The environment of Seyferts, Liners and HII galaxies in a Complete AGN sample

Abstract

We use a complete AGN sample (Ho et al. 1997) to study the environment of Seyferts, LINERs and HII galaxies. For each AGN we search for companions in the UZC redshift catalogue and compute local as well as large scale neighbour density and distance to the nearest neighbour. We find that on small scale (~ 0.2 h^-1 Mpc) LINERs exhibit denser environments than Seyferts and HII galaxies at 3 sigma significance level. The same result is not confirmed when densities are computed on large scales. LINERs also exhibit closer nearest neighbours than Seyferts and HII galaxies (at 2 sigma c.l.). However, when excluding AGNs in early type galaxy hosts, the neighbour density characteristics of LINERs Seyferts and HII galaxies turn out to be similar, a result that confirms that the excess of neighbours around LINERs is most likely due to a morphology-density effect.