  We present new multi-band imaging data in the optical (BVRI and Halpha) and
near infrared bands (JHK) of 15 candidate ring galaxies from the sample of
Appleton & Marston (1997). We use these data to obtain color composite images,
global magnitudes and colors of both the ring galaxy and its companion(s), and
radial profiles of intensity and colors. We find that only nine of the observed
galaxies have multi-band morphologies expected for the classical collisional
scenario of ring formation, indicating the high degree of contamination of the
ring galaxy sample by galaxies without a clear ring morphology. The radial
intensity profiles, obtained by masking the off-centered nucleus, peak at the
position of the ring, with the profiles in the continuum bands broader than
that in the Halpha line. The images as well as the radial intensity and color
profiles clearly demonstrate the existence of the pre-collisional stellar disk
outside the star-forming ring, which is in general bluer than the disk internal
to the ring. The stellar disk seems to have retained its size, with the disk
outside the ring having a shorter exponential scale length as compared to the
values expected in normal spiral galaxies of comparable masses. The rings in
our sample of galaxies are found to be located preferentially at around
half-way through the stellar disk. The most likely reason for this preference
is bias against detecting rings when they are close to the center (they would
be confused with the resonant rings), and at the edge of the disk the gas
surface density may be below the critical density required for star formation.
Most of the observed characteristics point to relatively recent collisions (<80
Myr ago) according to the N-body simulations of Gerber et al. (1996).
