Modeling and predicting the shape of the far-infrared to submillimeter emission in ultra-compact HII regions and cold clumps
Abstract
Context. Dust properties are very likely affected by the environment in which dust grains evolve. For instance, some analyses of cold clumps (7-17 K) indicate that the aggregation process is favored in dense environments. However, studying warm (30-40 K) dust emission at long wavelength (λ > 300 µm) has been limited because it is difficult to combine far infrared-to-millimeter (FIR-to-mm) spectral coverage and high angular resolution for observations of warm dust grains. Aims. Using Herschel data from 70 to 500µm, which are part of the Herschel infrared Galactic (Hi-GAL) survey combined with 1.1 mm data from the Bolocam Galactic Plane Survey (BGPS), we compared emission in two types of environments: ultracompact HII (UCHII) regions, and cold molecular clumps (denoted as cold clumps). With this comparison we tested dust emission models in the FIR-to-mm domain that reproduce emission in the diffuse medium, in these two environments (UCHII regions and cold clumps). We also investigated their ability to predict the dust emission in our Galaxy. Methods. We determined the emission spectra in twelve UCHII regions and twelve cold clumps, and derived the dust temperature (T) using the recent two-level system (TLS) model with three sets of parameters and the so-called T-β (temperature-dust emissivity index) phenomenological models, with β set to 1.5, 2 and 2.5. Results. We tested the applicability of the TLS model in warm regions for the first time. This analysis indicates distinct trends in the dust emission between cold and warm environments that are visible through changes in the dust emissivity index. However, with the use of standard parameters, the TLS model is able to reproduce the spectral behavior observed in cold and warm regions, from the change of the dust temperature alone, whereas a T-β model requires β to be known.
Additional Information
© 2014 ESO. Received 29 August 2013. Accepted 24 September 2014. Published online 26 November 2014. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The authors acknowledge the support of the French Agence National de la Recherche (ANR) through the programme "CIMMES" (ANR-11-BS56-0029). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Attached Files
Published - aa22566-13.pdf
Submitted - 1409.6892v2.pdf
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Additional details
- Eprint ID
- 53826
- Resolver ID
- CaltechAUTHORS:20150116-110154783
- NASA/JPL/Caltech
- ANR-11-BS56-0029
- Agence National de la Recherche (ANR)
- NASA
- Created
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2015-01-16Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field