ESO-LP : A Planck/ESO legacy sample of the most massive clusters

Exploiting the most massive galaxy clusters as probes of cosmology and structure formation.

Contact at IAS: Nabila Aghanim (PI)

The Planck survey is the first all-sky survey capable of blind cluster detection since the ROSAT All Sky Survey (RASS). Recently released to the general community, the Planck catalogue of Sunyaev-Zeldovich sources (PSZ) provides us with a unique sample of objects including a complete census of massive clusters (M ≥ 5 × 10¹⁴ M_ʘ) out to z ~ 1 distributed across the sky. Using ESO facilities, NTT/EFOSC2 and VLT/FORS2, in a well-coordinated follow-up programme including Northern telescopes, we propose to achieve the full redshift determination of the whole PSZ clusters over the 65% cleanest sky area. Combining the redshift measurement with the SZ flux from Planck, we will estimate cluster masses for the whole catalogue, filling a unique window in the M-z space with the most massive high-redshift clusters. The evolution of the mass function of this well understood catalogue will be used to put constraints on cosmological parameters, in particular σ₈ and Ω_m, with an accuracy better than 1%. With such tight constraints, and in combination with CMB, SZ-selected clusters may put the most stringent limits on the neutrino mass. ESO-NTT and VLT are key facilities for the success of this programme, and their spectroscopic and photometric data will allow us to construct a lasting legacy catalogue of massive clusters for studies of galaxy clusters and the evolution of their constituent galaxies.