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arXiv · 1611.04589

Dynamical friction in the primordial neutrino sea

Chiamaka Okoli·Morag I. Scrimgeour·Niayesh Afshordi·Michael J. Hudson
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Abstract

Standard big bang cosmology predicts a cosmic neutrino background at $T_\nu \simeq 1.95~$K. Given the current neutrino oscillation measurements, we know most neutrinos move at large, but non-relativistic, velocities. Therefore, dark matter haloes moving in the sea of primordial neutrinos form a neutrino wake behind them, which would slow them down, due to the effect of {\it dynamical friction}. In this paper, we quantify this effect for realistic haloes, in the context of the halo model of structure formation, and show that it scales as $m_\nu^4$ $\times$ relative velocity, and monotonically grows with the halo mass. Galaxy redshift surveys can be sensitive to this effect (at $>3\sigma$ confidence level, depending on survey properties, neutrino mass and hierarchy) through redshift space distortions (RSD) of distinct galaxy populations.

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Chiamaka Okoli, Morag I. Scrimgeour, Niayesh Afshordi, Michael J. Hudson. 2016-11-14. Dynamical friction in the primordial neutrino sea. https://doi.org/10.1093/mnras/stx560

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