On the black hole mass-bulge mass relation

TLDR: In this paper, the authors examined the relation between the mass of the central black holes in nearby galaxies, Mbh, and the stellar mass of surrounding spheroid or bulge, Mbulge.

Abstract: We have reexamined the relation between the mass of the central black holes in nearby galaxies, Mbh, and the stellar mass of the surrounding spheroid or bulge, Mbulge. For a total of 30 galaxies bulge masses were derived through Jeans equation modeling or adopted from dynamical models in the literature. In stellar mass-to-light ratios, the spheroids and bulges span a range of a factor of 8. The bulge masses were related to well-determined black hole masses taken from the literature. With these improved values for Mbh, compared to Magorrian et al., and our redetermination of Mbulge, we find that the Mbh-Mbulge relation becomes very tight. We find Mbh ~ M with an observed scatter of 0.30 dex, a fraction of which can be attributed to measurement errors. The scatter in this relation is therefore comparable to the scatter in the relations of Mbh with σ and the stellar concentration. These results confirm and refine the work of Marconi & Hunt. For Mbulge ~ 5 × 1010 M☉ the median black hole mass is 0.14% ± 0.04% of the bulge mass.