Uncovering the Census of Black Holes in sub-Milky Way Mass Galaxies

Supermassive black holes are fundamental components of galaxies, as demonstrated by the correlations between black hole mass and large-scale galaxy bulge properties. Our understanding of the underlying physics driving the empirical scaling relations is not well understood by the present sample of galaxies for which dynamical BH masses have been measured. In particular, black hole mass determinations have been preferentially made in massive galaxies, leaving a small subset of seven dwarfs. We will address this bias using ALMA interferometric technique to detect and weigh black holes in nearby low-mass galaxies those are suitable for CO(2-1) high-resolution observations and gas-dynamical modeling methods. We target galaxies with total stellar masses smaller than that of our Milky Way those are currently missing in the existing sample of black hole mass measurements. We aim to provide the missing census of local black holes in a wide range of galaxies with diverse evolutionary histories, then determine the occupation fraction of central black holes in low-mass galaxies, which has substantial implications for the formation and growth of all supermassive black holes. In the era of ALMA, we hope to achieve a breakthrough in our understanding the black hole seeds formations mechanisms and co-evolution of black holes and galaxies.