Cosmological and Astrophysical Probes of Sterile Neutrinos

Sterile neutrinos have been proposed to tackle a number of outstanding questions in physics, including the phenomena of dark matter, neutrino masses and the baryon asymmetry of the Universe. I will review current limits on GeV-, MeV- and keV-scale sterile neutrinos from cosmology and astrophysics. In particular, I will focus on how primordial abundance determinations, Cosmic Microwave Background observations and stellar kinematic inferences from dwarf spheroidal galaxies allow us to set robust constraints across this mass scale. I will then end with a short discussion on how sterile neutrinos could relax cosmological bounds on neutrino masses and what implications this would have for experiments like KATRIN.