The properties of isolated Main galaxies in different redshift bins

In order to decrease the effect of radial selection function, we have constructed a volume-limited sample that extends to Zmax = 0.12, and limits the absolute magnitude region: −22.40 ⩽ M ⩽ −20.97. It contains 55,054 galaxies. By three-dimensional cluster analysis, two isolated galaxy samples are extracted from volume-limited sample at the dimensionless neighbourhood radii r = 1.2 and r = 1.4. We analyse the basic properties of isolated galaxies identified at r = 1.2 in different redshift bins, and compare these properties of isolated galaxies with that of volume-limited sample in different redshift bins. It turns out that isolated galaxies have the same basic properties as volume-limited sample in different redshift bins. This indicates that these basic properties of galaxies have no correlation with environment around galaxies. When comparing basic properties of isolated galaxy sample identified at r = 1.2 with that of isolated galaxy sample identified at r = 1.4, we find that isolated galaxy samples identified at different radii have the same properties. This demonstrates that isolated galaxies identified at neighbourhood radii r ⩾ 1.2 by cluster analysis have definite basic properties and can be considered good isolated galaxy samples.