{"paper":{"title":"The flare and spiral structure of the Milky Way's disc as traced by young giant stars","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Young giant stars map the Milky Way's flaring disc and extend spiral arm segments by 2-4 kpc.","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"E. Poggio, M. G. Lattanzi, R. Andrae, R. Drimmel, S. Khanna","submitted_at":"2026-05-12T18:00:05Z","abstract_excerpt":"We explore the three-dimensional structure of a sample of $\\sim$ 16000 young giant stars in the Galactic disc out to $\\sim$8 kpc in heliocentric distance. This population traces a thin disc with a local vertical scale height of $h_{Z \\odot} = 77 \\pm 4$ pc, that progressively thickens toward the outer Galaxy with a prominent Galactic flare, rising exponentially with a radial scale length of $h_{fl} = 3.5 \\pm 0.3 \\, \\rm{kpc}$. Our analysis incorporates both the survey selection function and the vertical displacements caused by the Galactic warp and corrugations, which, if neglected, would lead t"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"the young giants trace coherent spiral arm segments, extending previous maps based on upper main sequence (UMS) and OB stars by 2-4 kpc... supports a pitch angle of roughly 20 degrees for the Perseus Arm... shows that the Local/Orion arm stretches at least 10 kpc in length... reveals it as an extended structure with a gentle curvature... identify a new segment likely associated with the Scutum Arm","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"the survey selection function and the vertical displacements caused by the Galactic warp and corrugations can be accurately modeled and subtracted; if neglected or mis-modeled, the derived disc scale height would be significantly biased (explicitly stated in the abstract as a necessary correction).","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Young giant stars reveal a flaring Milky Way disc with 3.5 kpc radial scale and extended spiral arms including a curved Perseus segment and a new Scutum-associated feature.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Young giant stars map the Milky Way's flaring disc and extend spiral arm segments by 2-4 kpc.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"e7444a332ceb61d6db0110c09b74451d977a2ebbd2baff38cc0eb0b2e0b1904f"},"source":{"id":"2605.12603","kind":"arxiv","version":1},"verdict":{"id":"52c331ca-8825-4b29-8ac5-59bcb926253b","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T20:25:04.271754Z","strongest_claim":"the young giants trace coherent spiral arm segments, extending previous maps based on upper main sequence (UMS) and OB stars by 2-4 kpc... supports a pitch angle of roughly 20 degrees for the Perseus Arm... shows that the Local/Orion arm stretches at least 10 kpc in length... reveals it as an extended structure with a gentle curvature... identify a new segment likely associated with the Scutum Arm","one_line_summary":"Young giant stars reveal a flaring Milky Way disc with 3.5 kpc radial scale and extended spiral arms including a curved Perseus segment and a new Scutum-associated feature.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"the survey selection function and the vertical displacements caused by the Galactic warp and corrugations can be accurately modeled and subtracted; if neglected or mis-modeled, the derived disc scale height would be significantly biased (explicitly stated in the abstract as a necessary correction).","pith_extraction_headline":"Young giant stars map the Milky Way's flaring disc and extend spiral arm segments by 2-4 kpc."},"references":{"count":81,"sample":[{"doi":"10.1051/0004-6361/201628461","year":2017,"title":"Amˆores, E. B., Robin, A. C., & Reyl´e, C. 2017, A&A, 602, A67, doi: 10.1051/0004-6361/201628461","work_id":"81779b10-e554-4915-8ee3-0e9035a6e2a5","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/1538-4365/acd53e","year":2023,"title":"2023, ApJS, 267, 8, doi: 10.3847/1538-4365/acd53e Beers, T","work_id":"cb509f82-5e13-41dd-9fcb-3e37b1150bbf","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.48550/arxiv.2507.15473","year":2025,"title":"2025, arXiv e-prints, arXiv:2507.15473, doi: 10.48550/arXiv.2507.15473","work_id":"0d4e217d-06ce-44fb-99d1-961c632196e9","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1093/mnrasl/slad190","year":2024,"title":"Asano, T., Kawata, D., Fujii, M. S., & Baba, J. 2024, MNRAS, 529, L7, doi: 10.1093/mnrasl/slad190","work_id":"d9877ca2-8ef5-4faf-8e3c-7612d4fc8ff3","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1086/683116","year":2015,"title":"Bailer-Jones, C. A. L. 2015, PASP, 127, 994, doi: 10.1086/683116 20","work_id":"b708c294-d41a-40b4-bd4d-b3a57c94033c","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":81,"snapshot_sha256":"3485436317c4922dae2f192369d2b331082a1829d07bd998779af4c1aff9db06","internal_anchors":3},"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"}