[Todos] IAFE-Seminario: "Morphological Properties of Superclusters of Galaxies"]

[difusion en iafe.uba.ar]

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                   SEMINARIO EN EL IAFE
              Instituto de Astronomía y Física del Espacio
                   2010 - 40 aniversario IAFE
                         CONICET-UBA
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        "Morphological Properties of Superclusters of Galaxies"
                     Dr. Laerte Sodré
  Departamento de Astronomía, Universidad de San Pablo, Brasil
                     Viernes 22 de octubre 2010, 11:30hs.
                     Aula del Edificio IAFE

Resumen: We studied superclusters of galaxies in a volume-limited sample
extracted from the Sloan Digital Sky Survey Data Release 7 (SDSS/DR7) and
from mock catalogues based on a semi-analytical model of galaxy evolution
in the Millenium Simulation. A density field method was applied to a
sample of galaxies brighter than M_r= -21+5log h to identify
superclusters, taking into account selection and boundary effects. In
order to evaluate the influence of threshold density, we have chosen two
thresholds: the first maximizes the number of objects (D1), and the second
constrains the maximum supercluster size to ~120 h^{-1} Mpc (D2). We have
performed a morphological analysis, using Minkowski Functionals, based on
a parameter which increases monotonically from filaments to pancakes. An
anti-correlation was found between supercluster richness (and total
luminosity or size) and the morphological parameter, indicating that
filamentary structures tend to be richer, larger and more luminous than
pancakes in both observed and mock catalogues. We have also used the mock
samples to compare supercluster morphologies identified in position and
velocity spaces, concluding that our morphological classification is not
biased by the peculiar velocities. Monte Carlo simulations designed to
investigate the reliability of our results with respect to random
fluctuations show that these results are robust. Our analysis indicates
that filaments and pancakes present different luminosity and size
distributions.