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We explore how the local environment is related to the redshift, type, andluminosity of active galactic nuclei (AGN). Recent simulations and observationsare converging on the view that the extreme luminosity of quasars is fueled inmajor mergers of gas-rich galaxies. In such a picture, quasars are expected tobe located in regions with a higher density of galaxies on small scales wheremergers are more likely to take place. However, in this picture, the activityobserved in low-luminosity AGN is due to secular processes that are lessdependent on the local galaxy density. To test this hypothesis, we compare thelocal photometric galaxy density on kiloparsec scales around spectroscopic TypeI and Type II quasars to the local density around lower luminosityspectroscopic Type I and Type II AGN. To minimize projection effects andevolution in the photometric galaxy sample we use to characterize AGNenvironments, we place our random control sample at the same redshift as ourAGN and impose a narrow redshift window around both the AGN and controltargets. We find that higher luminosity AGN have more overdense environmentscompared to lower luminosity AGN on all scales out to our $2\Mpchseventy$limit. Additionally, in the range $0.3\leqslant z\leqslant 0.6$, Type IIquasars have similarly overdense environments to those of bright Type I quasarson all scales out to our $2\Mpchseventy$ limit, while the environment of dimmerType I quasars appears to be less overdense than the environment of Type IIquasars. We see increased overdensity for Type II AGN compared to Type I AGN onscales out to our limit of $2\Mpchseventy$ in overlapping redshift ranges. Wealso detect marginal evidence for evolution in the number of galaxies within$2\Mpchseventy$ of a quasar with redshift.

AGN Environments in the Sloan Digital Sky Survey I: Dependence on Type, Redshift, and Luminosity