Galaxy Zoo DESI: large-scale bars as a secular mechanism for triggering AGN

Izzy L. Garland; Mike Walmsley; Maddie S. Silcock; Leah M. Potts; Josh Smith; Brooke D. Simmons; Chris J. Lintott; Rebecca J. Smethurst; James M. Dawson; William C. Keel; Sandor Kruk; Kameswara Bharadwaj Mantha; Karen L. Masters; David O'Ryan; Jürgen J. Popp; Matthew R. Thorne

arXiv · 2406.20096

Galaxy Zoo DESI: large-scale bars as a secular mechanism for triggering AGN

Izzy L. Garland·Mike Walmsley·Maddie S. Silcock·Leah M. Potts·Josh Smith·Brooke D. Simmons·Chris J. Lintott·Rebecca J. Smethurst·James M. Dawson·William C. Keel·Sandor Kruk·Kameswara Bharadwaj Mantha·Karen L. Masters·David O'Ryan·Jürgen J. Popp·Matthew R. Thorne

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Abstract

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 which drive this secular co-evolution are poorly understood. We investigate the role that both strong and weak large-scale galactic bars play in mediating this relationship. Using 72,940 disc galaxies in a volume-limited sample from Galaxy Zoo DESI, we analyse the active galactic nucleus (AGN) fraction in strongly barred, weakly barred, and unbarred galaxies up to z = 0.1 over a range of stellar masses and colours. After controlling for stellar mass and colour, we find that the optically selected AGN fraction is 31.6 +/- 0.9 per cent in strongly barred galaxies, 23.3 +/- 0.8 per cent in weakly barred galaxies, and 14.2 +/- 0.6 per cent in unbarred disc galaxies. These are highly statistically robust results, strengthening the tantalising results in earlier works. Strongly barred galaxies have a higher fraction of AGNs than weakly barred galaxies, which in turn have a higher fraction than unbarred galaxies. Thus, while bars are not required in order to grow a 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 galaxy stellar masses and colours.

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Izzy L. Garland, Mike Walmsley, Maddie S. Silcock, Leah M. Potts, Josh Smith, Brooke D. Simmons, Chris J. Lintott, Rebecca J. Smethurst, James M. Dawson, William C. Keel, Sandor Kruk, Kameswara Bharadwaj Mantha, Karen L. Masters, David O'Ryan, Jürgen J. Popp, Matthew R. Thorne. 2024-06-28. Galaxy Zoo DESI: large-scale bars as a secular mechanism for triggering AGN. https://arxiv.org/abs/2406.20096

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