{"paper":{"title":"A lack of constraints on the cold opaque HI mass: HI spectra in M31 and M33 prefer multi-component models over a single cold opaque component","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Adam K. Leroy, Amanda A. Kepley, Andreas Schruba, Dyas Utomo, Eric W. Koch, Erik W. Rosolowsky, I-Da Chiang, Jeremy Chastenet, Julianne Dalcanton, Karin M. Sandstrom, Snezana Stanimirovic, Thomas G. Williams","submitted_at":"2021-04-06T17:13:43Z","abstract_excerpt":"Previous work has argued that atomic gas mass estimates of galaxies from 21 cm HI emission are systematically low due to a cold opaque atomic gas component. If true, this opaque component necessitates a ~35% correction factor relative to the mass from assuming optically-thin HI emission. These mass corrections are based on fitting HI spectra with a single opaque component model that produces a distinct \"top-hat\" shaped line profile. Here, we investigate this issue using deep, high spectral resolution HI VLA observations of M31 and M33 to test if these top-hat profiles are instead superposition"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2104.02678","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/2104.02678/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"}