SIMBAD references

We show how future measurements of the Sunyaev-Zel'dovich effect (SZE) can be used to constrain the cosmological parameters. We combine the SZ information expected from the Planck full-sky survey, N(S), where no redshift information is included, with the N(z) obtained from an optically identified SZ-selected survey covering less than 1 per cent of the sky. We demonstrate how with a small subsample (~300 clusters) of the whole SZ catalogue observed optically it is possible to reduce the degeneracy among the cosmological parameters drastically. We have studied the requirements for performing the optical follow-up and we show the feasibility of such a project. Finally, we have compared the cluster expectations for Planck with those expected for Newton-XMM during their lifetimes. It is shown that, owing to its larger sky coverage, Planck will detect a factor of ∼5 times more clusters than Newton-XMM and also provide a larger redshift coverage.