LIFTING THE VEIL OF DUST FROM NGC 0959: THE IMPORTANCE OF A PIXEL-BASED TWO-DIMENSIONAL EXTINCTION CORRECTION

ABSTRACTWe present the results of a study of the late-type spiral galaxy NGC 0959, before and after application of thepixel-based dust extinction correction described in Tamura et al. (Paper I). Galaxy Evolution Explorer far-UV,and near-UV, ground-based Vatican Advanced Technology Telescope, UBVR , and Spitzer/ Infrared Array Camera3.6, 4.5, 5.8, and 8.0 μ m images are studied through pixel color–magnitude diagrams and pixel color–colordiagrams (pCCDs). We define groups of pixels based on their distribution in a pCCD of ( B − 3.6 μ m)versus (FUV − U ) colors after extinction correction. In the same pCCD, we trace their locations beforethe extinction correction was applied. This shows that selecting pixel groups is not meaningful when usingcolors uncorrected for dust. We also trace the distribution of the pixel groups on a pixel coordinate map ofthe galaxy. We find that the pixel-based (two-dimensional) extinction correction is crucial for revealing thespatial variations in the dominant stellar population, averaged over each resolution element. Different types andmixtures of stellar populations, and galaxy structures such as a previously unrecognized bar, become readilydiscernible in the extinction-corrected pCCD and as coherent spatial structures in the pixel coordinate map.