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

• Published in: Astronomy and astrophysics (Berlin) Vol. 622; p. A109
• Main Authors: Bel, J., Pezzotta, A., Carbone, C., Sefusatti, E., Guzzo, L.
• Format: Journal Article
• Language: English
• Published: Heidelberg EDP Sciences 01.02.2019
• Subjects: Astrophysics; Cold dark matter; Dark matter; Dependence; Divergence; large-scale structure of Universe; Neutrinos; Physics; Power spectra; Variation; Velocity; Velocity distribution; matter: fluctuation; numerical methods; numerical calculations; velocity: power spectrum; large-scale structure of Universe; velocity: spectrum; neutrino: mass; neutrino: massive; cosmological model; correction: nonlinear; redshift; dark matter: density; dark matter
• ISSN: 0004-6361; 1432-0746; 1432-0756
• DOI: 10.1051/0004-6361/201834513

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 depends 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 rms of the matter fluctuations in spheres of 8 h−1 Mpc, describing the nonlinear corrections with 3% accuracy on scales below k = 0.7 h Mpc−1.