There are links to all the available colour--colour plots in [2].
Merged databases allow us to create colour--colour plots for WFC data. It is also possible to overlay synthetic stellar and QSO catalogues available as IDL databases. (Note only colour--colour plots and not colour--magnitude plots are included here because the synthetic values are only meaningful relative to each other).
The two cases for which plots of g-r versus r-i, u-g versus g-r and
u-g versus g-i are available are shown in Figs.
and
.
Figure: Colour--Colour plots for the Lockman Hole field with synthetic data overlaid: (a) g-r vs r-i, stars only with synthetic stars and QSOs, (b) g-r vs r-i, galaxies and noise only, (c) u-g vs g-r, stars only with synthetic data, (d) u-g vs g-r, galaxies and noise only, (e) u-g vs g-i, stars only with synthetic data, (f) u-g vs g-i, galaxies and noise only.
Figure: Colour--Colour plots for the MKN 205 field with synthetic data overlaid: (a) g-r vs r-i, stars only with synthetic stars and QSOs, (b) g-r vs r-i, galaxies and noise only, (c) u-g vs g-r, stars only with synthetic data, (d) u-g vs g-r, galaxies and noise only, (e) u-g vs g-i, stars only with synthetic data, (f) u-g vs g-i, galaxies and noise only.
Little variability is seen across diferent fields (over a relatively small number of fields which have both merged data and the necessary bands) for the g-r vs r-i plots. (The other colour--colour plots are currently only available in the fields shown here). Noise objects are usually outlying compared to galaxies.
Although the synthetic stellar data is in good agreement with the WFC data in
the g-r vs r-i plots, the agreement is less pronouced for the other two
plots, with the break in the synthetic curve absent from the WFc data.
Note the strange distribution of noise objects in Fig. (d).
Another interesting point is that certain bands seem to select
out the noise objects (i for the MKN 205 field, U for the Lockman Hole field).
For MKN 205, i is the band with the longest exposure time, while on the other
hand, for the Lockman Hole, U is the shallowest band (remembering noise
objects are found at the faint end of the magnitude distribution).