Selection effects on X-ray and strong-lensing clusters in various cosmologies

Galaxy clusters are hotter and more X-ray luminous than in quiescence while they undergo major mergers, which also transiently increase their strong-lensing efficiency. We use semi-analytic models for both effects to study how cluster dynamics in different dark-energy models a. ects the X-ray selected cluster population and its strong-lensing optical depth. We find that mergers increase the number of observable X-ray clusters by factors of a few and considerably broaden their redshift distribution. Strong-lensing optical depths are increased by a very similar amount. Quite independent of cosmology, X-ray bright clusters above a flux limit of 10(-13.5) erg s(-1) cm(-2) produce similar to 60% of the strong-lensing optical depth, and only similar to 1% above a flux limit of 10(-11.5) erg s(-1) cm(-2) if mergers are taken into account.