On the black hole mass-bulge mass relation

We have reexamined the relation between the mass of the central black holes in nearby galaxies, M-bh, and the stellar mass of the surrounding spheroid or bulge, M bulge. 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 M-bh, compared to Magorrian et al., and our redetermination of M-bulge, we find that the M-bh-M-bulge relation becomes very tight. We find M-bh similar to M-bulge(1.12+/-0.06) with an observed scatter of less than or similar to0.30 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 M-bh with sigma and the stellar concentration. These results confirm and refine the work of Marconi & Hunt. For the M-bulge similar to5 x 10(10) M-circle dot the median black hole mass is 0.14% +/- 0.04% of the bulge mass.