A study of galaxies near low-redshift quasars
  The impact of quasars on their galaxy neighbors is an important factor in the
understanding of the galaxy evolution models. The aim of this work is to
characterize the close environments of quasars at low redshift (z$<$0.2) with
the most statistically complete sample up to date using the seventh data
release of the Sloan Digital Sky Survey. We have used 305 quasar-galaxy
associations with spectroscopically measured redshifts within the projected
distance range of 350 kpc, to calculate how surface densities of galaxies,
colors, star-formation rates, oxygen abundances, dust extinction and ionization
changes as a function of the distance to the quasars. We also identify and
exclude the AGN from our main galaxy sample and calculate surface density of
different galaxy types. We have done this in three different quasar-galaxy
redshift difference ranges $|\Delta$z$|<$ 0.001, 0.006, and 0.012. Our results
suggest that there is a significant increase of the galaxy surface density
around quasars, indicating quasar formation by merging scenario. We also
observe a gap in the surface densities of AGN and blue galaxies at a distance
of approximately 150 kpc from the quasar. We see no significant changes of star
formation rate, color and ionization as function of distance from the quasar.
From this investigation we cannot see any effects from quasars on their galaxy
companions.
