The effect of circumstellar matter on the double-peaked type Ic supernovae and implications for LSQ14efd, iPTF15dtg and SN 2020bvc

Abstract

Double peaked light curves are observed for some Type Ic supernovae (SNe Ic) including LSQ14efd, iPTF15dtg and SN 2020bvc. One possible explanation of the first peak would be shock-cooling emission from massive extended material around the progenitor, which is produced by mass eruption or rapid expansion of the outermost layers of the progenitor shortly before the supernova explosion. We investigate the effects of such circumstellar matter (CSM) on the multi-band optical light curves of SNe Ic using the radiation hydrodynamics code STELLA. Two different SNe Ic progenitor masses at the pre-SN stage (3.93$M_\odot$ and 8.26$M_\odot$) are considered in the SN models. The adopted parameter space consists of the CSM mass of $M_\mathrm{CSM} = 0.05 - 0.3 M_\odot$, the CSM radius of $R_\mathrm{CSM} = 10^{13} - 10^{15}$cm and the explosion energy of $E_\mathrm{burst} = (1.0 - 12.0)\times10^{51}$erg. We also investigate the effects of the radioactive nickel distribution on the overall shape of the light curve and the color evolution. Comparison of our SN models with the double peaked SNe Ic LSQ14efd, iPTF15dtg and SN 2020bvc indicate that these three SNe Ic had a similar CSM structure (i.e., $M_\mathrm{CSM} \approx 0.1 - 0.2 M_\odot$ and $R_\mathrm{CSM} = 10^{13} - 10^{14}~\mathrm{cm}$), which might imply a common mechanism for the CSM formation. The implied mass loss rate of $\dot{M} \gtrsim 1.0~M_\odot~\mathrm{yr^{-1}}$ is too high to be explained by the previously suggested scenarios for pre-SN eruption, which calls for a novel mechanism.