TY - JOUR
T1 - Damping wing-like features in the stacked Ly α forest: Potential neutral hydrogen islands at z < 6
AU - Zhu, Yongda
AU - Becker, George D.
AU - Bosman, Sarah E.I.
AU - Cain, Christopher
AU - Keating, Laura C.
AU - Nasir, Fahad
AU - D'Odorico, Valentina
AU - Bañados, Eduardo
AU - Bian, Fuyan
AU - Bischetti, Manuela
AU - Bolton, James S.
AU - Chen, Huanqing
AU - D'Aloisio, Anson
AU - Davies, Frederick B.
AU - Davies, Rebecca L.
AU - Eilers, Anna Christina
AU - Fan, Xiaohui
AU - Gaikwad, Prakash
AU - Greig, Bradley
AU - Haehnelt, Martin G.
AU - Kulkarni, Girish
AU - Lai, Samuel
AU - Puchwein, Ewald
AU - Qin, Yuxiang
AU - Ryan-Weber, Emma V.
AU - Satyavolu, Sindhu
AU - Spina, Benedetta
AU - Walter, Fabian
AU - Wang, Feige
AU - Wolfson, Molly
AU - Yang, Jinyi
N1 - Publisher Copyright:
© 2024 The Author(s).
PY - 2024/9
Y1 - 2024/9
N2 - Recent quasar absorption line observations suggest that reionization may end as late as z ≈ 5.3. As a means to search for large neutral hydrogen islands at z < 6, we revisit long dark gaps in the Ly β forest in Very Large Telescope/X-Shooter and Keck/Echellette Spectrograph and Imager quasar spectra. We stack the Ly α forest corresponding to both edges of these Ly β dark gaps and identify a damping wing-like extended absorption profile. The average redshift of the stacked forest is z = 5.8. By comparing these observations with reionization simulations, we infer that such a damping wing-like feature can be naturally explained if these gaps are at least partially created by neutral islands. Conversely, simulated dark gaps lacking neutral hydrogen struggle to replicate the observed damping wing features. Furthermore, this damping wing-like profile implies that the volume-averaged neutral hydrogen fraction must be 〈x H I〉 ≥ 6.1 ± 3.9 per cent at z = 5.8. Our results offer robust evidence that reionization extends below z = 6.
AB - Recent quasar absorption line observations suggest that reionization may end as late as z ≈ 5.3. As a means to search for large neutral hydrogen islands at z < 6, we revisit long dark gaps in the Ly β forest in Very Large Telescope/X-Shooter and Keck/Echellette Spectrograph and Imager quasar spectra. We stack the Ly α forest corresponding to both edges of these Ly β dark gaps and identify a damping wing-like extended absorption profile. The average redshift of the stacked forest is z = 5.8. By comparing these observations with reionization simulations, we infer that such a damping wing-like feature can be naturally explained if these gaps are at least partially created by neutral islands. Conversely, simulated dark gaps lacking neutral hydrogen struggle to replicate the observed damping wing features. Furthermore, this damping wing-like profile implies that the volume-averaged neutral hydrogen fraction must be 〈x H I〉 ≥ 6.1 ± 3.9 per cent at z = 5.8. Our results offer robust evidence that reionization extends below z = 6.
KW - cosmology: observations
KW - dark ages, reionization, first stars
KW - intergalactic medium
KW - large-scale structure of Universe
KW - quasars: absorption lines
UR - http://www.scopus.com/inward/record.url?scp=85198234902&partnerID=8YFLogxK
U2 - 10.1093/mnrasl/slae061
DO - 10.1093/mnrasl/slae061
M3 - Article
AN - SCOPUS:85198234902
SN - 1745-3925
VL - 533
SP - L49-L56
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
IS - 1
ER -