Jarrett L. Johnson

Home     |     News     |     Recent research topics     |     Publications     |     Curriculum vitae

The first planets: the critical metallicity for planet formation (in prep) The first planets formed only when a sufficient amount of dust was generated in the interstellar medium of early galaxies. The growth of the stellar seeds of supermassive black holes The the most massive stars ever formed may have collapsed to become the protogalactic seeds of supermassive black holes. The contribution of supernovae to cosmic reionization High energy radiation generated in supernova shocks may account for the reionization of ~ 10 percent of the hydrogen in the Universe. Angular momentum transport by radiation in accretion discs Radiation emitted from black hole accretion discs carries angular momentum out of the disc and so partially drives the accretion flow. Suppression of accretion onto low-mass Population III stars If low-mass Population III stars formed in the early Universe, there is a strong chance that they can be identified in the Galaxy today. Accretion onto black holes formed by direct collapse Watch a movie showing the formation of, and accretion of primordial gas onto, a black hole formed by direct collapse at z ~ 15. Population III star clusters in the reionized universe In rare regions, Population III star clusters may be found by the James Webb Space Telescope even after reionization. Observational signatures of primordial starbursts Watch a movie showing the expansion of the H II region formed around a primordial dwarf galaxy at z ~ 12.