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

Publication date: 
Main author: 
De La Torre S.
IAA authors: 
Prada, F.
De La Torre S., Jullo E., Giocoli C., Pezzotta A., Bel J., Granett B.R., Guzzo L., Garilli B., Scodeggio M., Bolzonella M., Abbas U., Adami C., Bottini D., Cappi A., Cucciati O., Davidzon I., Franzetti P., Fritz A., Iovino A., Krywult J., Le Brun V., Le Fèvre O., Maccagni D., Małek K., Marulli F., Polletta M., Pollo A., Tasca L.A.M., Tojeiro R., Vergani D., Zanichelli A., Arnouts S., Branchini E., Coupon J., De Lucia G., Ilbert O., Moutard T., Moscardini L., Peacock J.A., Metcalf R.B., Prada F., Yepes G.
Astronomy and Astrophysics
Publication type: 
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, EG, for the first time at z &gt; 0.6. We find values of E G(0.6) = 0.16±0.09 and E G(0.86) = 0.09±0.07, when EG is averaged over scales above 3 h-1 Mpc. We find that our EG measurements exhibit slightly lower values than expected for standard relativistic gravity in a ΛCDM background, although the results are consistent within 1-2σ. © ESO, 2017.
ADS Bibcode: 
Cosmological parameters; Cosmology: observations; Dark energy; Galaxies: high-redshift; Large-scale structure of Universe