Confirmation of Enhanced Long-wavelength Dust Emission in OMC 2/3
Abstract
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 blackbody dust spectra was considerably lower than what is typically measured on ∼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 that 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 μm to 1 cm. The data at 2 mm and shorter are generally consistent with a modified blackbody spectrum and a single value of β ∼ 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2020
- DOI:
- arXiv:
- arXiv:1905.05221
- Bibcode:
- 2020ApJ...893...13M
- Keywords:
-
- Dust continuum emission;
- Interstellar dust;
- Molecular clouds;
- Dense interstellar clouds;
- Interstellar filaments;
- Star formation;
- Protostars;
- 412;
- 836;
- 1072;
- 371;
- 842;
- 1569;
- 1302;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 19 pages, 8 figures, ApJ (in press)