{"paper":{"title":"Gas-rich ultra-diffuse galaxies: alleviating the MOND tension with hyperconical modified gravity","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"Outer-radius HMG reduces MOND tension for gas-rich ultra-diffuse galaxies but still overpredicts most observed velocities.","cross_cats":["gr-qc"],"primary_cat":"astro-ph.GA","authors_text":"Robert Monjo","submitted_at":"2026-03-30T09:08:37Z","abstract_excerpt":"Gas-rich ultra-diffuse galaxies (UDGs) are an unusually sharp test for gravity models tied to the baryonic Tully--Fisher relation because several systems appear to rotate too slowly for their baryonic masses. This study revisits the six isolated gas-rich UDGs analysed by Mancera Pi\\~na et al. with the current outer-radius prescription of hyperconical modified gravity (HMG), using the published baryonic masses and circular velocities at the outer radii. The scan over the neighbourhood-scale parameter drives the model towards the asymptotic branch of HMG. For that limit, the HMG velocities are s"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We conclude that the present outer-radius HMG implementation alleviates the difficulties of MOND, but is still not sufficient to account for the published central values of the UDG sample. Gas-rich UDGs therefore provide a useful discriminant between MOND and HMG.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That scanning the neighbourhood-scale parameter to select the asymptotic branch of HMG constitutes a valid, non-post-hoc application of the model to these galaxies without further tuning or justification.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"HMG asymptotic predictions fit UDG outer velocities better than MOND (chi-squared 18 vs 616) but worse than Newtonian baryons (chi-squared 10), yielding per-galaxy tensions of 0.2-2.1 sigma.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Outer-radius HMG reduces MOND tension for gas-rich ultra-diffuse galaxies but still overpredicts most observed velocities.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"075677bb0b96f266eff06dce02527a978040cef9e3fa389cdf03d63bbdc8d6be"},"source":{"id":"2604.09652","kind":"arxiv","version":2},"verdict":{"id":"6a142d4f-3467-4ad5-861f-0cdc8f0ad299","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T22:05:19.334595Z","strongest_claim":"We conclude that the present outer-radius HMG implementation alleviates the difficulties of MOND, but is still not sufficient to account for the published central values of the UDG sample. Gas-rich UDGs therefore provide a useful discriminant between MOND and HMG.","one_line_summary":"HMG asymptotic predictions fit UDG outer velocities better than MOND (chi-squared 18 vs 616) but worse than Newtonian baryons (chi-squared 10), yielding per-galaxy tensions of 0.2-2.1 sigma.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That scanning the neighbourhood-scale parameter to select the asymptotic branch of HMG constitutes a valid, non-post-hoc application of the model to these galaxies without further tuning or justification.","pith_extraction_headline":"Outer-radius HMG reduces MOND tension for gas-rich ultra-diffuse galaxies but still overpredicts most observed velocities."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.09652/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":2,"snapshot_sha256":"348c6c0d7750cc3142798143cd2be0c544624f280fafadd9fd1083e8aaf72684"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}