Adding mid-IR fluxes
fluxes from the Spitzer Wide-area Infrared Survey (SWIRE) and the
UKIDSS survey EDR data, the figure on the left shows the K-[3.6] versus
J-K colour. In red all objects classified as point like in the near-IR
images and in blue those classified as stars. Also shown some galaxy
templates (blue, cyan, green, magenta) and a QSO type I template (red).
Red diamonds mark those sources with spectroscopically confirmed
redshift, most of them beeing QSO I. The fit of the models to the data
is remarkable. The z=0 point for the templates is marked by a white
filled circle while z=1,2,3 are marked by triangles.