INVESTIGADORES
VALOTTO Carlos Alberto
artículos
Título:
Galaxy Peculiar Velocities and Infall onto Groups
Autor/es:
CECCARELLI, M. L.; VALOTTO, C.; LAMBAS, D. G.; PADILLA, N; GIOVANELLI, R; HAYNES, M.
Revista:
ASTROPHYSICAL JOURNAL
Editorial:
The University of Chicago Press
Referencias:
Lugar: Chicago, Estados Unidos; Año: 2005 vol. 622 p. 853 - 861
ISSN:
0004-637X
Resumen:
We perform statistical analysis to study the infall of galaxies onto
groups and clusters in the nearby universe. The study is based on the
Updated Zwicky Catalog and Southern Sky Redshift Survey 2 group catalogs
and peculiar velocity samples. We find a clear signature of infall of
galaxies onto groups over a wide range of scales
5h-1Mpc<r<30h-1Mpc, with an infall amplitude
on the order of a few hundred kilometers per second. We obtain a
significant increase in the infall amplitude with group virial mass
(MV) and luminosity of group member galaxies (Lg).
Groups with MV<1013 Msolar show
infall velocities Vinf~=150 km s-1, whereas for
MV>1013 Msolar a larger infall is
observed, Vinf~=200 km s-1. Similarly, we find
that galaxies surrounding groups with Lg<1015
Lsolar have Vinf~=100 km s-1, whereas
for Lg>1015 Lsolar groups, the
amplitude of the galaxy infall can be as large as Vinf~=250
km s-1. The observational results are compared with the
results obtained from mock group and galaxy samples constructed from
numerical simulations, which include galaxy formation through
semianalytical models. We obtain a general agreement between the results
from the mock catalogs and the observations. The infall of galaxies onto
groups is suitably reproduced in the simulations, and, as in the
observations, larger virial mass and luminosity groups exhibit the
largest galaxy infall amplitudes. We derive estimates of the integrated
mass overdensities associated with groups by applying linear theory to
the infall velocities after correcting for the effects of distance
uncertainties obtained using the mock catalogs. The resulting
overdensities are consistent with a power law with δ~1 at r~10
h-1 Mpc.