  We analyse the relation between AGN host properties and large scale
environment for a representative red and blue AGN host galaxy sample selected
from the DR4 SDSS. A comparison is made with two carefully constructed control
samples of non-active galaxies, covering the same redshift range and color
baseline. The cross-correlation functions show that the density distribution of
neighbours is almost identical for blue galaxies, either active, or non-active.
Although active red galaxies inhabit environments less dense compared to
non-active red galaxies, both reside in environments considerably denser than
those of blue hosts. Moreover, the radial density profile of AGN, relative to
galaxy group centres is less concentrated than galaxies. This is particularly
evident when comparing red AGN and non-active galaxies.
  The properties of the neighbouring galaxies of blue and red AGN and non
active galaxies reflect this effect. While the neighbourhood of the blue
samples is indistinguishable, the red AGN environs show an excess of blue-star
forming galaxies with respect to their non-active counterpart. On the other
hand, the active and non-active blue systems have similar environments but
markedly different morphological distributions, showing an excess of blue
early-type AGN, which are argued to be late stage mergers. This comparison
reveals that the observable differences between active red and blue host galaxy
properties including star formation history and AGN activity depends on the
environment within which the galaxies form and evolve.
