Encircling the dark: constraining dark energy via cosmic density in spheres

S. Codis (1) , C. Pichon (2, 3) , F. Bernardeau (2, 4) , C Uhlemann (5) , S. Prunet (6)

1 CITA - Canadian Institute for Theoretical Astrophysics
2 IAP - Institut d'Astrophysique de Paris
3 KIAS - Korean Institute of Advanced Studies
4 IPHT - Institut de Physique Théorique - UMR CNRS 3681
5 Utrecht University [Utrecht]
6 CFHT - Canada-France-Hawaii Telescope Corporation

The recently published analytic probability density function for the mildly non-linear cosmic density field within spherical cells is used to build a simple but accurate maximum likelihood estimate for the redshift evolution of the variance of the density, which, as expected, is shown to have smaller relative error than the sample variance. This estimator provides a competitive probe for the equation of state of dark energy, reaching a few percent accuracy on $w_p$ and $w_a$ for a Euclid-like survey. The corresponding likelihood function can take into account the configuration of the cells via their relative separations. A code to compute one-cell density probability density functions for arbitrary initial power spectrum, top-hat smoothing and various spherical collapse dynamics is made available online so as to provide straightforward means of testing the effect of alternative dark energy models and initial power-spectra on the low-redshift matter distribution.

Keywords: cosmology: theory; large-scale structure of Universe; methods: numerical; methods: analytical

Domains: Physics [physics]

S. Codis, C. Pichon, F. Bernardeau, C Uhlemann, S. Prunet. Encircling the dark: constraining dark energy via cosmic density in spheres. Monthly Notices of the Royal Astronomical Society, 2016, 460, pp.1549-1554. ⟨cea-01677531⟩