2023RAA....23l5002B

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_peak are ≈ -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 ⁵⁶Ni model since the required ⁵⁶Ni mass (0.56 M_⊙) is comparable to those of energetic SNe Ic, while the rest four SNe cannot be accounted for the ⁵⁶Ni model since their derived ⁵⁶Ni masses are ≳1 M_⊙ or the ratios of the ⁵⁶Ni mass to the ejecta mass are larger than 0.2. This indicates that some LSNe might be powered by ⁵⁶Ni decay, while most of them need additional energy sources. We then use the magnetar plus ⁵⁶Ni model and the fallback plus ⁵⁶Ni model to fit the LCs of the four LSNe that cannot be explained by the ⁵⁶Ni 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 in the literature, if they were (mainly) powered by magnetars or fallback. We suggest that the magnetar plus ⁵⁶Ni model is more reasonable than the fallback plus ⁵⁶Ni model, since the validity of the fallback plus ⁵⁶Ni model depends on the value of accretion efficiency (η) and favors a large η value, and the magnetar plus ⁵⁶Ni model yields smaller χ²/dof values. It should be pointed out that, however, the fallback plus ⁵⁶Ni model is still a promising model that can account for the four SNe in our sample as well as other LSNe.