Aims. We present and release photometric redshifts for a uniquely large and deep sample of 522286 objects with i AB ≤ 25 in the Canada-France Hawaii Telescope Legacy Survey (CFHTLS) "Deep Survey" fields D1, D2, D3, and D4, which cover a total effective area of 3.2 deg 2 . Methods. We use 3241 spectroscopic redshifts with 0 ≤ z ≤ 5 from the VIMOS VLT Deep Survey (VVDS) as a calibration and training set to derive these photometric redshifts. Using the "Le Phare" photometric redshift code, we developed a robust calibration method based on an iterative zero-point refinement combined with a template optimisation procedure and the application of a Bayesian approach. This method removes systematic trends in the photometric redshifts and significantly reduces the fraction of catastrophic errors (by a factor of 2), a significant improvement over traditional methods. We use our unique spectroscopic sample to present a detailed assessment of the robustness of the photometric redshift sample. Results. For a sample selected at i AB ≤ 24, we reach a redshift accuracy of σ ∆z/(1+z) = 0.029 with η = 3.8% of catastrophic errors (η is defined strictly as those objects with |∆z|/(1 + z) > 0.15). The reliability of our photometric redshifts decreases for faint objects: we find σ ∆z/(1+z) = 0.025, 0.034 and η = 1.9%, 5.5% for samples selected at i AB = 17.5-22.5 and 22.5-24 respectively. We find that the photometric redshifts of starburst galaxies are less reliable: although these galaxies represent only 22% of the spectroscopic sample, they are responsible for 50% of the catastrophic errors. An analysis as a function of redshift demonstrates that our photometric redshifts work best in the redshift range 0.2 ≤ z ≤ 1.5. We find an excellent agreement between the photometric and the VVDS spectroscopic redshift distributions at i AB ≤ 24. Finally, we compare the redshift distributions of i selected galaxies on the four CFHTLS deep fields, showing that cosmic variance is still present on fields of 0.7-0.9 deg 2 . These photometric redshifts are made publicly available at http://terapix.iap.fr (complete ascii catalogues) and http://cencos.oamp.fr/cencos/CFHTLS/ (searchable database interface).Key words. galaxies: distances and redshifts -galaxies: photometry -methods: data analysis Article published by EDP Sciences and available at http://www.edpsciences.org/aa or http://dx

This paper presents the "First Epoch" sample from the VIMOS VLT Deep Survey (VVDS). The VVDS goals, observations, data reduction with the VIPGI pipeline and redshift measurement scheme with KBRED are discussed. Data have been obtained with the VIsible Multi Object Spectrograph (VIMOS) on the ESO-VLT UT3, allowing us to observe 600 slits simultaneously at a spectral resolution R 230. A total of 11 564 objects have been observed in the VVDS-02h and VVDS-CDFS "Deep" fields over a total area of 0.61 deg 2 , selected solely on the basis of apparent magnitude 17.5 ≤ I AB ≤ 24. The VVDS efficiently covers the redshift range 0 < z ≤ 5. It is successfully going through the "redshift desert" 1.5 < z < 2.2, while the range 2.2 < z < 2.7 remains of difficult access because of the VVDS wavelength coverage. A total of 9677 galaxies have a redshift measurement, 836 objects are stars, 90 objects are AGN, and a redshift could not be measured for 961 objects. There are 1065 galaxies with a measured redshift z ≥ 1.4. When considering only the primary spectroscopic targets, the survey reaches a redshift measurement completeness of 78% overall (93% including less reliable flag 1 objects), with a spatial sampling of the population of galaxies of ∼25% and ∼30% in the VVDS-02h and VVDS-CDFS respectively. The redshift accuracy measured from repeated observations with VIMOS and comparison to other surveys is ∼276 km s −1. From this sample we are able to present for the first time the redshift distribution of a magnitude-limited spectroscopic sample down to I AB = 24. The redshift distribution N(z) has a median of z = 0.62, z = 0.65, z = 0.70, and z = 0.76, for magnitudelimited samples with I AB ≤ 22.5, 23.0, 23.5 and 24.0 respectively. A high redshift tail above redshift 2 and up to redshift 5 becomes readily apparent for I AB > 23.5, probing the bright star-forming population of galaxies. This sample provides an unprecedented dataset to study galaxy evolution over ∼90% of the life of the universe.

