Ongoing Star Formation In AGN Host Galaxy Disks: A View From Core-collapse Supernovae

TL;DR

This study compares the distribution of young stars in AGN host galaxies and star-forming galaxies using supernovae as tracers, revealing differences that suggest ongoing star formation is linked to AGN activity.

Contribution

It provides new evidence of non-exponential supernova distributions in AGN hosts, indicating ongoing star formation in extended disks associated with AGN activity.

Findings

Supernovae in star-forming galaxies follow an exponential distribution.

Supernovae in AGN hosts deviate from exponential distribution, with deficits and over-densities at specific radii.

The results support a connection between extended disk star formation and central AGN activity.

Abstract

The normalized radial distribution of young stellar populations (and cold gas) in nearby galactic disks is compared between AGN host galaxies and starforming galaxies (both with Hubble types between S0/a and Scd) by using type II supernovae (SNe) as tracers. A subset of 140 SNe\,II with available supernova position measurements are selected from the SAI-SDSS image catalog by requiring available SDSS spectroscopy data of their host galaxies. Our sample is finally composed of 46 AGNs and 94 starforming galaxies. Both directly measured number distributions and inferred surface density distributions indicate that a) the SNe detected in starforming galaxies follow an exponential law well; b) by contrast, the SNe detected in AGN host galaxies significantly deviate from an exponential law, which is independent of both morphological type and redshift. Specifically, we find a detection deficit around $R_{\mathrm{SN}}/R_{25,\mathrm{cor}}\sim0.5$ and an over-detection at outer region $R_{\mathrm{SN}}/R_{25,\mathrm{cor}}\sim0.6-0.8$. This finding provides a piece of evidence supporting that there is a link between ongoing star formation (and cold gas reservoir) taking place in the extended disk and central AGN activity.