Galaxy-wide outflows inz~ 1.5 luminous obscured quasars revealed through near-IR slit-resolved spectroscopy

Abstract

Aims. The co-evolution of galaxies and supermassive black holes (SMBHs) requires that some sort of feedback mechanism is operating during the active galactic nuclei (AGN) phases. AGN driven winds are the most likely candidates for such feedback mechanism, but direct observational evidence of their existence and of their effects on the host galaxies are still scarce and their physical origin is still hotly debated. Methods. X-Shooter observations of a sample of X-ray selected, obscured quasars at z ∼ 1.5, selected on the basis of their observed red colors and X-ray-to-optical flux ratio, have shown the presence of outflowing ionized gas identified by broad [OIII] emission lines in 6 out of 8 objects, confirming the efficiency of the selection criteria. Here we present slit-resolved spectroscopy for the two brightest sources, XID2028 and XID5321, to study the complex emission and absorption line kinematics. Results. We detect outflow extended out to ∼10 kpc from the central black hole, both as blueshifted and redshifted emission. Interestingly, we also detect kpc scale outflows in the [OII] emission lines and in the neutral gas component, traced by the sodium D and magnesium absorption lines, confirming that a substantial amount of the outflowing mass is in the form of neutral gas. Conclusions. The measured gas velocities and the outflow kinetic powers, inferred under reasonable assumptions on the geometry and physical properties of these two systems, favor an AGN origin for the observed winds.

SINFONI spectra of heavily obscured AGNs in COSMOS: Evidence of outflows in a MIR/O target atz~ 2.5

“…Fiore et al 2003;Mignoli et al 2004;Alexander et al 2002;Del Moro et al 2009;Della Ceca et al 2015) have found that sources with high f x / f O are characterised, on average, by red optical to near-infrared colours (R − K Vega > 5) and column densities in the X-ray of the order of 10 21−23 cm −2 . Moreover, VLT X-Shooter Perna et al 2015) and SINFONI observations of a small subsample of obscured QSOs at z ∼ 1.5, selected on the basis of their observed red colours and high f x / f O ratio, have confirmed the presence of ionised outflowing material in 75% of objects and a dust-reddened type 1 nature. These objects appear similar to infrared bright (K Vega ≤ 16) dust-reddened Type 1 QSOs selected by combining radio with near-infrared (NIR) and optical catalogues at lower redshift (z 1; Glikman et al 2004Glikman et al , 2007.…”

“…Black crosses represent the 1 mJy fluxlimited sample. Yellow stars denote the five objects observed with SINFONI; cyan stars and squares denote Melbourne et al (2011) andBrand et al (2007) targets, respectively (two targets present in both samples are indicated with stars); blue symbols denote the Perna et al (2015) targets. Star and square symbols indicate IFU and long-slit observations, respectively.…”

“…1 we also show the z ∼ 2 DOGs presented in Melbourne et al (2011;cyan stars) and in Brand et al (2007; cyan squares) for which K-band magnitude is available, and the z ∼ 1.5 dust-reddened type 1 sources presented in Perna et al (2015;blue symbols). The properties of these targets are discussed in Sect.…”

“…When more than one emission line is fitted, we constrained the centroids and the line flux ratios according to atomic physics, while the widths were fixed to be the same as each emission line (see Perna et al 2015). …”

AGN–starburst evolutionary connection: a physical interpretation based on radiative feedback

“…Direct observational evidence of powerful outflows has been recently reported in X-ray obscured QSO at z ∼ 1.5 Perna et al 2015). These luminous (L 10 46 erg/s), X-ray absorbed (NH ∼ 10 21 − 10 22 cm −2 ) red QSO show fast outflows with velocities in the range v ∼ 1200 − 1800 km/s.…”