Galaxy properties in clusters. II. Backsplash Galaxies
  We explore the properties of galaxies on the outskirts of clusters and their
dependence on recent dynamical history in order to understand the real impact
that the cluster core has on the evolution of galaxies. We analyse the
properties of more than 1000 galaxies brighter than $M_{^{0.1}r}$=-19.6 on the
outskirts of 90 clusters ($1<r/r_{vir}<2$) in the redshift range $0.05<z<0.10$.
Using the line of sight velocity, we selected high and low velocity subsamples.
Theoretical predictions indicate that a significant fraction of the first
subsample should be backsplash galaxies, that is, objects that have already
orbited near the cluster centre. A significant proportion of the sample of high
relative velocity HV galaxies seems to be composed of infalling objects. Our
results suggest that, at fixed stellar mass, late type galaxies in the low
velocity LV sample are systematically older, redder and have formed fewer stars
during the last 3 Gyrs than galaxies in the HV sample. This result is
consistent with models that assume that the central regions of clusters are
effective in quenching the star formation by means of processes such as ram
pressure stripping or strangulation. At fixed stellar mass, LV galaxies show
some evidence of having higher surface brightness and smaller size than HV
galaxies. These results are consistent with the scenario where galaxies that
have orbited the central regions of clusters are more likely to suffer tidal
effects, producing loss of mass as well as a redistribution of matter towards
more compact configurations. Finally, we found a higher fraction of ET galaxies
in the LV sample, supporting the idea that the central region of clusters of
galaxies may contribute to the transformation of morphological types towards
earlier types.
