This is the second paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). In this paper, a complete SN sample is constructe
d, and the observed (uncorrected for host-galaxy extinction) luminosity functions (LFs) of SNe are derived. These LFs solve two issues that have plagued previous rate calculations for nearby SNe: the luminosity distribution of SNe and the host-galaxy extinction. We select a volume-limited sample of 175 SNe, collect photometry for every object, and fit a family of light curves to constrain the peak magnitudes and light-curve shapes. The volume-limited LFs show that they are not well represented by a Gaussian distribution. There are notable differences in the LFs for galaxies of different Hubble types (especially for SNe Ia). We derive the observed fractions for the different subclasses in a complete SN sample, and find significant fractions of SNe II-L (10%), IIb (12%), and IIn (9%) in the SN II sample. Furthermore, we derive the LFs and the observed fractions of different SN subclasses in a magnitude-limited survey with different observation intervals, and find that the LFs are enhanced at the high-luminosity end and appear more standard with smaller scatter, and that the LFs and fractions of SNe do not change significantly when the observation interval is shorter than 10 days. We also discuss the LFs in different galaxy sizes and inclinations, and for different SN subclasses. Some notable results are ... (abridged).
This is the first paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). We have obtained 2.3 million observations of 14,88
2 sample galaxies over an interval of 11 years (March 1998 through Dec. 2008). We considered 1036 SNe detected in our sample and used an optimal subsample of 726 SNe (274 SNe~Ia, 116 SNe~Ibc, 324 SNe~II) to determine our SN rates. This is the largest and most homogeneous set of nearby SNe ever assembled for this purpose, and ours is the first local SN rate analysis based on CCD imaging and modern image-subtraction techniques. In this paper, we lay the foundation of the study. We derive the recipe for the control-time calculation for SNe with a known luminosity function, and provide details on the construction of the galaxy and SN samples used in the calculations. Compared with a complete volume-limited galaxy sample, our sample has a deficit of low-luminosity galaxies but still provides enough statistics for a reliable rate calculation. There is a strong Malmquist bias, so the average size (luminosity or mass) of the galaxies increases monotonically with distance, and this trend is used to showcase a correlation between SN rates and galaxy sizes. Very few core-collapse SNe are found in early-type galaxies, providing strong constraints on the amount of recent star formation within these galaxies. The small average observation interval ($sim 9$ days) of our survey ensures that our control-time calculations can tolerate a reasonable amount of uncertainty in the luminosity functions of SNe. We perform Monte Carlo simulations to determine the limiting magnitude of each image and the SN detection efficiency as a function of galaxy Hubble type ... (abridged)
