The VIMOS Public Extragalactic Redshift Survey (VIPERS)

Gravity test from the combination of redshift-space distortions and galaxy-galaxy lensing at 0.5 < z < 1.2^⋆

¹ Aix-Marseille Univ, CNRS, LAM, Laboratoire d’Astrophysique de Marseille, UMR , 7326 Aix Marseille, France
e-mail: sylvain.delatorre@lam.fr
² INAF–Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano – via E. Bianchi 46, 23807 Merate, Italy
³ Dipartimento di Fisica, Università di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy
⁴ Aix-Marseille Univ, Univ. Toulon, CNRS, CPT, 13284 Marseille, France
⁵ Università degli Studi di Milano, via G. Celoria 16, 20133 Milano, Italy
⁶ INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, 20133 Milano, Italy
⁷ INAF–Osservatorio Astronomico di Bologna, via Gobetti 93/3, 40129 Bologna, Italy
⁸ INAF–Osservatorio Astrofisico di Torino, 10025 Pino Torinese, Italy
⁹ Laboratoire Lagrange, UMR 7293, Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
¹⁰ Dipartimento di Fisica e Astronomia – Alma Mater Studiorum Università di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹¹ Institute of Physics, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406 Kielce, Poland
¹² National Centre for Nuclear Research, ul. Hoza 69, 00-681 Warszawa, Poland
¹³ INFN, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁴ Aix-Marseille Université, Jardin du Pharo, 58 bd Charles Livon, 13284 Marseille Cedex 7, France
¹⁵ IRAP, 9 Av. du colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
¹⁶ Astronomical Observatory of the Jagiellonian University, Orla 171, 30-001 Cracow, Poland
¹⁷ School of Physics and Astronomy, University of St. Andrews, St. Andrews, KY16 9SS, UK
¹⁸ INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica Bologna, via Gobetti 101, 40129 Bologna, Italy
¹⁹ INAF–Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
²⁰ Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
²¹ INFN, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
²² INAF–Osservatorio Astronomicodi Roma, via Frascati 33, 00040 Monte Porzio Catone (RM), Italy
²³ Department of Astronomy, University of Geneva, Ch. d’Ecogia 16, 1290 Versoix, Switzerland
²⁴ INAF–Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste, Italy
²⁵ Department of Astronomy & Physics, Saint Mary’s University, 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
²⁶ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
²⁷ Instituto de Física Teórica, (UAM/CSIC), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
²⁸ Campus of International Excellence UAM+CSIC, Cantoblanco, 28049 Madrid, Spain
²⁹ Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, 18080 Granada, Spain
³⁰ Departamento de Física Teórica, M-8, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain

Received: 17 December 2016
Accepted: 2 August 2017

Abstract

We carry out a joint analysis of redshift-space distortions and galaxy-galaxy lensing, with the aim of measuring the growth rate of structure; this is a key quantity for understanding the nature of gravity on cosmological scales and late-time cosmic acceleration. We make use of the final VIPERS redshift survey dataset, which maps a portion of the Universe at a redshift of z ≃ 0.8, and the lensing data from the CFHTLenS survey over the same area of the sky. We build a consistent theoretical model that combines non-linear galaxy biasing and redshift-space distortion models, and confront it with observations. The two probes are combined in a Bayesian maximum likelihood analysis to determine the growth rate of structure at two redshifts z = 0.6 and z = 0.86. We obtain measurements of fσ₈(0.6) = 0.48 ± 0.12 and fσ₈(0.86) = 0.48 ± 0.10. The additional galaxy-galaxy lensing constraint alleviates galaxy bias and σ₈ degeneracies, providing direct measurements of f and σ₈: [f(0.6),σ₈(0.6)] = [0.93 ± 0.22,0.52 ± 0.06] and [f(0.86),σ₈(0.86)] = [0.99 ± 0.19,0.48 ± 0.04]. These measurements are statistically consistent with a Universe where the gravitational interactions can be described by General Relativity, although they are not yet accurate enough to rule out some commonly considered alternatives. Finally, as a complementary test we measure the gravitational slip parameter, E_G, for the first time at z > 0.6. We find values of E̅_G(0.6) = 0.16±0.09 and E̅_G(0.86) = 0.09±0.07, when E_G is averaged over scales above 3 h^-1 Mpc. We find that our E_G measurements exhibit slightly lower values than expected for standard relativistic gravity in a ΛCDM background, although the results are consistent within 1−2σ.