We present a study characterizing the environments of galaxies in the redshift range of 0.4 < z < 1 based on data from the POWIR near infrared imaging and DEEP2 spectroscopic redshift surveys , down to a stellar mass of \log~ { } M _ { \ast } = 10.25 ~ { } M _ { \odot } .
Galaxy environments are measured in terms of nearest neighbour densities as well as fixed aperture densities and kinematical and dynamical parameters of neighbour galaxies within a radius of 1 h ^ { -1 } Mpc .
We disentangle the correlations between galaxy stellar mass , galaxy colour and galaxy environment , using not only galaxy number densities , but also other environmental characteristics such as velocity dispersion , mean harmonic radius , and crossing time .
We find that galaxy colour and the fraction of blue galaxies depends very strongly on stellar mass at 0.4 < z < 1 , while a weak additional dependence on local number densities is in place at lower redshifts ( 0.4 < z < 0.7 ) .
This environmental influence is most visible in the colours of intermediate mass galaxies ( 10.5 < \log~ { } M _ { \ast } < 11 ) , whereas colours of lower and higher mass galaxies remain largely unchanged with redshift and environment .
At a fixed stellar mass , the colour-density relation almost disappears , while the colour-stellar mass relation is present at all local densities .
We find a weak correlation between stellar mass and environment at intermediate redshifts , which contributes to the overall colour-density relation .
We furthermore do not find a significant correlation between galaxy colour and virial mass , i.e. , parent dark matter halo mass .
Galaxy stellar mass thus appears to be the crucial defining parameter for intrinsic galaxy properties such as ongoing star formation and colour .