Toward understanding the 3.4 micron and 9.7 micron extinction feature variations from the local diffuse interstellar medium to the Galactic center
arXiv:0812.2016 · doi:10.5047/eps.2008.12.006
Abstract
Observationally, both the 3.4micron aliphatic hydrocarbon C--H stretching absorption feature and the 9.7micron amorphous silicate Si--O stretching absorption feature show considerable variations from the local diffuse interstellar medium (ISM) to Galactic center (GC): both the ratio of the visual extinction (A_V) to the 9.7micron Si--O optical depth (\tausil) and the ratio of A_V to the 3.4micron C--H optical depth (\tauahc) of the solar neighborhood local diffuse ISM are about twice as much as that of the GC. In this work, we try to explain these variations in terms of a porous dust model consisting of a mixture of amorphous silicate, carbonaceous organic refractory dust (as well as water ice for the GC dust).
6 pages, 6 figures, uses eps.cls. Accepted for publication in "Earth, Planets and Space" (special issue on Cosmic Dust)
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- The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point
- Line derived infrared extinction towards the Galactic Center
- The gas-to-extinction ratio and the gas distribution in the Galaxy
- On the Optical-to-Silicate Extinction Ratio as a Probe of the Dust Size in Active Galactic Nuclei
- Probing the Interstellar Dust in Galaxies over > 10 Gyr of Cosmic History
- A systematic study on the properties of aromatic and aliphatic hydrocarbon dust in active galactic nuclei with AKARI near-infrared spectroscopy