  We investigate the extent and the properties of the MgII cool, low-density
absorbing gas located in the halo and in the circum-galactic environment of
quasars, using a sample of 31 projected quasar pairs with impact parameter
pd<200kpc in the redshift range 0.5<z<1.6. In the transverse direction, we
detect 18 MgII absorbers associated with the foreground quasars, while no
absorption system originated by the gas surrounding the quasar itself is found
along the line-of-sight. This suggests that the quasar emission induces an
anisotropy in the absorbing gas distribution. Our observations indicate that
the covering fraction (fc) of MgII absorption systems with rest frame
equivalent width Wr(2796)>0.3Ang. ranges from fc~1.0 at pd<65kpc to fc~0.2 at
pd>150kpc, and appears to be higher than for galaxies. Our findings support a
scenario where the luminosity/mass of the host galaxies affect the extent and
the richness of the absorbing MgII circum-galactic medium.
