Gravitational waves and small-field astrometry

TL;DR

This paper explores how small-field astrometry can detect gravitational waves, analyzing the differential effects within finite fields, supported by theoretical derivations and numerical simulations.

Contribution

It provides a detailed theoretical and numerical analysis of gravitational wave effects in small-field astrometry, highlighting limitations due to calibration absorption.

Findings

Small-field missions have limited sensitivity to gravitational waves.

Differential effects are largely absorbed by standard calibration procedures.

Theoretical derivations support numerical simulation results.

Abstract

Astrometric observations can, in principle, be used to detect gravitational waves. In this paper we give a practical overview of the gravitational wave effects which can be expected specifically in small-field astrometric data. Particular emphasis is placed on the differential effect between pairs of sources within a finite field of view. We also present several general findings that are not restricted to the small-field case. A detailed theoretical derivation of the general astrometric effect of a plane gravitational wave is provided. Numerical simulations, which underline our theoretical findings, are presented. We find that small-field missions suffer from significant detrimental properties, largely because their relatively small fields only allow the measurement of small differential effects which can be expected to be almost totally absorbed by standard plate calibrations.