The redshiftspace momentum power spectrum  II. Measuring the growth rate from the combined 2MTF and 6dFGSv surveys
Abstract
Measurements of the growth rate of structure, fσ_{8}, in the lowredshift Universe allow stringent tests of the cosmological model. In this work, we provide new constraints on fσ_{8} at an effective redshift of z = 0.03 using the combined density and velocity fields measured by the 2MTF and 6dFGSv surveys. We do this by applying a new estimator of the redshiftspace density and momentum (densityweighted velocity) power spectra, developed in the first paper of this series, to measured redshifts and peculiar velocities from these data sets. We combine this with models of the density and momentum power spectra in the presence of complex survey geometries and with an ensemble of simulated galaxy catalogues that match the survey selection functions and galaxy bias. We use these simulations to estimate the errors on our measurements and identify possible systematics. In particular, we are able to identify and remove biases caused by the nonGaussianity of the power spectra by applying the BoxCox transformation to the power spectra prior to fitting. After thorough validation of our methods we recover a constraint of fσ _8(z_{eff}=0.03)=0.404^{+0.082}_{0.081} from the combined 2MTF and 6dFGSv data. This measurement is fully consistent with the expectations of general relativity and the Λ cold dark matter cosmological model. It is also comparable and complementary to constraints using different techniques on similar data, affirming the usefulness of our method for extracting cosmology from velocity fields.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2019
 DOI:
 10.1093/mnras/stz1576
 arXiv:
 arXiv:1906.02874
 Bibcode:
 2019MNRAS.487.5235Q
 Keywords:

 galaxies: statistics;
 cosmological parameters;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 15 pages, 9+1 figures, published in MNRAS, Jun/2019. This is the second in "The RedshiftSpace Momentum Power Spectrum" series of papers