The line profile of a relativistic Keplerian ring in a massive neutrino halo

If a massive neutrino halo transparent to light surrounds a compact body (galactic nucleus or black hole), then the strong gravitational field inside the halo will radically alter the spectral line profiles of a light-emitting Keplerian ring. This paper gives precise solutions of the spectral profile in a core-halo structure of matter and neutrino, and the result is compared with the no-halo case. The distribution of the neutrino mass is also given under typical circumstances.