{
  "abstract": "Searches for black holes in binaries must distinguish dark companions from faint luminous stars. This is challenging for hot stars, whose spectra contain few broad lines. We develop a Fourier-domain method that converts isolated, broadened lines into calibrated constraints on faint companions. Doppler shifts are encoded in the Fourier phase, while the line profile defines a smooth amplitude envelope. A faint secondary introduces an oscillatory perturbation to the log-amplitude. Expanding to first order in the secondary-to-primary line-depth ratio, $α$, yields a nearly linear model for a likelihood-ratio test against the single-star model. The method applies to single or multiple epochs without full spectral disentangling. At small velocity separation $v$, the companion signal becomes degenerate with the primary line profile, and the fractional uncertainty from the log-amplitude scales as $Δα/α\\propto v^{-4}$. If the primary velocity is known, the Fourier phase provides a more favorable detection channel whose sensitivity scales as $v^{-1}$. We demonstrate the method on archival FEROS spectra of CPD$-41^\\circ$7742, detecting the known secondary in He I 6678 Angstrom and obtaining a stringent non-detection in He II 5411 Angstrom, where its contribution is expected to be negligible. The framework yields detection efficiencies as functions of line-depth ratio, velocity separation, noise, and instrumental setup. These can be combined across lines, epochs, and targets to construct selection functions for spectroscopic black-hole searches, including those enabled by SDSS-V and Gaia.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.33225",
  "author_total": 6,
  "authors": [
    {
      "name": "Sahar Shahaf"
    },
    {
      "name": "Hans-Walter Rix"
    },
    {
      "name": "Johanna Müller-Horn"
    },
    {
      "name": "Jaime I. Villaseñor"
    },
    {
      "name": "Tomer Shenar"
    },
    {
      "name": "Rhys Seeburger"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8256kpaxqckt4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.33225",
  "fulltext_url": null,
  "id": "8256kpaxqckt4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.33225",
  "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",
      "astro-ph.IM"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7223922163",
  "pdf_url": "https://arxiv.org/pdf/2610.33225",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8256kpaxqckt4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.33225",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.33225"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Faint Companions to Hot Stars. Spectroscopic Detection Sensitivity and Implications for Survey Design",
  "title_text": "Faint Companions to Hot Stars. Spectroscopic Detection Sensitivity and Implications for Survey Design",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/8256kpaxqckt4",
  "venue": "arXiv",
  "versions": []
}