The case of 1.5 eV neutrino hot dark matter

TL;DR

This paper proposes that 1.5 eV neutrinos could account for galaxy cluster lensing data and contribute significantly to hot dark matter, with implications for structure formation and reionization.

Contribution

It introduces an isothermal fermion model with 1-2 eV neutrinos explaining lensing data and suggests sterile neutrinos could explain hot dark matter and reionization.

Findings

Neutrino mass of 1-2 eV fits galaxy cluster lensing data.

Sterile neutrinos may account for 20% of hot dark matter.

Baryonic structure formation can occur via gravitational hydrodynamics alone.

Abstract

The lensing data of the galaxy cluster Abell 1689 can be explained by an isothermal fermion model with a mass of 1-2 eV. The best candidate is the 1.5 eV neutrino; its mass will be searched down to 0.2 eV in KATRIN 2015. If its righthanded (sterile) modes were created too, there is 20% neutrino hot dark matter. Their condensation on clusters explains the reionization of the intercluster gas without Pop. III stars. Baryonic structure formation is achieved by gravitional hydrodynamics alone, without dark matter trigger.