Quantitative Constraints on the Reionization History from the IGM Damping Wing Signature in Two Quasars at z > 7

By F. Davies, J. Hennawi, E. Bañados, Zarija Lukic, R. Decarli, Xiaohui Fan, E. Farina, C. Mazzucchelli, Hans-Walter Rix, B. Venemans and 3 more. Astrophysical Journal, 2018

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During reionization, neutral hydrogen in the intergalactic medium (IGM) imprints a damping wing absorption feature on the spectrum of high-redshift quasars. A detection of this signature provides compelling evidence for a significantly neutral universe, and enables measurements of the hydrogen neutral fraction xH i(z) at that epoch. Obtaining reliable quantitative constraints from this technique, however, is challenging due to stochasticity induced by the patchy inside-out topology of reionization, degeneracies with quasar lifetime, and the unknown unabsorbed quasar spectrum close to rest-frame Lyα. We combine a large-volume semi-numerical simulation of reionization topology with 1D radiative transfer through high-resolution hydrodynamical simulations of the high-redshift universe to construct models of quasar transmission spectra during reionization. Our state-of-the-art approach captures the distribution of damping wing strengths in biased quasar halos that should have reionized earlier, as well as the erosion of neutral gas in the quasar environment caused by its own ionizing radiation. Combining this detailed model with our new technique for predicting the quasar continuum and its associated uncertainty, we introduce a Bayesian statistical method to jointly constrain the neutral fraction of the universe and the quasar lifetime from individual quasar spectra. We apply this methodology to the spectra of the two quasars with the highest redshifts known, ULAS J1120+0641 and ULAS J1342+0928, and measure volume-averaged neutral fractions and (posterior medians and 68% credible intervals) when marginalized over quasar lifetimes of 103 ≤ tq ≤ 108 yr.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/4f50654140ea3753ed63d5deaa930841e35f0737

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Citations in the corpus

Inferences on the timeline of reionization at z ∼ 8 from the KMOS Lens-Amplified Spectroscopic Survey (2019, background): “Ouchi et al. (2010); McGreer et al. (2014); Sobacchi & Mesinger (2015); Mesinger et al. (2015); Davies et al. (2018); Greig et al. (2018); Mason et al. (2018a) and the Planck Collaboration et al. (2016).”
The GLASS-JWST Early Release Science Program. I. Survey Design and Release Plans (2022, background): “Multiple lines of evidence indicate that the universe was reionized at z 6 (e.g., Planck Collaboration et al. 2020; Mason et al. 2018a, 2019a; Hoag et al. 2019a; Davies et al. 2018; Greig et al. 2019; Morales et al. 2021; Qin et al. 2021).”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, background): “The evolution of the observed Ly-α Emitter (LAE) luminosity function at z > 6 (Clément et al. 2012; Schenker et al. 2013) and the Ly-α absorption profile toward very distant quasars (Mortlock 2016; Greig et al. 2017; Davies et al. 2018) are other indirect probes of the EoR.”
Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions (2019, methodology): “4. z>7 Quasi-stellar Objects (QSOs): = - +x 0.48H 0.26 0.26 I¯ at z=7.09 and = - +x 0.60H 0.23 0.20 I¯ at z=7.54 (Davies et al. 2018a) from the IGM Lyα damping wing signature (Miralda-Escudé 1998) in the quasars ULAS J1120 +0641 (Mortlock et al. 2011) and ULAS J1342+0928 (Bañados et al. 2018).”
Pōniuā‘ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole (2020, methodology): “Specifically, neutral gas fractions of 〈xHI〉 ∼ 0.48 at z = 7.09 and 〈xHI〉 ∼ 0.60 at z = 7.54 have been reported (Davies et al. 2018a).”
Large Ly α opacity fluctuations and low CMB τ in models of late reionization with large islands of neutral hydrogen extending to z < 5.5 (2018, background): “This evolution is also in excellent agreement with the determination of QHII at z = 7.1 and 7.5 by Davies et al. (2018a) and at z = 7.1 by Greig et al. (2017) from the red damping wing and the short near-zones in the two highest redshift QSOs known.”