ACME - Parameter Estimation in Gravitational-Wave Astronomy with Bilby

Friday 11 Sept 2026, 09:00 → 13:00 Europe/Paris

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Giancarlo Cella (INFN Pisa)

This tutorial focuses on parameter estimation for gravitational-wave signals using Bilby. It introduces the full analysis workflow, from the definition of signal models to the interpretation of posterior distributions, with an emphasis on realistic data conditions and practical implementation. Participants work with the bilby.gw framework to analyze signals from compact binary coalescences. The tutorial covers waveform modeling based on the Post-Newtonian approximation and Effective One Body formalism, as well as detector noise characterization and the role of calibration and assumptions about stationarity and Gaussianity. Particular attention is given to parameter degeneracies and to the interpretation of uncertainties. Through guided exercises, participants perform complete inference runs, explore the impact of prior choices, and test the robustness of results under controlled variations of the analysis setup. Additional topics include injection studies and extensions toward more complex inference scenarios. The goal is to provide a solid and practical understanding of gravitational-wave parameter estimation and to enable participants to carry out and critically assess their own analyses.

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• 09:00 Orientation: source, detectors, likelihood, and posterior.
• 09:10 PN, EOB, and phenomenological waveforms; compare signals over a justified band.
• 09:40 Lab 1: inspect noise and reproduce a likelihood ratio.
• 10:10 Lab 2: complete a reduced BBH inference and inspect its diagnostics.
• 10:45–11:00 Break.
• 11:00 Lab 3: distance–inclination degeneracy and prior sensitivity.
• 11:40 Lab 4: waveform, noise, calibration, and glitch robustness.
• 12:20 Lab 5: GW150914 data, posterior interpretation, and residuals.
• 12:45 Injection validation, extensions, and closing discussion.

 

Note: times are indicative

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