{"paper":{"title":"SAPPHIRES: A Galaxy Over-Density in the Heart of Cosmic Reionization at $z=8.47$","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Andrew J. Bunker, Christopher N. A. Willmer, Eiichi Egami, Feige Wang, Fengwu Sun, Jakob M. Helton, Masami Ouchi, Peter Behroozi, Roberto Maiolino, Tiger Yu-Yang Hsiao, Wei Leong Tee, Weizhe Liu, Xiangyu Jin, Xiaojing Lin, Yichen Liu, Yi Xu, Yongda Zhu, Yoshinobu Fudamoto, Yuichi Harikane, Zhiyuan Ji","submitted_at":"2025-03-19T18:00:01Z","abstract_excerpt":"We report the discovery of a galaxy proto-cluster candidate (dubbed MACS0416-OD-z8p5) at a spectroscopic redshift of $z\\sim8.47$, dating back to $\\sim550$Myr after the Big Bang. The observations are part of the JWST Cycle-3 treasury program, Slitless Areal Pure-Parallel HIgh-Redshift Emission Survey (SAPPHIRES) with NIRCam-grism. Using wide field slitless spectroscopy (WFSS) obtained in the MACS0416 parallel field, we robustly confirm nine galaxies at $z_{\\rm spec}\\sim8.47$ via emission line detections of [OIII]5008A (with $>5\\,\\sigma$) and tentatively confirm one additional galaxy (at $\\sim3\\"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2503.15597","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/2503.15597/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"}