{"paper":{"title":"Star-forming blue ETGs in two newly discovered galaxy overdensities in the HUDF at z=1.84 and 1.9: unveiling the progenitors of passive ETGs in cluster cores","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Anton M. Koekemoer, Audrey Galametz, Benjamin J. Weiner, Casey Papovich, Caterina Lani, Chistopher J. Conselice, Claudia Scarlata, Harry I. Tepliz, Jeffrey A. Newman, Laura Pentericci, Marc Huertas-Company, Marco Castellano, Marc Rafelski, Matthew L. N. Ashby, Norman A. Grogin, Ray A. Lucas, Simona Mei, Steven L. Finkelstein","submitted_at":"2014-03-28T20:00:04Z","abstract_excerpt":"We present the discovery of two galaxy overdensities in the Hubble Space Telescope UDF: a proto-cluster, HUDFJ0332.4-2746.6 at $z = 1.84 \\pm 0.01$, and a group, HUDFJ0332.5-2747.3 at $z =1.90 \\pm 0.01$. Assuming viralization, the velocity dispersion of HUDFJ0332.4-2746.6 implies a mass of $M_{200}= (2.2 \\pm 1.8) \\times 10^{14} M_{\\odot}$, consistent with the lack of extended X-ray emission. Neither overdensity shows evidence of a red sequence. About $50\\%$ of their members show interactions and/or disturbed morphologies, which are signatures of merger remnants or disk instability. Most of thei"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1403.7524","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"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"}