A new powerful and highly variable disc wind in an AGN-star-forming galaxy, the case of MCG-03-58-007

Abstract

We present the discovery of a new candidate for a fast disc wind, in the nearby Seyfert 2 galaxy MCG-03-58-007. This wind is discovered in a deep Suzaku observation that was performed in 2010. Overall the X-ray spectrum of MCG-03-58-007 is highly absorbed by a neutral column density of N_H ∼10²³ cm^-2, in agreement with the optical classification as a type 2 active galactic nucleus. In addition, this observation unveiled the presence of two deep absorption troughs at E = 7.4 ± 0.1 and 8.5 ± 0.2 keV. If associated with blueshifted Fe XXVI, these features can be explained with the presence of two highly ionized (log ξ/erg cm s^-1 ∼5.5) and high column density (N_H ∼ 5-8 × 10²³ cm^-2) outflowing absorbers with v_out1 ∼ -0.1c and v_out2 ∼ -0.2c. The disc wind detected during this observation is most likely launched from within a few hundreds gravitational radii from the central black and has a kinetic output that matches the prescription for significant feedback. The presence of the lower velocity component of the disc wind is independently confirmed by the analysis of a follow-up XMM-Newton and NuSTAR observation. A faster (v_out ∼ -0.35c) component of the wind is also seen in this second observation. During this observation we also witnessed an occultation event lasting Δt ∼ 120 ks, which we ascribe to an increase of the opacity of the disc wind (ΔN_H ∼ 1.4 × 10²⁴ cm^-2). Our interpretation is that the slow zone (v_out ∼ -0.1c) of the wind is the most stable but inhomogeneous component, while the faster zones could be associated with two different inner streamlines of the wind.