{
  "id": "2210.12834",
  "version": "v1",
  "published": "2022-10-23T19:48:28.000Z",
  "updated": "2022-10-23T19:48:28.000Z",
  "title": "Cover Your Basis: Comprehensive Data-Driven Characterization of the Binary Black Hole Population",
  "authors": [
    "Bruce Edelman",
    "Ben Farr",
    "Zoheyr Doctor"
  ],
  "comment": "18 pages, 11 figure, 3 tables",
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA"
  ],
  "abstract": "We introduce the first complete non-parametric model for the astrophysical distribution of the binary black hole (BBH) population. Constructed from basis splines, we use these models to conduct the most comprehensive data-driven investigation of the BBH population to date, simultaneously fitting non-parametric models for the BBH mass ratio, spin magnitude and misalignment, and redshift distributions for the first time. Using the BBHs in GWTC-3, we report the same features recovered with similarly flexible models of the mass distribution, most notably the peaks in merger rates at primary masses of ${\\sim}10\\,M_\\odot$ and ${\\sim}35\\,M_\\odot$. We find a suppressed merger rate at low primary masses and a mass ratio distribution consistent with a power law. The distribution for primary spin misalignments we infer peaks away from alignment, while the magnitude distribution exhibits broad agreement with previous inferences: the majority of BBH spins are small ($a<0.5$), the distribution peaks at $a\\sim0.2$, and there is mild support for a non-spinning subpopulation, which may be resolved with larger catalogs. With a modulated power law describing the BBH merger rate's evolution in redshift, we see hints of the rate evolution either flattening or decreasing at $z\\sim0.2-0.5$, but the full distribution remains entirely consistent with a monotonically increasing power law. We conclude with a discussion of the astrophysical context of our new findings and how non-parametric methods in gravitational-wave population inference are uniquely poised to complement to the parametric approach as we enter the data-rich era of gravitational-wave astronomy.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-10-23T19:48:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "binary black hole population",
      "comprehensive data-driven characterization",
      "power law",
      "merger rate",
      "mass ratio distribution consistent"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 18,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}