Voids in galaxy catalogues: dynamical properties

CECCARELLI, L.; PADILLA, N.; VALOTTO, C.; LAMBAS, D. G

Capilla del Monte, Argentina

Congreso; Reunión 49 de la Asociación Argentina de Astronomía; 2006

Asociación Argentina de Astronomía

We perform a statistical study on the distribution and dynamics of voids in the 2dFGRS. Our statistics are tested and calibrated using mock catalogues. The void-galaxy cross-correlation redshift-space distortions show evidence of the continuing growth of voids, confirming another prediction of the hierarchical clustering scenario. A non-linear outflow model can be used to provide quantitative estimates of the outflow velocities around 2dFGRS voids. These results are consistent with maximum outflows of 110 km/s, 210 km/s and 270 km/s for voids of <r_{void}>=7.5, 12.5 and 17.5 h^{-1} Mpc, assuming a galaxy bias of b=1. We find that it would also be possible to detect differences in the velocity dispersion of galaxies in the directions parallel and perpendicular to the void walls.