The black hole mass–stellar velocity dispersion correlation: bulges versus pseudo-bulges

We investigate the correlation between the supermassive black holes (SMBHs) mass (M bh ) and the stellar velocity dispersion ( * ) in two types of host galaxies: the early-type bulges (disc galaxies with classical bulges or elliptical galaxies) and pseudo-bulges. In the form log (M bh /M ) = + log ( * /200 km s -1 ), the best-fitting results for the 39 early-type bulges are the slope = 4.06 0.28 and the normalization = 8.28 0.05; the best-fitting results for the nine pseudo-bulges are = 4.5 1.3 and = 7.50 0.18. Both relations have intrinsic scatter in log M bh of 0.27 dex. The M bh - * relation for pseudo-bulges is different from the relation in the early-type bulges over the 3 significance level. The contrasting relations indicate the formation and growth histories of SMBHs depend on their host type. The discrepancy between the slope of the M bh - * relations using different definition of velocity dispersion vanishes in our sample, a uniform slope will constrain the coevolution theories of the SMBHs and their host galaxies more effectively. We also find the slope for the 'core' elliptical galaxies at the high-mass range of the relation appears steeper ( 5-6), which may be the imprint of their origin of dissipationless mergers.