Maximum-Posterior Hyperparameters of the Broken Power Law + 2 Peak Population Model from GWTC-4
- Document #:
- LIGO-T2500311-v4
- Document type:
- T - Technical notes
| LIGO-T2500311-v2
06 Oct 2025, 12:02 |
- Abstract:
This document provides the maximum-posterior hyperparameters for the Broken Power Law + 2 Peak (BP2P) population model, inferred from the GWTC-4 catalog (https://dcc.ligo.org/LIGO-P2400004/public). The model describes the primary black hole mass distribution as a broken power-law between minimum and maximum masses,with two Gaussian peaks at \( \sim 10~M_\odot \) and \( \sim 35~M_\odot \). The file includes the posterior values for mass, spin, and merger-rate hyperparameters. These results allow users to reproduce the GWTC-4 population model and to generate synthetic distributions for compact binary coalescences. For additional resources and visualization tools, see: https://cbc-population-distributions.readthedocs.io/en/latest/.
Hyperparameters for the BP2 model are stored in the file:
* baseline5_widesigmachi2_mass_NotchFilterBinnedPairingMassDistribution_
redshift_powerlaw_mag_iid_spin_magnitude_gaussian_tilt_iid_spin_orientation_result.hdf5
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The file can be easily read by using bilby, see the example:
https://cbc-population-distributions.readthedocs.io/en/latest/guide/setup.html#read-the-hyperparams-file* GWTC4_BrokenPowerLawTwoPeaks_baseline5_population.hdf5
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This is the CBC distribution drawn from the hyperparameters (BP2). We drew about 1 million samples, including binary
neutron stars, neutron star black hole systems, and binary black holes. These data can be used to simulate and predict observing scenarios for future observational campaigns, as well as to estimate the implications for electromagnetic counterparts.
- Files in Document:
- Other Files:
- Keywords:
- Rate & Population CBC observing-scenarios
- Notes and Changes:
- Include the CBC distribution file