Signatures of AGN induced metal loss in the stellar population

TL;DR

This study uses the fossil record technique on CALIFA galaxies to show that active galactic nuclei (AGN) can influence the chemical enrichment of their host galaxies by causing drops in metallicity, likely through outflows or gas inflows.

Contribution

It provides observational evidence linking AGN activity to metallicity drops in galaxies, highlighting the role of AGN-induced outflows in galaxy evolution.

Findings

Galaxies with AGN are more likely to show metallicity drops.

Star-forming galaxies have deeper metallicity decreases when drops occur.

Metallicity drops may result from gas inflows or outflows triggered by starbursts.

Abstract

One way the AGN are expected to influence the evolution of their host galaxies is by removing metal content via outflows. In this article we present results that show that AGN can have an effect on the chemical enrichment of their host galaxies using the fossil record technique on CALIFA galaxies. We classified the chemical enrichment histories of all galaxies in our sample regarding whether they show a drop in the value of their metallicity. We find that galaxies currently hosting an AGN are more likely to show this drop in their metal content compared to the quiescent sample. Once we separate the sample by their star-forming status we find that star-forming galaxies are less likely to have a drop in metallicity but have deeper decreases when these appear. This behavior could be evidence for the influence of either pristine gas inflows or galactic outflows triggered by starbursts, both of which can produce a drop in metallicity.