Molecular gas dynamics around nuclei of galaxies

TL;DR

This paper reviews recent high-resolution ALMA and NOEMA observations revealing molecular gas dynamics and fueling mechanisms around galaxy nuclei, including inflows, rings, and nuclear spirals, with implications for black hole growth.

Contribution

It presents new high-resolution observations of molecular gas near galaxy nuclei, directly linking gas dynamics to black hole fueling processes.

Findings

Detection of nuclear trailing spirals indicating AGN fueling

Molecular inflow observed in some galaxies at 10-20 pc scales

Black hole masses derived directly from gas dynamics

Abstract

Recent molecular line observations with ALMA in several nearby Seyferts have revealed the existence of molecular tori, and the nature of gas flows at 10-20~pc scale. At 100~pc scale, or kpc-scale, previous NOEMA work on gravitational torques had shown that only about one third of Seyfert galaxies experienced molecular inflow and central fueling, while in most cases the gas was stalled in rings. At higher resolution, i.e. 10-20~pc scale, it is possible now to see in some cases AGN fueling due to nuclear trailing spirals, influenced by the black hole potential. This brings smoking gun evidence for nuclear fueling. In our sample galaxies, the angular resolution of up to 60~mas allows us to reach the black hole (BH) sphere of influence and the BH mass can be derived more directly than with the M-sigma relation.