{
  "abstract": "Black hole ringdowns are modelled as a superposition of quasinormal modes (QNMs), although the branch cut of the Green's function produces a nonoscillatory tail that may contaminate early-time ringdown analyses. Within linear perturbation theory, we quantify this branch-cut contribution for the scattering of localised Gaussian wave packets by a Kerr black hole with mass $M$. Defining the onset of ringdown as the earliest time at which the QNM and branch-cut contributions reconstruct the waveform, we evaluate the branch-cut amplitude relative to the QNM amplitude. For wave packets with a characteristic frequency $ω_0\\sim 1/M$, the branch-cut amplitude is typically of order $10\\%$ of the QNM amplitude at ringdown onset with only a mild dependence on spin. We further find that the tail waveform before convolving with a source is almost independent of spin. The spin dependence of the relative amplitude therefore resides primarily in the excitation of the QNMs. Our results suggest that the branch-cut contribution may affect the accuracy of black hole spectroscopy, particularly near the onset of ringdown.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.39058",
  "author_total": 2,
  "authors": [
    {
      "name": "Ansh Gupta"
    },
    {
      "name": "Naritaka Oshita"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8sf9r1gt5ecjb.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.39058",
  "fulltext_url": null,
  "id": "8sf9r1gt5ecjb",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.39058",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.39058",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8sf9r1gt5ecjb.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.39058",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.39058"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Early-time tails in Kerr black hole ringdown",
  "title_text": "Early-time tails in Kerr black hole ringdown",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:45Z",
  "url": "https://research.draconitic.com/paper/8sf9r1gt5ecjb",
  "venue": "arXiv",
  "versions": []
}