Benchmarking Dust Emission Models in M101

We present a comparative study of four physical dust models and two single-temperature modified blackbody by fitting them to the resolved WISE, Spitzer, Herschel photometry M101 (NGC 5457). Using identical data grid-based technique, we compare resulting radiation field properties derived from models. find that mass yielded different can vary up factor 3 (factor 1.4 between only), although fits have similar quality. Despite differences in their definition carriers mid-IR aromatic features, all show same spatial variations for abundance grain population. well determined metallicity gradient gas maps, calculate an approximate upper limit on as function radius. All are found exceed this maximum estimate over some range galactocentric radii. renormalizing match Milky Way high latitude cirrus spectrum constraints reduce bring total below at