2023/12/07 by Wangzheng Zhang, M. C. Chu, Zhang, Wangzheng +7 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2312.04278
Neutrinos are believed to be the most abundant fermions in the Universe, but their masses are unknown, except for being non-zero but much smaller than other fermions. Cosmological relic neutrinos could also have non-zero chemical potentials (or asymmetries). Using neutrino-involved N-body simulations, we investigate the neutrino effects on the matter pairwise velocity, which itself is an interesting probe of cosmology. We find that for light-halo ([1011,1013] M_\odot) mean pairwise velocity, in the transition range ([4,15] Mpc), the effects of neutrino masses overwhelm the effects of neutrino asymmetries, while in the two-halo-group range ([25,50] Mpc), for both light and heavy haloes ([1013,1015] M_\odot), the effects of neutrino asymmetries dominate, making it possible to disentangle the two effects. We provide fitting formulae to quantify the effects of neutrino mass and asymmetry on halo-halo pairwise velocities.