Reionization of the Universe induced by Primordial Black Holes

Abstract

In this paper I will discuss the possibility of a reionization of the Universe due to the photons emitted by evaporating primordial black holes (PBHs); this process should happen during the last stages of the PBHs life, when the particle emission is very intense. I will study the time evolution of the ionization degree x, of the plasma temperature $T_e$ and of the photon number density $n_{\gamma }$ characterizing the Universe after the recombination epoch: a system of coupled differential equations for these variables is solved in an analytical way by assuming, as a photon source, PBHs having an initial mass $M\sim 10^{14}$ g. The results I obtain prove that such a kind of reionization is possible, being able to increase the ionization degree of the Universe from a value x=0.002 (just after the recombination) to values near 1 (when the black holes evaporation ends).

Plain Tex, 6 pages. Contribution to the 12th Italian Conference on General Relativity and Gravitational Physics. Figures on request

Cited by in corpus (9)

• Primordial Black Holes
• Fundamental Particle Structure in the Cosmological Dark Matter
• Clustering of primordial black holes: Basic results
• Primordial black hole constraints with Hawking radiation -- a review
• Evolution of a Primordial Black Hole Population
• Clustering of Primordial Black Holes. II. Evolution of Bound Systems
• Constraints on primordial black holes and primeval density perturbations from the epoch of reionization
• Cosmic evolution during primordial black hole evaporation
• The influence of quarks and gluons jets coming from primordial black holes on the reionization of the Universe