{"paper":{"title":"A JWST redshift for the host galaxy of EP250207b of z=3.2: a collapsar origin is viable","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Agnes P. C. van Hoof, Andrea Rossi, Andrew J. Levan, Antonio Martin-Carrillo, Ashley Chrimes, Daniele B. Malesani, Daniel Mata S\\'anchez, Francesca Onori, Francesco Carotenuto, Franz E. Bauer, Gregory Corcoran, Hui Sun, Javi S\\'anchez-Sierras, Joe Bright, Jonathan Quirola-V\\'asquez, Joyce N. D. van Dalen, Laura Cotter, Manuel A.P. Torres, Maria E. Ravasio, Morgan Fraser, Nial R. Tanvir, Nikhil Sarin, Paul O'Brien, Peter G. Jonker, Rob A.J. Eyles-Ferris, Steve Schulze, Ting-Wan Chen","submitted_at":"2026-08-04T12:35:36Z","abstract_excerpt":"We present James Webb Space Telescope (JWST) and Hubble Space Telescope (HST) observations of the field of the fast X-ray transient (FXT) detected by Einstein Probe, EP250207b, to resolve any ambiguity about the host galaxy and redshift of the FXT. EP250207b was originally associated with a nearby galaxy at z=0.082, based on its low chance alignment probability, and a binary neutron star merger origin was proposed. However, we report the detection of a background galaxy at z=3.2 at the location of EP250207b. Assuming this galaxy is the actual host galaxy, the rest-frame energetics and timescal"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.03582","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/2608.03582/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"}