Hydrogen reionization history. Left panel: the predictions of the timeline of the neutral hydrogen fraction x_HI, compared with observational constraints derived from galaxies and quasars (A. Konno et al. 2014; I. D. McGreer et al. 2015; B. Greig et al. 2017, 2019; E. Bañados et al. 2018; F. B. Davies et al. 2018; A. K. Inoue et al. 2018; C. A. Mason et al. 2018, 2019; M. Ouchi et al. 2018; A. Hoag et al. 2019; I. Jung et al. 2020; F. Wang et al. 2020; L. R. Whitler et al. 2020; J. Yang et al. 2020; H. Goto et al. 2021; A. M. Morales et al. 2021; Y. Ning et al. 2022; Y. Zhu et al. 2022, 2024; X. Jin et al. 2023; T. Morishita et al. 2023; D. Ďurovčíková et al. 2024; T. Y.-Y. Hsiao et al. 2024; M. Nakane et al. 2024; M. Tang et al. 2024; H. Umeda et al. 2024). Right panel: the ionizing emissivity ﹩{\dot{n}}_{{\rm{ion}}}﹩ as a function of redshift, compared with observations (G. D. Becker & J. S. Bolton 2013; P. Gaikwad et al. 2023; P. Rinaldi et al. 2024). The red solid line represents the timeline derived from our fiducial values. The blue dashed line represents the result for a redshift-dependent ξ_ion based on the JWST measurements by R. Begley et al. (2025): ﹩\mathrm{log}({\xi }_{{\rm{ion}}})=(0.023\pm 0.005)z+(25.12\pm 0.03)﹩. The green dotted–dashed line shows the result from another similar measurements of M. Llerena et al. (2025): ﹩\mathrm{log}({\xi }_{{\rm{ion}}})=(0.006\pm 0.012)z+(24.82\pm 0.07)﹩. The red shaded region represents the values of ﹩24.15\lt \langle \mathrm{log}{f}_{{\rm{esc}}}{\xi }_{{\rm{ion}}}\rangle \lt 24.54﹩, constrained by the errors of the measured CMB optical depth by the Planck satellite (see Figure 4).