The Munich Near-Infrared Cluster Survey – IX. Galaxy evolution to z ∼ 2 from optically selected catalogues

We present B-, R- and I-band-selected galaxy catalogues based on the Munich Near-Infrared Cluster Survey (MUNICS) which, together with the previously used K-selected sample, serve as an important probe of galaxy evolution in the redshift range 0 ≤ z ≤ 2. Furthermore, used in comparison they are ideally suited to study selection effects in extragalactic astronomy. The construction of the B-, R- and I-selected photometric catalogues, containing ∼9000, ∼9000 and ∼6000 galaxies, respectively, is described in detail. The catalogues reach 50 per cent completeness limits for point sources of B ≃ 24.5 mag, R ≃ 23.5 mag and I ≃ 22.5 mag and cover an area of about 0.3 deg 2 . Photometric redshifts are derived for all galaxies with an accuracy of δz/(1 + z) ≃ 0.057, very similar to the K-selected sample. Galaxy number counts in the B, V, R, I, J and K bands demonstrate the quality of the data set. The rest-frame colour distributions of galaxies at different selection bands and redshifts suggest that the most-massive galaxies have formed the bulk of their stellar population at earlier times and are essentially in place at redshift unity. We investigate the influence of selection band and environment on the specific star formation rate (SSFR). We find that K-band selection indeed comes close to selection in stellar mass, while B-band selection purely selects galaxies in SFR. We use a galaxy group catalogue constructed on the K-band-selected MUNICS sample to study possible differences of the SSFR between the field and the group environment, finding a marginally lower average SSFR in groups as compared to the field, especially at lower redshifts. The field-galaxy luminosity function in the B and R band as derived from the R-selected sample evolves out to z ≃ 2 in the sense that the characteristic luminosity increases but the number density decreases. This effect is smaller at longer rest-frame wavelengths and gets more pronounced at shorter wavelengths. Parametrizing the redshift evolution of the Schechter parameters as M*(z) = M* (0) + a In (1 + z) and Φ*(z) = Φ* (0) (1 + z) b , we find evolutionary parameters a ≃ -2.1 and b ≃ -2.5 for the B band, and a ≃ - 1.4 and b ≃ -1.8 for the R band.