Description
At the end of 2023, an X-ray XMM Heritage programme of 3.6 Ms was allocated to perform a deep uniform survey of the 10 deg^2 Euclid Deep Field Fornax. More than 500 low-mass X-ray clusters will be detected out to a redshift of 2. We present the progress of this ongoing XMM campaign and plans for the Euclid DR1 release. The exceptional multi-wavelength data set to be obtained on this field will allow us to trace back the joint X-ray optical/IR properties of the galaxy group population, along with the evolution of AGN activity. Comparing detailed joint instrumental simulations of the X-ray and optical catalogues for the Wide and Deep Euclid surveys will provide a unique understanding of the Euclid cluster selection function. In this way, the sources of systematic uncertainties in the cosmological analysis of the Euclid clusters will be clarified.
