{"paper":{"title":"The CMB optical depth constrains the duration of reionization","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"Alexander van Engelen, Anson D'Aloisio, Christopher Cain, Darby Kramer, Garett Lopez, Kevin S. Croker","submitted_at":"2025-05-21T18:00:02Z","abstract_excerpt":"Recently, it was pointed out that invoking a large value of the CMB optical depth, $\\tau_{\\rm CMB} = 0.09$, could help resolve tensions between DESI DR2 BAO data and the CMB. This is larger than the value of $\\tau_{\\rm CMB} = 0.058$ measured from the Planck low-$\\ell$ polarization data. Traditionally, $\\tau_{\\rm CMB}$ is thought of as a constraint on reionization's midpoint. However, recent observations and modeling of the Ly$\\alpha$ forest of high-$z$ quasars at $5 < z < 6$ have tightly constrained the timing of the last $10-20\\%$ of reionization, adding nuance to this interpretation. Here, w"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2505.15899","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/2505.15899/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"}