![\"Phase-Space](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/05\/Phase-Space-Crystallization.png\")
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\n Correlations of crystallization metrics with cluster mass, Galactocentric distance, and a dynamical-age proxy. Top row: Cindex versus log(Mcl\/M\u2299), RGC, and log10(tage\/trh). Bottom row: the N\u22c6-corrected residual index Cresid versus the same quantities. Spearman rank coefficients and two-sided p-values are printed in each panel. Star symbols mark Tier 1 clusters. \u2014 astro-ph.GA <\/p>\n
We develop a model-independent framework to quantify phase-space \u201ccrystallization\u201d, the degree of ordered radial and kinematic substructure, in 79 Galactic globular clusters using the Gaia EDR3-based membership catalogue of E. Vasiliev & H. Baumgardt (2021a).<\/p>\n
We construct a scalar crystallization index, C_index, by combining a radial inhomogeneity metric (z_rad) and a local, cluster-centric tangential-velocity metric (z_vel) standardized against empirical nulls.<\/p>\n
The population distribution is strongly non-Gaussian: most clusters are consistent with smooth, equilibrium expectations, while a small high-C tail (C_index >= 2) identifies dynamically complex systems, including NGC 5139 (omega Cen) and NGC 104 (47 Tuc). Correlation and fixed-N tests show that sample size affects detectability, but does not by itself explain all high-rank objects.<\/p>\n
Through synthetic injection tests in dynamically \u201cquiet\u201d control clusters, we demonstrate sensitivity to ultra-cold, shell-confined kinematic components, ruling out single-shell structures comprising more than a few to ~ 10-20% of core stars in the best-sampled control clusters.<\/p>\n
We find no evidence, within the sensitivity of the adopted diagnostics, for phase-space structures that require explanations beyond known dynamical processes. However, C_index provides a useful tool for ranking clusters by dynamical extremeness, serving both as a diagnostic for internal complexity and as a quantitative metric for prioritizing follow-up dynamical or technosignature-oriented observations.<\/p>\n
Bo-Lun Huang, Zhen-Zhao Tao, Tong-Jie Zhang<\/p>\n
Comments: 23 pages, 7 figures, 3 tables. Accepted for publication in The Astrophysical Journal (ApJ)
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2605.06072 [astro-ph.GA] (or arXiv:2605.06072v1 [astro-ph.GA] for this version)
https:\/\/doi.org\/10.48550\/arXiv.2605.06072<\/a>
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Submission history
From: Bolun Huang
[v1] Thu, 7 May 2026 11:58:24 UTC (1,220 KB)
https:\/\/arxiv.org\/abs\/2605.06072<\/a>
Astrobiology, SETI,<\/p>\n","protected":false},"excerpt":{"rendered":"Correlations of crystallization metrics with cluster mass, Galactocentric distance, and a dynamical-age proxy. Top row: Cindex versus log(Mcl\/M\u2299),…\n","protected":false},"author":2,"featured_media":434248,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[68737,203705,156286,119260,203706,152152,198218,85,46,203707,203708,203709,141,120494],"class_list":["post-434247","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-technosignature","tag-47-tucanae","tag-astro-ph-ga","tag-biosignature","tag-gaia-edr3","tag-globular-clusters","tag-https-astrobiology-com-2026-05-astronomy","tag-il","tag-israel","tag-ngc-104","tag-ngc-5139","tag-omega-centauri","tag-science","tag-seti"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/434247","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=434247"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/434247\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/434248"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=434247"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=434247"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=434247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}