{"paper":{"title":"Late-time Hubble Space Telescope Observations of AT 2018cow. II. Evolution of a UV bright Underlying Source 2--4 Yr Post-discovery","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.HE","authors_text":"Anthony L. Piro, C\\'esar Rojas-Bravo, Charles D. Kilpatrick, Maria R. Drout, M. R. Magee, Ryan J. Foley, Yuyang Chen","submitted_at":"2023-03-06T21:21:06Z","abstract_excerpt":"In this second of a two-paper series, we present a detailed analysis of three HST observations taken $\\sim$2--4 years post-discovery, examining the evolution of a UV-bright underlying source at the precise position of AT 2018cow. While observations at $\\sim$2--3 years post-discovery revealed an exceptionally blue ($L_\\nu\\propto \\nu^{1.99}$) underlying source with relatively stable optical brightness, fading in the NUV was observed at year 4, indicating flattening in the spectrum (to $L_\\nu\\propto \\nu^{1.64}$). The resulting spectral energy distributions can be described by an extremely hot but"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2303.03501","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/2303.03501/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"}