FIR and Submm Optical Properties of Astrophysically Relevant Minerals
Abstract
The Herschel and Planck missions have opened up the spectral domain in the far infrared and submillimeter range. This spectral domain reveals the emission of cold (T ≤ 50 K) dust grains of nanometer size (10-100 nm), emission which is used to study star formation, to estimate interstellar clouds masses and more generally to study the evolution of the interstellar medium in our Galaxy and in external galaxies. To get reliable interpretation of the observations it is therefore crucial to properly understand the physic of dust emission and to know as well as possible the FIR and submm optical properties of interstellar dust. In this article we will review the theoretical and experimental works aiming at studying the physics of dust analogues in the FIR/submm domain. The mass absorption coefficient of amorphous silicate nano grains decreases with the temperature and shows a complex shape with the wavelength depending on the micro structure of the materials. For wavelengths shorter than ∼ 500 µm the spectral index is in the range 1.6-2.3 whereas at longer wavelengths it changes and its value may be outside this range. Therefore, a single spectral index is not always adequate to correctly fit the experimental measurements in the 100 - 1000 µm domain. These results must be taken into account in astronomical modeling either by using optical constants measured in the FIR/submm domain and at low temperature or by using physical models able to reproduce the experimental data.
- Publication:
-
Proceedings of The Life Cycle of Dust in the Universe: Observations
- Pub Date:
- 2013
- DOI:
- 10.22323/1.207.0044
- Bibcode:
- 2013lcdu.confE..44D