Comparing compact binary parameter distributions I: Methods

TL;DR

This paper develops methods to quantify the information content in gravitational-wave observations of compact binary mergers, enabling differentiation between progenitor models as detector sensitivity and data volume increase.

Contribution

It introduces practical tools and diagnostics to estimate the distinguishability of progenitor models based on observational data and discusses the importance of precise calibration for full exploitation.

Findings

Information content scales with the number of observations.

Model distinguishability depends on changes in mass distributions.

Multi-observable analysis requires precise calibration.

Abstract

Being able to measure each merger's sky location, distance, component masses, and conceivably spins, ground-based gravitational-wave detectors will provide a extensive and detailed sample of coalescing compact binaries (CCBs) in the local and, with third-generation detectors, distant universe. These measurements will distinguish between competing progenitor formation models. In this paper we develop practical tools to characterize the amount of experimentally accessible information available, to distinguish between two a priori progenitor models. Using a simple time-independent model, we demonstrate the information content scales strongly with the number of observations. The exact scaling depends on how significantly mass distributions change between similar models. We develop phenomenological diagnostics to estimate how many models can be distinguished, using first-generation and future instruments. Finally, we emphasize that multi-observable distributions can be fully exploited only with very precisely calibrated detectors, search pipelines, parameter estimation, and Bayesian model inference.