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

¹ Aix-Marseille Univ., Université de Toulon, CNRS, CPT, Marseille, France
e-mail: jbel@cpt.univ-mrs.fr
² INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate, Italy
³ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Magrans s/n, 08193 Barcelona, Spain
⁴ Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Spain
⁵ Università degli Studi di Milano, via G. Celoria 16, 20133 Milano, Italy
⁶ INAF – Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy
⁷ INFN – Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
⁸ INFN – Sezione di Milano, via G. Celoria 16, 20133 Milano, Italy

Received: 26 October 2018
Accepted: 29 November 2018

Abstract

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.