Using N -body simulations of flat , dark energy dominated cosmologies , we show that galaxies around simulated binary systems resembling the Local Group ( LG ) have low peculiar velocities , in good agreement with observational data .
We have compared results for LG-like systems selected from large , high resolution simulations of three cosmologies : a \Lambda CDM model , a \Lambda WDM model with a 2 keV warm dark matter candidate and a quintessence model ( QCDM ) with an equation of state parameter w = -0.6 .

The Hubble flow is significant colder around LGs selected in a flat , \Lambda dominated cosmology than around LGs in open or critical models , showing that a dark energy component manifests itself on the scales of nearby galaxies , cooling galaxy peculiar motions .
Flows in the \Lambda WDM and QCDM models are marginally colder than in the \Lambda CDM one .

The results of our simulations have been compared to existing data and a new data set of 28 nearby galaxies with robust distance measures ( Cepheids and Surface Brightness Fluctuations ) .
The measured line-of-sight velocity dispersion is \sigma _ { H } = 88 \pm 20 km/sec \times ( R/7 Mpc ) .
The best agreement with observations is found for LGs selected in the \Lambda CDM cosmology in environments with -0.1 < \delta \rho / \rho < 0.6 on scales of 7 Mpc , in agreement with existing observational estimates on the local matter density .

These results provide new , independent evidence for the presence of dark energy on scales of few Mpc , corroborating the evidence gathered from observations of distant objects and the early Universe .