The local black hole mass function derived from the M_{BH}-P and the M_{BH}-n relations

TL;DR

This paper derives the supermassive black hole mass function for nearby galaxies using empirical relations with galaxy structural parameters, providing a new estimate consistent with previous high-mass results and offering insights into low-mass black hole populations.

Contribution

It introduces a novel method to estimate the SMBH mass function using Sersic index and pitch angle distributions, applicable to a volume-limited galaxy sample.

Findings

The SMBH mass function aligns with previous high-mass estimates.

The low-mass end of the SMBH mass function is more consistent with black hole evolution models.

The method provides a simple observational approach based on galaxy structural parameters.

Abstract

We present a determination of the supermassive black hole (SMBH) mass function for early- and late-type galaxies in the nearby universe (z<0.0057), established from a volume-limited sample consisting of a statistically complete collection of the brightest spiral galaxies in the southern hemisphere. The sample is defined by limiting luminosity (redshift-independent) distance, D_L=25.4 Mpc, and a limiting absolute B-band magnitude, M_B=-19.12. These limits define a sample of 140 spiral, 30 elliptical (E), and 38 lenticular (S0) galaxies. We established the Sersic index distribution for early-type (E/S0) galaxies in our sample. Davis et al. (2014) established the pitch angle distribution for their sample, which is identical to our late-type (spiral) galaxy sample. We then used the pitch angle and the Sersic index distributions in order to estimate the SMBH mass function for our volume-limited sample. The observational simplicity of our approach relies on the empirical relation between the mass of the central (SMBH) and the Sersic index (Graham et al. 2007) for an early-type galaxy or the logarithmic spiral arm pitch angle (Berrier et al. 2013) for a spiral galaxy. Our SMBH mass function agrees well at the high-mass end with previous values in the literature. At the low-mass end, while inconsistencies exist in previous works that still need to be resolved, our work is more in line with expectations based on modeling of black hole evolution.