UltraVISTA (PIs J. Dunlop, M. Franx, J. Fynbo, O. LeFèvre, Programme ID 179.A-2005, 198.A-2003) is an ultra-deep near-infrared ESO Public Survey targeting the central region of the COSMOS field. This public survey started in April 2010 and has been completed during the VISTA Public Survey Cycle II in 2022.

This new release (DR4.1) contains two independent multi-wavelength photometric catalogues, computed using different techniques. The CLASSIC catalogue is generated using an aperture photometric measurement method as that adopted in the previous COSMOS2015 catalogue. The second catalogue, labelled FARMER, is created using a new profile-fitting photometric tool which the UltraVISTA team developed. The FARMER catalogue uses a source list derived independently from the CLASSIC one. The data present in the previous COSMOS2015 catalogue have been reprocessed to take advantage of the improved astrometry from the Gaia reference catalogue.

About 1 million sources are measured with all available broad-band data, with both methods. Photometric redshifts and physical parameters are computed for both catalogues using LePhare (Arnouts et al. 2002; Ilbert et al. 2006) and EAZY (Brammer et al. 2008). At i < 21, sources have sub-percent photometric redshift precision and even the faintest sources at 25 < i < 27 reach a photometric redshift accuracy of 5 %.

The principal improvements in COSMOS2020 catalogues compared to previous COSMOS2015 catalogue are the significantly deeper optical and near-infrared images from the Subaru-HSC and VISTA/VIRCAM imaging surveys. In addition, this release contains the definitive reprocessing of all Spitzer data ever taken on COSMOS.

More details about the release content can be found in the accompanying Phase3 release documentation and in the dedicated paper Weaver et al. 2022.

The catalogues are available via the ESO archive Science Portal or programmatically.