In the context of the VLA-COSMOS Deep project, additional VLA A array observations at 1.4 GHz were obtained for the central degree of the COSMOS field and combined with the existing data from the VLA-COSMOS Large project. A newly constructed Deep mosaic with a resolution of 2. 5 was used to search for sources down to 4σ with 1σ ≈ 12 μJy beam −1 in the central 50 × 50 . This new catalog is combined with the catalog from the Large project (obtained at 1. 5 × 1. 4 resolution) to construct a new Joint catalog. All sources listed in the new Joint catalog have peak flux densities of 5σ at 1. 5 and/or 2. 5 resolution to account for the fact that a significant fraction of sources at these low flux levels are expected to be slightly resolved at 1. 5 resolution. All properties listed in the Joint catalog, such as peak flux density, integrated flux density, and source size, are determined in the 2. 5 resolution Deep image. In addition, the Joint catalog contains 43 newly identified multi-component sources.

Based on a sample of over 1, 800 radio AGN at redshifts out to z ∼ 5, which have typical stellar masses within ∼ 3 × (10 10 − 10 11 ) M ⊙ , and 3 GHz radio data in the COSMOS field, we derived the 1.4 GHz radio luminosity functions for radio AGN (L 1.4GHz ∼ 10 22 − 10 27 W Hz −1 ) out to z ∼ 5. We constrained the evolution of this population via continuous models of pure density and pure luminosity evolutions, and we found best-fit parametrizations of Φ * ∝ (1 + z) (2.00±0.18)−(0.60±0.14)z , and L * ∝ (1 + z) (2.88±0.82)−(0.84±0.34)z , respectively, with a turnover in number and luminosity densities of the population at z ≈ 1.5. We converted 1.4 GHz luminosity to kinetic luminosity taking uncertainties of the scaling relation used into account. We thereby derived the cosmic evolution of the kinetic luminosity density provided by the AGN and compared this luminosity density to the radio-mode AGN feedback assumed in the Semi-Analytic Galaxy Evolution (SAGE) model, i.e., to the redshift evolution of the central supermassive black hole accretion luminosity taken in the model as the source of heating that offsets the energy losses of the cooling, hot halo gas, and thereby limits further stellar mass growth of massive galaxies. We find that the kinetic luminosity exerted by our radio AGN may be high enough to balance the radiative cooling of the hot gas at each cosmic epoch since z ∼ 5. However, although our findings support the idea of radio-mode AGN feedback as a cosmologically relevant process in massive galaxy formation, many simplifications in both the observational and semi-analytic approaches still remain and need to be resolved before robust conclusions can be reached.

We present a detailed analysis of the Galaxy Stellar Mass Function (GSMF) of galaxies up to z = 2.5 as obtained from the VIMOS VLT Deep Survey (VVDS). Our survey offers the possibility to investigate the GSMF using two different samples: (1) an optical (I-selected 17.5 < I AB < 24) main spectroscopic sample of about 6500 galaxies over 1750 arcmin 2 and (2) a near-IR (K-selected K AB < 22.34 and K AB < 22.84) sample of about 10 200 galaxies, with photometric redshifts accurately calibrated on the VVDS spectroscopic sample, over 610 arcmin 2 . We apply and compare two different methods to estimate the stellar mass M stars from broad-band photometry based on different assumptions about the galaxy star-formation history. We find that the accuracy of the photometric stellar mass is satisfactory overall, and show that the addition of secondary bursts to a continuous star formation history produces systematically higher (up to 40%) stellar masses. We derive the cosmic evolution of the GSMF, the galaxy number density and the stellar mass density in different mass ranges. At low redshift (z 0.2) we find a substantial population of low-mass galaxies (<10 9 M ) composed of faint blue galaxies (M I − M K 0.3). In general the stellar mass function evolves slowly up to z ∼ 0.9 and more rapidly above this redshift, in particular for low mass systems. Conversely, a massive population is present up to z = 2.5 and has extremely red colours (M I − M K 0.7-0.8). We find a decline with redshift of the overall number density of galaxies for all masses (59 ± 5% for M stars > 10 8 M at z = 1), and a mild mass-dependent average evolution ("mass-downsizing"). In particular our data are consistent with mild/negligible (<30%) evolution up to z ∼ 0.7 for massive galaxies (>6 × 10 10 M ). For less massive systems the no-evolution scenario is excluded. Specifically, a large fraction (≥50%) of massive galaxies have been assembled and converted most of their gas into stars at z ∼ 1, ruling out "dry mergers" as the major mechanism of their assembly history below z 1. This fraction decreases to ∼33% at z ∼ 2. Low-mass systems have decreased continuously in number density (by a factor of up to 4.1 ± 0.9) from the present age to z = 2, consistent with a prolonged mass assembly also at z < 1. The evolution of the stellar mass density is relatively slow with redshift, with a decrease of a factor of 2.3 ± 0.1 at z = 1 and about 4.5 ± 0.3 at z = 2.5.

