HerMES: SPIRE/Sub-millimetre Emission from Radio Selected AGN
  We examine the rest-frame far-infrared emission from powerful radio sources
with 1.4GHz luminosity densities of 25<=log(L_1.4/WHz^-1)<=26.5 in the
extragalactic Spitzer First Look Survey field. We combine Herschel/SPIRE flux
densities with Spitzer/IRAC and MIPS infrared data to obtain total (8-1000um)
infrared luminosities for these radio sources. We separate our sources into a
moderate, 0.4<z<0.9, and a high, 1.2<z<3.0, redshift sub-sample and we use
Spitzer observations of a z<0.1 3CRR sample as a local comparison. By
comparison to numbers from the SKA Simulated Skies we find that our moderate
redshift sample is complete and our high redshift sample is 14per cent
complete. We constrain the ranges of mean star formation rates (SFRs) to be
3.4-4.2, 18-41 and 80-581Msun/yr for the local, moderate and high redshift
samples respectively. Hence, we observe an increase in the mean SFR with
increasing redshift which we can parameterise as ~(1+z)^Q, where Q=4.2+/-0.8.
However we observe no trends of mean SFR with radio luminosity within the
moderate or high redshift bins. We estimate that radio-loud AGN in the high
redshift sample contribute 0.1-0.5per cent to the total SFR density at that
epoch. Hence, if all luminous starbursts host radio-loud AGN we infer a
radio-loud phase duty cycle of 0.001-0.005.
