{
  "annotation_id": "e57608d0-59eb-4648-9b84-8e536a27de87",
  "date_created": "2026-02-17T05:53:20.450000Z",
  "date_modified": "2026-02-17T05:53:20.450000Z",
  "file_hash": "5be9e17b4a5a5b0adddd87b156187ff1109bca783c18b67e8df7abab5ffa6d67",
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  "record": {
    "abstract": "The NANOGrav 15-year (NG15) data set provides evidence for a gravitational-wave background (GWB) signal at nanohertz frequencies, which is expected to originate either from a cosmic population of inspiraling supermassive black-hole binaries or new particle physics in the early Universe. A firm identification of the source of the NG15 signal requires an accurate reconstruction of its frequency spectrum. In this paper, we provide such a spectral characterization of the NG15 signal based on a piecewise power-law (PPL) ansatz that strikes a balance between existing alternatives in the literature. Our PPL reconstruction is more flexible than the standard constant-power-law model, which describes the GWB spectrum in terms of only two parameters: an amplitude A and a spectral index gamma. Concurrently, it better approximates physically realistic GWB spectra -- especially those of cosmological origin -- than the free spectral model, since the latter allows for arbitrary variations in the GWB amplitude from one frequency bin to the next. Our PPL reconstruction of the NG15 signal relies on individual PPL models with a fixed number of internal nodes (i.e., constant power law, broken power law, doubly broken power law, etc.) that are ultimately combined in a Bayesian model average. The data products resulting from our analysis provide the basis for fast refits of spectral GWB models.",
    "arxiv_id": "2601.09481",
    "authors": [
      "Gabriella Agazie",
      "Akash Anumarlapudi",
      "Anne M. Archibald",
      "Zaven Arzoumanian",
      "Jeremy G. Baier",
      "Paul T. Baker",
      "Bence B\u00e9csy",
      "Amit Bhoonah",
      "Laura Blecha",
      "Adam Brazier",
      "Paul R. Brook",
      "Sarah Burke-Spolaor",
      "Rand Burnette",
      "Robin Case",
      "J. Andrew Casey-Clyde",
      "Maria Charisi",
      "Shami Chatterjee",
      "Tyler Cohen",
      "James M. Cordes",
      "Neil J. Cornish",
      "Fronefield Crawford",
      "Thankful Cromartie",
      "Kathryn Crowter",
      "Megan E. DeCesar",
      "Paul B. Demorest",
      "Heling Deng",
      "Lankeswar Dey",
      "Timothy Dolch",
      "Elizabeth C. Ferrara",
      "William Fiore",
      "Emmanuel Fonseca",
      "Gabriel E. Freedman",
      "Emiko C. Gardiner",
      "Nate Garver-Daniels",
      "Peter A. Gentile",
      "Kyle A. Gersbach",
      "Joseph Glaser",
      "Brenda D. G\u00f3mez-Cortes",
      "Deborah C. Good",
      "Kayhan G\u00fcltekin",
      "C. J. Harris",
      "Jeffrey S. Hazboun",
      "Ross J. Jennings",
      "Aaron D. Johnson",
      "Megan L. Jones",
      "David L. Kaplan",
      "Luke Zoltan Kelley",
      "Matthew Kerr",
      "Joey S. Key",
      "Nima Laal",
      "Michael T. Lam",
      "William G. Lamb",
      "Bjorn Larsen",
      "T. Joseph W. Lazio",
      "Natalia Lewandowska",
      "Monica Leys",
      "Tingting Liu",
      "Duncan R. Lorimer",
      "Jing Luo",
      "Ryan S. Lynch",
      "Chung-Pei Ma",
      "Dustin R. Madison",
      "Cayenne Matt",
      "Alexander McEwen",
      "James W. McKee",
      "Maura A. McLaughlin",
      "Natasha McMann",
      "Bradley W. Meyers",
      "Patrick M. Meyers",
      "Chiara M. F. Mingarelli",
      "Andrea Mitridate",
      "Cherry Ng",
      "David J. Nice",
      "Stella Koch Ocker",
      "Ken D. Olum",
      "Timothy T. Pennucci",
      "Benetge B. P. Perera",
      "Polina Petrov",
      "Nihan S. Pol",
      "Henri A. Radovan",
      "Scott M. Ransom",
      "Paul S. Ray",
      "Joseph D. Romano",
      "Jessie C. Runnoe",
      "Alexander Saffer",
      "Shashwat C. Sardesai",
      "Ann Schmiedekamp",
      "Carl Schmiedekamp",
      "Kai Schmitz",
      "Brent J. Shapiro-Albert",
      "Xavier Siemens",
      "Joseph Simon",
      "Sophia V. Sosa Fiscella",
      "Ingrid H. Stairs",
      "Daniel R. Stinebring",
      "Kevin Stovall",
      "Abhimanyu Susobhanan",
      "Joseph K. Swiggum",
      "Jacob Taylor",
      "Stephen R. Taylor",
      "Mercedes S. Thompson",
      "Jacob E. Turner",
      "Michele Vallisneri",
      "Rutger van Haasteren",
      "Sarah J. Vigeland",
      "Haley M. Wahl",
      "Si Wang",
      "Kevin P. Wilson",
      "Caitlin A. Witt",
      "David Wright",
      "Olivia Young"
    ],
    "categories": [
      "astro-ph.HE",
      "astro-ph.CO",
      "gr-qc",
      "hep-ph"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "title": "The NANOGrav 15 yr Data Set: Piecewise Power-Law Reconstruction of the Gravitational-Wave Background",
    "url": "https://arxiv.org/abs/2601.09481",
    "version": "v1"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "ca657b2d-f3e8-45c8-84b1-733205ccb4a6",
    "id": "arXiv Dataset",
    "type": "Model",
    "variant": "snapshot-2026-01-17",
    "version": "0.1.0"
  },
  "user_id": 1000002
}