A UNIFIED ENERGY-RESERVOIR MODEL CONTAINING CONTRIBUTIONS FROM 56Ni AND NEUTRON STARS AND ITS IMPLICATION FOR LUMINOUS TYPE Ic SUPERNOVAE

Most type Ic core-collapse supernovae produce Ni-56 and neutron stars (NSs) or black holes. The dipole radiation of nascent NSs has usually been neglected in explaining supernovae (SNe) with peak absolute magnitudes M-peak in any band greater than or similar to -19.5 mag, while the Ni-56 can be neglected in fitting most type Ic superluminous supernovae whose M-peak in any band is less than or similar to -21 mag, since the luminosity from a magnetar (highly magnetized NS) can outshine that from a moderate amount of Ni-56. For luminous SNe Ic with -21 less than or similar to M-peak less than or similar to -19.5 mag, however, both contributions from Ni-56 and NSs cannot be neglected without serious modeling since they are not SLSNe and the Ni-56 mass could be up to similar to 0.5 M-circle dot. In this paper we propose a unified model that contains contributions from both Ni-56 and a nascent NS. We select three luminous SNe Ic-broad-lined, SN 2010ay, SN 2006nx, and SN 14475, and show that, if these SNe are powered by Ni-56, the ratio of M-Ni to M-ej is unrealistic. Alternatively, we invoke the magnetar model and the hybrid (Ni-56 + NS) model and find that they can fit the observations, indicating that our models are valid and necessary for luminous SNe Ic. Owing to the lack of late-time photometric data, we cannot break the parameter degeneracy and thus distinguish among the model parameters, but we can expect that future multi-epoch observations of luminous SNe can provide stringent constraints on Ni-56 yields and the parameters of putative magnetars.