Abstract
Recent observations of GN-z11 with JWST have revealed a Lyα emission line with an equivalent width (EW) of 18 ± 2 Å. At z = 10.6, this galaxy is expected to lie in the heart of reionization. We use a series of inhomogeneous reionization simulations to derive the distribution of the Lyα EW after traveling through the neutral intergalactic medium with varying average neutral gas fraction, x H I. We use these distributions to place an upper limit of x H I < 0.88 at z = 10.6 at 95% confidence level. We compare our upper limit to different reionization history models, which include the recently identified enhancement at the bright end of the luminosity function at z > 8. We find that models in which faint galaxies have a higher escape fraction compared to bright galaxies are favored by the new data.
Original language | English (US) |
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Article number | L40 |
Journal | Astrophysical Journal Letters |
Volume | 949 |
Issue number | 2 |
DOIs | |
State | Published - Jun 1 2023 |
Bibliographical note
Publisher Copyright:© 2023. The Author(s). Published by the American Astronomical Society.