Synthetic light curves of shocked dense circumstellar shells

We investigate numerically the light curves (LCs) of shocked circumstellar shells, which it has been suggested might reproduce the observed LC of superluminous SN 2006gy analytically. In the previous analytical model, the effects of recombination and bolometric correction on LCs were not taken into account. To see these effects, we perform numerical radiation hydrodynamic calculations of shocked shells using stella, which can treat multigroup radiation transfer numerically with realistic opacities. We show that the effects of recombination and bolometric correction are significant and that the analytical model should be compared with the bolometric LC rather than a single-band LC. We find that shocked circumstellar shells having a rapid LC decline initially because of adiabatic expansion, rather than luminosity increase, and these shocked shells fail to explain the LC properties of SN 2006gy. However, our synthetic LCs are qualitatively similar to those of superluminous SN 2003ma and SN 1988Z and the latter objects may be related to shocked circumstellar shells.