0 Assigned ID: 454 ----- Attempting Submission 1 (Fri Apr 10 13:20:27 GMT 2015) ----- HST has invested thousands of orbits in carefully measuring intermediate-redshift galaxy structures and morphologies (structures hereafter), photometric redshifts and stellar populations, forming the bedrock of our measurements of galaxy evolution. Yet, studies of nearby galaxies show that the structures of galaxies and their spectral energy distributions (SEDs) are strongly affected by dust. Given that the 0.5<z<1 galaxy population appears more gas and dust rich than the local population, a model-independent measurement of the effects of dust on galaxy structures and SEDs is urgently needed. We propose to use long-wavelength Spitzer IRAC and MIPS data for the HST-COSMOS survey to select samples of star-forming dusty disk galaxies with 0.5<z<1 and M*>1e10 M_sun in a way that depends neither on dust attenuation nor on galaxy inclination. This selection yields a sample of very similar disk galaxies, viewed from random viewing angles; COSMOS is the ideal dataset owing to its large size, its superb depth, and its widely-used public catalogs of galaxy structures. Following the methods we have developed using the SDSS, we will measure changes in F814W-derived galaxy structure with axis ratio (inclination), measuring for the first time ever the differential effects of dust attenuation on galaxy structures at 0.5<z<1. We will measure the change in SEDs with axis ratio, providing a model-independent measure of the difference in attenuation between face-on and edge-on as a function of galaxy parameters. Finally, we will critically assess individual galaxy attenuation measures from stellar population model plus dust fits, providing a crucial test of these widely used methods. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 0 Regular false false false false false SUPPORTED