Optical supernovae in the pilot galaxies

Since several supernovae have been optically identified in our pilot galaxies in the past decade, we can also use these to estimate the fractional radio supernova rate. Table 3 lists the optical supernovae (Barbon et al. 1989, van den Bergh 1996) which would have been detectable by the pilot study if they were radio sources.

  
Table 3: Optical supernovae which could have been detected in the pilot study

Five optical SNe (2 Type Ib, 3 Type II) could have been detected as radio sources at the 1986J level, and four (1 Type Ib, 3 Type II) at the 1978K level. This suggests (with large uncertainty because of the small number of optical detections) that RSNe like 1986J represent no more than 30% of Type II SNe (and no more than 20% of Types Ib and II combined), in agreement with the rates derived earlier. It also suggests (again with large uncertainty) that RSNe like 1978K represent no more than 25% of Types Ib and II SNe combined, which is somewhat more restrictive than our earlier result.

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