The 2014 XXL consortium meeting

The XXL survey is the largest XMM programme to date (more than 6 Ms) and aims at a detailed mapping of the structure growth out to a redshift of ~ 1.5 – 4 over two areas of 25 deg2 each. The XMM observations were completed in May 2013. Somme 500 clusters of galaxies and 30 000 AGNs are expected in fine. An extensive multi-wavelength follow-up programme is associated with the project and will allow unprecedented studies of the group population at z~0.5, an unbiased census of the z>1 clusters and a detailed mapping of the large scale structures traced by AGNs. More than 100 scientists around the world are associated with the project, representing many fields of extragalactic astronomy: AGN, cluster and galaxy physics, observers (X-ray, optical, radio, infra-red), simulators and theorists. The annual consortium meetings are important benchmarks in the life of the project: presentation of the on-going data analyses and science; review of the working group activities; science and follow-up plans for the coming year. In parallel, a significant amount of time is left free for personal discussions – during lunchtime or coffee breaks – and for small group meetings.

For the 2014 meeting, emphasis will be put on:

(1) The spectroscopic follow-up of clusters and the finalisation of the cluster catalogue.

(2) The results from the cross-correlation between the X-ray, optical and IR cluster catalogues. This is a critical step in the understanding of the selection function, of galaxy and cluster physics, which is an essential ingredient of the cosmological analysis.

(3) The spectroscopic follow-up of AGN-hosts (in which a large effort has been invested) in order to study the environment of X-ray AGNs; local galaxy environment as well as the effects of the hot ICM on AGNs will allow us to study the triggering mechanisms in clusters and groups of galaxies.

(4) The comparison of the spatial distributions of X-ray AGNs and galaxies in order to investigate their relative biasing.