We measure the evolution of the galaxy Luminosity Function as a function of large-scale environment up to z = 1.5 from the VIMOS-VLT Deep Survey ( VVDS ) first epoch data .
The 3D galaxy density field is reconstructed using a gaussian filter of smoothing length 5 h ^ { -1 } Mpc and a sample of 6582 galaxies with 17.5 \leq I _ { AB } \leq 24 and measured spectroscopic redshifts .
We split the sample in four redshift bins up to z = 1.5 and in under-dense and over-dense environments according to the average density contrast \delta = 0 .
There is a strong dependence of the Luminosity Function ( LF ) with large-scale environment up to z = 1.2 : the LF shape is observed to have a steeper slope in under-dense environments .
We find \alpha = -1.32 \pm 0.07 , -1.35 \pm 0.10 , -1.42 \pm 0.18 in under-dense environments and \alpha = -1.08 \pm 0.05 , -1.06 \pm 0.06 , -1.22 \pm 0.12 in over-dense environments in the redshift bins z = [ 0.25 - 0.6 ] , [ 0.6 - 0.9 ] , [ 0.9 - 1.2 ] , respectively using a best-fit Schechter luminosity function .
We find a continuous brightening of \Delta M ^ { * } \sim 0.6 mag from z = 0.25 to z = 1.5 both in under-dense and over-dense environments .
The rest-frame B -band luminosity density continuously increases in under-dense environments from z = 0.25 to z = 1.5 whereas its evolution in over-dense environments presents a peak at z \sim 0.9 .
We interpret the peak by a complex interplay between the decrease of the star formation rate and the increasing fraction of galaxies at \delta > 0 due to hierarchical growth of structures .
As the environmental dependency of the LF shape is already present at least up to z = 1.2 , we therefore conclude that either the shape of the LF is imprinted very early on in the life of the Universe , a ‘ nature ’ process , or that ‘ nurture ’ physical processes shaping up environment relation have already been efficient earlier than a look-back time corresponding to 30 % of the current age of the Universe .