HII regions throughout the history of the Universe

Project leader

Funding source

Swedish Research Council - Vetenskapsrådet (VR)

Project Details

Start date: 01/01/2010
End date: 31/12/2012
Funding: 1800000 SEK


I propose to study the evolution of HII regions (regions containing ionized gas) at various size scales with state of the art numerical techniques. Such regions are produced by ionizing radiation produced by hot, massive stars or in some cases from accretion discs around black holes. At the largest scales HII regions grew in the intergalactic medium during the epoch of reionization (0.5 - 1 billion years after the Big Bang), when the first generations of galaxies were being assembled. We will investigate the contributions of different kinds of sources (stars and accreting central black holes in galaxies) to reionization, and how these could be distinguished. We will also improve on previous predictions of the redshifted 21cm signal by including variations in the excitation temperature in the calculations, as well as develop tools for the interpretation (in terms of cosmology and galaxy evolution) of the upcoming measurements of the redshifted 21cm radiation with the LOFAR telescope and through dynamical simulations address the question of how reionization affected early galaxy formation. On smaller scales, in galaxies, HII regions grow inside the turbulent molecular clouds from which the stars have formed. We will study the effects of magnetic fields and stellar winds on the dynamics and structure of galactic HII regions, both on the scale of the entire HII region and on the smaller scale of dense clouds.

Last updated on 2017-24-03 at 12:19