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GR: Fachverband Gravitation und Relativitätstheorie

GR 16: Gravitational Waves I

GR 16.2: Talk

Thursday, March 14, 2024, 15:05–15:25, HBR 14: HS 2

Systematic Differences in the Source Properties of Gravitational Wave Signals — •Max Melching — Max-Planck-Institut für Gravitationsphysik (Albert Einstein Institut), Callinstraße 38, 30167 Hannover, Deutschland

Measurements of gravitational wave source properties are conducted in the framework of parameter estimation, utilizing Bayes' theorem to compute posterior probability distributions for all parameters. In this process, one predicts gravitational wave signals for certain parameter combinations and compares them to detector data in order to infer whether the modeled signal is contained in the data. However, the waveform models are not entirely faithful representations of numerical relativity because of the high computational cost involved in generating accurate simulations. Instead, several approximate models are used, which may lead to systematic differences in the inferred results. Consequently, being able to describe and understand model-induced uncertainties is crucial.

To date, however, no universal way of doing that exists. In this talk, I will explore a data-driven approach to identify significant systematic differences between models and apply this method to confident detections of the third gravitational-wave transient catalog GWTC-3 that has been published by the LIGO-Virgo-KAGRA collaborations. Additionally, I will talk about geometric ideas from the Fisher-matrix formalism that allow for interpreting signal differences as measurement uncertainties in the associated parameter space.

Keywords: gravitational waves; data analysis; parameter estimation; GWTC-3; Fisher matrix