Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations

Details Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations

2008-10-14

arxiv.org/abs/0810.2543v1

Astrophys.J.691:1159-1167,2009

Astronomy and Astrophysics

Astrophysics

10 pages, 6 figures. Accepted for publication in the Astrophysical Journal

Scientific paper

10.1088/0004-637X/691/2/1159

[abridged] We present an X-ray study of the low-luminosity active galactic nucleus (AGN) in NGC4258 using data from Suzaku, XMM-Newton, and the Swift/BAT survey. We find that signatures of X-ray reprocessing by cold gas are very weak in the spectrum of this Seyfert-2 galaxy; a weak, narrow fluorescent-Kalpha emission line of cold iron is robustly detected in both the Suzaku and XMM-Newton spectra but at a level much below that of most other Seyfert-2 galaxies. We conclude that the circumnuclear environment of this AGN is very "clean" and lacks the Compton-thick obscuring torus of unified Seyfert schemes. From the narrowness of the iron line, together with evidence for line flux variability between the Suzaku and XMM-Newton observations, we constrain the line emitting region to be between $3\times 10^3r_g$ and $4\times 10^4r_g$ from the black hole. We show that the observed properties of the iron line can be explained if the line originates from the surface layers of a warped accretion disk. In particular, we present explicit calculations of the expected iron line from a disk warped by Lens-Thirring precession from a misaligned central black hole. Finally, the Suzaku data reveal clear evidence for large amplitude 2-10keV variability on timescales of 50ksec as well as smaller amplitude flares on timescales as short as 5-10ksec. If associated with accretion disk processes, such rapid variability requires an origin in the innermost regions of the disk ($r\approx 10r_g$ or less).

Affiliated with

Also associated with

No associations

Rating

Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Probing the accretion disk and central engine structure of NGC4258 with Suzaku and XMM-Newton observations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-302252