An astrometric search method for individually resolvable gravitational wave sources with Gaia

TL;DR

This paper introduces a novel method for detecting gravitational waves using Gaia's astrometric data, efficiently compressing large datasets to identify signals from supermassive black hole binaries with minimal sensitivity loss.

Contribution

It presents the first astrometric search technique for resolvable GW sources, demonstrating data compression and sensitivity analysis with mock Gaia data.

Findings

Data compression by over a million times with less than 1% sensitivity loss

Successful recovery of artificial GW signals from simulated Gaia data

Characterization of Gaia's sensitivity and directional response to GWs

Abstract

Gravitational waves (GWs) cause the apparent position of distant stars to oscillate with a characteristic pattern on the sky. Astrometric measurements (e.g. those made by Gaia) therefore provide a new way to search for GWs. The main difficulty facing such a search is the large size of the data set; Gaia observes more than one billion stars. In this letter the problem of searching for GWs from individually resolvable supermassive black hole binaries using astrometry is addressed for the first time; it is demonstrated how the data set can be compressed by a factor of more than $10^6$, with a loss of sensitivity of less than $1\%$. This technique is successfully used to recover artificially injected GWs from mock Gaia data. Repeated injections are used to calculate the sensitivity of Gaia as a function of frequency, and Gaia's directional sensitivity variation, or antenna pattern. Throughout the letter the complementarity of Gaia and pulsar timing searches for GWs is highlighted.