Structure formation with clustering quintessence
Vernizzi, Filippo (IPhT - CEA Saclay)

I present a study of large-scale structure formation in the presence of a scalar field dark energy with zero speed of sound. This model is motivated by stability properties of the field. After a short review on the phenomenology of clustering quintessence in linear perturbations, I discuss the nonlinear aspect. First I compute the bispectrum of the density field and show that it is modified by the clustering of quintessence at low redshift, which can potentially be used to detect or rule out our model. I will then study the nonlinear regime using the spherical collapse model. Quintessence contributes to the mass of virialized objects, which represents an observational signature for future galaxies and cluster surveys