{"paper":{"title":"Assembling GW231123 in star clusters through the combination of stellar binary evolution and hierarchical mergers","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.HE"],"primary_cat":"astro-ph.GA","authors_text":"Cristiano Ugolini, Lavinia Paiella, Manuel Arca Sedda, Marica Branchesi, Mario Spera","submitted_at":"2025-09-12T18:00:03Z","abstract_excerpt":"GW231123 is the most massive binary black hole (BBH) merger detected to date by the LIGO-Virgo-KAGRA collaboration. With at least one black hole (BH) in the upper-mass gap and both BHs exhibiting high spins ($\\chi_{1,2} \\gtrsim 0.8$), this event challenges standard isolated binary evolution models. A compelling alternative is a dynamical origin in star clusters, where stellar binaries and hierarchical mergers may both contribute to the formation of similar BBHs. In this work, we investigate the formation of GW231123-like events in different cluster environments using the B-POP semi-analytic po"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2509.10609","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2509.10609/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}