The estimation of black-hole masses in distant radio galaxies

TL;DR

This study estimates supermassive black hole masses in 2442 distant radio galaxies using optical and radio data, revealing a peak in black hole growth around redshift 1.9, supporting a self-regulating growth model.

Contribution

It provides a comparative analysis of black hole mass estimates from optical and radio data and constructs relationships with redshift for a large galaxy sample.

Findings

Black hole mass estimates peak at redshift ~1.9.

Optical and radio data yield similar black hole growth patterns.

Supports a self-regulating model of black hole growth.

Abstract

We have estimated the masses of the central supermassive black holes of 2442 radio galaxies froma catalog compiled using data from the NED, SDSS, and CATS databases. Mass estimates based on optical photometry and radio data are compared. Relationships between the mass of the central black hole $M_p^{bh}$ and the redshift $z_p$ are constructed for both wavelength ranges. The distribution of the galaxies in these diagrams and systematic effects influencing estimation of the black-hole parameters are discussed. Upperenvelope cubic regression fits are obtained using the maximum estimates of the black-hole masses. The optical and radio upper envelopes show similar behavior, and have very similar peaks in position, $z_p \simeq 1.9$, and amplitude, $\log M_p^{bh}$ = 9.4. This is consistent with a model in which the growth of the supermassive black holes is self-regulating, with this redshift corresponding to the epoch when the accretion-flow phase begins to end and the nuclear activity falls off.