Supernova frequency estimates

The frequencies of type I and II supernovae (SN) occurring in galaxies of different types are estimated on data obtained using the 40 cm astrograph at the Shternberg Crimean station. All galaxies from several different fields brighter than 13 m according to the Zwicky catalog were employed for determining the supernovae frequency. Observations of type Sb, Sbc, and Sc galaxies show that the patrol time for SN I per square kpc was 160,000 yr and three SN I were discovered, whereas the patrol time for SN II was 130,000 yr and two SN II were discovered. The total frequency was determined to be 340,000 SN/sq kpc-yr. It is suggested that approximately 0.00002 SN/sq kpc-yr can be expected in the solar neighborhood if the radial supernova distribution corresponds to that obtained previously. These results for the frequency of supernova outbursts are found to agree well with data on the supernova frequency in the Galaxy, the Large Magellanic Cloud, and M31.