Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated

Understanding the ionizing photon escape from galaxies is essential for studying cosmic reionization. With a sample of 23 Lyman continuum (LyC) leakers (among which eight are high-confidence leakers) at 3 <  z  < 4.5 in the GOODS-S field, we investigate their morphologies using high-resolution...

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Main Authors: Shuairu Zhu, Zhen-Ya Zheng, Fang-Ting Yuan, Chunyan Jiang, Ruqiu Lin
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/adc125
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author Shuairu Zhu
Zhen-Ya Zheng
Fang-Ting Yuan
Chunyan Jiang
Ruqiu Lin
author_facet Shuairu Zhu
Zhen-Ya Zheng
Fang-Ting Yuan
Chunyan Jiang
Ruqiu Lin
author_sort Shuairu Zhu
collection DOAJ
description Understanding the ionizing photon escape from galaxies is essential for studying cosmic reionization. With a sample of 23 Lyman continuum (LyC) leakers (among which eight are high-confidence leakers) at 3 <  z  < 4.5 in the GOODS-S field, we investigate their morphologies using high-resolution data from the Hubble Space Telescope and the James Webb Space Telescope. We find that 20 of the 23 LyC leakers (seven out of eight high-confidence leakers) show merging signatures via visual inspection, while the remaining three are starbursts. The merger fraction of our sample is significantly higher than that of normal galaxies at similar or higher redshifts. Even when using the nonparametric method, which may miss some mergers in a sample, the merger fraction remains high, especially for the high-confidence leakers. Based on our previous finding that LyC leakers are not necessarily starbursts while some are in the star formation main sequence, we further find that those in the main sequence show merger signatures. Our results suggest that LyC leakers are either starbursts or mergers, both of which can facilitate the LyC photon escape, in addition to generating more LyC photons. Furthermore, we show that high- z LyC leakers are statistically more extended than those selected at low redshift, which exhibit a higher merger fraction as size increases. This is likely due to the observational bias that the spatial resolution limits the detection of high- z compact galaxies, while low redshift LyC leakers are more selected as compact starbursts.
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spelling doaj-art-f76d70cf89ad475c995950b5a41f3a542025-08-20T01:54:53ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019822L5810.3847/2041-8213/adc125Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers DominatedShuairu Zhu0https://orcid.org/0000-0002-2528-0761Zhen-Ya Zheng1https://orcid.org/0000-0002-9634-2923Fang-Ting Yuan2https://orcid.org/0000-0001-6763-5869Chunyan Jiang3https://orcid.org/0000-0002-0003-8557Ruqiu Lin4https://orcid.org/0000-0003-3987-0858Shanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China ; zhengzy@shao.ac.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, People’s Republic of ChinaShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China ; zhengzy@shao.ac.cnShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China ; zhengzy@shao.ac.cnShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China ; zhengzy@shao.ac.cnShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People’s Republic of China ; zhengzy@shao.ac.cn; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing 100049, People’s Republic of ChinaUnderstanding the ionizing photon escape from galaxies is essential for studying cosmic reionization. With a sample of 23 Lyman continuum (LyC) leakers (among which eight are high-confidence leakers) at 3 <  z  < 4.5 in the GOODS-S field, we investigate their morphologies using high-resolution data from the Hubble Space Telescope and the James Webb Space Telescope. We find that 20 of the 23 LyC leakers (seven out of eight high-confidence leakers) show merging signatures via visual inspection, while the remaining three are starbursts. The merger fraction of our sample is significantly higher than that of normal galaxies at similar or higher redshifts. Even when using the nonparametric method, which may miss some mergers in a sample, the merger fraction remains high, especially for the high-confidence leakers. Based on our previous finding that LyC leakers are not necessarily starbursts while some are in the star formation main sequence, we further find that those in the main sequence show merger signatures. Our results suggest that LyC leakers are either starbursts or mergers, both of which can facilitate the LyC photon escape, in addition to generating more LyC photons. Furthermore, we show that high- z LyC leakers are statistically more extended than those selected at low redshift, which exhibit a higher merger fraction as size increases. This is likely due to the observational bias that the spatial resolution limits the detection of high- z compact galaxies, while low redshift LyC leakers are more selected as compact starbursts.https://doi.org/10.3847/2041-8213/adc125High-redshift galaxiesReionization
spellingShingle Shuairu Zhu
Zhen-Ya Zheng
Fang-Ting Yuan
Chunyan Jiang
Ruqiu Lin
Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
The Astrophysical Journal Letters
High-redshift galaxies
Reionization
title Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
title_full Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
title_fullStr Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
title_full_unstemmed Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
title_short Lyman Continuum Leakers at z > 3 in the GOODS-S Field: Mergers Dominated
title_sort lyman continuum leakers at z 3 in the goods s field mergers dominated
topic High-redshift galaxies
Reionization
url https://doi.org/10.3847/2041-8213/adc125
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AT zhenyazheng lymancontinuumleakersatz3inthegoodssfieldmergersdominated
AT fangtingyuan lymancontinuumleakersatz3inthegoodssfieldmergersdominated
AT chunyanjiang lymancontinuumleakersatz3inthegoodssfieldmergersdominated
AT ruqiulin lymancontinuumleakersatz3inthegoodssfieldmergersdominated