| タイトル | All-Sky Observational Evidence for An Inverse Correlation Between Dust Temperature and Emissivity Spectral Index |
| 本文（外部サイト） | http://hdl.handle.net/2060/20120013322 |
| 著者（英） | Fixsen, D. J.; Liang, Z.; Gold, B. |
| 著者所属（英） | Johns Hopkins Univ. |
| 発行日 | 2012-01-04 |
| 言語 | eng |
| 内容記述 | We show that a one-component variable-emissivity-spectral-index model (the free- model) provides more physically motivated estimates of dust temperature at the Galactic polar caps than one- or two-component fixed-emissivity-spectral-index models (fixed- models) for interstellar dust thermal emission at far-infrared and millimeter wavelengths. For the comparison we have fit all-sky one-component dust models with fixed or variable emissivity spectral index to a new and improved version of the 210-channel dust spectra from the COBE-FIRAS, the 100-240 micrometer maps from the COBE-DIRBE and the 94 GHz dust map from the WMAP. The best model, the free-alpha model, is well constrained by data at 60-3000 GHz over 86 per cent of the total sky area. It predicts dust temperature (T(sub dust)) to be 13.7-22.7 (plus or minus 1.3) K, the emissivity spectral index (alpha) to be 1.2-3.1 (plus or minus 0.3) and the optical depth (tau) to range 0.6-46 x 10(exp -5) with a 23 per cent uncertainty. Using these estimates, we present all-sky evidence for an inverse correlation between the emissivity spectral index and dust temperature, which fits the relation alpha = 1/(delta + omega (raised dot) T(sub dust) with delta = -.0.510 plus or minus 0.011 and omega = 0.059 plus or minus 0.001. This best model will be useful to cosmic microwave background experiments for removing foreground dust contamination and it can serve as an all-sky extended-frequency reference for future higher resolution dust models. |
| NASA分類 | Astrophysics |
| レポートNO | GSFC.JA.6333.2012 |
| 権利 | Copyright, Distribution under U.S. Government purpose rights |
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