Search for Continuous Gravitational Waves: Optimal StackSlide method at fixed computing cost

TL;DR

This paper develops an analytical method to optimize the StackSlide semi-coherent search for continuous gravitational waves at fixed computational cost, improving sensitivity by balancing data usage and mismatches.

Contribution

It introduces a novel analytical framework for optimizing StackSlide parameters under ideal conditions, accounting for both bounded and unbounded regimes and mismatch contributions.

Findings

Optimal data usage depends on the regime (bounded or unbounded).

Both fine- and coarse-grid mismatches equally affect the average mismatch.

Potential sensitivity gains over previous search methods.

Abstract

Coherent wide parameter-space searches for continuous gravitational waves are typically limited in sensitivity by their prohibitive computing cost. Therefore semi-coherent methods (such as StackSlide) can often achieve a better sensitivity. We develop an analytical method for finding optimal StackSlide parameters at fixed computing cost under ideal conditions of gapless data with Gaussian stationary noise. This solution separates two regimes: an unbounded regime, where it is always optimal to use all the data, and a bounded regime with a finite optimal observation time. Our analysis of the sensitivity scaling reveals that both the fine- and coarse-grid mismatches contribute equally to the average StackSlide mismatch, an effect that had been overlooked in previous studies. We discuss various practical examples for the application of this optimization framework, illustrating the potential gains in sensitivity compared to previous searches.