Bibcode
Patiri, S. G.; Betancort-Rijo, J. E.; Prada, F.
Bibliographical reference
Astronomy and Astrophysics, Volume 541, id.L4
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5
2012
Journal
Citations
10
Refereed citations
9
Description
We report the detection, with a high level of confidence, of coherent
outflows around voids found in the seventh data release of the Sloan
Digital Sky Survey (SDSS DR7). In particular, we developed a robust
⟨|cos θ|⟩ statistical test to quantify the strength of
redshift-space distortions (RSD) associated with extended coherent
velocity fields. We consistently find that the vector that joins void
centers with galaxies that lie in shells around them is more likely to
be perpendicular to the line-of-sight than parallel to it. This effect
is clear evidence for the existence of outflows in the vicinity of
voids. We show that the RSD exist for a wide range of void radius and
shell thickness, but they are more evident in the largest voids in our
sample. For instance, we find that the ⟨|cos θ|⟩ for
galaxies located in shells within 2 h-1Mpc from the edge of
voids larger than 15 h-1Mpc deviates 3.81σ from
uniformity. The measurements presented in this work provide useful
information to constrain cosmological parameters, in particular
Ωm and σ8.
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