A m\'enage \`a trois of eV-scale sterile neutrinos, cosmology, and
  structure formation
  We show that sterile neutrinos with masses ~1 eV or larger, as motivated by
several short-baseline oscillation anomalies, can be consistent with
cosmological constraints if they are charged under a hidden sector force
mediated by a light boson. In this case, sterile neutrinos experience a large
thermal potential that suppresses mixing between active and sterile neutrinos
in the early Universe, even if vacuum mixing angles are large. Thus, the
abundance of sterile neutrinos in the Universe remains very small, and their
impact on Big Bang Nucleosynthesis, Cosmic Microwave Background, and
large-scale structure formation is negligible. It is conceivable that the new
gauge force also couples to dark matter, possibly ameliorating some of the
small-scale structure problems associated with cold dark matter.
