Gravitational-wave constraints on causal nonlocal kernels: Ringdown bounds and spectral density limits from GWTC-3 — Data release and analysis code

Data release and analysis code accompanying the paper "Gravitational-wave constraints on causal nonlocal kernels: Ringdown bounds and spectral density limits from GWTC-3" (Balfagón, 2026). This repository contains: (1) A Bayesian ringdown analysis pipeline (bilby/dynesty) constraining universal quasi-normal mode deformations from 17 GWTC-3 binary black hole events, yielding |ε_Ω| < 0.05 (90% C.L.) with cumulative log Bayes factor ln B = −0.46 ± 0.77. (2) A dispersion analysis mapping published LVK modified dispersion relation bounds and the GW170817 speed measurement onto the Stieltjes spectral parameter space (μ_char, M₀), excluding infrared-extended spectral densities with μ < 10⁻⁶ m⁻². (3) Extracted ringdown data segments and PSDs for all 17 events, full nested-sampling posterior chains, and publication-ready figures. All results are consistent with general relativity. The fiducial CETΩ prediction (|ε_Ω| ~ 10⁻¹⁸) lies 16 orders of magnitude below the current observational ceiling, identifying sub-millimetre gravity experiments as the most promising direct probe.