Follow-up obs. of the type IIn SN KISS15s

KISS15s shows long-duration optical continuum and emission line light curves, indicating that KISS15s is powered by a continuous interaction between the expanding ejecta and dense circumstellar medium (CSM). The H{alpha} emission line profile can be decomposed into four Gaussians of narrow, intermediate, blueshifted intermediate, and broad velocity width components, with a full width at half maximum of <~100, ~2000, and ~14000km/s for the narrow, intermediate, and broad components, respectively.

The presence of the blueshifted intermediate component, of which the line-of-sight velocity relative to the systemic velocity is about -5000km/s, suggests that the ejecta-CSM interaction region has an inhomogeneous morphology and anisotropic expansion velocity. We found that KISS15s shows increasing infrared continuum emission, which can be interpreted as hot dust thermal emission of T~1200K from newly formed dust in a cool, dense shell in the ejecta-CSM interaction region.