A faster implementation of the hierarchical search algorithm for detection of gravitational waves from inspiraling compact binaries

TL;DR

This paper introduces an enhanced hierarchical search algorithm for gravitational wave detection that significantly accelerates data analysis by extending the domain of hierarchy to include the signal's time of arrival, achieving a 65-70 fold speedup.

Contribution

The paper presents a novel extension of the hierarchical search algorithm incorporating the signal's time of arrival, improving efficiency and speed in gravitational wave data analysis.

Findings

Achieved a 65-70 times speedup over flat search methods.

Demonstrated effectiveness with 2PN waveforms in simulated LIGO noise.

Addressed issues related to template placement and trigger thresholds.

Abstract

The first scientific runs of kilometer scale laser interferometric detectors like LIGO are underway. Data from these detectors will be used to look for signatures of gravitational waves (GW) from astrophysical objects like inspiraling neutron star/blackhole binaries using matched filtering. The computational resources required for online flat-search implementation of the matched filtering are large if searches are carried out for small total mass. In this paper we report an improved implementation of the hierarchical search, wherein we extend the domain of hierarchy to an extra dimension - namely the time of arrival of the signal in the bandwidth of the interferometer. This is accomplished by lowering the Nyquist sampling rate of the signal in the trigger stage. We show that this leads to further improvement in the efficiency of data analysis and speeds up the online computation by a factor of $\sim 65 - 70$ over the flat search. We also take into account and discuss issues related to template placement, trigger thresholds and other peculiar problems that do not arise in earlier implementation schemes of the hierarchical search. We present simulation results for 2PN waveforms embedded in the noise expected for initial LIGO detectors.