Voids in the 2dFGRS and LambdaCDM simulations: Spatial and Dymanical Properties

LAURA CECCARELLI; NELSON PADILLA; CARLOS VALOTTO; DIEGO G LAMBAS

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2006 vol. 373 p. 1440 - 1450

0035-8711

We perform a statistical study on the distribution and dynamics of voidsin the 2dFGRS.  Our statistics are tested and calibrated using mock 2dFGRScatalogues.  We analyse the dynamics around voidsin mock and real 2dFGRS surveys.  The void-galaxy cross-correlation redshift-space distortions  show evidence of the continuing growth of voids, confirming anotherprediction of the hierarchical clustering scenario. A non-linear outflow model can be used to provide quantitative estimates of the outflow velocitiesaround 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 $b=1$.As an application for future surveys, our study of the mock catalogues showsthat direct measurements of the expansion of voids can be obtained using peculiar velocity data.We find that it would also be possible to detect differences in the velocity dispersionof galaxies in the directions parallel and perpendicular to the void walls.