Detecting very long-lived gravitational-wave transients lasting hours to weeks

TL;DR

This paper investigates the detection of very long-lived gravitational-wave transients lasting hours to weeks, addressing computational challenges with data compression techniques and proposing an efficient radiometer algorithm.

Contribution

It introduces a novel data compression method for detecting long-duration gravitational-wave signals and adapts the radiometer algorithm to handle Earth's rotation effects.

Findings

Demonstrated an efficient detection algorithm using coarse-graining.

Identified challenges related to Earth's rotation in long transient searches.

Provided solutions to computational difficulties in long-duration signal detection.

Abstract

We explore the possibility of very long-lived gravitational-wave transients (and detector artifacts) lasting hours to weeks. Such very long signals are both interesting in their own right and as a potential source of systematic error in searches for persistent signals, e.g., from a stochastic gravitational-wave background. We review possible mechanisms for emission on these time scales and discuss computational challenges associated with their detection: namely, the substantial volume of data involved in a search for very long transients can require vast computer memory and processing time. These computational difficulties can be addressed through a form of data compression known as coarse-graining, in which information about short time spans is discarded in order to reduce the computational requirements of a search. Using data compression, we demonstrate an efficient radiometer (cross-correlation) algorithm for the detection of very long transients. In the process, we identify features of a very long transient search (related to the rotation of the Earth) that make it more complicated than a search for shorter transient signals. We implement suitable solutions.