Dark Sector Coupling Bends the Superclusters
  The galaxy clusters exhibit noticeably anisotropic pattern in their
clustering, which is vividly manifested by the presence of rich filament-like
superclusters. The more anisotropic the clustering of galaxy clusters is, the
more straight the rich filament-like superclusters become. Given that the
degree of the anisotropy in the largest-scale clustering depends sensitively on
the nature of dark energy, the supercluster straightness may play a
complimentary role in testing dynamic dark energy models. Here we focus on the
coupled dark energy (cDE) models which assume the existence of dark sector
coupling between scalar field dark energy and nonbaryonic dark matter.
Determining the spines of the superclusters identified in the publicly
available group catalogs from the CODECS (COupled Dark Energy Cosmological
Simulations) for four different cDE models as well as for the LCDM model, we
quantify the straightness of each supercluster as the spatial extent of its
spine per member cluster where a supercluster spine represents the main stem of
the minimal spanning tree constructed out of the member clusters. It is shown
that the dark sector coupling plays a role in making the supercluster less
straight relative to the LCDM case and that in a cDE model with supergravity
potential the superclusters are least straight. We also find that the
difference in the degree of the supercluster straightness between the cDE and
the LCDM cases increases with redshifts. A physical interpretation of our
result as well as its cosmological implication are discussed.
