Reionization - A probe for the stellar population and the physics of the early universe

Understand

We calculate the reionization history for different models of the stellar population and explore the effects of primordial magnetic fields, dark matter decay and dark matter annihilation on reionization.

• We find that stellar populations based on a Scalo-type initial mass function for Population II stars can be ruled out as sole sources for reionization, unless star formation efficiencies of more than 10% or very high photon escape fractions from the parental halo are adopted.
• When considering primordial magnetic fields, we find that the additional heat injection from ambipolar diffusion and decaying MHD turbulence has significant impact on the thermal evolution and the ionization history of the post-recombination universe and on structure formation.
• The magnetic Jeans mass changes the typical mass scale of the star forming halos, and depending on the adopted stellar model we derive upper limits to the magnetic field strength between 0.7 and $5 $nG (comoving).