Résumé :
Dark matter could light up the first stars in the universe if the dark
matter is made up of weakly interacting neutrinos, right-handed neutrinos,
or also called sterile neutrinos. We have shown that sterile neutrino
decays could speed up the formation of molecular hydrogen and light up
the first stars as early as 20-100 million years after the big bang.
The light from these first stars could ionize the interstellar gas
by 150-400 million years after the big bang, in accordance with the
observations.
Formation of central galactic black holes, as well as structure on
subgalactic scales favor some form of warm dark matter, such as
sterile neutrinos, as dark matter. The kick required to accelerate
pulsars may be another key argument.
The consensus of several indirect pieces of evidence leads one to believe
that the long sought-after dark-matter particle may, indeed, be a sterile
neutrino. The Galactic center black hole and its mass may provide a lower
limit for the mass of the sterile neutrino. The X-ray emission from
neighboring galaxies, the Virgo cluster as well as the X-ray background
give an upper limit at almost the same number; the Lyman $\alpha$-forest
gives also a lower limit. Dwarf spheroidal galaxies may give the final
clue, as they are dominated all the way by dark matter, and presumably
are virgin galaxies from the early days of the cosmos.
This may lead to a decisive step in determining the nature and mass of the
dark matter particles, suggesting as one solution a Weakly Interacting
Neutrino, or WIN, of a few to a few tens of keV.
