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B. Roscherr, B.E. Schaefer (Yale University)
Over the past decade a new subclass of Type II supernovae has emerged, the Type IIn subclass. These SNe IIn have spectra that are dominated by narrow emission lines. The light curves also generally fade quite slowly, at least at early times. These characteristics are believed to be due to the scattering of the SNe light off dense circumstellar dust and/or due to the SNe ejecta-circumstellar dust shock interaction. Light echoes are expected to be important whenever a SN explodes in a dense dust shell, as might be common for massive stars with high rates of mass loss. We have written a Monte Carlo simulation of light scattering off dust in a circumstellar shell and can use it to predict the emission of a Type II-L or II-P SNe after scattering in the shell as a function of wavelength, for all time. Our simulation allows us to explore a wide range of parameters. We find that, while we can obtain reasonable fits to any one color at a time, the U, B, V and R-band light curves cannot simultaneously be fit to observed IIn light curves with a simple light echo model. This indicates that the ejecta-gas shock interaction may be the dominant effect in the evolution of the light curves in Type IIn SNe.
The author(s) of this abstract have provided an email address for comments about the abstract: bruce.roscherr@yale.edu