# Study of Central Intensity Ratio of Seyfert Galaxies in nearby Universe

## TL;DR

This study investigates the Central Intensity Ratio (CIR) in nearby Seyfert galaxies, revealing its strong anti-correlation with SMBH mass and its potential as a quick, reliable estimator of black hole mass independent of central engine activity.

## Contribution

It introduces CIR as a new photometric parameter for analyzing galaxy centers and demonstrates its effectiveness in estimating SMBH mass across different galaxy types.

## Key findings

- CIR strongly anti-correlates with SMBH mass.
- Elliptical galaxies have higher SMBH masses for a given CIR.
- CIR is less affected by central engine flux than spectroscopic parameters.

## Abstract

We use the recently discovered simple photometric parameter Central Intensity Ratio (CIR, Aswathy & Ravikumar 2018) determined for a sample of 57 nearby (z < 0.02) Seyfert galaxies to explore the central features of galaxies and their possible connection with galaxy evolution. The sample of galaxies shows strong anti-correlation between CIR and mass of their central supermassive black holes (SMBH). The SMBH masses of ellipticals are systematically higher for a given CIR value than that for lenticulars and spirals in the sample. However, the correlation between CIR and central velocity dispersion is weak. CIR appears less influenced by the excess flux produced by the central engine in these galaxies, when compared to spectroscopic parameters like velocity dispersion and OIV flux, and proves a fast and reliable tool for estimating central SMBH mass.