A Study of 90 GHz Dust Emissivity on Molecular Cloud and Filament Scales
Hensley, Brandon; Friesen, Rachel; Sadavoy, Sarah; Mroczkowski, Tony; Hacar, Alvaro; Naess, Sigurd; Devlin, Mark; Salatino, Maria; Xu, Zhilei; Stanke, Thomas; Clark, S. E.; Sievers, Jonathan; Romero, Charles; Dicker, Simon R.; Duff, Shannon M.; Schillaci, Alessandro; Sarazin, Craig; Orlowski-Scherer, John; Stutz, Amelia; Lowe, Ian; Mason, Brian; Bhandarkar, Tanay
United States, Canada, Austria, Germany, Chile
Abstract
Recent observations from the MUSTANG2 instrument on the Green Bank Telescope have revealed evidence of enhanced long-wavelength emission in the dust spectral energy distribution (SED) in the Orion Molecular Cloud (OMC) 2/3 filament on 25″ (0.1 pc) scales. Here we present a measurement of the SED on larger spatial scales (map size 0.°5-3° or 3-20 pc), at somewhat lower resolution (120″, corresponding to 0.25 pc at 400 pc) using data from the Herschel satellite and Atacama Cosmology Telescope (ACT). We then extend the 120″-scale investigation to other regions covered in the Herschel Gould Belt Survey (HGBS), specifically the dense filaments in the southerly regions of Orion A, Orion B, and Serpens-S. Our data set in aggregate covers approximately 10 deg2, with continuum photometry spanning from 160 μm to 3 mm. These OMC 2/3 data display excess emission at 3 mm, though less (10.9% excess) than what is seen at higher resolution. Strikingly, we find that the enhancement is present even more strongly in the other filaments we targeted, with an average excess of 42.4% and 30/46 slices showing an inconsistency with the modified blackbody to at least 4σ. Applying this analysis to the other targeted regions, we lay the groundwork for future high-resolution analyses. Additionally, we also consider a two-component dust model motivated by Planck results and an amorphous grain dust model. While both of these have been proposed to explain deviations in emission from a generic modified blackbody, we find that they have significant drawbacks, requiring many spectral points or lacking experimental data coverage.