Cosmic histories of star formation and reionization: An analysis with a power-law approximation

Abstract

With a simple power-law approximation of high-redshift ($\gtrsim 3.5$) star formation history, i.e., ${\dot{\rho }}_{\ast }(z)\propto [(1+z)/4.5{]}^{-\alpha }$, we investigate the reionization of intergalactic medium (IGM) and the consequent Thomson scattering optical depth for cosmic microwave background (CMB) photons. A constraint on the evolution index $\alpha$ is derived from the CMB optical depth measured by the {\it Wilkinson Microwave Anisotropy Probe} (WMAP) experiment, which reads $\alpha \approx 2.18\lg {\mathcal{N}}_{\gamma }-3.89$, where the free parameter ${\mathcal{N}}_{\gamma }$ is the number of the escaped ionizing ultraviolet photons per baryon. Moreover, the redshift for full reionization, $z_f$, can also be expressed as a function of $\alpha$ as well as ${\mathcal{N}}_{\gamma }$. By further taking into account the implication of the Gunn-Peterson trough observations to quasars for the full reionization redshift, i.e., $6\lesssim z_f\lesssim 7$, we obtain $0.3\lesssim \alpha \lesssim 1.3$ and $80\lesssim {\mathcal{N}}_{\gamma }\lesssim 230$. For a typical number of $\sim 4000$ of ionizing photons released per baryon of normal stars, the fraction of these photons escaping from the stars, $f_{\mathrm{esc}}$, can be constrained to within the range of $(2.0-5.8)$.

10 pages, 4 figures, accepted for publication in JCAP

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• The redshift distribution of SWIFT Gamma-Ray Bursts: evidence for evolution
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Cited by in corpus (3)

• Gamma-ray Burst Cosmology
• The star formation history inferred from long gamma-ray bursts with high pseudo-redshifts
• Implications of the cosmic infrared background excess for the cosmic star formation