The VIMOS - VLT Deep Survey ⋆ Evolution of the galaxy luminosity function up to z = 2 in first epoch data

We investigate the evolution of the galaxy luminosity function from the VIMOS-VLT Deep Survey (VVDS) from the present to z = 2 in five (U , B, V , R and I) rest-frame band-passes. We use the first epoch VVDS deep sample of 11,034 spectra selected at 17.5 ≤ IAB ≤ 24.0, on which we apply the Algorithm for Luminosity Function (ALF), described in this paper. We observe a substantial evolution with redshift of the global luminosity functions in all bands. From z = 0.05 to z = 2, we measure a brightening of the characteristic magnitude M∗ included in the magnitude range 1.8− 2.4, 1.6− 2.2, 1.0− 1.7, 0.9− 1.6 and 0.8− 1.4 in the U , B, V , R and I rest-frame bands, respectively. We confirm this differential evolution of the luminosity function with rest-frame wavelength, from the measurement of the comoving density of bright galaxies (M ≤ M∗(z = 0.1)). This density increases by a factor of around 2.5, 2.2, 1.7, 1.4, 1.3 between z = 0.05 and z = 1 in the U , B, V , R, I bands, respectively. We also measure a possible steepening of the faint-end slope of the luminosity functions, with ∆α ∼ − 0.3 between z = 0.05 and z = 1, similar in all bands.