We reproduce in Figure 
the isochrones for a E + A galaxy
with solar metallicity. We have plotted the B-R versus the R-K
colors resulting from the prescription in the previous section.
The first panel shows just the isochrones resulting from the
superimposition of a 20 Gyr galaxy and a 0-2 Gyr burst of
star formation involving 0-10% galaxy mass. The subsequent panels
show individual isochrones (mass 0-8%). Superimposed on these
are the colors of radio galaxies shifted to zero redshift.
It is seen that the colors of several galaxies do not lie
on the 0% mass isochron (just the old population).
However, successive panels indicate
that the colors are consistent with a recent burst of star
formation.
Since we
do not have several colors, it is not meaningful to obtain a fit to
these numbers.
For better
prediction, a larger number of colors, and perhaps
high resolution spectra are needed.
Dunlop et al. (1989) have shown that colors can be used
to decide between
various star formation models. This will form part of a future study.
