摘要：

Dust enshrouded Asymptotic Giant Branch (AGB) stars and their more massive counterparts, Red Supergiants (RSG), are among the brightest near- and mid-infrared (IR) sources in a galaxy. These stars constitute a tiny fraction of a galaxy's stellar mass, and yet can account for large fractions of the integrated near and mid-IR flux. Underestimating the AGB and RSG contributions to the IR luminosity can result in severely over-estimating a galaxy's stellar mass as well as inflation of the star formation rate estimated from the 8-micron rest-frame flux. Despite their importance, the AGB and RSG flux contribution has only been measured in a handful of galaxies at a handful of wavelengths. Recent Spitzer Space Telescope observations of the Small and Large Magellanic Clouds offer the first opportunity to quantify the IR contribution of the complete population of Thermally-pulsing (TP-)AGB stars and RSG stars to the total integrated IR light from 1 -24 microns. We find that the TP-AGB + RSG flux contribution peaks at 30% at 3--5 microns in the SMC and 25% in the LMC. Even at 8 microns these stars account for 20% of the SMC flux, with nearly half of that flux coming from a handful (3% of the AGB population) of extreme carbon stars. In the LMC, where PAH emission in the interstellar medium is stronger, the 8 micron TP-AGB + RSG flux contribution is much smaller, 4%.

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