paper

The effects of dust in simple environments: Large Magellanic Cloud HII regions

arXiv:astro-ph/0108367 · doi:10.1086/324434

Abstract

We investigate the effects of dust on Large Magellanic Cloud (LMC) HII region spectral energy distributions using arcminute-resolution far-ultraviolet (FUV), H-alpha, far-infrared (FIR), and radio images. Widely-used indicators of the amount of light lost to dust (attenuation) at H-alpha and in the FUV correlate with each other, although often with substantial scatter. There are two interesting systematic discrepancies. First, H-alpha attenuations estimated from the Balmer decrement are lower than those estimated from the H-alpha-to-thermal radio luminosity ratio. Our data, at this stage, cannot unambiguously identify the source of this discrepancy. Second, the attenuation at 1500 angstroms and UV spectral slope, beta, correlate, although the slope and scatter are substantially different from the correlation first derived for starbursting galaxies by Calzetti et al. Combining our result with those of Meurer et al. for ultra-luminous infrared galaxies and Calzetti et al. for starbursting galaxies, we conclude that no single relation between beta and 1500 angstrom attenuation is applicable to all star-forming systems.

15 pages; 11 embedded postscript figures; 1 GIF figure; to appear in ApJ on 20 January 2002, vol. 565, no. 1. Section 5.1 (the discussion of the discrepancies between Balmer-derived and Radio-derived H alpha attenuations) has changed considerably to take into account small number statistics for high-mass stars in the model HII region IMFs. The abstract and conclusions have been modified

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