Star formation in galaxies hosting AGN: A flat trend of star-formation
  rate with X-ray luminosity of galaxies hosting AGN in the SCUBA-2 Cosmology
  Legacy Survey
  Feedback processes from active galactic nuclei (AGN) are thought to play a
crucial role in regulating star formation in massive galaxies. Previous studies
using \textit{Herschel} have resulted in conflicting conclusions as to whether
star formation is quenched, enhanced, or not affected by AGN feedback. We use
new deep 850 $\mu$m observations from the SCUBA-2 Cosmology Legacy survey
(S2CLS) to investigate star formation in a sample of X-ray selected AGN,
probing galaxies up to $L_{0.5-7~\rm keV} = 10^{46}$ erg s$^{-1}$. Here we
present the results of our analysis on a sample of 1957 galaxies at $ 1 < z < 3
$, using both S2CLS and ancilliary data at seven additional wavelengths
(24--500 \mcm) from \textit{Herschel} and \textit{Spitzer}. We perform a
stacking analysis, binning our sample by redshift and X-ray luminosity. By
fitting analytical spectral energy distributions (SEDs) to decompose
contributions from cold and warm dust, we estimate star-formation rates for
each `average' source. We find that the average AGN in our sample resides in a
star-forming host galaxy, with SFRs ranging from 80 - 600 $M_{\odot}$
year$^{-1}$. Within each redshift bin, we see no trend of SFR with X-ray
luminosity, instead finding a flat distribution of SFR across $\sim$3 orders of
magnitude of AGN luminosity. By studying instantaneous X-ray luminosities and
SFRs, we find no evidence that AGN activity affects star formation in host
galaxies.
