Gas flows in galactic nuclei: observational constraints on BH-galaxy coevolution

TL;DR

This paper reviews recent high-resolution observations of gas flows in galactic nuclei, providing insights into black hole-galaxy co-evolution through inflows and outflows observed with advanced interferometers.

Contribution

It summarizes recent observational constraints on gas dynamics in galactic nuclei, highlighting the role of inflows and outflows in black hole and galaxy co-evolution.

Findings

Evidence of gas outflows in starbursts and active galaxies.

Observations of gas inflows and outflows with ALMA and IRAM.

Implications for feedback mechanisms in galaxy evolution.

Abstract

Galaxy nuclei are a unique laboratory to study gas flows. High-resolution imaging of the gas flows in galactic nuclei are instrumental in the study of the fueling and the feedback of star formation and nuclear activity in nearby galaxies. Several fueling mechanisms can be now confronted in detail with observations done with state-of-the-art interferometers. Furthermore, the study of gas flows in galactic nuclei can probe the feedback of activity on the interstellar medium of galaxies. Feedback action from star formation and AGN activity is invoked to prevent galaxies from becoming overly massive, but also to explain scaling laws like black hole (BH)-bulge mass correlations and the bimodal color distribution of galaxies. This close relationship between galaxies and their central supermassive BH can be described as co-evolution. There is mounting observational evidence for the existence of gas outflows in different populations of starbursts and active galaxies, a manifestation of the feedback of activity. We summarize the main results recently obtained from the observation of galactic inflows and outflows in a variety of active galaxies with current millimeter interferometers like ALMA or the IRAM array.