Top: temperatures of sources in the catalogue (colour scale in thermodynamic kelvins). Bottom: spectral indices β of the MBB SED model. The catalogue was filtered using the condition of Eq. (16). The size of each circle representing an object is proportional to the logarithm of the source flux density in janskys. This figure also makes clear the extent that sources in PCCS2+2E trace cirrus; see also the smaller region in Fig. 1.