The link between brightest cluster galaxy properties and large scale
  extensions of 38 DAFT/FADA and CLASH clusters in the redshift range 0.2<z<0.9
  In the context of large scale structure formation, clusters of galaxies are
located at the nodes of the cosmic web, and continue to accrete galaxies and
groups along filaments. They show sometimes a very large extension and a
preferential direction. Brightest cluster galaxies (BCGs) are believed to grow
through the accretion of many small galaxies, and their structural properties
are expected to vary with redshift. In some cases BCGs show an orientation
comparable to that of the cluster to which they belong. We analyse the
morphological properties of 38 BCGs from the DAFT/FADA and CLASH surveys and
compare the position angles of their major axes to the direction of the cluster
elongation at Mpc scale. The morphological properties of the BCGs were studied
by applying the GALFIT software to HST images and fitting the light
distribution with one or two Sersic laws, or with a Nuker plus a Sersic law.
The cluster elongations were estimated by computing density maps of red
sequence galaxies. The analysis of the 38 BCGs shows that in 11 cases a single
Sersic law is sufficient to account for the surface brightness, while for all
the other clusters two laws are necessary. For the outer Sersic component, the
effective radius increases with decreasing redshift, and the effective surface
brightness decreases with effective radius, following the Kormendy law. An
agreement between the major axis of the BCG and the cluster elongation at large
scale within +-30 deg is found for 12 clusters out of the 21 for which both PAs
can be defined. The variation with redshift of the effective radius of the
outer Sersic component agrees with the growing of BCGs by accretion of smaller
galaxies from z=0.9 to 0.2. The directions of the elongations of BCGs and of
their host clusters and large scale structures agree for 12 objects out of 21,
implying that a larger sample is necessary to reach more definite conclusions.
