Enhanced Merger Fractions in a Reionization-Era Protocluster

Fuente: arXiv
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Autori principali: Marcelin, Lorraine C., Champagne, Jaclyn B., Wang, Feige, Fan, Xiaohui, Pudoka, Maria, Tee, Wei Leong, Zhu, Yongda
Natura: Preprint
Pubblicazione: 2025
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author Marcelin, Lorraine C.
Champagne, Jaclyn B.
Wang, Feige
Fan, Xiaohui
Pudoka, Maria
Tee, Wei Leong
Zhu, Yongda
author_facet Marcelin, Lorraine C.
Champagne, Jaclyn B.
Wang, Feige
Fan, Xiaohui
Pudoka, Maria
Tee, Wei Leong
Zhu, Yongda
contents Mergers play a critical role in galaxy evolution, but their relationship to their surrounding environments is unexplored at high redshift. We investigate the galaxy merger rate among 124 [OIII] emitters at $5.3<z<6.9$ as a function of local galaxy density. Identified in the ASPIRE JWST/NIRCam grism survey, we investigate three density regimes: a $z=6.6$ quasar-centered protocluster, two overdensities at $z=5.4$ and $z=6.2$, and field galaxies. We evaluate merger candidates through close pair and morphological criteria in NIRCam imaging, finding that the $z=6.6$ protocluster contains the highest fraction of galaxies meeting either criterion. We observe a $>3σ$ enhancement of the merger fraction amongst all three overdense structures compared to the field. Eleven galaxies are classified as ``active mergers" satisfying both merger criteria, all of which occur within the overdensity samples. We conclude that environment affects the merger rates of galaxies at $z>6$, leading to increased specific star formation at the 4$σ$ level.
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id arxiv_https___arxiv_org_abs_2505_18262
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enhanced Merger Fractions in a Reionization-Era Protocluster
Marcelin, Lorraine C.
Champagne, Jaclyn B.
Wang, Feige
Fan, Xiaohui
Pudoka, Maria
Tee, Wei Leong
Zhu, Yongda
Astrophysics of Galaxies
Mergers play a critical role in galaxy evolution, but their relationship to their surrounding environments is unexplored at high redshift. We investigate the galaxy merger rate among 124 [OIII] emitters at $5.3<z<6.9$ as a function of local galaxy density. Identified in the ASPIRE JWST/NIRCam grism survey, we investigate three density regimes: a $z=6.6$ quasar-centered protocluster, two overdensities at $z=5.4$ and $z=6.2$, and field galaxies. We evaluate merger candidates through close pair and morphological criteria in NIRCam imaging, finding that the $z=6.6$ protocluster contains the highest fraction of galaxies meeting either criterion. We observe a $>3σ$ enhancement of the merger fraction amongst all three overdense structures compared to the field. Eleven galaxies are classified as ``active mergers" satisfying both merger criteria, all of which occur within the overdensity samples. We conclude that environment affects the merger rates of galaxies at $z>6$, leading to increased specific star formation at the 4$σ$ level.
title Enhanced Merger Fractions in a Reionization-Era Protocluster
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2505.18262