Searches for stochastic gravitational-wave backgrounds

Abstract

These lecture notes provide a brief introduction to methods used to search for a stochastic background of gravitational radiation -- a superposition of gravitational-wave signals that are either too weak or too numerous to individually detect. The focus of these notes is on relevant data analysis techniques, not on the particular astrophysical or cosmological sources that are responsible for producing the background. The lecture notes are divided into two main parts: (i) an overview, consisting of a description of different types of gravitational-wave backgrounds and an introduction to the method of cross-correlating data from multiple detectors, which can be used to extract the signal from the noise; (ii) details, extending the previous discussion to non-trivial detector response, non-trivial overlap functions, and a recently proposed Bayesian method to search for the gravitational-wave background produced by stellar-mass binary black hole mergers throughout the universe. Suggested exercises for the reader are given throughout the text, and compiled in an appendix.

Lectures for the 2018 Les Houches Summer School on Gravitational Waves (55 pages; 31 figures). Fixed some minor typos in a few equations

References in corpus (7)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs
• Expected properties of the first gravitational wave signal detected with pulsar timing arrays
• GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences
• Mapping gravitational-wave backgrounds using methods from CMB analysis: Application to pulsar timing arrays
• Anisotropies in the stochastic gravitational-wave background: Formalism and the cosmic string case
• Correlated noise in networks of gravitational-wave detectors: subtraction and mitigation