{"paper":{"title":"Gamma-ray Signatures of r-Process Radioactivity from the Collapse of Magnetized White Dwarfs","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Accretion-induced collapse of magnetized white dwarfs produces both r-process and iron-peak gamma-ray lines, unlike neutron star mergers.","cross_cats":["nucl-th"],"primary_cat":"astro-ph.HE","authors_text":"Daniel Kasen, David Radice, Tetyana Pitik, Yong-Zhong Qian","submitted_at":"2026-03-09T18:00:08Z","abstract_excerpt":"We predict the gamma-ray line emission from $r$-process nuclei synthesized in the ejecta of the accretion-induced collapse (AIC) of a magnetized, rapidly rotating white dwarf. Using ejecta from a two-dimensional general-relativistic neutrino-magnetohydrodynamic simulation, further evolved with a radiation-hydrodynamics code coupled to an in-situ nuclear reaction network, we construct angle-dependent gamma-ray spectra in the $0.01$-$10\\,\\mathrm{MeV}$ band via composition-dependent ray-tracing through the ejecta. The emission between $\\sim$1 and $10\\,$d is dominated by $^{132}$I ($t_{1/2} = 2.3\\"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The simultaneous presence of r-process and iron-peak gamma-ray lines is distinctive of AIC ejecta and absent in binary neutron star mergers, where iron-peak nuclei are generally not synthesized.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The 2D GR neutrino-MHD simulation plus subsequent radiation-hydrodynamics evolution accurately captures the ejecta composition, velocity structure, and r-process yields without significant 3D effects or nuclear data uncertainties that would alter the predicted line fluxes.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Simulations predict time-dependent gamma-ray lines from r-process and iron-peak decays in accretion-induced white dwarf collapse, detectable to ~10 Mpc and absent in neutron star mergers.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Accretion-induced collapse of magnetized white dwarfs produces both r-process and iron-peak gamma-ray lines, unlike neutron star mergers.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"a5f0631f81892696e03b78818b5991e037aa94bbc5ce72e550d5f1ba42112d7b"},"source":{"id":"2603.08792","kind":"arxiv","version":2},"verdict":{"id":"966b15e2-0a6a-4f8c-bbcf-5cd502ccbdbc","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T13:11:10.502157Z","strongest_claim":"The simultaneous presence of r-process and iron-peak gamma-ray lines is distinctive of AIC ejecta and absent in binary neutron star mergers, where iron-peak nuclei are generally not synthesized.","one_line_summary":"Simulations predict time-dependent gamma-ray lines from r-process and iron-peak decays in accretion-induced white dwarf collapse, detectable to ~10 Mpc and absent in neutron star mergers.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The 2D GR neutrino-MHD simulation plus subsequent radiation-hydrodynamics evolution accurately captures the ejecta composition, velocity structure, and r-process yields without significant 3D effects or nuclear data uncertainties that would alter the predicted line fluxes.","pith_extraction_headline":"Accretion-induced collapse of magnetized white dwarfs produces both r-process and iron-peak gamma-ray lines, unlike neutron star mergers."},"references":{"count":54,"sample":[{"doi":"","year":null,"title":"Between∼1 and10d, 132I accounts for∼60–70% of the total gamma-ray output, sustained by secular equilib- rium with its parent132Te (t1/2 = 3.2d)","work_id":"c232bbb0-ec7f-47c2-afa8-e494a985fd9c","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"The gamma-ray spectra exhibit well-resolved emis- sionfeaturesfromr-process– 132I, 131I, 132Te, 133Xe, and others–that provide unambiguous signatures of neutron-rich nucleosynthesis","work_id":"79cb65c5-3b61-4bfc-b127-30286f84b712","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Atd= 10 Mpc, the brightest r-process lines remain detectable by GammaTPC and GRAMS, and are marginally above the e- ASTROGAM threshold","work_id":"c2ab01d7-13f5-4c11-8224-fa05c9cd17fc","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"4), demonstrating that the long expo- suretimesrequiredbygamma-raytelescopesdonot wash out the isotopic signatures","work_id":"0fac53c1-3c31-43e5-b9e2-d207de85d71d","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"The gamma-ray energy budget is dominated by io- dine (Z= 53), which contributes∼40% of the to- tal escaping gamma-ray energy despite comprising only∼5% of the ejecta mass (Fig. 5). The to- tal time-in","work_id":"72749509-07e4-4099-a751-186b48f7c064","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":54,"snapshot_sha256":"4be31c15e89e1cf0c8cec612ef2c110001610628e735611f60061f6c981d6a2f","internal_anchors":13},"formal_canon":{"evidence_count":1,"snapshot_sha256":"bdd4802a53bd498ce3dd190839403293b346e86f83b50240f7cea125b4ae133f"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}