  We present near-infrared images obtained with the HST NICMOS camera for a
sample of 9 luminous (LIGs: L_IR (8-1000 microns) >~ 10^11 L_sun) and 15
ultra-luminous (ULIGS: L_IR >~ 10^12 L_sun) infrared galaxies. The sample
includes representative systems classified as warm (f_25/f_60 > 0.2) and cold
(f_25/f_60 <~ 0.2) based on the mid-infrared colors and systems with nuclear
emission lines classified as HII (i.e. starburst), QSO, Seyfert and LINER. The
morphologies of the sample galaxies are diverse and provide further support for
the idea that they are created by the collision or interactions of spiral
galaxies. Although no new nuclei are seen in the NICMOS images, the NICMOS
images do reveal new spiral structures, bridges, and circumnuclear star
clusters...
