Monte Carlo Radiation Transport for Astrophysical Transients Powered by Circumstellar Interaction

In this paper, we introduce $\mathtt{\text{SuperLite}}$, an open-source Monte Carlo radiation transport code designed to produce synthetic spectra for astrophysical transient phenomena affected by circumstellar interaction. $\mathtt{\text{SuperLite}}$ utilizes Monte Carlo methods for semi-implicit, semi-relativistic radiation transport in high-velocity shocked outflows, employing multi-group structured opacity calculations. The code enables rapid post-processing of hydrodynamic profiles to generate high-quality spectra that can be compared with observations of transient events, including superluminous supernovae, pulsational pair-instability supernovae, and other peculiar transients. We present the methods employed in $\mathtt{\text{SuperLite}}$ and compare the code’s performance to that of other radiative transport codes, such as $\mathtt{\text{SuperNu}}$ and CMFGEN. We show that $\mathtt{\text{SuperLite}}$ has successfully passed standard Monte Carlo radiation transport tests and can reproduce spectra of typical supernovae of Type Ia, Type IIP and Type IIn.