Dust spectral energy distributions in the era of Herschel and Planck: a hierarchical bayesian-fitting technique
We present a hierarchical Bayesian method for fitting infrared spectral energy distributions (SEDs) of dust emission to observed fluxes. Under the standard assumption of optically thin single temperature ( T ) sources, the dust SED as represented by a power-law-modified blackbody is subject to a str...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2012 May 24
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| In: |
The astrophysical journal
Year: 2012, Volume: 752, Issue: 1, Pages: 17 |
| ISSN: | 1538-4357 |
| DOI: | 10.1088/0004-637X/752/1/55 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1088/0004-637X/752/1/55 Verlag, Volltext: http://stacks.iop.org/0004-637X/752/i=1/a=55 
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| Author Notes: | Brandon C. Kelly, Rahul Shetty, Amelia M. Stutz, Jens Kauffmann, Alyssa A. Goodman, Ralf Launhardt |
| Summary: | We present a hierarchical Bayesian method for fitting infrared spectral energy distributions (SEDs) of dust emission to observed fluxes. Under the standard assumption of optically thin single temperature ( T ) sources, the dust SED as represented by a power-law-modified blackbody is subject to a strong degeneracy between T and the spectral index β. The traditional non-hierarchical approaches, typically based on χ 2 minimization, are severely limited by this degeneracy, as it produces an artificial anti-correlation between T and β even with modest levels of observational noise. The hierarchical Bayesian method rigorously and self-consistently treats measurement uncertainties, including calibration and noise, resulting in more precise SED fits. As a result, the Bayesian fits do not produce any spurious anti-correlations between the SED parameters due to measurement uncertainty. We demonstrate that the Bayesian method is substantially more accurate than the χ 2 fit in recovering the SED parameters, as well as the correlations between them. As an illustration, we apply our method to Herschel and submillimeter ground-based observations of the star-forming Bok globule CB244. This source is a small, nearby molecular cloud containing a single low-mass protostar and a starless core. We find that T and β are weakly positively correlated—in contradiction with the χ 2 fits, which indicate a T -β anti-correlation from the same data set. Additionally, in comparison to the χ 2 fits the Bayesian SED parameter estimates exhibit a reduced range in values. |
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| Item Description: | Published 2012 May 24 Gesehen am 02.08.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1538-4357 |
| DOI: | 10.1088/0004-637X/752/1/55 |