Large-scale galactic bars as a secular mechanism for black hole growth

Despite the evidence that supermassive black holes (SMBHs) co-evolve with their host galaxy, and that most of the growth of these SMBHs occurs via merger-free processes, the underlying mechanisms driving this secular co-evolution are poorly understood. I will discuss the role that both strong and weak large-scale galactic bars play in mediating this relationship up to z = 0.1 over a range of stellar masses and colours. After controlling for stellar mass and colour, I show to a high statistical significance that strongly barred galaxies have a higher fraction of AGN than weakly barred galaxies, which in turn have a higher fraction than unbarred galaxies. Thus, while bars are not required in order to grow an SMBH in a disc galaxy, large-scale galactic bars appear to facilitate AGN fuelling, and the presence of a strong bar makes a disc galaxy more than twice as likely to host an AGN than an unbarred galaxy at all stellar masses and colours. I will then highlight some preliminary results on this relationship’s variation with bulge prominence. I will discuss the effect of bar strength on AGN presence when we disentangle their complex relationship with bulge prominence.