{
  "schema_version": 1,
  "purpose": "Educational GW150914 timing and single-template matched-filter normalization, not a discovery search or parameter estimation.",
  "source_release": "https://gwosc.org/events/GW150914/",
  "dataset_doi": "10.7935/K5MW2F23",
  "source_accessed": "2026-09-23",
  "source_checksums": "https://gwosc.org/GW150914data/md5.txt",
  "technical_notes": "https://gwosc.org/techdetails/",
  "attribution": "This example uses data from the Gravitational Wave Open Science Center, a service of LIGO Laboratory, the LIGO Scientific Collaboration, and the Virgo Collaboration. The numerical-relativity waveform was supplied by the SXS Collaboration through GWOSC.",
  "input_rights": "GWOSC release: CC BY 4.0. Inputs are fetched from GWOSC and are not redistributed with this example.",
  "inputs": [
    {
      "role": "H1",
      "filename": "H-H1_LOSC_4_V2-1126259446-32.hdf5",
      "url": "https://gwosc.org/GW150914data/H-H1_LOSC_4_V2-1126259446-32.hdf5",
      "sha256": "6e6976e932074a3b4e4a398ed02c62e30fcaa2781811762caea04937133583f6",
      "release_md5": "50441a42c13fc1f14e5c4ea5527f1515",
      "expected_dqmask": 127,
      "expected_injmask": 31
    },
    {
      "role": "L1",
      "filename": "L-L1_LOSC_4_V2-1126259446-32.hdf5",
      "url": "https://gwosc.org/GW150914data/L-L1_LOSC_4_V2-1126259446-32.hdf5",
      "sha256": "56706e68c811b15548f1d7ed69d7c48d5fcc62aeb21fbaf131355f3cc5c07189",
      "release_md5": "361ae6a040a9fef7897b1e0124d5b0a1",
      "expected_dqmask": 127,
      "expected_injmask": 23
    },
    {
      "role": "template",
      "filename": "GW150914_4_NR_waveform.txt",
      "url": "https://gwosc.org/GW150914data/GW150914_4_NR_waveform.txt",
      "sha256": "ed49c3e83f90e70ac85386f183031b7de3d3d6aa78e75a7d284e5a53a5cc0b76",
      "origin": "SXS:BBH:0305, mass ratio 1.221, aligned spins, detector-frame total mass 74.6 solar masses; release amplitude and phase adjusted to agree with these data.",
      "columns": ["time relative to the release waveform reference peak, seconds", "dimensionless strain"],
      "expected_samples": 2769
    }
  ],
  "analysis": {
    "gps_start": 1126259446,
    "gps_reference": 1126259462,
    "duration_seconds": 32,
    "sample_rate_hz": 4096,
    "offsource_intervals_seconds_from_start": [[0, 14], [18, 32]],
    "peak_search_seconds_from_start": [16.2, 16.6],
    "strain_window": "symmetric Tukey, alpha=0.125; subtract full-record mean before windowing",
    "template_window": "first round(0.1*fs) samples multiplied by sin(linspace(0,pi/2))^2; last round(0.005*fs) by cos(linspace(0,pi/2))^2; pad remaining 32-second array with zeros",
    "psd": "Arithmetic mean of periodic-Hann periodograms, segment-mean removed, 50% overlap within each offsource interval separately; linear interpolation of PSD onto full-record frequencies",
    "correlation": "Complex two-quadrature circular matched filter evaluated only in the declared interior event interval; positive frequency bins including band endpoints; DC and Nyquist omitted",
    "time_estimator": "Maximum modulus on native sample grid, no sub-sample interpolation; convert template-start lag using its first-column time offset",
    "random_seed": null,
    "configurations": [
      {"name": "baseline", "psd_segment_seconds": 4, "band_hz": [35, 350]},
      {"name": "psd_2_seconds", "psd_segment_seconds": 2, "band_hz": [35, 350]},
      {"name": "psd_8_seconds", "psd_segment_seconds": 8, "band_hz": [35, 350]},
      {"name": "low_30_hz", "psd_segment_seconds": 4, "band_hz": [30, 350]},
      {"name": "low_40_hz", "psd_segment_seconds": 4, "band_hz": [40, 350]},
      {"name": "high_500_hz", "psd_segment_seconds": 4, "band_hz": [35, 500]}
    ]
  },
  "reference_environment": {"platform": "macOS-27.0-arm64-arm-64bit", "python": "3.9.6", "numpy": "2.0.2", "scipy": "1.13.1", "h5py": "3.14.0"},
  "numerical_tolerances": {"independent_check_relative": 1e-10, "rerun_snr_absolute": 1e-7, "rerun_time_seconds_absolute": 1e-10},
  "interpretation": [
    "The waveform was selected using knowledge of the event. This is a worked calculation, not independent detection evidence.",
    "The two quadratures are a waveform and its band-limited Hilbert partner, not a general model of physical polarization or coalescence phase.",
    "The PSD is estimated from only 28 seconds and is treated as fixed. Its finite-sample uncertainty and nonstationarity are not propagated.",
    "L1 injection mask 23 records a continuous-wave hardware injection; all three transient-injection absence bits are set. Do not require every detector to have mask 31.",
    "The 32-second record, finite waveform, tapers, hard band, circular correlation, and sample-grid timing define this result. No parameter posterior, calibration uncertainty, false-alarm probability, or search background is computed."
  ]
}