Light Curves and Spectra from a Unimodal Core-collapse Supernova

Abstract

To assess the effectiveness of optical emission as a probe of spatial asymmetry in core-collapse supernovae (CCSNe), we apply the radiative transfer software SuperNu to a unimodal CCSN model. The SNSPH radiation hydrodynamics software was used to simulate an asymmetric explosion of a 16 zero-age main-sequence binary star. The ejecta has 3.36 with 0.024 of radioactive 56 Ni, with unipolar asymmetry along the z -axis. For 96 discrete angular views, we find a ratio between maximum and minimum peak total luminosities of ∼1.36. The brightest light curves emerge from views orthogonal to the z -axis. Multigroup spectra from UV to IR are obtained. We find a shift in wavelength with viewing angle in a near-IR Ca ii emission feature, consistent with Ca being mostly in the unimode. We compare emission from the gray gamma-ray transfer in SuperNu and from the detailed gamma-ray transfer code Maverick . Relative to the optical light curves, the brightness of the gamma-ray emission is more monotonic with respect to viewing angle. UBVRI broadband light curves are also calculated. Parallel with the unimode, the U and B bands have excess luminosity at days post-explosion, due to 56 Ni on the unimode. We compare our CCSN model with SN 2002ap, which is thought to have a similar ejecta morphology.