  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.

Cosmology and Nongalactic Astrophysics