Confirmation of Enhanced Long Wavelength Dust Emission in OMC 2/3. (arXiv:1905.05221v1 [astro-ph.GA])

Confirmation of Enhanced Long Wavelength Dust Emission in OMC 2/3. (arXiv:1905.05221v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mason_B/0/1/0/all/0/1">Brian Mason</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dicker_S/0/1/0/all/0/1">Simon Dicker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sadavoy_S/0/1/0/all/0/1">Sarah Sadavoy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stanchfield_S/0/1/0/all/0/1">Sara Stanchfield</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mroczkowski_T/0/1/0/all/0/1">Tony Mroczkowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Romero_C/0/1/0/all/0/1">Charles Romero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Friesen_R/0/1/0/all/0/1">Rachel Friesen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarazin_C/0/1/0/all/0/1">Craig Sarazin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sievers_J/0/1/0/all/0/1">Jonathan Sievers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stanke_T/0/1/0/all/0/1">Thomas Stanke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Devlin_M/0/1/0/all/0/1">Mark Devlin</a>

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 3.3mm 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 $sim 0.1 pc$ 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 $160 mu m$ to $1 cm$. The data at 2mm
and shorter are generally consistent with a modified black body spectrum and a
single value of $beta sim 1.7$. The 3mm and 1cm 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. The 3mm and 1cm data could be explained by a much flatter
dust spectrum, corresponding to $beta sim 0.7$, at wavelengths shorter than
2mm.

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 3.3mm 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 $sim 0.1 pc$ 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 $160 mu m$ to $1 cm$. The data at 2mm
and shorter are generally consistent with a modified black body spectrum and a
single value of $beta sim 1.7$. The 3mm and 1cm 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. The 3mm and 1cm data could be explained by a much flatter
dust spectrum, corresponding to $beta sim 0.7$, at wavelengths shorter than
2mm.

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