Spectral variability of IRAS 18325-5926 and constraints on the geometry of the scattering medium

Abstract

We analyze Suzaku and XMM-Newton data of the highly variable Seyfert 2, IRAS 18325-5926. The spectra of the source are well modeled as a primary component described as an absorbed power law and a secondary power law component which is consistent with being scattered emission from an on-axis extended highly ionized medium. We show that while the primary component varies on a wide range of timescales from $10^4-10^8$ s, the scattered emission is variable only on timescales longer than $10^5$ s. This implies that the extent of the scattering medium is greater than $10^{16}$ cm. The ratio of the scattered to primary flux ($\sim 0.03$) implies a column density for the scattering medium to be $\sim 10^{23}$ cm${}^{-2}$. We argue that for such a medium to be highly ionized it must be located less than $10^{17}$ cm from the X-ray source. Thus we localize the position and extent of scattering region to be $\sim$ a few $\times 10^{16}$ cm, with an average particle density of $\sim 10^6$ cm${}^{-3}$. We consider the physical interpretation of these results and as an aside, we confirm the presence of a broad Iron line emission in both the {\it XMM-Newton} and {\it Suzaku} observations.

7 pages, 5 figures, 2 tables, Accepted for publication in ApJ

References in corpus (6)

• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes
• Fe K Emission and Absorption in the XMM-EPIC Spectrum of the Seyfert Galaxy IC 4329a
• A Multi-Wavelength Study of the Nature of Type 1.8/1.9 Seyfert Galaxies
• The X-ray reflector in NGC 4945: a time and space resolved portrait
• A Detection of an X-ray Wind and an Ionized Disk in the Chandra HETGS Observation of the Seyfert 2 Galaxy IRAS 18325-5926

Cited by in corpus (4)

• Suzaku Observations of Moderately Obscured (Compton-thin) Active Galactic Nuclei Selected by Swift/BAT Hard X-ray Survey
• X-ray time delays from the Seyfert 2 galaxy IRAS 18325-5926
• Highly ionized disc and transient outflows in the Seyfert galaxy IRAS 18325-5926
• The Iron K Line Profile of IRAS 18325-5926