Euclid preparation: X. The Euclid photometric-redshift challenge

Understand

Forthcoming large photometric surveys for cosmology require precise and accurate photometric redshift (photo-z) measurements for the success of their main science objectives.

• However, to date, no method has been able to produce photo-$z$s at the required accuracy using only the broad-band photometry that those surveys will provide.
• An assessment of the strengths and weaknesses of current methods is a crucial step in the eventual development of an approach to meet this challenge.
• We report on the performance of 13 photometric redshift code single value redshift estimates and redshift probability distributions (PDZs) on a common set of data, focusing particularly on the 0.2--2.6 redshift range that the Euclid mission will probe.