The DESI DR1 Peculiar Velocity Survey: growth rate measurements from galaxy and momentum correlation functions

Le résumé fourni par la source

Joint analysis of the local peculiar velocity and galaxy density fields offers a promising route to testing cosmological models of gravity. We present a measurement of the normalised growth rate of structure, f σ 8 , from the two-point correlations of velocity and density tracers from the DESI DR1 Peculiar Velocity and Bright Galaxy Surveys, the largest catalogues of their kind assembled to date. We fit the two-point correlation measurements with non-linear correlation function models, constructed from density and momentum power spectra generated using 1-loop Eulerian perturbation theory, and validate our methodology using representative mock catalogues. We find f σ 8 = 0.391 − 0.081 + 0.080 , consistent to within 1 σ with accompanying analyses of the same datasets using power spectrum and maximum-likelihood fields methods. Combining these growth rate results from different methods including appropriate correlations, we find a consensus determination f σ 8 ( z = 0.07 ) = 0.4497 ± 0.0548 , consistent with predictions from Planck+ΛCDM cosmology. Jointly fitting to this consensus low-redshift growth rate and the DESI DR1 full-shape clustering dataset, we measure gravitational growth index , consistent with the prediction of general relativity.

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