On the Black Hole – Bulge Mass Ratios in Narrow-Line Seyfert I Galaxies

We present estimated ratios of the central black hole mass to the bulge mass (M_bh/M_bulge) for 15 Narrow Line Seyfert I galaxies (NLS1s). It is found that NLS1s apparently have lower mass ratios: the average mass ratio is about 1×10^-4 with a spread of 2, which is one order of magnitude lower than for Broad Line AGNs and quiescent galaxies. This lower value, as compared to that established essentially for all other types of galaxies, can be accounted for by an underestimation of the black hole masses and an overestimation of the bulge masses in the NLS1s.