SPECTROSCOPIC DETERMINATION OF THE LOW-REDSHIFT TYPE Ia SUPERNOVA RATE FROM THE SLOAN DIGITAL SKY SURVEY

Supernova rates (SNRs) are directly coupled to high-mass stellar birth and evolution. As such, they are one of the few direct measures of the history of cosmic stellar evolution. In this paper, we describe a probabilistic technique for identifying supernovae within spectroscopic samples of galaxies. We present a study of 52 Type Ia supernovae ranging in age from -14 days to +40 days extracted from a parent sample of similar to 350,000 spectra from the SDSS DR5. We find an SNR of 0.472(-0.039)(+0.048) (Systematic)(-0.071)(+0.081)(Statistical)SNu at a redshift of < z > = 0.1. This value is higher than other values at low redshift at the 1 sigma level, but is consistent at the 3 sigma level. In this paper, we demonstrate the potential for the described approach to detect supernovae in future spectroscopic surveys.