{"paper":{"title":"Low-Frequency Radio Recombination Lines Away From the Inner Galactic Plane","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.GA","authors_text":"Akshatha K. Vydula, Alan E. E. Rogers, David Lewis, Judd D. Bowman, Kelsie Crawford, Matthew Kolopanis, Nivedita Mahesh, Peter Sims, Raul A. Monsalve, Steven G. Murray, Titu Samson","submitted_at":"2023-02-27T22:49:46Z","abstract_excerpt":"Diffuse radio recombination lines (RRLs) in the Galaxy are possible foregrounds for redshifted 21~cm experiments. We use EDGES drift scans centered at $-26.7^o$~declination to characterize diffuse RRLs across the southern sky. We find RRLs averaged over the large antenna beam ($ 72^o \\times 110^o $) reach minimum amplitudes between right ascensions~2-6~h. In this region, the C$\\alpha$ absorption amplitude is $33\\pm11$~mK (1$\\sigma$) averaged over 50-87~MHz ($27\\gtrsim z \\gtrsim15$ for the 21~cm line) and increases strongly as frequency decreases. C$\\beta$ and H$\\alpha$ lines are consistent wit"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2302.14185","kind":"arxiv","version":4},"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/2302.14185/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"}