Mixed Populations in Globular Clusters: Et Tu, 47 Tuc?
  We exploit the large number of archival HST images of 47 Tuc to examine its
subgiant branch (SGB) and main sequence (MS) for signs of multiple populations.
In the cluster core, we find that the cluster's SGB exhibits a clear spread in
luminosity, with at least two distinct components: a brighter one with a spread
that is real but not bimodal, and a second one about 0.05 mag fainter,
containing about 10% of the stars. In a less crowded field 6 arcminutes from
the center, we find that the MS is broadened much more than can be accounted
for by photometric errors, and that this broadening increases at fainter
magnitudes.
