IATE   20350
INSTITUTO DE ASTRONOMIA TEORICA Y EXPERIMENTAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Void Dynamics
Autor/es:
PADILLA, NELSON D.; DANTE J. PAZ; LARES, MARCELO; CECCARELLI, LAURA; LAMBAS, DIEGO G.; CAI, YAN-CHUAN; LI, BAOJIU
Lugar:
Tallinn
Reunión:
Simposio; IAU308 Symposium "The Zeldovich Universe"; 2014
Institución organizadora:
Unión Astronómica Internacional
Resumen:
Cosmic voids are becoming key players in testing the physics of our
Universe. Here we concentrate on the abundances and the dynamics of
voids as these are among the best candidates to provide information on
cosmological parameters. Cai, Padilla \& Li (2014) use the abundance
of voids to tell apart Hu \& Sawicki $f(R)$ models from General
Relativity. An interesting result is that even though, as expected,
voids in the dark matter field are emptier in $f(R)$ gravity due to the
fifth force expelling away from the void centres, this result is
reversed when haloes are used to find voids. The abundance of voids in
this case becomes even lower in $f(R)$ compared to GR for large voids.
Still, the differences are significant and this provides a way to tell
apart these models. The velocity field differences between $f(R)$ and
GR, on the other hand, are the same for halo voids and for dark matter
voids. Paz et al. (2013), concentrate on the velocity profiles around
voids. First they show the necessity of four parameters to describe the
density profiles around voids given two distinct void populations,
voids-in-voids and voids-in-clouds. This profile is used to predict
peculiar velocities around voids, and the combination of the latter with
void density profiles allows the construction of model void-galaxy
cross-correlation functions with redshift space distortions. When these
models are tuned to fit the measured correlation functions for voids and
galaxies in the Sloan Digital Sky Survey, small voids are found to be of
the void-in-cloud type, whereas larger ones are consistent with being
void-in-void. This is a novel result that is obtained directly from
redshift space data around voids. These profiles can be used to remove
systematics on void-galaxy Alcock-Pacinsky tests coming from
redshift-space distortions.