First study of reionization in the planck 2015 normalized closed (n-ary logical and)CDM inflation model

Abstract

We study reionization in two non-flat (n-ary logical and)CDM inflation models that best fit the Planck 2015 cosmic microwave background (CMB) anisotropy observations, ignoring or in conjunction with baryon acoustic oscillation distance measurements.We implement a principal component analysis (PCA) to estimate the uncertainties in the reionization history from a joint quasar- CMB data set. A thorough Markov Chain Monte Carlo analysis is done over the parameter space of the PCAmodes for both non-flat(n-ary logical and)CDMinflationmodels aswell as the original Planck 2016 tilted, spatially flat (n-ary logical and)CDM inflation model. Although both flat and non-flat models can closely match the low-redshift (z ≲ 6) observations, we notice a possible tension between high-redshift (z ~ 8) Lyman a emitter data and the non-flat models. This is solely due to the fact that the closed models have a relatively higher reionization optical depth compared to the flat one, which in turn demands more high-redshift ionizing sources and favours an extended reionization starting as early as z ≈ 14. We conclude that as opposed to flat cosmology, for the non-flat cosmology models (i) the escape fraction needs steep redshift evolution and even unrealistically high values at some redshifts and (ii) most of the physical parameters require to have non-monotonic redshift evolution, especially apparent when Lyman a emitter data are included in the analysis.