Comparative Study of Asymmetry Origin of Galaxies in Different
  Environments. I. Optical observations
  This paper presents the first of two analyses about the influence of
environment on the formation and evolution of galaxies observed in the nearby
universe. For our study, we used three different samples representing different
density environments: galaxies in Compact Groups (HCGs), Isolated Pairs of
Galaxies (KPGs), and Isolated Galaxies (KIGs), which were taken as reference.
Using both characteristic isophotal parameters and evidence of asymmetries in
the optical and the near-infrared, we are able to establish differences in the
characteristics of galaxies with different morphologies in different
environments, allowing us to better understand their different formation
histories. In this first paper, we present the isophotal and asymmetry analyses
of a sample of 214 galaxies in different environments observed in the optical
(V and I images). For each galaxy, we have determined different characteristic
isophotal parameters and (V-I) color profiles, as a function of semi-major
axis, and performed a full asymmetry analysis in residual images using the V
filter. Evidence of asymmetry in the optical is almost missing in the KIG
sample and significantly more common in the KPG than in the HCG samples. Our
isophotal analysis suggests that the stellar populations in the HCG galaxies
are older and more dynamically relaxed than in the KPG. The HCG galaxies seem
to be at a more advanced stage of interaction than the KPGs. One possible
explanation is that these structures formed at different epochs: compact groups
of galaxies would have formed before close pairs of galaxies, which only began
interacting recently. However, similarities in the formation process of
galaxies with same morphology suggest CGs and close pairs of galaxies share
similar conditions; they are new structures forming relatively late in
low-density environments.
