A selection of colour-colour and colour-magnitude diagrams is presented for galaxies and stars in the UKIDSS (from DR3plus).

Objects were extracted from source tables via SQL queries (see the SQL links below for specific selection criteria). Only unique and primary objects were selected, and the probability threshold for each object to be classified as galaxy or star was set to 90%. Quality flags for detection reliability were set, and the detection offset was limited to 1 arcsec in each band.

Galaxy magnitudes and colours are presented as observed, i.e. not corrected by galactic extinction (such corrections are however available for all of the observed bands in lasSource, dxsSource, and udsSource).

Contour plots for various colour-colour and colour-magnitude combinations regard the following surveys:

• Large Area Survey: Galaxies (SQL) and Stars (SQL);
• Galactic Plane Survey: Stars (SQL);
• Galactic Cluster Survey: Stars (SQL);
• Deep Extragalactic Survey: Galaxies (SQL) and Stars (SQL);
• Ultra Deep Survey: Galaxies (SQL) and Stars (SQL).

Note: the accuracy of contour plots is limited by the binning employed, which subdivides the plotted ranges of colours and magnitudes in 30 to 90 intervals (depending on sample sizes).