2009/08/26 by Jonathan R. Pritchard, Abraham Loeb, J. Stuart B. Wyithe · 47 citations
Physics and Astronomy · #Amplitude #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #COSMIC cancer database #Cosmic microwave background #Dark Ages #Galaxies: Formation, Evolution, Phenomena #Galaxy #Hydrogen line #Intergalactic medium #Ionization #Lyman-alpha forest #Optics #Physics #Radio Astronomy Observations and Technology #Redshift #Reionization #astro-ph.CO
paper · pdf · doi:10.1111/j.1365-2966.2010.17150.x
published in Monthly Notices of the Royal Astronomical Society 408(1), 57-70 (Oxford University Press) · 15 pages, 16 figures, submitted to MNRAS
arxiv created 2009/08/26 · openalex publication_date 2010/09/02 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In this paper, we explore the constraints on the reionization history that are provided by current observations of the Lyα forest and the cosmic microwave background. Rather than using a particular semi-analytic model, we take the novel approach of parametrizing the ionizing sources with arbitrary functions and perform likelihood analyses to constrain possible reionization histories. We find model-independent conclusions that reionization is likely to be mostly complete by z= 8 and that the intergalactic medium was 50 per cent ionized at z= 9–10. Upcoming low-frequency observations of the redshifted 21-cm line of neutral hydrogen are expected to place significantly better constraints on the hydrogen neutral fraction at 6 ≲z≲ 12. We use our constraints on the reionization history to predict the likely amplitude of the 21-cm power spectrum and show that observations with the highest signal-to-noise ratio will most likely be made at frequencies corresponding to z= 9–10. This result provides an important guide to the upcoming 21-cm observations. Finally, we assess the impact that measurement of the neutral fraction will have on our knowledge of reionization and the early source population. Our results show that a single measurement of the neutral fraction mid-way through the reionization era will significantly enhance our knowledge of the entire reionization history.