A historical supernova's lower limit to the galactic stellar collapse rate

This paper re-investigates the rate of the galactic supernova given by historical supernova. The influence of various selection effects, including galactic extinction, and the type and scale height of supernova, are considered in detail. A lower limit to the rate of stellar collapse in the galaxy is set at >1/20yr−1. If the recently proposed six candidates are included, the lower limit become >1/12yr−1. These lower limits do not greatly differ from the rates given by the heavy element content and the stellar formation of the Galaxy, this implies that the variation and the activity in galactic evolution may not be very strong.