We present the VLA-COSMOS 3 GHz Large Project based on 384 h of observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz (10 cm) toward the two square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 µJy beam −1 over the two square degrees at an angular resolution of 0.75 . To fully account for the spectral shape and resolution variations across the broad (2 GHz) band, we image all data with a multiscale, multifrequency synthesis algorithm. We present a catalog of 10 830 radio sources down to 5σ, out of which 67 are combined from multiple components. Comparing the positions of our 3 GHz sources with those from the Very Long Baseline Array (VLBA)-COSMOS survey, we estimate that the astrometry is accurate to 0.01 at the bright end (signal-to-noise ratio, S /N 3 GHz > 20). Survival analysis on our data combined with the VLA-COSMOS 1.4 GHz Joint Project catalog yields an expected median radio spectral index of α = −0.7. We compute completeness corrections via Monte Carlo simulations to derive the corrected 3 GHz source counts. Our counts are in agreement with previously derived 3 GHz counts based on single-pointing (0.087 square degrees) VLA data. In summary, the VLA-COSMOS 3 GHz Large Project simultaneously provides the largest and deepest radio continuum survey at high (0.75 ) angular resolution to date, bridging the gap between last-generation and next-generation surveys.

Abstract. 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 ∆α ∼ −0.3 between z = 0.05 and z = 1, similar in all bands.

We study the composition of the faint radio population selected from the Karl G. Jansky Very Large Array Cosmic Evolution Survey (VLA-COSMOS) 3 GHz Large Project, which is a radio continuum survey performed at 10 cm wavelength. The survey covers a 2.6 square degree area with a mean rms of ∼2.3 µJy/beam, cataloging 10 830 sources above 5σ, and enclosing the full 2 square degree COSMOS field. By combining these radio data with optical, near-infrared (UltraVISTA), and mid-infrared (Spitzer/IRAC) data, as well as X-ray data (Chandra), we find counterparts to radio sources for ∼93% of the total radio sample reaching out to z 6; these sources are found in the unmasked areas of the COSMOS field, i.e., those not affected by saturated or bright sources in the optical to near-infrared (NIR) bands. We further classify the sources as star-forming galaxies or AGN based on various criteria, such as X-ray luminosity; observed mid-infrared color; UV-far-infrared spectral energy distribution; rest-frame, near-UV optical color that is corrected for dust extinction; and radio excess relative to that expected from the star formation rate of the hosts. We separate the AGN into subsamples dominated by low-to-moderate and moderate-to-high radiative luminosity AGN, i.e., candidates for highredshift analogs to local low-and high-excitation emission line AGN, respectively. We study the fractional contributions of these subpopulations down to radio flux levels of ∼11 µJy at 3 GHz (or ∼20 µJy at 1.4 GHz assuming a spectral index of -0.7). We find that the dominant fraction at 1.4 GHz flux densities above ∼200 µJy is constituted of low-to-moderate radiative luminosity AGN. Below densities of ∼100 µJy the fraction of star-forming galaxies increases to ∼60%, followed by the moderate-to-high radiative luminosity AGN (∼20%) and low-to-moderate radiative luminosity AGN (∼20%). Based on this observational evidence, we extrapolate the fractions down to sensitivities of the Square Kilometer Array (SKA). Our estimates suggest that at the faint flux limits to be reached by the (Wide, Deep, and UltraDeep) SKA1 surveys, a selection based only on radio flux limits can provide a simple tool to efficiently identify samples highly (>75%) dominated by star-forming galaxies.