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arXiv · 2307.11837

Clash of Titans: The Impact of Cluster Mergers in the Galaxy Cluster Red Sequence

Franklin Aldás·Alfredo Zenteno·Facundo Gómez·Daniel Hernandez-Lang·Eleazar R. Carrasco·Cristian A. Vega-Martínez·J. L. Nilo Castellón
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Abstract

Merging of galaxy clusters are some of the most energetic events in the Universe, and they provide a unique environment to study galaxy evolution. We use a sample of 84 merging and relaxed SPT galaxy clusters candidates, observed with the Dark Energy Camera in the $0.11<z<0.88$ redshift range, to build colour-magnitude diagrams to characterize the impact of cluster mergers on the galaxy population. We divided the sample between relaxed and disturbed, and in two redshifts bin at $z = 0.55$. When comparing the high-z to low-z clusters we find the high-z sample is richer in blue galaxies, independently of the cluster dynamical state. In the high-z bin we find that disturbed clusters exhibit a larger scatter in the Red Sequence, with wider distribution and an excess of bluer galaxies compared to relaxed clusters, while in the low-z bin we find a complete agreement between the relaxed and disturbed clusters. Our results support the scenario in which massive cluster halos at $z<0.55$ galaxies are quenched as satellites of another structure, i.e. outside the cluster, while at $z \geq 0.55$ the quenching is dominated by in-situ processes.

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Franklin Aldás, Alfredo Zenteno, Facundo Gómez, Daniel Hernandez-Lang, Eleazar R. Carrasco, Cristian A. Vega-Martínez, J. L. Nilo Castellón. 2023-07-21. Clash of Titans: The Impact of Cluster Mergers in the Galaxy Cluster Red Sequence. https://doi.org/10.1093/mnras%2Fstad2261

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