Collective flavor conversion including the neutrino halo in core-collapse supernovae

We investigate collective neutrino oscillation (CNO) including neutrino halo effects in an iron core-collapse supernova model. We find that CNO suddenly occurs beyond the propagating shock front evolved from a 9.6M(circle dot) star. Also, we find that neutrinos inwardly scattered by background matter can be ignored outside the shock front where CNO can occur, compared with outward-going neutrinos. Neutrinos get free from matter suppression and scattering with background matter beyond the shock front. Neutrino halo with wider intersection angles produces additional flavor transformation and sharpens the spectral splits.