There is a relatively new paper https://arxiv.org/abs/1805.12028 of MiniBooNE on measurements of neutrino oscillations that can only be explained by the postulate of a sterile neutrino. I also read that results from other experiments like IceCube that don't confirm the findings.
Nevertheless I wonder if such a sterile neutrino could not be a good candidate for dark matter. However, on wikipedia: https://en.wikipedia.org/wiki/MiniBooNE it is said that cosmological data give a lower bound of a sterile neutrino to 0.26eV. Is there any possibility that such a particle could turn out as a dark matter candidate ? It was noted that the cosmological bound of the sterile neutrino mass would be quite model-dependent. Which are the models that are responsible for the low cosmological bound of the sterile neutrino mass ?