A Joint Search for Gravitational Wave Bursts with AURIGA and LIGO

TL;DR

This paper presents the first joint search for gravitational wave bursts using AURIGA's resonant bar detector and LIGO's interferometers, focusing on methodology and setting upper limits in the absence of detection.

Contribution

It introduces a novel joint analysis method combining resonant and interferometric detectors and discusses the first unified approach between these different gravitational wave detection communities.

Findings

No gravitational wave bursts detected in the analyzed data.

Established a methodology for joint analysis of different detector types.

Set upper limits on gravitational wave event rates.

Abstract

The first simultaneous operation of the AURIGA detector and the LIGO observatory was an opportunity to explore real data, joint analysis methods between two very different types of gravitational wave detectors: resonant bars and interferometers. This paper describes a coincident gravitational wave burst search, where data from the LIGO interferometers are cross-correlated at the time of AURIGA candidate events to identify coherent transients. The analysis pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA candidate events and on the significance of the cross-correlation test in LIGO. The false alarm rate is estimated by introducing time shifts between data sets and the network detection efficiency is measured with simulated signals with power in the narrower AURIGA band. In the absence of a detection, we discuss how to set an upper limit on the rate of gravitational waves and to interpret it according to different source models. Due to the short amount of analyzed data and to the high rate of non-Gaussian transients in the detectors noise at the time, the relevance of this study is methodological: this was the first joint search for gravitational wave bursts among detectors with such different spectral sensitivity and the first opportunity for the resonant and interferometric communities to unify languages and techniques in the pursuit of their common goal.