Investigating the presence of 500 um submillimeter excess emission in
  local star forming galaxies
  Submillimeter excess emission has been reported at 500 microns in a handful
of local galaxies, and previous studies suggest that it could be correlated
with metal abundance. We investigate the presence of an excess submillimeter
emission at 500 microns for a sample of 20 galaxies from the Key Insights on
Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) that span a
range of morphologies and metallicities (12+log(O/H)=7.8-8.7). We probe the
far-infrared (IR) emission using images from the Spitzer Space Telescope and
Herschel Space Observatory in the wavelength range 24-500 microns. We model the
far-IR peak of the dust emission with a two-temperature modified blackbody and
measure excess of the 500 micron photometry relative to that predicted by our
model. We compare the submillimeter excess, where present, with global galaxy
metallicity and, where available, resolved metallicity measurements. We do not
find any correlation between the 500 micron excess and metallicity. A few
individual sources do show excess (10-20%) at 500 microns; conversely, for
other sources, the model overpredicts the measured 500 micron flux density by
as much as 20%, creating a 500 micron "deficit". None of our sources has an
excess larger than the calculated 1-sigma uncertainty, leading us to conclude
that there is no substantial excess at submillimeter wavelengths at or shorter
than 500 microns in our sample. Our results differ from previous studies
detecting 500 micron excess in KINGFISH galaxies largely due to new, improved
photometry used in this study.
