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Abstract
We use a sample of about 22 000 galaxies at 0.65 <z <1.2 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) Public Data Release 1 (PDR1) catalogue, to constrain the cosmological model through a measurement of the galaxy clustering ratio eta(g,R). This statistic has favourable properties, which is defined as the ratio of two quantities characterizing the smoothed density field in spheres of a 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, which captures 2point clustering information independently of the linear bias and linear redshiftspace distortions of the specific galaxy tracers. In this paper, we discuss how to extend the application of eta(g,R) to quasilinear scales and how to control and remove observational selection effects, which are typical of redshift surveys as VIPERS, in detail. We verify the accuracy and efficiency of these procedures using mock catalogues that match the survey selection process. These results show the robustness of eta(g,R) to nonlinearities and observational effects, which is related to its very definition as a ratio of quantities that are similarly affected. At an effective redshift z = 0.93, we measured the value eta(g,R)(15) = 0.141 +/ 0.013 at R = 5 h(1) Mpc. Within a flat Lambda CDM cosmology and by including the best available priors on H0, n(s) and baryon density, we obtain a matter density parameter at the current epoch Omega(m,0) = 0.270(0.025)(+0.029). In addition to the great precision achieved on our estimation of Omega(m) using VIPERS PDR1, this result is remarkable because it appears to be in good agreement with a recent estimate at z similar or equal to 0.3, which was obtained by applying the same technique to the SDSSLRG catalogue. It, therefore, supports the robustness of the present analysis. Moreover, the combination of these two measurements at z similar to 0.3 and z similar to 0.9 provides us with a very precise estimate of Omega(m,0) = 0.274 +/ 0.017, which highlights the great consistency between our estimation and other cosmological probes, such as baryonic acoustic oscillations, cosmic microwave background, and supernovae.
Original language  English 

Article number  A37 
Number of pages  17 
Journal  Astronomy & Astrophysics 
Volume  563 
DOIs  
Publication status  Published  1 Mar 2014 
Keywords
 cosmological parameters
 dark matter
 largescale structure of Universe
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Astronomy and Astrophysics at Edinburgh
Heavens, A., Best, P., Cockell, C., Dunlop, J., Ferguson, A., Lawrence, A., McLure, R., Peacock, J., Rice, K. & Taylor, A.
1/04/12 → 31/03/16
Project: Research