The Universe Is Reionizing at z ∼ 7: Bayesian Inference of the IGM Neutral Fraction Using Lyα Emission from Galaxies
By C. Mason, T. Treu, M. Dijkstra, A. Mesinger, M. Trenti, L. Pentericci, S. de Barros, E. Vanzella. 2017
219 citations recorded by the source corpus.
We present a new flexible Bayesian framework for directly inferring the fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR, z ∼ 6–10) from detections and non-detections of Lyman Alpha (Lyα) emission from Lyman Break galaxies (LBGs). Our framework combines sophisticated reionization simulations with empirical models of the interstellar medium (ISM) radiative transfer effects on Lyα. We assert that the Lyα line profile emerging from the ISM has an important impact on the resulting transmission of photons through the IGM, and that these line profiles depend on galaxy properties. We model this effect by considering the peak velocity offset of Lyα lines from host galaxies’ systemic redshifts, which are empirically correlated with UV luminosity and redshift (or halo mass at fixed redshift). We use our framework on the sample of LBGs presented in Pentericci et al. and infer a global neutral fraction at z ∼ 7 of , consistent with other robust probes of the EoR and confirming that reionization is ongoing ∼700 Myr after the Big Bang. We show that using the full distribution of Lyα equivalent width detections and upper limits from LBGs places tighter constraints on the evolving IGM than the standard Lyα emitter fraction, and that larger samples are within reach of deep spectroscopic surveys of gravitationally lensed fields and James Webb Space Telescope NIRSpec.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/0011965da7f9bad21cd10ce925633563ee7da7b2
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Citations in the corpus
- Pōniuā‘ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole (2020, background): “Studies of the Lyα emission from z > 6 galaxies have suggested neutral fractions of 〈xHI〉 = 0.59+0.11−0.15 at z ∼ 7 and 〈xHI〉 > 0.76 at z ∼ 8 (Mason et al. 2018, 2019).”
- Inferences on the timeline of reionization at z ∼ 8 from the KMOS Lens-Amplified Spectroscopic Survey (2019, methodology): “…spanning opposite ends of the galaxy UV luminosity function: the IGM attenuation of Lyα from UV bright and UV faint galaxies is expected to be different due to differing Lyα escape paths through their interstellar and circumgalactic media (e.g., Stark et al. 2010, 2017; Mason et al. 2018b).”
- Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions (2019, methodology): “The first quasars and large Lyα surveys at z7 allow detailed inferences of the neutral fraction as a function of redshift from the magnitude of Lyα damping (e.g., Bañados et al. 2018; Mason et al. 2018).”
- The GLASS-JWST Early Release Science Program. I. Survey Design and Release Plans (2022, background): “These rates could be explained if substantial H I ISM reservoirs in these systems result in Lyα emission that emerges from the ISM at substantially redshifted velocities (Mason et al. 2018b; Endsley et al. 2022).”
- Big Three Dragons: A z = 7.15 Lyman-break galaxy detected in [O iii] 88 μm, [C ii] 158 μm, and dust continuum with ALMA (2018, background): “This means that the Lyα visibility is indeed enhanced in brighter galaxies (see also Mainali et al. 2017; Mason et al. 2018b), which would give us a reasonable explanation on the high Lyα fraction in luminous galaxies.”