{"paper":{"title":"Revealing the hidden cosmic feast: A z=4.3 galaxy group hosting two optically dark, efficiently star-forming galaxies","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Bitten Gullberg, Carlos Gomez-Guijarro, Daizhong Liu, Francesco Valentino, Georgios Magdis, Hiddo Algera, Jacqueline Hodge, Malte Brinch, Minju Lee, Nikolaj B. Sillassen, Raphael Gobat, Shuowen Jin, Steven Gillman, Thomas R. Greve","submitted_at":"2025-01-09T14:51:13Z","abstract_excerpt":"We present the confirmation of a compact galaxy group candidate, CGG-z4, at $z=4.3$ in the COSMOS field. This structure was identified by two spectroscopically confirmed $z=4.3$ $K_s$-dropout galaxies with ALMA $870\\rm\\, \\mu m$ and 3 mm continuum detections, surrounded by an overdensity of NIR-detected galaxies with consistent photometric redshifts of $4.0<z<4.6$. The two ALMA sources, CGG-z4.a and CGG-z4.b, are detected with both CO(4-3) and CO(5-4) lines. [CI](1-0) is detected on CGG-z4.a, and H$_{2}$O($1_{1,0}-1_{0,1}$) absorption is detected on CGG-z4.b. We model an integrated spectral ene"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2501.05288","kind":"arxiv","version":2},"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/2501.05288/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"}