  We search for isolated galaxies using a volume-limited sample of galaxies
with 0.02< z < 0.04742 from SDSS DR7 supplemented by bright galaxies. We devise
a diagnostic tool to select isolated galaxies in different environments using
the projected separation (r_p) normalized by the virial radius of the nearest
neighbor (r_{vir,nei}) and the local background density. We find that the
isolation condition of r_p>r_{vir,nei} and \rho <\bar{\rho} well segregates the
CIG galaxies. We confirm the morphology conformity between the host and their
satellites, which suggests importance of hydrodynamic interaction among
galaxies within their virial radii in galaxy evolution.

Cosmology and Nongalactic Astrophysics