{"paper":{"title":"VLA Detection of RRLs from the radio nucleus of NGC 253 : Ionization by a weak AGN, an obscured SSC or a compact SNR ?","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"2), (2) IISc, (3) Nrao, India, K. R. Anantharamaiah (1), Niruj R. Mohan (1, USA), W. M. Goss (3) ((1) RRI","submitted_at":"2002-04-03T08:53:59Z","abstract_excerpt":"We have imaged the H92alpha and H75alpha radio recombination line (RRL) emissions from the starburst galaxy NGC 253 with a resolution of ~4 pc. The peak of the RRL emission at both frequencies coincides with the unresolved radio nucleus. Both lines observed towards the nucleus are extremely wide, with FWHM of ~200 km /s. Modeling the RRL and radio continuum data for the radio nucleus shows that the lines arise in gas whose density is ~10^4 \\cc and mass is few thousand Msun, which requires an ionizing flux of (6-20)x10^{51} photons /s. We consider a SNR expanding in a dense medium, a star clust"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0204051","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":""},"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"}