Using spectral modeling to break light-curve degeneracies of type II supernovae interacting with circumstellar material

Understand

A large fraction of red-supergiant stars seem to be enshrouded by circumstellar material (CSM) at the time of explosion.

• Relative to explosions in a vacuum, this CSM causes both a luminosity boost at early times as well as the presence of symmetric emission lines with a narrow core and electron-scattering wings typical of type IIn supernovae (SNe).
• For this study, we performed radiation-hydrodynamics and radiative transfer calculations for a variety of CSM configurations (i.e., compact, extended, and detached) and documented the resulting ejecta and radiation properties.
• We find that models with a dense, compact, and massive CSM of ~0.5Msun can match the early luminosity boost of type II-P SNe but fail to produce type IIn-like spectral signatures (aka ``flash features'').