{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"390e49034465d532dc8fc410b9d00ace48c0d2d1756df646d955ecf1c34aa5ec","created":"2026-10-03T07:18:04Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"795838b69db142feaf61aa8b29bc9720fe9402de777cea34212a1fc9fd6e8a94","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"grav.strong-field-tests.kerr-spectroscopy-precision","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"A newly merged black hole rings like a bell at frequencies fixed by its mass and spin if it is a Kerr black hole. Measuring two or more tones in one event tests this directly.","posed_since":"2004","precise":"For merger remnants, measure the complex frequencies of at least two independent quasinormal modes, for example $(l,m,n) = (2,2,0)$ together with $(2,2,1)$, $(3,3,0)$ or $(4,4,0)$, and constrain the fractional deviations $\\delta f$ and $\\delta \\tau$ from Kerr values for a common mass and spin. The target is $\\mid\\delta f\\mid, \\mid\\delta \\tau\\mid$ below 0.01. An answer is the measured deviations with uncertainties from a catalog of events.","problem_ref":null,"references":"","settled_by":"Multi-mode ringdown measurements with percent-level frequency and damping-time constraints from next-generation ground detectors or LISA.","status_note":"GW250114 gave two modes at $4.1\\,\\sigma$ with the overtone frequency consistent with Kerr to plus or minus $30\\,\\text{percent}$ and the damping rate unconstrained (LIGO-Virgo-KAGRA 2025).","title":"Do remnant black hole ringdown tones match Kerr at percent precision?","topic_ref":"bc4b175d5b29c50050e1c97990c34784beaa0b526c07994422c4f929f682a68b"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"140b021e704aeaafa181884dad7d2bffc67d70cc4cc34bf112245d74ea7a16fd","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8108d70c27c4b5185fa2743ef9495e569581fc119a3fe76a4cded58950a84b26","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"4dmrwff1PLrulwjjwFMTPynmS_qqdylTcwfsxHiL1r-tzRch3qurC9Bs3f7_H6PX438Pi2xW2lqQUF6G8poYAQ"},"schema":"pubphys.envelope/1"},"record_hash":"140b021e704aeaafa181884dad7d2bffc67d70cc4cc34bf112245d74ea7a16fd","leaf_index":1511}