Aims. We present an 8-band (u * , g , r , i , z , Y, J, K s ) optical to near-infrared deep photometric catalog based on the observations made with MegaCam and WIRCam at the CFHT, and compute photometric redshifts, z p in the north ecliptic pole (NEP) region. AKARI infrared satellite carried out a deep survey in the NEP region at near-to mid-infrared wavelengths. Our optical to nearinfrared catalog allows us to identify the counterparts and z p for the AKARI sources. Methods. We obtained seven-band (g , r , i , z , Y, J, K s ) imaging data, and we crossmatched them with existing u * -band data (limiting magnitude = 24.6 mag [5σ; AB]) to design the band-merged catalog. We included all z -band sources with counterparts in at least one of the other bands in the catalog. We used a template-fitting methods to compute z p for all the cataloged sources. Results. The estimated 4σ detection limits within a 1 arcsec aperture radius are 26.7, 25.9, 25.1, and 24.1 mag [AB] for the optical g , r , i , and z -bands and 23.4, 23.0, and 22.7 mag for the near-infrared Y, J, and K s -bands, respectively. There are a total of 85 797 sources in the band-merged catalog. An astrometric accuracy of this catalog determined by examining coordinate offsets with regard to 2MASS is 0.013 arcsec with a root mean square offset of 0.32 arcsec. We distinguish 5441 secure stars from extended sources using the u * − J versus g − K s colours, combined with the SExtractor stellarity index of the images. Comparing with galaxy spectroscopic redshifts, we find a photometric redshift dispersion, σ Δz/(1+z) , of 0.032 and catastrophic failure rate, Δz 1+z > 0.15, of 5.8% at z < 1, while a dispersion of 0.117 and a catastrophic failure rate of 16.6% at z > 1. We extend the estimate of the z p uncertainty over the full magnitude/redshift space with a redshift probability distribution function and find that our redshifts are highly accurate with z < 22 at z p < 2.5 and for fainter sources with z < 24 at z p < 1. From the investigation of photometric properties of AKARI infrared sources (23 354 sources) using the g z K s diagram, < 5% of AKARI sources with optical counterparts are classified as high-z (1.4 < z < 2.5) star-forming galaxies. Among the high-z star-forming galaxies, AKARI mid-infrared detected sources seem to be affected by stronger dust extinction compared with sources with non-detections in the AKARI mid-infrared bands.

Context. We present the revised near-to mid-infrared catalogue of the AKARI North Ecliptic Pole deep survey. The survey has the unique advantage of continuous filter coverage from 2 to 24 μm over nine photometric bands, but the initial version of the survey catalogue leaves room for improvement in the image analysis stage; the original images are strongly contaminated by the behaviour of the detector and the optical system. Aims. The purpose of this study is to devise new image analysis methods and to improve the detection limit and reliability of the source extraction. Methods. We removed the scattered light and stray light from the Earth limb, and corrected for artificial patterns in the images by creating appropriate templates. We also removed any artificial sources due to bright sources by using their properties or masked them out visually. In addition, for the mid-infrared source extraction, we created detection images by stacking all six bands. This reduced the sky noise and enabled us to detect fainter sources more reliably. For the near-infrared source catalogue, we considered only objects with counterparts from ground-based catalogues to avoid fake sources. For our ground-based catalogues, we used catalogues based on the CFHT/MegaCam z band, CFHT/WIRCam Ks band and Subaru/Scam z band. Objects with multiple counterparts were all listed in the catalogue with a merged flag for the AKARI flux. Results. The detection limits of all mid-infrared bands were improved by ∼20%, and the total number of detected objects was increased by ∼2000 compared with the previous version of the catalogue; it now has 9560 objects. The 5σ detection limits in our catalogue are 11, 9, 10, 30, 34, 57, 87, 93, and 256 μJy in the N2, N3, N4, S7, S9W, S11, L15, L18W, and L24 bands, respectively. The astrometric accuracies of these band detections are 0.48, 0.52, 0.55, 0.99, 0.95, 1.1, 1.2, 1.3, and 1.6 arcsec, respectively. The false-detection rate of all nine bands was decreased to less than 0.3%. In total, 27 770 objects are listed in the catalogue, 11 349 of which have mid-infrared fluxes.

Aims. We want to study the IR (>8 μm) emission of galaxies selected on the basis of their rest-frame UV light in a very homogeneous way (wavelength and luminosity) from z = 0 to z = 1. We compare their UV and IR rest-frame emission to study the evolution in dust attenuation with z as well as to check if a UV selection is capable of tracking all star formation. This UV selection will also be compared to a sample of Lyman break galaxies selected at z 1. Methods. We select galaxies in UV (1500-1800 Å) rest-frame at z = 0, z = 0.6-0.8, z = 0.8-1.2, and with as Lyman break galaxies at z = 0.9-1.3, the samples are compiled to sample the same range of luminosity at any redshift. The UV rest-frame data come from GALEX for z < 1 and the U-band of the EIS survey (at z = 1). The UV data are combined with the IRAS 60 μm observations at z = 0 and the Spitzer data at 24 μm for z > 0 sources. The evolution in the IR and UV luminosities with z is analysed for individual galaxies as well as in terms of luminosity functions. Results. The L IR /L UV ratio is used to measure dust attenuation. This ratio does not seem to evolve significantly with z for the bulk of our sample galaxies, but some trends are found for both galaxies with a strong dust attenuation and UV luminous sources: galaxies with L IR /L UV > 10 are more frequent at z > 0 than at z = 0, and the largest values of L IR /L UV are found for UV faint objects; in contrast, the most luminous galaxies of our samples (L UV > 2 × 10 10 L ), detected at z = 1, exhibit a lower dust attenuation than fainter ones. The value of L IR /L UV increases with the K rest-frame luminosity of the galaxies at all redshifts considered and shows a residual anticorrelation with L UV . The most massive and UV luminous galaxies exhibit quite high specific star formation rates. Lyman break galaxies exhibit systematically lower dust attenuation than UV-selected galaxies of same luminosity, but similar specific star formation rates. The analysis of the UV + IR luminosity functions leads to the conclusion that up to z = 1, most of the star formation activity of UV-selected galaxies is emitted in IR. Although we are able to infer information about all the star formation from our UV selection at z = 0.7, at z = 1 we miss a large fraction of galaxies more luminous than 10 11 L . The effect is found to be larger for Lyman break galaxies.