No CrossRef data available.
Published online by Cambridge University Press: 19 July 2016
The analysis of all published slitless quasar surveys suggests that the space density of quasars increases quickly with redshift up to z ∼ 2.45, then drops abruptly by about a factor of five, increases again up to z ∼ 3.8 at least to drop once more below the present day limit of sensitivity.