A first measurement of galaxy merger rate increasing in dynamically colder protoclusters at cosmic noon
Year: 2024
Type: article
Abstract: ABSTRACT The process of galaxy cluster formation likely leaves an imprint on the properties of its individual member galaxies. Understanding this process is essential for uncovering the evolutionary connections between galaxies and cosmic structures. Here, we study a sample of 10 protoclusters at $z\sim 2$–3 in different dynamical states that we estimate based on spectroscopic data of their members. We combine the dynamical information with Hubble Space Telescope imaging to measure galaxy sizes and pair fractions. Our analysis reveals a clear anticorrelation between the velocity dispersion of the protocluster and its galaxy pair fractions (indicative of merger rates). The velocity dispersion also anticorrelates with the dispersion in size among the member galaxies. These correlations may be explained by protoclusters in colder dynamical states maintaining a velocity dispersion and galaxy number density that boosts galaxy mergers, which in turn contributes to the structural expansion and compaction of galaxies. Our findings offer constraints for cosmological models regarding the evolution of galaxy morphology across different stages in the assembly of protoclusters.
Institutions: University of Science and Technology of China, Chinese Academy of Sciences, Purple Mountain Observatory, Shanghai Jiao Tong University, Shanghai Key Laboratory for Particle Physics and Cosmology, University of Chile, National Astronomical Observatories, Anhui University of Science and Technology, Nanjing Normal University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,012
Funders: National Science Foundation, Chinese Academy of Sciences South America Center for Astronomy, National Natural Science Foundation of China, Chinese Academy of Sciences, Anhui University, Government of Jiangsu Province, Anhui University of Science and Technology, Agencia Nacional de Investigación y Desarrollo, National Key Research and Development Program of China, Fondo Nacional de Desarrollo Científico y Tecnológico
Awards: G2168769579, G24806095, G258439731, G263487293, 星系恒星形成与尘埃遮蔽相关规律研究, G3074252549, G3183642665, G3339230730, G3415161141, G4709373102, THE ROLE OF THE BRIGHTEST GALAXIES IN THE EPOCH OF REIONIZATION, G5442466879, G5834573078, G5896889093, G6816673849, G7710731797, G8399539837, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA), G896239237, G935600370
OpenAlex ID: W4405436663