Quantifying Nuclear Molecular Gas Content with ALMA CO Observations of Luminous Infrared Galaxies

Black hole mass scaling relations have been a hot topic in the past few decades due to the mysterious impact that black holes seem to have on global galaxy properties despite their small gravitational regions of influence. In this project we utilize state of the art CO observations from ALMA of several luminous infrared galaxies to reach 10s of parsec resolution, allowing us to both quantify the amount of cold nuclear molecular gas and take a closer look at the detailed structure of these extreme environments. Black hole masses in these sources have been measured dynamically from AO-assisted integral-field spectroscopy in the past, but the spatial resolution was still not high enough to account for the nuclear structure we see. What we detect with ALMA is a surprising amount of extra cold molecular gas very close to these black holes, which had made its way into previous dynamical measurements as part of the black hole mass. We use these direct measurements of molecular gas to precisely evaluate its contribution to these dynamical measurements, accounting for as much as 10% of black hole mass. This redefines some of the measurements seen in scaling relations and is significant especially to simulations of both fueling and feedback within galactic nuclei.