The VIMOS Public Extragalactic Redshift Survey (VIPERS): $\Omega_{\rm m_0}$ from the galaxy clustering ratio measured at $z \sim 1$

Understand

We use a sample of about 22,000 galaxies at $0.65<z<1.2$ from the VIPERS PDR-1 catalogue, to constrain the cosmological model through a measurement of the galaxy {\it clustering ratio} $\eta_{g,R}$.

• This statistic has favourable properties, being defined as the ratio of two quantities characterizing the smoothed density field in spheres of given radius $R$: the value of its correlation function on a multiple of this scale, $\xi(nR)$, and its variance $\sigma^2(R)$.
• For sufficiently large values of $R$, this is a universal number, capturing 2-point clustering information independently of the linear bias and linear redshift-space distortions of the specific galaxy tracers.
• In this paper we discuss in detail how to extend the application of $\eta_{g,R}$ to quasi-linear scales and how to control and remove observational selection effects which are typical of redshift surveys as VIPERS.