Dust heating in the cores of 3CRR radio galaxies

We have undertaken a Spitzer campaign to measure the IR structures and spectra of low-redshift 3CRR radio galaxies. The results show that the 3.6 - 160 μm infrared properties vary systematically with integrated source power, and so demonstrate that contemporary core activity is characteristic of the behaviour of sources over their lifetimes. IR synchrotron emission is seen from jets and hotspots in some cases. Thermal emission is found from a jet/gas interaction in NGC7385. Most of the near-IR integrated colours of the low-redshift 3CRR radio galaxies are similar to those of passive galaxies, so that IR colours are poor indicators of radio activity.