{"paper":{"title":"Ram-pressure stripping caught in action in a young cluster at $z = 2.51$","license":"http://creativecommons.org/licenses/by/4.0/","headline":"ALMA data show five galaxies in a z=2.51 forming cluster with elongated gas tails extending beyond their stars, indicating ram-pressure stripping.","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Anita Zanella, Can Xu, Daizhong Liu, David Elbaz, Emanuele Daddi, Francesco Valentino, Hanwen Sun, Ke Xu, Kotaro Kohno, Longyue Chen, Luwenjia Zhou, Mengyuan Xiao, Qiaoyang Hao, Raphael Gobat, Renyue Cen, Tadayuki Kodama, Tao Wang, Tiancheng Yang, Zhi-Yu Zhang","submitted_at":"2025-03-27T17:36:57Z","abstract_excerpt":"Galaxy clusters in the local Universe are dominated by massive quiescent galaxies with old ages, formed at high redshifts. Whether their quenching is driven by internal processes or environmental effects is a matter of debate that has been challenging to resolve due to the lack of observations during their peak formation epoch. Here we report clear evidence from the Atacama Large Millimeter/submillimeter Array of extended and elongated gas tails in five galaxies in a forming cluster at z = 2.51. The single-tailed gas distributions, which extend notably beyond the stellar emission probed by JWS"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"These represent the most distant confirmed cases of RPS, highlighting the critical role of environmental effects in gas removal at high redshifts, an often overlooked quenching pathway.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The elongated gas tails are produced by ram-pressure stripping rather than by outflows, tidal forces, or projection effects, based on the galaxies appearing isolated and lacking merger signatures (abstract).","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"ALMA observations reveal ram-pressure stripping in five galaxies at z=2.51, the most distant confirmed instances, indicating environmental gas removal in a protocluster.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"ALMA data show five galaxies in a z=2.51 forming cluster with elongated gas tails extending beyond their stars, indicating ram-pressure stripping.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"eafabdf8a3cd20100c561827903afd34c0d39fcbab902569353298e93644466d"},"source":{"id":"2503.21724","kind":"arxiv","version":4},"verdict":{"id":"4709a799-af59-437a-a4d6-965c8ab4cb93","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-22T22:08:18.540265Z","strongest_claim":"These represent the most distant confirmed cases of RPS, highlighting the critical role of environmental effects in gas removal at high redshifts, an often overlooked quenching pathway.","one_line_summary":"ALMA observations reveal ram-pressure stripping in five galaxies at z=2.51, the most distant confirmed instances, indicating environmental gas removal in a protocluster.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The elongated gas tails are produced by ram-pressure stripping rather than by outflows, tidal forces, or projection effects, based on the galaxies appearing isolated and lacking merger signatures (abstract).","pith_extraction_headline":"ALMA data show five galaxies in a z=2.51 forming cluster with elongated gas tails extending beyond their stars, indicating ram-pressure stripping."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2503.21724/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":1,"snapshot_sha256":"5971f05279e43df7c8f359465e881a8cb9f0e8c8af98ad3c339c36feafa3c980"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}