RN light curves as power laws. The declines for all 10 RNe are presented on a plot of
V-band magnitude vs.
t −
t
0 (the time after the first rise in the eruption). If the flux varies as a power law, then the light curve would appear as
a straight line on this plot. The power-law index (α) will equal to the slope in this plot divided by 2.5. Many of the RNe
appear as roughly a broken power law. However, there is substantial variation about this broken power law, arising from flares
and plateaus. The median α values are −1.4 and −2.9 at early and late times, with break times from 6 to 77 days plus IM Nor
at around 235 days. This is to be compared with the "universal decline law" of Hachisu & Kato (2007), where the α values should
be −1.75 and −3.0 at early and late times, with break times up to 80 days for RNe.