Sterile neutrinos and structure formation

Understand

Warm dark matter is consistent with the observations of the large-scale structure, and it can also explain the cored density profiles on smaller scales.

• However, it has been argued that warm dark matter could delay the star formation.
• This does not happen if warm dark matter is made up of keV sterile neutrinos, which can decay into X-ray photons and active neutrinos.
• The X-ray photons have a catalytic effect on the formation of molecular hydrogen, the essential cooling ingredient in the primordial gas.