The Study of the Physical Properties and Energy Sources of Five Luminous Type Ibc Supernovae

Abstract In this paper, we study five luminous supernovae (LSNe) Ibc (SN~2009ca, ASASSN-15mj, SN~2019omd, SN~2002ued, and SN~2021bmf) whose peak absolute magnitudes $M_{\rm peak}$ are $\approx -19.5$ to $-21$ mag by fitting their multi-band light curves (LCs) with different energy source models. We find that SN~2009ca might be powered by the \Ni model since the required \Ni mass (0.56 \Msun) is comparable to those of energetic SNe Ic, while the rest four SNe cannot be accounted for the \Ni model since their derived \Ni masses are $\gtrsim 1$~$M_\odot$ or the ratios of the \Ni mass to the ejecta mass are larger than 0.2. This indicates that some LSNe might be powered by \Ni decay, while most of them need additional energy sources. We then use the magnetar plus \Ni model and the fallback plus \Ni model to fit the LCs of the four LSNe that cannot be explained by the \Ni model, finding that the two models can account for the four SNe, and the derived parameters are comparable to those of LSNe or superluminous SNe (SLSNe) in the literature, if they were (mainly) powered by magnetars or fallback. We suggest that the magnetar plus \Ni model is more reasonable than the fallback plus \Ni model, since the validity of the fallback plus \Ni model depends on the value of accretion efficiency ($\eta$) and favors a large $\eta$ value, and the magnetar plus \Ni model yield smaller $\chi^2$/dof values. It should be pointed out that, however, the fallback plus \Ni model is still a promising model that can account for the four SNe in our sample as well as other LSNe.