  A sample of 27 ultraluminous infrared galaxy (ULIRG) systems has been imaged
at 1.6 microns using the HST Near Infrared Camera and Multi-Object Spectrometer
(NICMOS). These ULIRGs are from a larger sample also imaged with HST in the
I-band. Images and catalog information for the NICMOS subsample, as well as
brief morphological descriptions of each system are presented. Inspection of
the infrared images and a comparison with optical images of these systems shows
that at least 85% are obviously composed of two or more galaxies involved in a
close interaction or merger event, with as many as 93% showing some signs of
interaction history. Approximately 37% of the systems show either spectroscopic
or morphological characteristics of an active galactic nucleus (AGN). The
infrared morphologies of these systems are generally less complicated or
disturbed than their optical morphologies, indicating that some of the
small-scale features seen in optical images are likely due to complicated
patterns of dust obscuration, as well as widely distributed star formation
activity. In some systems the high-resolution HST infrared images have revealed
nuclear remnants that are obscured or unidentified in ground-based imaging,
which has led to changes in previously determined interaction stage
classifications or system content. In general, however, the NICMOS images
support previous conclusions from previous HST optical imaging.
