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

Abstract

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, $f\ddot{I}{ƒ}_8$, 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 $f\ddot{I}{ƒ}_8=0.391_{-0.081}^{+0.080}$, consistent to within $1\ddot{I}ƒ$ 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 $f\ddot{I}{ƒ}_8(z=0.07)=0.4497\pm 0.0548$, consistent with predictions from \textit{Planck}$+\hat{I}›$CDM cosmology. Jointly fitting to this consensus low-redshift growth rate and the DESI DR1 full-shape clustering dataset, we measure gravitational growth index ${\hat{I}}_{\mathrm{L}}^3=0.580_{-0.110}^{+0.110}$, consistent with the prediction of general relativity.

20 pages, 10 figures, 3 tables. Published in the Open Journal of Astrophysics