A new determination of supernova rates and a comparison with indicators for galactic star formation

We have computed new estimates of the local rates of supernovae (SNe) adding the updated log of Evans' visual search to our SN search database. In this way, we have accumulated the largest SN statistics ever assembled for this purpose. The new SN rates are corrected on an empirical basis for the bias in the inner regions of galaxies and that in inclined spirals. We also tested an alternative approach based on the simple model proposed by Hatano et al. (1998) for the SN and dust distribution in spirals. It turns out that, although the two approaches give similar average rates, the Hatano et al. model appears to overcorrect the SN rate of distant galaxies. We used these updated statistics to probe the SN rates with different tracers of the star formation activity in galaxies, namely integrated colors, infrared luminosities and nuclear activities. We found a clear relation between the core-collapse SN rate and the integrated galaxy color, which appears consistent with the prediction of galaxy evolutionary models. We also compared SN rates in galaxies with different L_FIR with unfavorable outcome, and we argue that L_FIR is not a universal measurement of SFR. Finally, we confirm that the SN rate is not enhanced in AGN host galaxies which indicates that the nuclear engine does not significantly stimulate the extranuclear SF.