Confirmation of Enhanced Long Wavelength Dust Emission in OMC 2/3
  Previous continuum observations from the MUSTANG camera on the Green Bank
Telescope (GBT) of the nearby star-forming filament OMC 2/3 found elevated
emission at 3.3 mm relative to shorter wavelength data. As a consequence, the
inferred dust emissivity index obtained from modified black body dust spectra
was considerably lower than what is typically measured on $\sim 0.1 \, {\rm
pc}$ scales in nearby molecular clouds. Here we present new observations of OMC
2/3 collected with the MUSTANG-2 camera on the GBT which confirm this elevated
emission. We also present for the first time sensitive 1 cm observations made
with the Ka-band receiver on the GBT which also show higher than expected
emission. We use these observations--- along with Herschel, JCMT, Mambo, and
GISMO data--- to assemble spectral energy distributions (SEDs) of a variety of
structures in OMC 2/3 spanning the range $160 \, {\rm \mu m}$ to $1 \, {\rm
cm}$. The data at 2 mm and shorter are generally consistent with a modified
black body spectrum and a single value of $\beta \sim 1.6$. The 3 mm and 1 cm
data, however, lie well above such an SED. The spectrum of the long wavelength
excess is inconsistent with both free-free emission and standard "Spinning
Dust" models for Anomalous Microwave Emission (AME). The 3 mm and 1 cm data
could be explained by a flatter dust emissivity at wavelengths shorter than 2
mm, potentially in concert with AME in some regions.
