Suppression of Star Formation in the Hosts of Low-Excitation Radio
  Galaxies
  The feedback from radio-loud active galactic nuclei (R-AGN) may help maintain
low star formation (SF) rates in their early-type hosts, but the observational
evidence for this mechanism has been inconclusive. We study systematic
differences of aggregate spectral energy distributions (SEDs) of various
subsets of $\sim$4000 low-redshift R-AGN from Best & Heckman (2012) with
respect to (currently) inactive control samples selected to have matching
redshift, stellar mass, population age, axis ratio, and environment. Aggregate
SEDs, ranging from the ultraviolet (UV) through mid-infrared (mid-IR, 22
$\mu$m), were constructed using a Bayesian method that eliminates biases from
non-detections in GALEX and WISE. We study rare high-excitation sources
separately from low-excitation ones, which we split by environment and host
properties. We find that both the UV and mid-IR emission of non-cluster R-AGNs
(80% of sample) are suppressed by $\sim$0.2 dex relative to that of the control
group, especially for moderately massive galaxies (log $M_* \lesssim$ 11). The
difference disappears for high-mass R-AGN and for R-AGN in clusters, where
other, non-AGN quenching/maintenance mechanisms may dominate, or where the
suppression of SF due to AGN may persist between active phases of the central
engine, perhaps because of the presence of a hot gaseous halo storing AGN
energy. High-excitation (high accretion rate) sources, which make up 2% of the
R-AGN sample, also show no evidence of SF suppression (their UV is the same as
in controls), but they exhibit a strong mid-IR excess due to AGN dust heating.
