Reconsidering the dynamical states of galaxy clusters using PCA and UMAP

Haggar, Roan; De Luca, Federico; De Petris, Marco; Sazonova, Elizaveta; Taylor, James E.; Knebe, Alexander; Gray, Meghan E.; Pearce, Frazer R; Contreras-Santos, Ana; Cui, Weiguang; Kuchner, Ulrike; Paun, Robert A. Mostoghiu; Power, Chris

Abstract

Numerous metrics exist to quantify the dynamical state of galaxy clusters, both observationally and within simulations. Many of these correlate strongly with one another, but it is not clear whether all of these measures probe the same intrinsic properties. In this work, we use two different statistical approaches – principal component analysis (PCA) and uniform manifold approximation and projection (UMAP) – to investigate which dynamical properties of a cluster are in fact the best descriptors of its dynamical state. We use measurements taken directly from The Three Hundred suite of galaxy cluster simulations, as well as morphological properties calculated using mock X-ray and SZ maps of the same simulated clusters. We find that four descriptions of dynamical state naturally arise, and although correlations exist between these, a given cluster can be “dynamically relaxed” according to all, none, or some of these four descriptions. These results demonstrate that it is highly important for future observational and theoretical studies to consider in which sense clusters are dynamically relaxed. Cluster dynamical states are complex and multi-dimensional, and so it is not meaningful to classify them simply as “relaxed” and “unrelaxed” based on a single linear scale.

Citation

Haggar, R., De Luca, F., De Petris, M., Sazonova, E., Taylor, J. E., Knebe, A., Gray, M. E., Pearce, F. R., Contreras-Santos, A., Cui, W., Kuchner, U., Paun, R. A. M., & Power, C. (2024). Reconsidering the dynamical states of galaxy clusters using PCA and UMAP. Monthly Notices of the Royal Astronomical Society, 532(1), 1031–1048. https://doi.org/10.1093/mnras/stae1566

• Journal Article Type: Article
• Acceptance Date: Jun 21, 2024
• Online Publication Date: Jun 22, 2024
• Publication Date: 2024-07
• Deposit Date: Jun 30, 2024
• Publicly Available Date: Jun 30, 2024
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 532
• Issue: 1
• Pages: 1031–1048
• DOI: https://doi.org/10.1093/mnras/stae1566
• Public URL: https://nottingham-repository.worktribe.com/output/36580070
• Publisher URL: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stae1566/7697552