Constraining new fundamental physics with multiwavelength astrometry

TL;DR

This paper explores how multiwavelength astrometry can constrain new physics models that predict chromatic light deflection, providing the best current limits on photon mass and deflection parameters, and discusses future improvements.

Contribution

It demonstrates the use of multiwavelength astrometry to set new constraints on physics beyond General Relativity, including limits on photon mass and chromatic deflection.

Findings

Established world-best limits on chromatic gravitational deflection.

Provided the most stringent limit on photon mass for Mpc scales.

Outlined prospects for improving constraints with future observations.

Abstract

While the deflection of light is achromatic in General Relativity, it is not always so in several new-physics models (e.g. certain quantum-gravity and string-inspired models, models with nonminimal photon-gravity coupling or with massive photon etc.). We discuss how parameters of these models may be constrained by precise astrometry at different wavelenghts. From published observations of the gravitational lens MG J2016+112, we obtain world-best limits on chromatic gravitational deflection of light (and the unique limit on the photon mass relevant for distance scales >Mpc). We also outline prospects for further improvement of these limits.