First study of reionization in tilted flat and untilted non-flat dynamical dark energy inflation models

Journal Article · 07 June 2019 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stz1560 · OSTI ID:1530460

Mitra, Sourav ^[1]; Park, Chan-Gyung ^[2]; Choudhury, Tirthankar Roy  ^[3]; Ratra, Bharat ^[4]

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1. Department of Physics, Surendranath College, 24/2 M. G. Road, Kolkata 700009, India
2. Division of Science Education and Institute of Fusion Science, Chonbuk National University, Jeonju 54896, South Korea, Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA
3. National Centre for Radio Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411007, India
4. Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA

ABSTRACT We examine the effects of dark energy dynamics and spatial curvature on cosmic reionization by studying reionization in tilted spatially flat and untilted non-flat XCDM and ϕCDM dynamical dark energy inflation models that best fit the Planck 2015 cosmic microwave background (CMB) anisotropy and a large compilation of non-CMB data. We carry out a detailed statistical study, based on a principal component analysis and a Markov chain Monte Carlo analysis of a compilation of lower-redshift reionization data to estimate the uncertainties in the cosmological model reionization histories. We find that, irrespective of the nature of dark energy, there are significant differences between the reionization histories of the spatially flat and non-flat models. Although both the flat and non-flat models can accurately match the low-redshift (z ≲ 6) reionization observations, there is a clear discrepancy between high-redshift (z > 7) Lyman-α emitter data and the predictions from non-flat models. This is solely due to the fact that the non-flat models have a significantly larger electron scattering optical depth, τel, compared to the flat models, which requires an extended and much earlier reionization scenario supported by more high-redshift ionizing sources in the non-flat models. Non-flat models also require strong redshift evolution in the photon escape fraction, which can become unrealistically high (≳1) at some redshifts. However, τel is about 0.9-σ lower in the tilted flat ΛCDM model when the new Planck 2018 data are used and this reduction will partially alleviate the tension between the non-flat model predictions and the data.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0019038
• OSTI ID: 1530460
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 487; ISSN 0035-8711
• Publisher: Royal Astronomical SocietyCopyright Statement
• Country of Publication: United Kingdom
• Language: English