Towards low-latency real-time detection of gravitational waves from compact binary coalescences in the era of advanced detectors

TL;DR

This paper introduces a fast, low-latency time-domain algorithm using IIR filters for real-time gravitational wave detection from compact binary coalescences, enabling prompt electromagnetic follow-up observations.

Contribution

It presents a novel, computationally efficient time-domain detection algorithm that reduces latency and computational cost compared to traditional methods, suitable for advanced gravitational wave detectors.

Findings

Algorithm achieves near-zero detection delay

Computational cost remains low at lower frequencies

Outperforms frequency-domain methods in low-latency scenarios

Abstract

Electromagnetic (EM) follow-up observations of gravitational wave (GW) events will help shed light on the nature of the sources, and more can be learned if the EM follow-ups can start as soon as the GW event becomes observable. In this paper, we propose a computationally efficient time-domain algorithm capable of detecting gravitational waves (GWs) from coalescing binaries of compact objects with nearly zero time delay. In case when the signal is strong enough, our algorithm also has the flexibility to trigger EM observation before the merger. The key to the efficiency of our algorithm arises from the use of chains of so-called Infinite Impulse Response (IIR) filters, which filter time-series data recursively. Computational cost is further reduced by a template interpolation technique that requires filtering to be done only for a much coarser template bank than otherwise required to sufficiently recover optimal signal-to-noise ratio. Towards future detectors with sensitivity extending to lower frequencies, our algorithm's computational cost is shown to increase rather insignificantly compared to the conventional time-domain correlation method. Moreover, at latencies of less than hundreds to thousands of seconds, this method is expected to be computationally more efficient than the straightforward frequency-domain method.