On the 'snow-plow' phase of supernovae interacting with dense circumstellar media

Recently, Moriya et al. (2013) developed an analytic bolometric light curve model for supernovae interacting with dense circumstellar media. Because of the dense circumstellar medium, the shocked region is assumed to be radiative and make a thin dense shell. The model is based on the conservation of momentum in the shocked dense shell. However, the analytic model was mentioned to neglect the 'snow-plow' phase of the shocked dense shell by Ofek et al. (2014). The 'snow-plow' or momentum-conserving phase refers to the period in which the momentum injection from the supernova ejecta is almost terminated and the radiative shocked dense shell keeps moving due only to the momentum previously provided by the supernova ejecta. In this Note, I clarify that the analytic model of Moriya et al. (2013) does take the 'snow-plow' phase into account and the criticism of Ofek et al. (2014) is incorrect. In addition, Ofek et al. (2014) related the sudden luminosity break observed in the light curve of Type IIn SN 2010jl to the transition to the 'snow-plow' phase. However, I argue that the sudden transition to the 'snow-plow' phase is not consistent with the luminosity break observed in SN 2010jl. The luminosity break is likely to be related to other phenomena like the dense shell exiting the dense part of the circumstellar medium.