On the linearity of the black hole-bulge mass relation in active and in nearby galaxies.
Abstract (from CDS):
Analysis of (Palomar-Green) PG quasar observations suggests a nonlinear relation between the black hole mass, MBH, and the bulge mass, Mbulge, although a linear relation, as proposed for nearby galaxies, cannot be ruled out. New MBH values for nearby galaxies from K. Gebhardt et al., and Lbulge measurements for Seyfert 1 galaxies from S. N. Virani et al., are used here to obtain a more accurate value for the slope of the MBH-Mbulge relation. The combined sample of 40 active and nonactive galaxies suggests a significantly nonlinear relation, MBH∝M1.53±0.14bulge. Further support for a nonlinear relation is provided by the slope of the MBH-stellar velocity dispersion relation found recently, and by the low MBH found in late-type spiral galaxies. The mean MBH/Mbulge ratio is therefore not a universal constant, but rather drops from ∼0.5% in bright (MV~-22) ellipticals to ∼0.05% in low-luminosity (MV~-18) bulges. Hubble Space Telescope determinations of MBH in late-type spirals, and of the bulge magnitude in narrow-line Seyfert 1 galaxies (both predicted to have low MBH), can further test the validity of the nonlinear MBH-Mbulge relation.
Galaxies: Nuclei - Galaxies: Quasars: General