Dark matter from quasar microlensing

This paper puts forward the idea that nearly all quasars are being microlensed, and examines the consequences. A wide variety of tests of the microlensing hypothesis are presented, based on an extensive quasar monitoring programme and published observations of individual quasars. The observations suggest that there exists a large population of Jupiter-mass lensing objects, sufficient to make up the cosmological critical density. Further arguments imply that these objects are likely to be primordial black holes.