Supernova Ejecta Interacting with a Circumstellar Disk. I. Two-dimensional Radiation-hydrodynamic Simulations

Abstract We perform a series of two-dimensional radiation-hydrodynamic simulations of the collision between supernova ejecta and circumstellar media (CSMs). The hydrodynamic interaction of a fast flow and the surrounding media efficiently dissipates the kinetic energy of the fast flow and is considered as a dominant energy source for a specific class of core-collapse supernovae. Despite some observational evidence for aspherical ejecta and/or CSM structure, multidimensional effects in the ejecta–CSM interaction are relatively unexplored. Our numerical simulations equipped with an adaptive mesh refinement technique successfully reproduce hydrodynamic instabilities developing around the ejecta–CSM interface. We also investigate effects of disklike CSMs on the dynamical evolution of supernova ejecta and bolometric light curves. We find that emission powered by ejecta–disk interaction exhibits significant viewing angle dependence. For a line of sight close to the symmetry axis, the observer directly sees the supernova ejecta, leading to a short brightening timescale. For an observer seeing the emission through the CSM disk, thermal photons diffuse throughout the CSM, and thus the light curve is severely smeared out.