Low redshift quasars in the SDSS Stripe 82. The local environments
  We study the environments of low redshift (z < 0.5) quasars based on a large
and homogeneous dataset from the Stripe 82 region of the Sloan Digital Sky
Survey (SDSS). We have compared the < 1 Mpc scale envi- ronments of 302 quasars
that were resolved in our recent study to those of 288 inactive galaxies with
closely matched redshifts. Crucially, the lu- minosities of the inactive
galaxies and the quasar host galaxies are also closely matched, unlike in most
previous studies. The environmental overdensities were studied by measuring the
num- ber density of galaxies within a projected distance of 200 kpc to 1 Mpc.
The galaxy number density of the quasar environments is comparable to that of
the inactive galaxies with similar luminosities, both classes of ob- jects
showing significant excess compared to the background galaxy density for
distances < 400 kpc. There is no significant dependence of the galaxy number
density on redshift, quasar or host galaxy luminosity, black hole mass or radio
loudness. This suggests that the fueling and triggering of the nuclear activity
is only weakly dependent on the local environment of quasars, and the quasar
phase may be a short-lived common phase in the life cycle of all massive
galaxies.
