavy absorber in the second component is fragmented into many clouds, each of which is composed of radial zones with different ionization states and column densities, the main body (N_H \approx 10^24.2cm-2, log ξ \approx 1.6), the envelope (N_H \approx 10^22.1cm-2, log ξ \approx 1.9) and presumably a completely opaque core. These parameters of the ionized absorbers, as well as the intrinsic spectral shape of the X-ray source, are unchanged at all. The central X-ray source is moderately extended, and its luminosity is not significantly variable. The observed flux and spectral variations are mostly explained by variation of the geometrical partial covering fraction of the central source from 0 (uncovered) to \sim0.63 by the intervening ionized clouds in the line of sight. The ionized iron K-edge of the heavily absorbed component explains most of the seemingly broad line-like feature, a well-known spectral characteristic of MCG-6-30-15. The direct component and the absorbed component anti-correlate, cancelling their variations each other, so that the fractional spectral variation becomes the minimum at the iron energy band; another observational characteristic of MCG-6-30-15 is thus explained.

Accepted to Publications of the Astronomical Society of Japan

References in corpus (6)

• An absorption origin for the X-ray spectral variability of MCG-6-30-15
• X-ray absorption by Broad Line Region Clouds in Mrk 766
• X-ray Absorption and Reflection in Active Galactic Nuclei
• Tracing a Disk Wind in NGC 3516
• The absorption-dominated model for the X-ray spectra of type I active galaxies: MCG-6-30-15
• On the light-bending model of X-ray variability of MCG-6-30-15

Cited by in corpus (27)

• A hard X-ray view of the soft excess in AGN
• Detection of Coronal Magnetic Activity in Nearby Active Supermassive Black Holes
• Luminosity-dependent unification of Active Galactic Nuclei and the X-ray Baldwin effect
• Systematic Study of AGN Clumpy Tori with Broadband X-ray Spectroscopy: Updated Unified Picture of AGN Structure
• The narrow Fe K$\alpha$ line and the molecular torus in active galactic nuclei - an IR/X-ray view
• X-ray and Optical Correlation of Type I Seyfert NGC 3516 Studied with Suzaku and Japanese Ground-Based Telescopes
• Variability of the High Velocity Outflow in the Quasar PDS 456
• Suzaku Studies of the Central Engine in the Typical Type I Seyfert NGC 3227: Detection of Multiple Primary X-ray Continua with Distinct Properties
• X-ray reverberation lags of the Fe-K line due to AGN disc winds
• Application of Clumpy Torus Model to Broadband X-ray Spectra of Two Seyfert 1 Galaxies: IC 4329A and NGC 7469
• X-ray flaring in PDS 456 observed in a high-flux state
• Origin of the Broad Iron Line Feature and the Soft X-ray Variation in Seyfert Galaxies
• Multi-epoch X-ray spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 478
• Suzaku observation of IRAS 00521-7054, a peculiar type-II AGN with a very broad feature at 6 keV
• Nature of the Warm Absorber Outflow in NGC 4051
• Complex Narrow Line Seyfert 1s: High spin or high inclination?
• Reproductions of super-orbital X-ray light-curves with the precessing accretion ring model and implications on accretion flows through accretion rings
• Origin of the Characteristic X-ray Spectral Variations of IRAS 13224$-$3809
• Uncovering the primary X-ray emission and possible starburst component in the polarized NLS1 Mrk 1239
• Origin of the complex iron line structure and spectral variation in Mrk 766
• Can the relativistic light bending model explain X-ray spectral variations of Seyfert galaxies?
• Origin of the X-ray Broad Iron Spectral Feature in GRS 1915+105
• Simple interpretation of the seemingly complicated X-ray spectral variation of NGC 5548
• Broadband X-ray Spectral Study of Nuclear Structure in Local Obscured Radio Galaxies
• Variability of the X-ray Broad Iron Spectral Features in Active Galactic Nuclei and Black-hole Binaries
• The Origin of X-ray Emission in the Gamma-ray emitting Narrow-Line Seyfert 1 1H 0323+342
• Selection of Compton-thick AGN from a hard photometric sample using XMM-Newton observations