Dinámica en los entornos a grupos de galaxias

CECCARELLI, M. L.; GARCÍA LAMBAS, D.; VALOTTO, C.; PADILLA, N.

La Plata, Argentina

Congreso; 46a Reunión de la Asociación Argentina de Astronomía; 2003

Asociación Argentina de Astronomía

In this work we have performed a study of the infall of galaxies onto groups in the near universe assuming the spherical infall model (J. P. E. Peebles, The Large Scale Structure of the Universe, 1980; A. Yahil, The Virgo Cluster of Galaxies, 1985). The statistical analysis consisted in the study of galaxy dynamics in groups of external regions. The observational data were obtained from Giovanelli & Haynes (2003) peculiar velocities catalog, the updated Zwicky Catalog and Sky South Redshift Survey 2 groups catalogs (Ramella et. al, A.J. vol. 123 pag. 2676, 2002). We have obtained the mean galaxy infall velocity as a function of distance to the UZC/SSRS2 group centers. The results were compared with the theory of infall velocities derived from the model. We find that it gives an accurate description of the velocity field in a large scale range between 4 and 20 Mpc/h. Similar analyses were performed for mock catalogs specially designed to confront models to observations. We obtained a good agreement between the results of both catalogs. We investigated the existence of same entail beetwen virial mass and the mass overdensity. We studied the infall of mass particles to the haloes in the simulations and we compared with the infall of galaxies onto the groups in the mock catalogs. We obtain similar results which indicate that galaxies and mass have the same dynamical behavior in these regions.