Supermassive black holes do not correlate with galaxy disks or pseudobulges

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Abstract
The masses of supermassive black holes are known to correlate with the properties of the bulge components of their host galaxies1,2,3,4,5. In contrast, they seem not to correlate with galaxy disks1. Disk-grown ‘pseudobulges’ are intermediate in properties between bulges and disks6; it has been unclear whether they do1,5 or do not7,8,9 correlate with black holes in the same way that bulges do. At stake in this issue are conclusions about which parts of galaxies coevolve with black holes10, possibly by being regulated by energy feedback from black holes11. Here we report pseudobulge classifications for galaxies with dynamically detected black holes and combine them with recent measurements of velocity dispersions in the biggest bulgeless galaxies12. These data confirm that black holes do not correlate with disks and show that they correlate little or not at all with pseudobulges. We suggest that there are two different modes of black-hole feeding. Black holes in bulges grow rapidly to high masses when mergers drive gas infall that feeds quasar-like events. In contrast, small black holes in bulgeless galaxies and in galaxies with pseudobulges grow as low-level Seyfert galaxies. Growth of the former is driven by global processes, so the biggest black holes coevolve with bulges, but growth of the latter is driven locally and stochastically, and they do not coevolve with disks and pseudobulges.
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