A useful guide for gravitational wave observers to test modified gravity models

TL;DR

This paper proposes a method for gravitational wave observers to test modified gravity models by measuring potential time lags between gravitational waves and electromagnetic signals from the same galactic sources, aiding in distinguishing between gravity theories.

Contribution

It extends previous tests of modified gravity by providing a numerical calculation of expected time lags in dark matter emulator models within our galaxy.

Findings

Calculated time lag for sources up to 400 kpc in the galaxy.

Provided a graph illustrating potential time lags for observational use.

Suggested that gravitational wave analysis should consider non-coincident signals.

Abstract

We present an extension of a previously suggested test of all modified theories of gravity that would reproduce MOND at low accelerations. In a class of models, called "dark matter emulators", gravitational waves and other particles couple to different metrics. This leads to a detectable time lag between their detection at Earth from the same source. We calculate this time lag numerically for any event that occurs in our galaxy up to 400 kpc, and present a graph of this possible time lag. This suggests that, gravitational wave observers might have to consider the possibility of extending their analysis to non-coincident gravitational and electromagnetic signals, and the graph that we present might be a useful guideline for this effort.