Neutrino Halo profiles: HR-DEMNUni simulation analysis

TL;DR

This study uses high-resolution simulations to analyze neutrino profiles within dark matter haloes, updating fitting formulas, exploring profile dependence on neutrino mass and halo properties, and investigating observable neutrino wake effects.

Contribution

The paper provides new fitting parameters for neutrino profiles extending to lower halo masses and neutrino masses, and characterizes neutrino wake effects in massive haloes.

Findings

Neutrino profiles become closer to power laws in less massive haloes.

A forward-backward asymmetry in neutrino density profiles exceeds 10%.

Neutrino wakes are observable in haloes with masses above 3×10^{14} h^{-1} M_sun.

Abstract

Using the high-resolution HR-DEMNUni simulations, we computed neutrino profiles within virialized dark matter haloes. These new high-resolution simulations allowed us to revisit fitting formulas proposed in the literature and provided updated fitting parameters that extend to less massive haloes and lower neutrino masses than previously in the literature, in accordance with new cosmological limits. The trend we observe for low neutrino masses is that, for dark matter halo masses below $\sim 4\times10^{14}$$h^{-1}M_\odot$, the presence of the core becomes weaker and the profile over the whole radius is closer to a simple power law. We also characterized the neutrino density profile dependence on the solid angle within clustered structures: a forward-backward asymmetry larger than 10% was found when comparing the density profiles from neutrinos along the direction of motion of cold dark matter particles within the same halo. In addition, we looked for neutrino wakes around halo centres produced by the peculiar motion of the halo itself. Our results suggest that the wakes effect is observable in haloes with masses greater than $3\times10^{14}$ $h^{-1}M_\odot$ where a mean displacement of $0.06$\hmpc was found.