# An estimation of the Local growth rate from Cosmicflows-3 peculiar velocities

## TL;DR

This paper evaluates three estimators for local growth rate using Cosmicflows-3 peculiar velocities, testing their accuracy on simulations and real data, and finds results consistent with the standard cosmological model.

## Contribution

It introduces and tests three estimators for the local growth rate using Cosmicflows-3 data, accounting for observational errors and cosmic variance.

## Key findings

- Estimated local growth rate fσ8 = 0.43 ± 0.03 (obs) ± 0.11 (cosmic)
- Results support the ΛCDM cosmology
- Validated estimators on mock and constrained datasets

## Abstract

This article explores three usual estimators, noted as $v_{12}$ of the pairwise velocity, $\psi_1$ and $\psi_2$ of the observed two-point galaxy peculiar velocity correlation functions. These estimators are tested on mock samples of {\it Cosmicflows-3} dataset \citep{Tully:2016aa} , derived from a numerical cosmological simulation, and also on a number of constrained realizations of this dataset. Observational measurements errors and cosmic variance are taken into consideration in the study. The result is a local measurement of $f \sigma_8 = 0.43 \left( \pm 0.03 \right)_\mathrm{obs} \left( \pm 0.11 \right)_\mathrm{cosmic}$ out to $z=0.05$, in support of a $\Lambda$CDM cosmology.