Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption

We present a new analytical model for the attenuation to Epoch of Reionization (EoR) galaxies by proximate neutral hydrogen gas. Many galaxy spectra in the EoR taken by JWST have shown a flux deficit at wavelengths just redward of the Lyman break, and this has been regarded as resulting from Ly α da...

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Main Authors: Yoshihisa Asada, Guillaume Desprez, Chris J. Willott, Marcin Sawicki, Maruša Bradač, Gabriel Brammer, Florian Dubath, Kartheik G. Iyer, Nicholas S. Martis, Adam Muzzin, Gaël Noirot, Stéphane Paltani, Ghassan T. E. Sarrouh, Anishya Harshan, Vladan Markov
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
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Online Access:https://doi.org/10.3847/2041-8213/adc388
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author Yoshihisa Asada
Guillaume Desprez
Chris J. Willott
Marcin Sawicki
Maruša Bradač
Gabriel Brammer
Florian Dubath
Kartheik G. Iyer
Nicholas S. Martis
Adam Muzzin
Gaël Noirot
Stéphane Paltani
Ghassan T. E. Sarrouh
Anishya Harshan
Vladan Markov
author_facet Yoshihisa Asada
Guillaume Desprez
Chris J. Willott
Marcin Sawicki
Maruša Bradač
Gabriel Brammer
Florian Dubath
Kartheik G. Iyer
Nicholas S. Martis
Adam Muzzin
Gaël Noirot
Stéphane Paltani
Ghassan T. E. Sarrouh
Anishya Harshan
Vladan Markov
author_sort Yoshihisa Asada
collection DOAJ
description We present a new analytical model for the attenuation to Epoch of Reionization (EoR) galaxies by proximate neutral hydrogen gas. Many galaxy spectra in the EoR taken by JWST have shown a flux deficit at wavelengths just redward of the Lyman break, and this has been regarded as resulting from Ly α damping wing absorption by the increasing amount of neutral hydrogen in the line of sight. However, previous attenuation models for the intergalactic medium (IGM) commonly used in photometric redshift template-fitting codes assume that the Lyman break is rather sharp, which leads to systematic overestimation of photometric redshifts at z  > 7. In this Letter, we build and empirically calibrate a new attenuation model that takes the increased Ly α damping wing absorption into account. Our model consists of the canonical IGM absorption and an additional absorption component due to dense neutral hydrogen gas clouds proximate to the galaxy, and we derive the redshift evolution of H i column density of the proximate clouds by calibrating the model using CANUCS JWST observations. The resulting total transmission curve resolves the photometric redshift bias at z  > 7, an improvement that is robust to the choice of template-fitting code, template set, and photometric catalog used. The new attenuation model can be easily implemented in existing template-fitting codes and significantly improves the photometric redshift performance in the EoR.
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spelling doaj-art-2035b3039998483ca59ea93871c2629d2025-08-20T01:55:33ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019831L210.3847/2041-8213/adc388Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα AbsorptionYoshihisa Asada0https://orcid.org/0000-0003-3983-5438Guillaume Desprez1https://orcid.org/0000-0001-8325-1742Chris J. Willott2https://orcid.org/0000-0002-4201-7367Marcin Sawicki3https://orcid.org/0000-0002-7712-7857Maruša Bradač4https://orcid.org/0000-0001-5984-0395Gabriel Brammer5https://orcid.org/0000-0003-2680-005XFlorian Dubath6https://orcid.org/0000-0002-6533-2810Kartheik G. Iyer7https://orcid.org/0000-0001-9298-3523Nicholas S. Martis8https://orcid.org/0000-0003-3243-9969Adam Muzzin9https://orcid.org/0000-0002-9330-9108Gaël Noirot10Stéphane Paltani11https://orcid.org/0000-0002-8108-9179Ghassan T. E. Sarrouh12https://orcid.org/0000-0001-8830-2166Anishya Harshan13https://orcid.org/0000-0001-9414-6382Vladan Markov14https://orcid.org/0000-0002-5694-6124Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H 3C3, Canada ; asada@kusastro.kyoto-u.ac.jp; Department of Astronomy, Kyoto University , Sakyo-ku, Kyoto 606-8502, JapanDepartment of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H 3C3, Canada ; asada@kusastro.kyoto-u.ac.jp; Kapteyn Astronomical Institute, University of