Herschel photometric observations of the nearby low metallicity irregular galaxy NGC 6822

Galametz, M, Madden, S C, Galliano, F, Hony, S, Sauvage, M, Pohlen, M, Bendo, G J, Oliver, S and et al, (2010) Herschel photometric observations of the nearby low metallicity irregular galaxy NGC 6822. Astronomy and Astrophysics, 518. ISSN 0004-6361

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Abstract

We present the first Herschel PACS and SPIRE images of the low-metallicity galaxy NGC 6822 observed from 70 to 500 mu m and clearly resolve the H II regions with PACS and SPIRE. We find that the ratio 250/500 is dependent on the 24 mu m surface brightness in NGC 6822, which would locally link the heating processes of the coldest phases of dust in the ISM to the star formation activity. We model the SEDs of some regions H II regions and less active regions across the galaxy and find that the SEDs of H II regions show warmer ranges of dust temperatures. We derive very high dust masses when graphite is used in our model to describe carbon dust. Using amorphous carbon, instead, requires less dust mass to account for submm emission due to its lower emissivity properties. This indicates that SED models including Herschel constraints may require different dust properties than commonly used. The global G/D of NGC 6822 is finally estimated to be 186, using amorphous carbon.

Item Type: Article
Additional Information: There are other co-authors not recorded
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: EPrints Services
Date Deposited: 06 Feb 2012 20:58
Last Modified: 07 Jun 2012 10:26
URI: http://sro.sussex.ac.uk/id/eprint/28891
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