Testing Gravity with Cosmic Voids

PADILLA, NELSON D.

San Juan

Workshop; 57ª Reunión Anual de la Asociación Argentina de Astronomía; 2015

Cosmic voids are increasingly turning into key players in testing the physics of our Universe. Here we concentrate on the abundances and dynamics of voids since these are among the best candidates to provide information on our cosmology. Cai, Padilla Li use the abundance and density profiles of voids to tell apart Hu Sawicki models from General Relativity. An interesting result is that even though, as expected, voids in the dark matter field are emptier in gravity due to the fifth force expelling away from the void centres, they find the opposite when haloes are used to find voids. The abundance of voids in this case becomes even lower in compared to GR for large voids. The differences are significant and this provides a way to tell apart these models. The velocity field differences between and GR, on the other hand, are the same for halo voids and for dark matter voids.