Groningen , P.O. Box 800, 9700AV Groningen, The NetherlandsNRC Herzberg , 5071 West Saanich Road, Victoria, BC V9E 2E7, CanadaDepartment of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H 3C3, Canada ; asada@kusastro.kyoto-u.ac.jpFaculty of Mathematics and Physics, University of Ljubljana , Jadranska ulica 19, SI-1000 Ljubljana, Slovenia; Department of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USACosmic Dawn Center (DAWN) , Denmark; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, DK-2200 Copenhagen N, DenmarkDepartment of Astronomy, University of Geneva , ch. d’Ecogia 16, 1290 Versoix, SwitzerlandColumbia Astrophysics Laboratory, Columbia University , 550 West 120th Street, New York, NY 10027, USAFaculty of Mathematics and Physics, University of Ljubljana , Jadranska ulica 19, SI-1000 Ljubljana, SloveniaDepartment of Physics and Astronomy, York University , 4700 Keele Street, Toronto, ON M3J 1P3, CanadaDepartment of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H 3C3, Canada ; asada@kusastro.kyoto-u.ac.jp; Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USADepartment of Astronomy, University of Geneva , ch. d’Ecogia 16, 1290 Versoix, SwitzerlandDepartment of Physics and Astronomy, York University , 4700 Keele Street, Toronto, ON M3J 1P3, CanadaFaculty of Mathematics and Physics, University of Ljubljana , Jadranska ulica 19, SI-1000 Ljubljana, SloveniaFaculty of Mathematics and Physics, University of Ljubljana , Jadranska ulica 19, SI-1000 Ljubljana, SloveniaWe present a new analytical model for the attenuation to Epoch of Reionization (EoR) galaxies by proximate neutral hydrogen gas. Many galaxy spectra in the EoR taken by JWST have shown a flux deficit at wavelengths just redward of the Lyman break, and this has been regarded as resulting from Ly α damping wing absorption by the increasing amount of neutral hydrogen in the line of sight. However, previous attenuation models for the intergalactic medium (IGM) commonly used in photometric redshift template-fitting codes assume that the Lyman break is rather sharp, which leads to systematic overestimation of photometric redshifts at z  > 7. In this Letter, we build and empirically calibrate a new attenuation model that takes the increased Ly α damping wing absorption into account. Our model consists of the canonical IGM absorption and an additional absorption component due to dense neutral hydrogen gas clouds proximate to the galaxy, and we derive the redshift evolution of H i column density of the proximate clouds by calibrating the model using CANUCS JWST observations. The resulting total transmission curve resolves the photometric redshift bias at z  > 7, an improvement that is robust to the choice of template-fitting code, template set, and photometric catalog used. The new attenuation model can be easily implemented in existing template-fitting codes and significantly improves the photometric redshift performance in the EoR.https://doi.org/10.3847/2041-8213/adc388High-redshift galaxiesReionizationIntergalactic mediumCircumgalactic medium
spellingShingle Yoshihisa Asada
Guillaume Desprez
Chris J. Willott
Marcin Sawicki
Maruša Bradač
Gabriel Brammer
Florian Dubath
Kartheik G. Iyer
Nicholas S. Martis
Adam Muzzin
Gaël Noirot
Stéphane Paltani
Ghassan T. E. Sarrouh
Anishya Harshan
Vladan Markov
Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
The Astrophysical Journal Letters
High-redshift galaxies
Reionization
Intergalactic medium
Circumgalactic medium
title Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
title_full Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
title_fullStr Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
title_full_unstemmed Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
title_short Improving Photometric Redshifts of Epoch of Reionization Galaxies: A New Empirical Transmission Curve with Neutral Hydrogen Damping Wing Lyα Absorption
title_sort improving photometric redshifts of epoch of reionization galaxies a new empirical transmission curve with neutral hydrogen damping wing lyα absorption
topic High-redshift galaxies
Reionization
Intergalactic medium
Circumgalactic medium
url https://doi.org/10.3847/2041-8213/adc388
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