When to Sweat the Small Stuff: identifying the most informative events from ground-based gravitational-wave detectors

TL;DR

This paper analyzes how the information from gravitational-wave events accumulates, showing that numerous quiet signals often outweigh fewer loud ones, and proposes a cost-benefit analysis for detection thresholds.

Contribution

It introduces a simple framework to balance analysis costs against scientific gains in gravitational-wave detection, considering the impact of detection thresholds.

Findings

Quiet/distant signals often dominate information content.

Lowering detection thresholds increases event numbers but raises analysis costs.

Optimal thresholds depend on detector sensitivity and economic considerations.

Abstract

We explore scaling relations for the information carried by individual events, and how that information accumulates in catalogs like those from ground-based gravitational-wave detectors. For a variety of situations, the larger number of quiet/distant signals dominates the overall information over the fewer loud/close sources, independent of how many model parameters are considered. We consider implications for a range of astrophysical scenarios, including calibration uncertainty and standard siren cosmology. However, the large number of additional events obtained by lowering the detection threshold can rapidly increase costs. We introduce a simple analysis that balances the costs of analyzing increasingly large numbers of low information events against retaining a higher threshold and running a survey for longer. With the caveat that precise cost estimates are difficult to determine, current economics favor analyzing low signal-to-noise ratio events. However, the higher detection rates expected for next-generation detectors may argue for a higher signal-to-noise ratio threshold for optimal scientific return.