The VIMOS Public Extragalactic Redshift Survey (VIPERS)

Ω_m0 from the galaxy clustering ratio measured at z ~ 1^⋆

¹ Aix Marseille Université, CNRS, CPT, UMR 7332, 13288 Marseille, France
e-mail: jbel@cpt.univ-mrs.fr
² Institut Universitaire de France  
³ INAF – Osservatorio Astronomico di Brera, via Brera 28, 20122 Milano, via E. Bianchi 46, 23807 Merate, Italy
⁴ Dipartimento di Fisica, Università di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy
⁵ SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
⁶ Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
⁷ INFN, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
⁸ INAF – Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monte Porzio Catone ( RM), Italy
⁹ INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127, Bologna, Italy
¹⁰ INAF – Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, 20133 Milano, Italy
¹¹ INAF – Osservatorio Astrofisico di Torino, 10025 Pino Torinese, Italy
¹² Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
¹³ Canada-France-Hawaii Telescope, 65–1238 Mamalahoa Highway, Kamuela, HI 96743, USA
¹⁴ Laboratoire Lagrange, UMR7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
¹⁵ Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan
¹⁶ Dipartimento di Fisica e Astronomia – Università di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁷ INAF – Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste, Italy
¹⁸ Institute of Physics, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406 Kielce, Poland
¹⁹ Department of Particle and Astrophysical Science, Nagoya University, Furo-cho,Chikusa-ku, 464-8602 Nagoya, Japan
²⁰ INFN, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
²¹ Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, 75014 Paris, France
²² Astronomical Observatory of the Jagiellonian University, Orla 171, 30-001 Cracow, Poland
²³ National Centre for Nuclear Research, ul. Hoza 69, 00-681 Warszawa, Poland
²⁴ Max-Planck-Institut für Extraterrestrische Physik, 84571 Garching b. München, Germany
²⁵ Universitätssternwarte München, Ludwig-Maximillians Universität, Scheinerstr. 1, 81679 München, Germany
²⁶ Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3FX, UK
²⁷ INAF – Istituto di Astrofisica Spaziale e Fisica Cosmica Bologna, via Gobetti 101, 40129 Bologna, Italy
²⁸ INAF – Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
²⁹ Università degli Studi di Milano, via G. Celoria 16, 20130 Milano, Italy
³⁰ Université de Toulon, CNRS, CPT, UMR 7332, 83957 La Garde, France

Received: 22 May 2013
Accepted: 20 November 2013

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 (PDR-1) catalogue, to constrain the cosmological model through a measurement of the galaxy clustering ratio η_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, ξ(nR), and its variance σ²(R). For sufficiently large values of R, this is a universal number, which captures 2-point clustering information independently of the linear bias and linear redshift-space distortions of the specific galaxy tracers. In this paper, we discuss how to extend the application of η_g,R to quasi-linear 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 η_g,R to non-linearities 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 η_g,R(15) = 0.141 ± 0.013 at R = 5h^-1 Mpc. Within a flat ΛCDM 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 Ω_m,0 = 0.270_-0.025^+0.029. In addition to the great precision achieved on our estimation of Ω_m using VIPERS PDR-1, this result is remarkable because it appears to be in good agreement with a recent estimate at z ≃ 0.3, which was obtained by applying the same technique to the SDSS-LRG catalogue. It, therefore, supports the robustness of the present analysis. Moreover, the combination of these two measurements at z ~ 0.3 and z ~ 0.9 provides us with a very precise estimate of Ω_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.