Starburst Galaxies: Why the Calzetti Dust Extinction Law?
| Autor: | Michael A. Dopita, Joerg Fischera, Ralph S. Sutherland |
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| Rok vydání: | 2003 |
| Předmět: |
Physics
Extinction threshold Astrophysics (astro-ph) Extinction (astronomy) FOS: Physical sciences Sigma Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Galaxy Interstellar medium Space and Planetary Science Law Attenuation law Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 599:L21-L24 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | The empirical reddening function for starburst galaxies generated by Calzetti and her co-workers has proven very successful, and is now used widely in the observational literature. Despite its success, however, the physical basis for this extinction law, or more correctly, attenuation law remains weak. Here we provide a physical explanation for the Calzetti Law based on a turbulent interstellar medium. In essence, this provides a log-normal distribution of column densities, giving a wide range of column densities in the dusty foreground screen. Therefore, extended sources such as starburst regions or HII regions seen through it suffer a point-to-point stochastic extinction and reddening. Regions of high column densities are "black" in the UV, but translucent in the IR, which leads to a flatter extinction law, and a larger value of the total to selective extinction, R_V. We fit the Calzetti Law, and infer that the variance sigma of the log-normal distribution lies in the range 0.6 Comment: accepted for publication in ApJL |
| Databáze: | OpenAIRE |
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