The Clustering of Agn in the Sloan Digital Sky Survey

We present the two–point correlation function (2PCF) of narrow-line active galactic nuclei (AGN) selected within the First Data Release of the Sloan Digital Sky Survey. Using a sample of 13605 AGN in the redshift range 0.055 < z < 0.2, we find that the AGN auto–correlation function is consistent with the observed galaxy auto–correlation function on scales 0.2hMpc to > 100hMpc. The AGN hosts trace an intermediate population of galaxies and are not detected in either the bluest (youngest) disk–dominated galaxies or many of the reddest (oldest) galaxies. We show that the AGN 2PCF is dependent on the luminosity of the narrow [OIII] emission line (L[OIII]), with low L[OIII] AGN having a higher clustering amplitude than high L[OIII] AGN. This is consistent with lower activity AGN residing in more massive galaxies than higher activity AGN, and L[OIII] providing a good indicator of the fueling rate. Using a model relating halo mass to black hole mass in cosmological simulations, we show that AGN hosted by ∼ 10 M⊙ dark matter halos have a 2PCF that matches that of the observed sample. This mass scale implies a mean black hole mass for the sample of MBH ∼ 10 8 M⊙. Subject headings: galaxies: active — galaxies: formation — galaxies: statistics