Asymmetry of 56Ni ejecta and polarization in the type-IIP supernova 2004dj

I study the question of whether the asymmetry of Ni-56 ejecta that results in the asymmetry of the H alpha emission line at the nebular epoch of the type-IIP supernova SN 2004dj can account for the recently detected polarization of the supernova radiation. I have developed a model of the H alpha profile and luminosity with nonthermal ionization and excitation in a spherically symmetric envelope for an asymmetric bipolar Ni-56 distribution. I have calculated the polarized radiation transfer against the background of the recovered electron density distribution. The observed polarization is shown to be reproduced at the nebular epoch around day 140 for the same parameters of the envelope, and the Ni-56 distribution for which the evolution of the H alpha luminosity and profile is explained. Yet the model polarization decreases with time more slowly than is observed. The origin of the additional component responsible for the early polarization on day 107 is discussed.