Lyman Continuum Extinction by Dust in H Ii Regions of Galaxies
نویسنده
چکیده
We examine Lyman continuum extinction (LCE) in H II regions by comparing infrared fluxes of 49 H II regions in the Galaxy, M31, M33, and the LMC with estimated production rates of Lyman continuum photons. A typical fraction of Lyman continuum photons that contribute to hydrogen ionization in the H II regions of three spiral galaxies is . 50 %. The fraction may become smaller as the metallicity (or dust-to-gas ratio) increases. We examine the LCE effect on estimated star formation rates (SFR) of galaxies. The correction factor for the Galactic dust-to-gas ratio is 2-5. Subject headings: dust, extinction — H ii regions — galaxies: ISM — infrared: ISM: continuum — stars: formation
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