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

Abstract

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). For dark matter annihilation, we find an upper limit to the thermally averaged mass-weighted cross section of $10^{-33}{\mathrm{cm}}^3/s/eV$. For dark matter decay, our calculations yield a lower limit to the lifetime of dark matter particles of $3\times 10^{23}$ s. These limits are in agreement with constraints from recombination and the X-ray background and provide an independent confirmation at a much later epoch.

13 pages, 10 figures, accepted for publication at Phys.Rev.D

References in corpus (20)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Strong magnetic fields in normal galaxies at high redshifts
• Population III stars: hidden or disappeared ?
• The First Galaxies: Assembly, Cooling and the Onset of Turbulence
• Dark matter and the first stars: a new phase of stellar evolution
• Population III star formation in a Lambda CDM universe, II: Effects of a photodissociating background
• Early Cosmological HII/HeIII Regions and Their Impact on Second-Generation Star Formation
• Simulating Cosmic Reionization at Large Scales II: the 21-cm Emission Features and Statistical Signals
• Suppression of H_2 Cooling in the Ultraviolet Background
• Contraints on radiative dark-matter decay from the cosmic microwave background
• The Effects of Dark Matter Decay and Annihilation on the High-Redshift 21 cm Background
• How well do we understand cosmological recombination?
• The impacts of dark matter particle annihilation on recombination and the anisotropies of the cosmic microwave background
• Occurrence of Metal-free Galaxies in the Early Universe
• Formation of Massive Primordial Stars in a Reionized Gas
• On the First Generation of Stars
• Intergalactic medium heating by dark matter
• Probing Primordial Magnetic Fields with the 21cm Fluctuations
• Primordial magnetic fields and formation of molecular hydrogen
• Impact of Dark Matter Annihilation on the High-Redshift Intergalactic Medium

Cited by in corpus (7)

• Relative Role of Stars and Quasars in Cosmic Reionization
• The influence of magnetic fields on the thermodynamics of primordial star formation
• Dark stars: Implications and constraints from cosmic reionization and extragalactic background radiation
• Quark-Novae, cosmic reionization, and early r-process element production
• Cosmic constraints rule out s-wave annihilation of light dark matter
• The formation of the first galaxies and the transition to low-mass star formation
• The prospects of finding the first quasars in the universe