{"paper":{"title":"Compressed \\emph{Gaussian} likelihood for the \\textit{Planck} low-$\\ell$ data","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Nanoom Lee","submitted_at":"2026-06-03T17:59:58Z","abstract_excerpt":"We present a compressed \\emph{Gaussian} likelihood for the \\textit{Planck} CMB low-$\\ell$ E-mode polarization data, constructed from the \\texttt{Sroll2} likelihood which provides the tightest constraint on the reionization optical depth $\\tau$ to date. The non-Gaussian form of CMB low-$\\ell$ TT and EE likelihoods makes them incompatible with Fisher matrix analyses that require an analytic Gaussian $\\chi^2$, such as the Fisher-bias formalism and Fisher forecasts. We show that the $\\chi^2$ of an offset log-normal likelihood takes a Gaussian form in the log-transformed power spectrum amplitudes, "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.05166","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/2606.05166/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"}