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Damping wing-like features in the stacked Ly α forest: Potential neutral hydrogen islands at z < 6

Zhu, Yongda; Becker, George D; Bosman, Sarah E I; Cain, Christopher; Keating, Laura C; Nasir, Fahad; D’Odorico, Valentina; Bañados, Eduardo; Bian, Fuyan; Bischetti, Manuela; Bolton, James S; Chen, Huanqing; D’Aloisio, Anson; Davies, Frederick B; Davies, Rebecca L; Eilers, Anna-Christina; Fan, Xiaohui; Gaikwad, Prakash; Greig, Bradley; Haehnelt, Martin G; Kulkarni, Girish; Lai, Samuel; Puchwein, Ewald; Qin, Yuxiang; Ryan-Weber, Emma V; Satyavolu, Sindhu; Spina, Benedetta; Walter, Fabian; Wang, Feige; Wolfson, Molly; Yang, Jinyi

Damping wing-like features in the stacked Ly α forest: Potential neutral hydrogen islands at z < 6 Thumbnail


Authors

Yongda Zhu

George D Becker

Sarah E I Bosman

Christopher Cain

Laura C Keating

Fahad Nasir

Valentina D’Odorico

Eduardo Bañados

Fuyan Bian

Manuela Bischetti

Profile image of JAMES BOLTON

JAMES BOLTON James.Bolton@nottingham.ac.uk
Professor of Astrophysics

Huanqing Chen

Anson D’Aloisio

Frederick B Davies

Rebecca L Davies

Anna-Christina Eilers

Xiaohui Fan

Prakash Gaikwad

Bradley Greig

Martin G Haehnelt

Girish Kulkarni

Samuel Lai

Ewald Puchwein

Yuxiang Qin

Emma V Ryan-Weber

Sindhu Satyavolu

Benedetta Spina

Fabian Walter

Feige Wang

Molly Wolfson

Jinyi Yang



Abstract

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 〈xH I〉 ≥ 6.1 ± 3.9 per cent at z = 5.8. Our results offer robust evidence that reionization extends below z = 6.

Citation

Zhu, Y., Becker, G. D., Bosman, S. E. I., Cain, C., Keating, L. C., Nasir, F., D’Odorico, V., Bañados, E., Bian, F., Bischetti, M., Bolton, J. S., Chen, H., D’Aloisio, A., Davies, F. B., Davies, R. L., Eilers, A.-C., Fan, X., Gaikwad, P., Greig, B., Haehnelt, M. G., …Yang, J. (2024). Damping wing-like features in the stacked Ly α forest: Potential neutral hydrogen islands at z < 6. Monthly Notices of the Royal Astronomical Society: Letters, 533(1), L49-L56. https://doi.org/10.1093/mnrasl/slae061

Journal Article Type Article
Acceptance Date Jun 27, 2024
Online Publication Date Jun 29, 2024
Publication Date 2024-09
Deposit Date Jul 8, 2024
Publicly Available Date Jul 9, 2024
Journal Monthly Notices of the Royal Astronomical Society: Letters
Electronic ISSN 1745-3933
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 533
Issue 1
Pages L49-L56
DOI https://doi.org/10.1093/mnrasl/slae061
Keywords intergalactic medium, quasars: absorption lines, dark ages, reionization, first stars, large-scale structure of Universe, cosmology: observations
Public URL https://nottingham-repository.worktribe.com/output/36876976
Publisher URL https://academic.oup.com/mnrasl/advance-article/doi/10.1093/mnrasl/slae061/7701785

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