Was there an early reionization component in our universe?

Journal Article · 06 April 2018 · JCAP

DOI: https://doi.org/10.1088/1475-7516/2018/04/024 · OSTI ID:1431582

Villanueva-Domingo, Pablo  ^[1]; Gariazzo, Stefano  ^[1]; Gnedin, Nickolay Y.  ^[2]; Mena, Olga  ^[1]

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1. Valencia U., IFIC
2. Chicago U., Astron. Astrophys. Ctr.; Chicago U., KICP; Fermilab

A deep understanding of the epoch of reionization is still missing in our knowledge of the universe. While future probes will allow us to test the precise evolution of the free electron fraction from redshifts between z 6 and 0z 2, at present one could ask what kind of reionization processes are allowed by present cosmic microwave background temperature and polarization measurements. An early contribution to reionization could imply a departure from the standard picture where star formation determines the reionization onset. By considering a broad class of possible reionization parameterizations, we find that current data do not require an early reionization component in our universe and that only one marginal class of models, based on a particular realization of reionization, may point to that. In addition, the frequentist Akaike information criterion (AIC) provides strong evidence against alternative reionization histories, favoring the most simple reionization scenario, which describes reionization by means of only one (constant) reionization optical depth τ.

• Research Organization: Valencia U., IFIC; Chicago U., Astron. Astrophys. Ctr.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Chicago U., KICP
• Sponsoring Organization: US Department of Energy
• Grant/Contract Number: AC02-07CH11359
• OSTI ID: 1431582
• Report Number(s): FERMILAB-PUB-17-605-A; oai:inspirehep.net:1642197; arXiv:1712.02807
• Journal Information: JCAP, Journal Name: JCAP Vol. 04
• Country of Publication: United States
• Language: English