AGN feedback can produce metal enrichment on galaxy scales

TL;DR

This study demonstrates that AGN feedback can lead to significant metal enrichment in the circumgalactic medium, extending beyond the galaxy's core, as evidenced by detailed spectroscopic mapping of a quasar-associated nebula.

Contribution

It provides the first detailed spatially resolved evidence that AGN-driven outflows can enhance metal abundances up to 10 kpc from the galaxy center.

Findings

AGN outflows increase metal abundance up to 10 kpc from the nucleus.

O/H abundance is solar or slightly above at bubble edges.

Metal enrichment occurs at large extranuclear distances (>10 kpc).

Abstract

Giant (>100 kpc) nebulae associated with active galaxies provide rich information about the circumgalactic medium (CGM) around galaxies, its link with the interstellar medium (ISM) of the hosts and the mechanisms involved in their evolution. We have studied the giant nebula associated with the Teacup (z=0.085) quasar based on VLT MUSE integral field spectroscopy to investigate whether the well known giant (~10 kpc) active galactic nucleus (AGN) induced outflow has an impact on the distribution of heavy elements in and outside the host galaxy. For this, we have mapped the O/H and N/O abundances in two spatial dimensions across the giant nebula and within the galaxy by means of comparing emission line ratios with photoionisation model predictions. We have found that the widely studied AGN driven outflow responsible for the 10 kpc ionised bubble is enhancing the gas metal abundance up to 10 kpc from the AGN. O/H is solar or slightly higher in the bubble edges, in comparison with the subsolar abundances across the rest of the nebula (median O/H~0.63 O/H_sun)). The main conclusion is that AGN feedback can produce metal enrichment at large extranuclear distances in galaxies (>~10 kpc).