{"paper":{"title":"Age and metallicity of low-mass galaxies: from their centres to their stellar halos","license":"http://creativecommons.org/licenses/by/4.0/","headline":"The timing of a dominant satellite's infall explains the scatter in metallicity of stellar halos around low-mass galaxies.","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Antonela Monachesi, Elisa A. Tau, Facundo A. G\\'omez, Federico Marinacci, Freeke van de Voort, Rebekka Bieri, Robert J. J. Grand, R\\\"udiger Pakmor","submitted_at":"2025-11-25T19:47:37Z","abstract_excerpt":"We aim to analyse the metallicity and the ages of the stellar halos of low-mass galaxies to better understand their formation history. We use 17 simulated low-mass galaxies from the Auriga Project ($\\sim 3 \\times 10^8 \\, M_\\odot \\leq M_* \\lesssim 2 \\times 10^{10} \\, M_\\odot$). We study the metallicity and the ages of these galaxies and their stellar halos, as well as the relation between these two properties. We find that all galaxies have negative radial [Fe/H] gradients, and that the centres of less massive dwarfs are generally more metal poor than those of more massive dwarfs. We find no co"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We find that the dispersion in the mass-metallicity relation found in the stellar halos of low-mass galaxies can be explained with the infall time of their most dominant satellite: at a fixed accreted stellar halo mass, dwarf galaxies that accreted this satellite at later times have more metal-rich accreted stellar halos.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The Auriga Project simulations accurately reproduce the formation histories, stellar populations, and definitions of in-situ versus accreted material in real low-mass galaxies.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Simulations show negative metallicity gradients in all low-mass galaxies, U-shaped age profiles in most, and halo metallicity dispersion tied to the infall time of the dominant satellite.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The timing of a dominant satellite's infall explains the scatter in metallicity of stellar halos around low-mass galaxies.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"6d9479827acd8f19d4815959e27a18fa3391ec708771d9aefe251515e127627e"},"source":{"id":"2511.20806","kind":"arxiv","version":2},"verdict":{"id":"aa329646-ce0d-4468-a969-384c63742c73","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-17T04:34:29.951801Z","strongest_claim":"We find that the dispersion in the mass-metallicity relation found in the stellar halos of low-mass galaxies can be explained with the infall time of their most dominant satellite: at a fixed accreted stellar halo mass, dwarf galaxies that accreted this satellite at later times have more metal-rich accreted stellar halos.","one_line_summary":"Simulations show negative metallicity gradients in all low-mass galaxies, U-shaped age profiles in most, and halo metallicity dispersion tied to the infall time of the dominant satellite.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The Auriga Project simulations accurately reproduce the formation histories, stellar populations, and definitions of in-situ versus accreted material in real low-mass galaxies.","pith_extraction_headline":"The timing of a dominant satellite's infall explains the scatter in metallicity of stellar halos around low-mass galaxies."},"references":{"count":82,"sample":[{"doi":"","year":2001,"title":"2001, AJ, 122, 2524","work_id":"1ad1c8a6-4cf2-4cb1-941d-b174a594d851","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2014,"title":"L., van Zee, L., Dale, D","work_id":"41b9a16b-89bf-4351-8b64-bd9dfc023200","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2011,"title":"2011, MNRAS, 411, 1013","work_id":"08d29cee-89ff-43b1-8ae1-82441c6d28f7","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2006,"title":"2006, A&A, 459, 423","work_id":"91fbae99-9224-4466-b5b4-194d04b0f74d","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2018,"title":"Belokurov, V ., Erkal, D., Evans, N. W., Koposov, S. E., & Deason, A. J. 2018, MNRAS, 478, 611 Benítez-Llambay, A., Navarro, J. F., Abadi, M. G., et al. 2016, MNRAS, 456, 1185","work_id":"a55c98a6-d32b-456a-b33d-5ea872126921","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":82,"snapshot_sha256":"d835af927b733c0cf06ef4fca076c6a878481540a489c41516cf899acede3dfb","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"1377ad3b12c52fbe5f9276ee661816a23c034d765ff9f4f070414e9ab1466736"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}