  We present a deep near-infrared color--magnitude diagram of the Galactic
globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey
Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K_s
survey of the Magellanic System (VMC). The cluster stars comprising both the
subgiant and red-giant branches exhibit apparent, continuous variations in
color--magnitude space as a function of radius. Subgiant-branch stars at larger
radii are systematically brighter than their counterparts closer to the cluster
core; similarly, red-giant-branch stars in the cluster's periphery are bluer
than their more centrally located cousins. The observations can very well be
described by adopting an age spread of ~0.5 Gyr as well as radial gradients in
both the cluster's helium abundance (Y) and metallicity (Z), which change
gradually from Y = 0.28, Z = 0.005 in the cluster core to Y = 0.25, Z = 0.003
in its periphery. We conclude that the cluster's inner regions host a
significant fraction of second-generation stars, which decreases with
increasing radius; the stellar population in the 47 Tuc periphery is well
approximated by a simple stellar population.
