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

In this paper,we study five luminous supemovae(LSNe)Ibc(SN2009ca,ASASSN-15mj,SN2019omd,SN 2002ued,and SN 2021bmf)whose peak absolute magnitudes Mpeak 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 x2/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.