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Euclid photo-z data challenges

The data challenges are an on-going effort lead by the photo-z Organisation Unit (OU-PHZ) in the Euclid consortium. This page presents the photo-z data challenges, gather useful information and is the entry point for downloading the data.

The data challenges are the main activity of the work package "testing" (a team of ~30 people), whose overall goal of is to set up a framework to test photo-z algorithms using Euclid-like catalogues (simulated or based on real data, e.g. CANDELS data prepared by OU-MER), distributed to people to run their photo-z codes. We also develop quality control tools to compare the different algorithms and propose photo-z requirement updates for cosmic shear when necessary.

it is strongly encouraged to join the work package mailing list to get the most updated information about the challenges.

Your ESA "cosmos" login is required to access protected material (see detailed instructions here). The main repository  is located in

For any question on these pages, you may contact This email address is being protected from spambots. You need JavaScript enabled to view it..

Goal of the challenges

The photo-z data challenges aim at measuring the performance of photo-z codes to be used for the cosmic shear analysis of the Euclid mission. The data are prepared under the lead of the "testing" work package with people from OU-EXT, OU-MER and OU-PHZ teams.

Data challenges

  • DC1: The Data Challenge 1 is the first of a planned series of data analysis efforts which are coordinated among the various Euclid OU's.
  • DC2: The main goal of the Data Challenge 2 is to measure the performance of photo-z codes.
  • DC3: The goal of the Data Challenge 3 is to focus on the method and the calibration set, using simulations.