Black hole mass estimate for a sample of radio-loud narrow-line Seyfert 1 galaxies

TL;DR

This paper introduces a new method for estimating black hole masses in radio-loud narrow-line Seyfert 1 galaxies, revealing they are generally more massive than previous estimates and comparable to blazars.

Contribution

The paper proposes a novel approach linking accretion disk models to the Big Blue Bump for more accurate black hole mass estimation in RL-NLS1 galaxies.

Findings

Black hole masses are at least six times higher than previous virial estimates.

Eddington ratios are lower with the new mass estimates.

Black hole masses typically exceed 10^8 solar masses.

Abstract

We discuss the relationship between a standard Shakura & Sunyaev (1973) accretion disk model and the Big Blue Bump (BBB) observed in Type 1 AGN, and propose a new method to estimate black hole masses. We apply this method to a sample of 23 radio-loud narrow-line Seyfert 1 (RL-NLS1) galaxies, using data from WISE (Wide-field Infrared Survey Explorer), SDSS (Sloan Digital Sky Survey) and GALEX. Our black hole mass estimates are at least a factor $\sim$6 above previous results based on single epoch virial methods, while the Eddington ratios are correspondingly lower. Hence, the black hole masses of RL-NLS1 galaxies are typically above $10^8 M_{\sun}$, in agreement with the typical black hole mass of blazars.