Morphological Segregation in the Surroundings of Cosmic Voids
  We explore the morphology of galaxies living in the proximity of cosmic
voids, using a sample of voids identified in the Sloan Digital Sky Survey Data
Release 7. At all stellar masses, void galaxies exhibit morphologies of a later
type than galaxies in a control sample, which represent galaxies in an average
density environment. We interpret this trend as a pure environmental effect,
independent of the mass bias, due to a slower galaxy build-up in the rarefied
regions of voids. We confirm previous findings about a clear segregation in
galaxy morphology, with galaxies of a later type being found at smaller
void-centric distances with respect to the early-type galaxies. We also show,
for the first time, that the radius of the void has an impact on the
evolutionary history of the galaxies that live within it or in its
surroundings. In fact, an enhanced fraction of late-type galaxies is found in
the proximity of voids larger than the median void radius. Likewise, an excess
of early-type galaxies is observed within or around voids of a smaller size. A
significant difference in galaxy properties in voids of different sizes is
observed up to 2 Rvoid, which we define as the region of influence of voids.
The significance of this difference is greater than 3sigma for all the
volume-complete samples considered here. The fraction of star-forming galaxies
shows the same behavior as the late-type galaxies, but no significant
difference in stellar mass is observed in the proximity of voids of different
sizes.
