# The black hole mass-bulge mass correlation: bulges versus pseudo-bulges

## TL;DR

This study examines the relationship between supermassive black hole mass and bulge mass in different galaxy types, revealing distinct scaling relations for classical bulges, pseudo-bulges, and elliptical galaxies, which inform galaxy evolution models.

## Contribution

It provides updated and detailed scaling relations between black hole mass and bulge properties for various galaxy types, highlighting differences between classical bulges and pseudo-bulges.

## Key findings

- Pseudo-bulges host smaller black holes than classical bulges of similar mass.
- The tightest correlation is between black hole mass and dynamical mass with a slope of 0.90.
- Core ellipticals follow the same black hole mass relation as normal ellipticals.

## Abstract

We investigate the scaling relations between the supermassive black holes mass (M_bh) and the host bulge mass in elliptical galaxies, classical bulges, and pseudo-bulges. We use two-dimensional image analysis software BUDDA to obtain the structural parameters of 57 galaxies with dynamical M_bh measurement, and determine the bulge K-band luminosities (L_bul,K), stellar masses (M_s), and dynamical masses (M_d). The updated M_bh-L_bul,K, M_bh-M_s, and M_bh-M_d correlations for elliptical galaxies and classical bulges give M_bh~0.006M_s or 0.003M_d. The most tight relationship is log(M_bh/M_sun)=a+b log(M_d/10^11 M_sun), with a=8.46+/-0.05, b=0.90+/-0.06, and intrinsic scatter 0.27 dex. The pseudo-bulges follow their own relations, they harbor an order of magnitude smaller black holes than those in the same massive classical bulges, i.e. M_bh~0.0003M_s or 0.0002M_d. Besides the M_bh-\sigma (bulge stellar velocity dispersion) relation, these bulge type dependent M_bh-M_bul scaling relations provide information for the growth and coevolution histories of SMBHs and their host bulges. We also find the core elliptical galaxies obey the same M_bh-M_d relation with other normal elliptical galaxies, that is expected in the dissipationless merger scenario.