Galametz, M. and Bock, J. J. and Bradford, M. and Levenson, L. R. and Lu, N. and Schulz, B. (2010) Herschel photometric observations of the nearby low metallicity irregular galaxy NGC 6822. Astronomy and Astrophysics, 518 . L55. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20101119-104442883
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We present the first Herschel PACS and SPIRE images of the low-metallicity galaxy NGC 6822 observed from 70 to 500 μm and clearly resolve the H ii regions with PACS and SPIRE. We find that the ratio 250/500 is dependent on the 24 μm 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.
|Additional Information:||© 2010 ESO. Received 31 March 2010; Accepted 21 April 2010; Published online 16 July 2010. Herschel is an ESA space observatory with science instruments provided by Principal Investigator consortia. It is open for proposals for observing time from the worldwide astronomical community. We thank the referee for his comments that help to improve the quality of this paper. We also thank Erwin de Blok for the integrated H i map of NGC 6822. PACS has been developed by MPE (Germany); UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAF-IFSI/OAA/OAP/OAT, LENS, SISSA (Italy); IAC (Spain). This development has been supported by BMVIT (Austria), ESAPRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI/INAF (Italy), and CICYT/MCYT (Spain). SPIRE has been developed by Cardiff University (UK); Univ. Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); SNSB (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, Univ. Sussex (UK) and Caltech, JPL, NHSC, Univ. Colorado (USA). This development has been supported by CSA (Canada); NAOC (China); CEA, CNES, CNRS (France); ASI (Italy); MCINN (Spain); Stockholm Observatory (Sweden); STFC (UK); and NASA (USA).|
|Subject Keywords:||galaxies: ISM; galaxies: dwarf; galaxies: photometry|
|Official Citation:||Herschel photometric observations of the nearby low metallicity irregular galaxy NGC 6822 M. Galametz, S. C. Madden, F. Galliano, S. Hony, M. Sauvage, M. Pohlen, G. J. Bendo, R. Auld, M. Baes, M. J. Barlow, J. J. Bock, A. Boselli, M. Bradford, V. Buat, N. Castro-Rodríguez, P. Chanial, S. Charlot, L. Ciesla, D. L. Clements, A. Cooray, D. Cormier, L. Cortese, J. I. Davies, E. Dwek, S. A. Eales, D. Elbaz, W. K. Gear, J. Glenn, H. L. Gomez, M. Griffin, K. G. Isaak, L. R. Levenson, N. Lu, B. O'Halloran, K. Okumura, S. Oliver, M. J. Page, P. Panuzzo, A. Papageorgiou, T. J. Parkin, I. Pérez-Fournon, N. Rangwala, E. E. Rigby, H. Roussel, A. Rykala, N. Sacchi, B. Schulz, M. R. P. Schirm, M. W. L. Smith, L. Spinoglio, J. A. Stevens, S. Sundar, M. Symeonidis, M. Trichas, M. Vaccari, L. Vigroux, C. D. Wilson, H. Wozniak, G. S. Wright and W. W. Zeilinger A&A 518 L55 (2010) DOI: 10.1051/0004-6361/201014604|
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|Deposited By:||Jason Perez|
|Deposited On:||23 Nov 2010 00:34|
|Last Modified:||26 Dec 2012 12:39|
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