2020/05/31 by Carlos Hernández-Monteagudo, Jonás Chaves-Montero, Raúl E. Angulo +1 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1093/mnrasl/slab021
5 pages, 3 figures, matches accepted version in MNRAS letters
arxiv created 2021/03/23 · arxiv updated 2021/03/31
Fluctuations in sky maps of the galaxy redshifts, dubbed as angular redshift fluctuations (ARF), contain precise information about the growth rate of structures and the nature of gravity in the Universe. Specifically, ARF constrain the combination of cosmological parameters H/H0 fσ8(z), while being an intrinsically tomographic probe and largely insensitive to many observational systematic errors, all this without requiring the assumption of any redshift-to-distance relation under a given fiducial cosmology. We present the first cosmological constraints derived from ARF by using BOSS LOWZ+CMASS DR12 galaxy samples, obtaining 7%-accurate constraints on H/H0 fσ8(z) at more than 20 redshifts over the range z ∈ [0.26,0.72]. Our best-fitting value is 10% larger, but compatible at the 1.4σ level, than the ΛCDM expectation set by \it Planck observations of the Cosmic Microwave Background (CMB) radiation. Our tomographic measurements, combined with these CMB data, provides one of the strongest constraints on the gravity index γ, γ=0.44+0.09-0.07, which lies within 2σ from the prediction of General Relativity (γ\rm GR≃ 0.55).