# Testing the Strong Equivalence Principle: Detection of the External Field Effect in Rotationally Supported Galaxies

@article{Chae2020TestingTS, title={Testing the Strong Equivalence Principle: Detection of the External Field Effect in Rotationally Supported Galaxies}, author={Kyu-Hyun Chae and Federico Lelli and Harry Desmond and Stacy S. McGaugh and Pengfei Li and James M. Schombert}, journal={The Astrophysical Journal}, year={2020}, volume={904} }

The strong equivalence principle (SEP) distinguishes general relativity (GR) from other viable theories of gravity. The SEP demands that the internal dynamics of a self-gravitating system under freefall in an external gravitational field should not depend on the external field strength. We test the SEP by investigating the external field effect (EFE) in Milgromian dynamics (MOND), proposed as an alternative to dark matter in interpreting galactic kinematics. We report a detection of this EFE…

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## References

SHOWING 1-10 OF 61 REFERENCES

### A modification of the newtonian dynamics as a possible alternative to the hidden mass hypothesis

- Physics
- 1983

The author considers the possibility that there is not, in fact, much hidden mass in galaxies and galaxy systems. If a certain modified version of the Newtonian dynamics is used to describe the…

### Declining rotation curves of galaxies as a test of gravitational theory

- Physics
- 2016

Unlike Newtonian dynamics which is linear and obeys the strong equivalence principle, in any nonlinear gravitation such as Milgromian dynamics (MOND), the strong version of the equivalence principle…

### One Law To Rule Them All: The Radial Acceleration Relation of Galaxies

- Physics
- 2016

We study the link between baryons and dark matter (DM) in 240 galaxies with spatially resolved kinematic data. Our sample spans 9 dex in stellar mass and includes all morphological types. We consider…

### Does the missing mass problem signal the breakdown of Newtonian gravity

- Physics
- 1984

We consider a nonrelativistic potential theory for gravity which differs from the Newtonian theory. The theory is built on the basic assumptions of the modified dynamics, which were shown earlier to…

### TESTING FUNDAMENTAL PHYSICS WITH DISTANT STAR CLUSTERS: ANALYSIS OF OBSERVATIONAL DATA ON PALOMAR 14,,

- Physics
- 2009

We use the distant outer halo globular cluster Palomar 14 as a test case for classical versus modified Newtonian dynamics (MOND). Previous theoretical calculations have shown that the line-of-sight…

### New Relativistic Theory for Modified Newtonian Dynamics.

- PhysicsPhysical review letters
- 2021

A relativistic gravitational theory leading to modified Newtonian dynamics is proposed, a paradigm that explains the observed universal galactic acceleration scale and related phenomenology and its possible embedding in a more fundamental theory is discussed.

### Predictions and Outcomes for the Dynamics of Rotating Galaxies

- Physics
- 2020

A review is given of a priori predictions made for the dynamics of rotating galaxies. One theory - MOND - has had many predictions corroborated by subsequent observations. While it is sometimes…

### Scaling Relations for Molecular Gas and Metallicity: Impact on the Baryonic Tully–Fisher Relation

- Physics
- 2020

### A new formulation of the external field effect in MOND and numerical simulations of ultra-diffuse dwarf galaxies – application to NGC 1052-DF2 and NGC 1052-DF4

- PhysicsMonthly Notices of the Royal Astronomical Society
- 2019

The ultra-diffuse dwarf galaxy NGC 1052-DF2 (DF2) has ten (eleven) measured globular clusters (GCs) with a line-of-sight velocity dispersion of $\sigma=7.8^{+5.2}_{-2.2}\,$km/s…