Dust emissivity in the star-forming filament OMC 2/3

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1051/0004-6361/201527364
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Name affiliation
  1. National Research Council Canada. National Science Infrastructure
FormatText
TypeArticle
Journal titleAstronomy & Astrophysics
ISSN0004-6361
1432-0746
Volume588
Article numberA30
Pages1–11
SubjectStar formation; Star dust; Star extinction; ISM clouds
Abstract
We present new measurements of the dust emissivity index, β, for the high-mass, star-forming OMC 2/3 filament. We combined 160−500 μm data from Herschel with long-wavelength observations at 2 mm and fit the spectral energy distributions across a ≃2 pc long, continuous section of OMC 2/3 at 15 000 AU (0.08 pc) resolution. With these data, we measured β and reconstructed simultaneously the filtered-out large-scale emission at 2 mm. We implemented both variable and fixed values of β, finding that β = 1.7−1.8 provides the best fit across most of OMC 2/3. These β values are consistent with a similar analysis carried out with filtered Herschel data. Thus, we show that β values derived from spatial filtered emission maps agree well with those values from unfiltered data at the same resolution. Our results contradict the very low β values (~0.9) previously measured in OMC 2/3 between 1.2 mm and 3.3 mm data, which we attribute to elevated fluxes in the 3.3 mm observations. Therefore, we find no evidence of rapid, extensive dust grain growth in OMC 2/3. Future studies with Herschel data and complementary ground-based long-wavelength data can apply our technique to obtain reliable determinations of β in nearby cold molecular clouds.
Publication date
PublisherEDP Sciences
LanguageEnglish
Peer reviewedYes
Identifieraa27364-15
NPARC number23000369
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