title: Growth Rate of Cosmological Perturbations at z∼0.1 from a New Observational Test.
abstract: Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy redshift surveys is a powerful test of gravity and dark-energy theories on cosmological scales. Using ∼2×10(5) galaxies from the SDSS Data Release 7, we perform this test in the framework of gravitational instability to estimate the normalized growth rate of density perturbations fσ8=0.37±0.13 at z∼0.1, which is in agreement with the cold dark matter model with a cosmological constant. This unique measurement is complementary to those obtained with more traditional methods, including clustering analysis. The estimated accuracy at z∼0.1 is competitive with other methods when applied to similar data sets.
authors.affiliation: Department of Physics, Israel Institute of Technology-Technion, Haifa 32000, Israel.
authors.forename: Martin
authors.initials: M
authors.lastname: Feix
authors.affiliation: Department of Physics, Israel Institute of Technology-Technion, Haifa 32000, Israel.|Asher Space Science Institute, Israel Institute of Technology-Technion, Haifa 32000, Israel.
authors.forename: Adi
authors.initials: A
authors.lastname: Nusser
authors.affiliation: Department of Physics, Università Roma Tre, Via della Vasca Navale 84, Rome 00146, Italy.|INFN Sezione di Roma 3, Via della Vasca Navale 84, Rome 00146, Italy.|INAF, Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Branchini