Surprisingly Strong K-band Emission Found in Low Luminosity Active
  Galactic Nuclei
  We examine the near-infrared (NIR) emission from low-luminosity AGNs
(LLAGNs). Our galaxy sample includes 15 objects with detected 2-10 keV X-ray
emission, dynamical black hole mass estimates from the literature, and
available Gemini/NIFS integral field spectroscopy (IFU) data. We find evidence
for red continuum components at the center of most galaxies, consistent with
the hot dust emission seen in higher luminosity AGN. We decompose the spectral
data cubes into a stellar and continuum component, assuming the continuum
component comes from thermal emission from hot dust. We detect nuclear thermal
emission in 14 out of 15 objects. This emission causes weaker CO absorption
lines and redder continuum ($2.05-2.28\:\mu$m) in our $K$-band data, as
expected from hot dust around an AGN. The NIR emission is clearly correlated
with the 2-10 keV X-ray flux, with a Spearman coefficient of
$r_{spearman}=0.69$ suggesting a $>99\%$ significance of correlation, providing
further evidence of an AGN origin. Our sample has typical X-ray and NIR fluxes
$3-4$ orders of magnitude less luminous than previous work studying the NIR
emission from AGN. We find that the ratio of NIR to X-ray emission increases
towards lower Eddington ratios. The NIR emission in our sample is often
brighter than the X-ray emission, with our $K$-band AGN luminosities comparable
to or greater than the 2-10 keV X-ray luminosities in all objects with
Eddington ratios below $0.01\%$. The nature of this LLAGN NIR emission remains
unclear, with one possibility being an increased contribution from jet emission
at these low luminosities. These observations suggest JWST will be a useful
tool for detecting the lowest luminosity AGN.
