2023/11/19 by Amol Upadhye, Juliana Kwan, Upadhye, Amol +11
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Neutrino Physics Research
paper · pdf · doi:10.48550/arxiv.2311.11240
openalex publication_date 2023/11/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Cosmology is poised to measure the neutrino mass sum Mν and has identified several smaller-scale observables sensitive to neutrinos, necessitating accurate predictions of neutrino clustering over a wide range of length scales. The FlowsForTheMasses non-linear perturbation theory for the massive neutrino power spectrum, Δ2ν(k), agrees with its companion N-body simulation at the 10%-15% level for k ≤ 1~h/Mpc. Building upon the Mira-Titan IV emulator for the cold matter, we use FlowsForTheMasses to construct an emulator for Δ2ν(k) covering a large range of cosmological parameters and neutrino fractions Ων,0 h2 ≤ 0.01, which corresponds to Mν≤ 0.93~eV. Consistent with FlowsForTheMasses at the 3.5% level, it returns a power spectrum in milliseconds. Ranking the neutrinos by initial momenta, we also emulate the power spectra of momentum deciles, providing information about their perturbed distribution function. Comparing a Mν=0.15~eV model to a wide range of N-body simulation methods, we find agreement to 3% for k ≤ 3 kFS = 0.17~h/Mpc and to 19% for k ≤ 0.4~h/Mpc. We find that the enhancement factor, the ratio of Δ2ν(k) to its linear-response equivalent, is most strongly correlated with Ων,0 h2, and also with the clustering amplitude σ8. Furthermore, non-linearities enhance the free-streaming-limit scaling ∂ log(Δ2ν/ Δ2\rm m) / ∂ log(Mν) beyond its linear value of 4, increasing the Mν-sensitivity of the small-scale neutrino density.