Accurate fitting functions for peculiar velocity spectra in standard and massive-neutrino cosmologies

Understand

We estimate the velocity field in a large set of $N$-body simulations including massive neutrino particles, and measure the auto-power spectrum of the velocity divergence field as well as the cross-power spectrum between the cold dark matter density and the velocity divergence.

• We perform these measurements at four different redshifts and within four different cosmological scenarios, covering a wide range in neutrino masses.
• We find that the nonlinear correction to the velocity power spectra largely depend on the degree of nonlinear evolution with no specific dependence on the value of neutrino mass.
• We provide a fitting formula, based on the value of the r.m.s.