Non-Gaussian velocity distributions - The effect on virial mass estimates of galaxy groups

Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.23). 03/2011; 413. DOI: 10.1111/j.1745-3933.2011.01038.x
Source: arXiv

ABSTRACT We present a study of 9 galaxy groups with evidence for non-Gaussianity in
their velocity distributions out to 4R200. This sample is taken from 57 groups
selected from the 2PIGG catalog of galaxy groups. Statistical analysis
indicates that non-Gaussian groups have masses significantly higher than
Gaussian groups. We also have found that all non-Gaussian systems seem to be
composed of multiple velocity modes. Besides, our results indicate that
multimodal groups should be considered as a set of individual units with their
own properties. In particular, we have found that the mass distribution of such
units are similar to that of Gaussian groups. Our results reinforce the idea of
non-Gaussian systems as complex structures in the phase space, likely
corresponding to secondary infall aggregations at a stage before virialization.
The understanding of these objects is relevant for cosmological studies using
groups and clusters through the mass function evolution.

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