Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-24T03:31:10.594Z Has data issue: false hasContentIssue false

Dust properties and distribution in dwarf galaxies

Published online by Cambridge University Press:  01 June 2008

Ute Lisenfeld
Affiliation:
Universidad Granada, Spain email: [email protected], [email protected] Institute of Astronomy, University of Cambridge, UK email: [email protected]
Monica Relaño
Affiliation:
Universidad Granada, Spain email: [email protected], [email protected] Institute of Astronomy, University of Cambridge, UK email: [email protected]
José Vílchez
Affiliation:
Instituto de Astrofísica de Andalucía, Granada, Spain email: [email protected]
Eduardo Battaner
Affiliation:
Universidad Granada, Spain email: [email protected], [email protected]
Israel Hermelo
Affiliation:
Universidad Granada, Spain email: [email protected], [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We present a study of the extinction, traced by the Balmer decrement, in HII regions in the dwarf galaxies NGC 1569 and NGC 4214. We find that the large-scale extinction around the most prominent HII regions in both galaxies forms a shell in which locally the intrinsic extinction can adopt relatively high values (AV = 0.8 − 0.9 mag) despite the low metallicity and thus the low overall dust content. The small-scale extinction (spatial resolution ~0.3″) shows fluctuations that are most likely due to variations in the dust distribution. We compare the distribution of the extinction to that of the dust emission, traced by Spitzer emission at 8 and 24μm, and to the emission of cold dust at 850μm. We find in general a good agreement between all tracers, except for the 850μm emission in NGC 4214 which is more extended than the extinction and the other emissions. Whereas in NGC 1569 the dust emission at all wavelengths is very similar, NGC 4214 shows spatial variations in the 24-to-850μm ratio.

We furthermore compared the 24μm and the extinction-corrected Hα emission from HII regions in a sample of galaxies with a wide range of metallicities and found a good correlation, independent of metallicity. We suggest that this lack of dependence on metallicity might be due to the formation of dust shells with a relatively constant opacity, like the ones observed here, around ionizing stars.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

References

Armus, L., Heckman, T. M., & Miley, G. K., 1989, ApJ, 347, 727Google Scholar
Calzetti, D., Kennicutt, R. C., & Bianchi, L., et al. , 2005, ApJ, 633, 871Google Scholar
Calzetti, D., Kennicutt, R. C., & Engelbracht, C. W., 2007, ApJ 666, 870Google Scholar
Caplan, J. & Deharveng, L, 1986, A&A, 155, 297Google Scholar
Israel, F. P., A&A, 194, 24Google Scholar
Kiuchi, G., Ohta, K., Sawicki, M., & Allen, M., 2004, ApJ, 128, 2743Google Scholar
Kobulnicky, H. A. & Skillman, E., 1997, ApJ, 489, 636Google Scholar
Lisenfeld, U., Israel, F. P., Stil, J. M., & Sievers, A., 2002, A&A, 382, 860Google Scholar
Maíz-Apellániz, J., Cieza, L., & MacKenty, J. W., 2002, AJ, 124, 1601Google Scholar
Martin, C. L., 1998, ApJ, 506, 222Google Scholar
Pérez-González, P. G., Kennicutt, R. C., & Gordon, K. D., 2006, ApJ, 648, 987Google Scholar
Relaño, M., Lisenfeld, U., Vílchez, J. M., & Battaner, E., 2006, A&A, 452, 413Google Scholar
Relaño, M., Lisenfeld, U., Pérez-González, P. G., Vílchez, J. M., & Battaner, E., 2006, A&A 667, L141Google Scholar
Schlegel, D. J., Finkbeiner, D. P., & Davis, M., 1998, ApJ, 500, 525CrossRefGoogle Scholar
Walter, F., Taylor, C. L., Hüttemeister, S., Scoville, N., & McIntyre, V., 2001, ApJ, 121, 727CrossRefGoogle Scholar
Zubko, V., Dwek, E., & Arendt, R. G., ApJS, 152, 211CrossRefGoogle Scholar
Taylor, C. L., Hüttemeister, S., KLein, U., & Greve, A., 1999, A&A, 349, 424Google Scholar