Galaxy Zoo: are bars responsible for the feeding of active galactic nuclei at 0.2 < z < 1.0

We present a new study investigating whether active galactic nuclei (AGN) beyondthe local universe are preferentially fed via large-scale bars. Our investigation com-bines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS, COSMOS,and GOODS-S surveys to create samples of face-on, disc galaxies at 0.2 < z < 1.0. Weuse a novel method to robustly compare a sample of 120 AGN host galaxies, definedto have 10⁴² erg s⁻¹ < LX < 10⁴⁴ erg s⁻¹, with inactive control galaxies matched instellar mass, rest-frame colour, size, S´ersic index, and redshift. Using the GZH barclassifications of each sample, we demonstrate that AGN hosts show no statisticallysignificant enhancement in bar fraction or average bar likelihood compared to closely-matched inactive galaxies. In detail, we find that the AGN bar fraction cannot beenhanced above the control bar fraction by more than a factor of two, at 99.7% confidence. We similarly find no significant difference in the AGN fraction among barredand non-barred galaxies. Thus we find no compelling evidence that large-scale barsdirectly fuel AGN at 0.2 < z < 1.0. This result, coupled with previous results atz = 0, implies that moderate-luminosity AGN have not been preferentially fed bylarge-scale bars since z = 1. Furthermore, given the low bar fractions at z > 1,our findings suggest that large-scale bars have likely never directly been a dominantfueling mechanism for supermassive black hole growth.