EUCLID

Euclid is an M-class mission of the European Space Agency that launched on the 1st of July 2023, and started taking images on the 14th of February. By the end of the six year campaign Euclid will cover 15000 square degrees of the sky and observe more than 1.5 billion galaxies. 

Euclid will improve our knowledge on the cosmological model by an order of magnitude with respect to current constraints by making a 3D map of the universe. This will be achieved by means of two probes: weak gravitational lensing and galaxy clustering. Weak gravitational lensing occurs when the shapes of galaxies are slightly distorted by the bending of light from the matter in the line of sight (shapes are changed by about 1%). Because it is in space, Euclid is ideally equipped to observe these tiny distortions, as there is no burring of the images (seeing) due to the atmosphere. Images in the optical 550-950nm range will be taken by the VIS instrument, with 0.57 square degree  field-of-view and 0.1 arcsec pixel resolution, which will detect extended galaxies to 24.5 magnitude (at 10 sigma). 

Distances to galaxies of the weak lensing sample will be obtained via photometric redshifts, this is, inferred from the colours of galaxies observed in different bands. The synergy between Euclid and ground-based surveys will be essential for precise and accurate photometric redshifts. Euclid’s NISP instrument will also obtain precise spectra of 50M emission line galaxies.

The goal of the project CARTEU is to advance the cosmological analyses of Euclid in the essential areas of weak lensing measurements, photometric redshifts, and galaxy selection and detection bias. This project is producing key tools for the science analysis of the organization units OU-PHZ, OU-SHE  and SWG-W, thus consolidating the Spanish position in Euclid.