A Data Analysis Technique for the LIGO-ALLEGRO Stochastic Background Search

TL;DR

This paper presents a method for cross-correlating data from LIGO and ALLEGRO detectors to search for stochastic gravitational wave backgrounds, addressing differences in data sampling and demonstrating the approach's effectiveness.

Contribution

It introduces a Fourier domain technique to handle disparate sampling rates in cross-correlation analysis between LIGO and ALLEGRO data sets.

Findings

Effective cross-correlation method for heterogeneous data

Demonstrated equivalence to time-domain upsampling approach

Applicable to gravitational wave background searches

Abstract

We describe the cross-correlation measurements being carried out on data from the LIGO Livingston Observatory and the ALLEGRO resonant bar detector. The LIGO data are sampled at 16384 Hz while the ALLEGRO data are base-banded, i.e., heterodyned at 899 Hz and then sampled at 250 Hz. We handle these different sampling parameters by working in the Fourier domain, and demonstrate the approximate equivalence of this measurement to a hypothetical time-domain method in which both data streams are upsampled.