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 <= I-AB <= 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 1.8-2.5, 1.7-2.4, 1.2-1.9, 1.1-1.8 and 1.0-1.6 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 2.6, 2.2, 1.8, 1.5, 1.5 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 Delta a similar to -0.3 between z = 0.05 and z = 1, similar in all bands.