Dark winds on the horizon: Prospects for detecting neutrino and hot dark matter wakes in large-scale structure

Fuente: arXiv
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Autores principales: Nascimento, Caio B. de S., Loverde, Marilena
Formato: Preprint
Publicado: 2025
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author Nascimento, Caio B. de S.
Loverde, Marilena
author_facet Nascimento, Caio B. de S.
Loverde, Marilena
contents We explore the cosmological signatures of neutrino and Hot Dark Matter (HDM) wakes, which refers to the preferential accumulation of neutrinos (or, more broadly, HDM particles) downstream of moving cold dark matter structures. We improve on existing theoretical models, and provide forecasts for the detectability of the effect in future surveys under more realistic conditions than previously considered in the literature. We show that neutrino and HDM wakes are unlikely to be ever observed with the most natural tracer of a hot subcomponent of the total dark matter on cosmological scales, i.e. 2D weak lensing surveys. However, the effect can be detected at a high significance with idealistic 3D maps of a tracer of HDM, for sufficiently small values of the effective free-streaming length (e.g. present-day values of $k_{\textrm{fs},0} \gtrsim 0.1\textrm{Mpc}^{-1}$ to reach $\textrm{SNR} \gtrsim 1$, for a HDM species accounting for a percent of the total dark matter). HDM wakes are a smoking gun of the effects of free-streaming, which cannot be mimicked by changes to the background expansion history (such as allowing for the dark energy to be dynamical), and hence offer another avenue to search for massive neutrinos, and hot subcomponents of the total dark matter more broadly, in a way that complements traditional observables.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08574
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dark winds on the horizon: Prospects for detecting neutrino and hot dark matter wakes in large-scale structure
Nascimento, Caio B. de S.
Loverde, Marilena
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
We explore the cosmological signatures of neutrino and Hot Dark Matter (HDM) wakes, which refers to the preferential accumulation of neutrinos (or, more broadly, HDM particles) downstream of moving cold dark matter structures. We improve on existing theoretical models, and provide forecasts for the detectability of the effect in future surveys under more realistic conditions than previously considered in the literature. We show that neutrino and HDM wakes are unlikely to be ever observed with the most natural tracer of a hot subcomponent of the total dark matter on cosmological scales, i.e. 2D weak lensing surveys. However, the effect can be detected at a high significance with idealistic 3D maps of a tracer of HDM, for sufficiently small values of the effective free-streaming length (e.g. present-day values of $k_{\textrm{fs},0} \gtrsim 0.1\textrm{Mpc}^{-1}$ to reach $\textrm{SNR} \gtrsim 1$, for a HDM species accounting for a percent of the total dark matter). HDM wakes are a smoking gun of the effects of free-streaming, which cannot be mimicked by changes to the background expansion history (such as allowing for the dark energy to be dynamical), and hence offer another avenue to search for massive neutrinos, and hot subcomponents of the total dark matter more broadly, in a way that complements traditional observables.
title Dark winds on the horizon: Prospects for detecting neutrino and hot dark matter wakes in large-scale structure
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2511.08574