The abundance of Lyman-(\alpha) emitters in hierarchical models
  We present predictions for the abundance of Ly-$\alpha$ emitters in hierarchical structure formation models. We use the {\tt GALFORM} semi-analytical model to explore the impact on the predicted counts of varying assumptions about the escape fraction of Ly-$\alpha$ photons, the redshift at which the universe reionised and the cosmological density parameter. A model with a fixed escape fraction gives a remarkably good match to the observed counts over a wide redshift interval. We present predictions for the expected counts in a typical observation with the Multi Unit Spectroscopic Explorer instrument proposed for the Very Large Telescope. 
Morgan Le Delliou (CRAL, GAM, ICC), Cedric Lacey (CRAL, ICC), Carlton   M. Baugh (ICC), Bruno Guiderdoni (IAP), Roland Bacon...