UBVR and HST mid-UV and near-IR surface photometry and radial color gradients of late-type, irregular, and peculiar galaxies

Astrophys.J. 630 (2005) 784-803 We introduce a dataset of 142 mostly late-type spiral, irregular, and peculiar (interacting or merging) nearby galaxies observed in UBVR at the Vatican Advanced Technology Telescope (VATT), and present an analysis of their radial color gradients. We confirm that nearby elliptical and early- to mid-type spiral galaxies show either no or only small color gradients, becoming slightly bluer with radius. In contrast, we find that late-type spiral, irregular, peculiar, and merging galaxies become on average redder with increasing distance from the center. The scatter in radial color gradient trends increases toward later Hubble type. As a preliminary analysis of a larger data-set obtained with the Hubble Space Telescope (HST), we also analyze the color gradients of six nearby galaxies observed with NICMOS in the near-IR (H) and with WFPC2 in the mid-UV (F300W) and red (F814W). We discuss the possible implication of these results on galaxy formation and compare our nearby galaxy color gradients to those at high redshift. We present examples of images and UBVR radial surface brightness and color profiles, and of the tables of measurements; the full atlas and tables are published in the electronic edition only.