Using the Binary Black Hole Population to Study Cosmology and the Stochastic Gravitational-Wave Background

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Abstract:: The stochastic gravitational-wave background is the overall signal of gravitational waves produced by numerous astrophysical and cosmological sources, but, in particular, includes the superposition of all binary black hole coalescences in the universe. We use results from LIGO-Virgo-KAGRA to analyze the population of binary black hole coalescences and the gravitational-wave background expected to be caused by them. In analyzing the population of binary black hole coalescences, we consider several mass and redshift population models, using hierarchical Bayesian inference to infer the population. Using these population models, we compute the expected stochastic gravitational-wave background, finding agreement with previous analyses. However, since the catalogs are limited to low-redshift binary black holes, there is significant uncertainty in the empirically-predicted gravitational-wave background. Using a phenomenological model for the merger rate as a function of redshift, we explore how changing the model behavior at high redshifts affects the predicted gravitational-wave background spectrum.
This work uses data from LVK observing runs 1â€“3, but all work is by the authors and does not represent the LVK collaboration as a whole.

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LIGO Document T2400243-v4