Ongoing star formation in AGN host galaxy discs: A view from core-collapse supernovae

Abstract

The normalized radial distribution of young stellar populations (and cold gas) in nearby galactic discs is compared between active galactic nuclei (AGN) host galaxies and star-forming galaxies (both with Hubble types between S0/a and Scd) by using Type II supernovae (SNe II) as tracers. A subset of 140 SNe II with available SN position measurements is selected from the Sternberg Astronomical Institute (SAI)-Sloan Digital Sky Survey (SDSS) image catalogue by requiring available SDSS spectroscopy data of their host galaxies. Our sample is finally composed of 46 AGN and 94 star-forming galaxies. Both directly measured number distributions and inferred surface density distributions indicate that (a) the SNe detected in star-forming galaxies follow an exponential law well; (b) in 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 RSN/R25,cor ∼ 0.5 and an overdetection at outer region RSN/R25,cor ∼ 0.6-0.8. 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 disc and central AGN activity. © 2010 The Authors. Journal compilation © 2010 RAS.