Euclid: Cosmology forecasts from the voidgalaxy crosscorrelation function with reconstruction
Abstract
We have investigated the cosmological constraints that can be expected from measurement of the crosscorrelation of galaxies with cosmic voids identified in the Euclid spectroscopic survey, which will include spectroscopic information for tens of millions of galaxies over 15 000 deg^{2} of the sky in the redshift range 0.9 ≤ z < 1.8. We have done this using simulated measurements obtained from the Flagship mock catalogue, the official Euclid mock that closely matches the expected properties of the spectroscopic dataset. To mitigate anisotropic selectionbias effects, we have used a velocity field reconstruction method to remove largescale redshiftspace distortions from the galaxy field before voidfinding. This allowed us to accurately model contributions to the observed anisotropy of the crosscorrelation function arising from galaxy velocities around voids as well as from the AlcockPaczynski effect, and we studied the dependence of constraints on the efficiency of reconstruction. We find that Euclid voids will be able to constrain the ratio of the transverse comoving distance D_{M} and Hubble distance D_{H} to a relative precision of about 0.3%, and the growth rate fσ_{8} to a precision of between 5% and 8% in each of the four redshift bins covering the full redshift range. In the standard cosmological model, this translates to a statistical uncertainty ΔΩ_{m} = ±0.0028 on the matter density parameter from voids, which is better than what can be achieved from either Euclid galaxy clustering and weak lensing individually. We also find that voids alone can measure the dark energy equation of state to a 6% precision.
This paper is published on behalf of the Euclid Consortium.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 September 2023
 DOI:
 10.1051/00046361/202346121
 arXiv:
 arXiv:2302.05302
 Bibcode:
 2023A&A...677A..78R
 Keywords:

 cosmology: observations;
 cosmological parameters;
 largescale structure of Universe;
 surveys;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 20 pages, 13 figures, accepted version