The Nickel Mass Distribution of Normal Type II Supernovae

Core-collapse supernova (SN) explosions expose the structure and environment of massive stars at the moment of their death. We use the global fitting technique of Pejcha & Prieto to estimate a set of physical parameters of 19 normal SNe II, such as their distance moduli, reddenings, 56 Ni masses M Ni , and explosion energies E exp from multicolor light curves and photospheric velocity curves. We confirm and characterize known correlations between M Ni and bolometric luminosity at 50 days after the explosion, and between M Ni and E exp . We pay special attention to the observed distribution of M Ni coming from a joint sample of 38 SNe II, which can be described as a skewed-Gaussian-like distribution between 0.005 M ⊙ and 0.280 M ⊙ , with a median of 0.031 M ⊙ , mean of 0.046 M ⊙ , standard deviation of 0.048 M ⊙ , and skewness of 3.050. We use a two-sample Kolmogorov–Smirnov test and two-sample Anderson–Darling test to compare the observed distribution of M Ni to res