Izzy Garland

Both observations and simulations show that much of the black hole growth in the universe has occurred in galaxies with no major mergers in their history since approximately z = 2, meaning that a significant fraction of active galactic nuclei (AGN) reside in disk-dominated galaxies with calm interaction histories and little or no merger-generated bulge components. Recent studies — both spectroscopic and otherwise — indicate bar-driven black hole growth, although past results lack clarity because of complicating factors such as selection effects and the much longer lifetimes of bars relative to AGN. Simulations also predict that long-lived bars are responsible for the growth of pseudobulges, meaning that “bulgeless” barred galaxies are more likely to have younger bars, which should resolve many of the lifetime complications observed in the full population of barred disk galaxies. We present a sample of AGN hosted in strongly disk-dominated galaxies at redshifts 0.015  z  0.25, with high-resolution HST images permitting secure identification of barred and unbarred morphology and 100% optical longslit spectroscopic completeness of both AGN and galaxies. We combine HST and spatially-resolved spectroscopic data to quantify the galaxy structural parameters, stellar masses, and star formation rates, and determine the bar fraction in the host galaxies of these luminous AGN. We additionally compare our data to a matched sample of disk-dominated galaxies lacking an AGN. By statistically comparing the bar fraction in the two samples and controlling for confounding variables, we can constrain the secular growth of supermassive black holes. These carefully matched samples of merger-free AGN and inactive galaxies are a promising means of quantifying the role of secular black hole growth in galaxy evolution.