The Disks of Galaxies with Seyfert and Starburst Nuclei. I. Near-Infrared Colors and Color Gradients

摘要: We present near-infrared (NIR) broadband and color images of 26 galaxies that host Seyfert 1, 2, or starburst nuclei (SBNs). The study is focused on properties the rather than their nuclei, to this end, careful attention paid photometric accuracy reliable measurements low surface brightness outer disk. Inspection elliptically averaged radial profiles reveals (1) NIR mean colors inner disks are consistent with those a normal late-type stellar population do not differ significantly activity class; (2) gradients in similar both sign magnitude observed spirals; (3) red "ridges" parts J - H profile evident majority SBNs, but only few type 1 Seyferts no 2's; (4) circumnuclear blue "dips" seen 2 Seyferts. then construct find ridges, rings, filaments, images, SBNs NGC 7469, 1. application simple model these features yields evidence dust extinction excess μm emission. Color-color diagrams individual pixels confirm results also show mix most 2's comprises conspicuous contribution from an intermediate-age [(3-5) × 108 yr] population. It appears ongoing star formation signaled by presence (and gas); absence such types implies episodes either absent very old. However, while suggest burst did, fact, occur more 109 yr ago, 1's imply any star-forming must be older.