2016/06/30 by Bradley Greig, Andrei Mesinger, Zoltán Haiman +1 · 7 citations
Physics and Astronomy · #Anisotropy #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #Planck #QSOS #Quantum mechanics #Quasar #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stw3351
12 pages, 7 figures, 1 table. Accepted to MNRAS, matches online version
openalex created_date 2016/06/24 · openalex publication_date 2016/12/24 · arxiv created 2018/02/28 · arxiv updated 2018/03/01 · openalex updated_date 2026/08/05
We quantify the presence of Lyα damping wing absorption from a partially neutral intergalactic medium (IGM) in the spectrum of the z = 7.08 QSO, ULASJ1120+0641. Using a Bayesian framework, we simultaneously account for uncertainties in: (i) the intrinsic QSO emission spectrum; and (ii) the distribution of cosmic H i patches during the epoch of reionization (EoR). For (i), we use a new intrinsic Lyα emission line reconstruction method, sampling a covariance matrix of emission line properties built from a large data base of moderate-z QSOs. For (ii), we use the Evolution of 21-cm Structure (EOS; Mesinger et al.) simulations, which span a range of physically motivated EoR models. We find strong evidence for the presence of damping wing absorption redward of Lyα (where there is no contamination from the Lyα forest). Our analysis implies that the EoR is not yet complete by z = 7.1, with the volume-weighted IGM neutral fraction constrained to |x_\rm H \small I = 0.40+0.21 -0.19| at 1σ (|x_\rm H \small I = 0.40+0.41 -0.32| at 2σ). This result is insensitive to the EoR morphology. Our detection of significant neutral H i in the IGM at z = 7.1 is consistent with the latest Planck 2016 measurements of the CMB Thompson scattering optical depth.