Evidence for a circum-nuclear and ionised absorber in the X-ray obscured BroadLine Radio Galaxy 3C 445

TL;DR

This study presents Suzaku X-ray observations of 3C 445, revealing a complex absorber and reflection features that suggest a Compton-thick mirror and a possible ionised outflow, challenging its optical classification.

Contribution

First detailed measurement of reflection and absorber properties in 3C 445, proposing a scenario with a neutral or mildly ionised absorber linked to a disk-wind.

Findings

Detection of a strong reflection component (R~0.9).

Identification of a neutral or mildly ionised absorber with NH=2-3 x10^{23} cm^{-2}.

Evidence of variability in the ionised absorber over time.

Abstract

Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R~0.9) which together with the relatively strong neutral Fe Kalpha emission line (EW ~ 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X-ray continuum is strongly obscured by an absorber with a column density of NH =2-3 x10^{23} cm^{-2}. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log\xi ~ 1.0 erg cm s^{-1}. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial disk-wind located within the parsec scale molecular torus.