{"paper":{"title":"The Zero-Age Massive Stellar Population of W49A from VLA Observations","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.GA","authors_text":"A. F. McLeod, A. Ginsburg, A. Parra-L\\'opez, C. G. De Pree, D. Wilner, E. F. Jim\\'enez-Andrade, G. Bruzual, G. Su\\'arez, H. B. Liu, J. E. Mendoza-Torres, J. J. Tobin, M. Ju\\'arez-Gama, N. Cunningham, R. Galv\\'an-Madrid, R. Rivera-Soto, T. Nony, X. Lu","submitted_at":"2026-08-05T22:56:49Z","abstract_excerpt":"We use all-configuration VLA data at 3.3 cm with a physical resolution of ~2000 AU to infer the embedded zero-age massive stellar population of the W49A protocluster, as traced by its compact, ultracompact (UC), and hypercompact (HC) H II regions. Our method consists of visual source identification, the derivation of stellar ionizing-photon rates from the observed emission measure, and the further derivation of spectral types and stellar masses using state-of-the-art stellar calibrations. Considering the 101 robust detections, maximum-likelihood estimation fitting of the high-mass end (M > 11 "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.05453","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/2608.05453/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"}