{"paper":{"title":"Modeling the frequency-domain ringdown amplitude of comparable-mass mergers with greybody factors","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"A four-parameter greybody model reproduces the frequency-domain ringdown amplitude of comparable-mass aligned-spin mergers with mismatches around 10^{-5}.","cross_cats":["astro-ph.HE","hep-ph"],"primary_cat":"gr-qc","authors_text":"Emanuele Berti, Paolo Pani, Romeo Felice Rosato, Sophia Yi","submitted_at":"2025-12-17T19:00:11Z","abstract_excerpt":"It was recently shown that, in a binary coalescence, the greybody factor of the remnant black hole modulates the post-merger ringdown signal. In this work, we demonstrate that a simple four-parameter model based on the greybody factor accurately reproduces the frequency-domain amplitude of a large set of comparable-mass, aligned-spin numerical relativity waveforms from the SXS catalog, achieving mismatches of order ${\\cal O}(10^{-5})$ and improving existing models by roughly two orders of magnitude. We also identify the optimal initial frequency for applying the model in the frequency domain a"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"a simple four-parameter model based on the greybody factor accurately reproduces the frequency-domain amplitude of a large set of comparable-mass, aligned-spin numerical relativity waveforms from the SXS catalog, achieving mismatches of order O(10^{-5}) and improving existing models by roughly two orders of magnitude","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the greybody factor of the remnant black hole modulates the post-merger ringdown signal in a manner that a simple four-parameter model can capture accurately for comparable-mass aligned-spin mergers across the SXS catalog.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A four-parameter greybody factor model reproduces the frequency-domain ringdown amplitude of comparable-mass aligned-spin mergers with mismatches of order 10^{-5}, improving existing models by two orders of magnitude.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A four-parameter greybody model reproduces the frequency-domain ringdown amplitude of comparable-mass aligned-spin mergers with mismatches around 10^{-5}.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"5e9fa5b9f8032147ad59c323f2f0fe26bb30fcbd336a78ca3743a5c6360853be"},"source":{"id":"2512.15877","kind":"arxiv","version":2},"verdict":{"id":"e7b6d556-f96a-48cc-94ec-031ca196bd8b","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T21:17:52.970098Z","strongest_claim":"a simple four-parameter model based on the greybody factor accurately reproduces the frequency-domain amplitude of a large set of comparable-mass, aligned-spin numerical relativity waveforms from the SXS catalog, achieving mismatches of order O(10^{-5}) and improving existing models by roughly two orders of magnitude","one_line_summary":"A four-parameter greybody factor model reproduces the frequency-domain ringdown amplitude of comparable-mass aligned-spin mergers with mismatches of order 10^{-5}, improving existing models by two orders of magnitude.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the greybody factor of the remnant black hole modulates the post-merger ringdown signal in a manner that a simple four-parameter model can capture accurately for comparable-mass aligned-spin mergers across the SXS catalog.","pith_extraction_headline":"A four-parameter greybody model reproduces the frequency-domain ringdown amplitude of comparable-mass aligned-spin mergers with mismatches around 10^{-5}."},"references":{"count":53,"sample":[{"doi":"","year":null,"title":"The top-left panel of Fig","work_id":"0add7225-6b81-4db6-b7c8-450c32abd74c","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Using these values, we compute the corresponding reflectivity Rℓm(¯ω,χ)and construct the reduced spectrum Yℓm(ω) = Hℓm(ω)√ Rℓm(¯ω,χ)","work_id":"d2494c41-0564-45ac-aef3-8703ca52372c","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Since the minimum frequency of validity of the model is not known a priori, we consider a set of starting frequencies ¯ωi such that ¯ωi∈[0,¯ωcut]","work_id":"78d087f8-0297-4caa-8c34-d2eed1660abf","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Within the validity region of the model, the values ofAℓmandpℓmobtained from different¯ωi are expected to be consistent within their uncertainties","work_id":"0073e350-2dcd-45d8-a5d4-06222bee34b7","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Finally, we compare the fitted model with the data. In the top-left panel of Fig. 2, the dashed pink line shows the best-fit model for the simulation SXS:BBH:3982, while the solid black line corre- sp","work_id":"505e581c-516b-457c-9e1e-17b30414d532","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":53,"snapshot_sha256":"22c13ad64c06aeaebc931f0be5eaabdeff42f747f3052610cb3a984233aa8764","internal_anchors":15},"formal_canon":{"evidence_count":2,"snapshot_sha256":"d872881c0d925d85eb28dda19babd9abda6b893cb0b7f706a9fcd485a2268dea"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}