The Bolometric Light-curve Modeling of 98 Type I Superluminous Supernovae Using the Magnetar- and the Circumstellar Interaction Models Reveals Surprisingly High Ejecta Masses

Abstract We present the bolometric light-curve modeling of 98 hydrogen-poor superluminous supernovae (SLSNe-I) using three types of power inputs: the magnetar model and two kinds of circumstellar interaction models, applying the constant density and the steady wind scenario. The quasi-bolometric luminosities of the objects were calculated from the Zwicky Transient Facility g - and r -band data using the methodology of Chen et al., and then they were modeled with the Minim code. It was found that the light curves of 45 SLSNe-I can be fitted equally well with both the magnetar and the circumstellar material (CSM) models, 14 objects prefer the magnetar model, and 39 SLSNe-I favor the CSM model. The magnetar modeling yielded a mean spin period of P = 4.1 ± 0.20 ms and a magnetic field of B = 5.65 ± 0.43 · 10 14 G, consistent with the literature. However, the ejected mass was estimated to be significantly larger compared to previous studies presenting either multicolor light-curve modeling with MOSFiT or bolometric light-curve modeling: we obtained a mean value and standard error of 34.26 and 4.67 M ⊙ , respectively. The circumstellar interaction models resulted in even larger ejecta masses with a mean and standard error of 116.82 and 5.97 M ⊙ for the constant density model, and 105.99 and 4.50 M ⊙ for the steady wind model. Although the ejected mass depends strongly on the electron scattering opacity (assumed to be κ = 0.2 in this work) and the ejecta velocity, which were estimated to be globally larger compared to earlier studies, our results suggest that SLSNe-I are indeed explosions of the most-massive stars.