SIMBAD references

Two galaxies with observed type Ia supernovae have been identified in each of three Lyon groups of galaxies not associated with the Virgo cluster. The difference of well-determined apparent magnitudes at lihgt curve maximum of the supernovae in each group is delta-B </= 0.2 mag, delta-V </= 0.2 mag. Previously, Branch and Tammann found that the observed apparent magnitudes at maximum light for type Ia supernovae in three galaxies, each with _two observed supernovae, are nearly identical. The consistency of these two independent results further suggests that the set of all type Ia supernovae contains a large subset of 'standard candles'.