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Stellar kinematics from the symmetron fifth force in the Milky Way disk

O�Hare, Ciaran A.?J.; Burrage, Clare

Stellar kinematics from the symmetron fifth force in the Milky Way disk Thumbnail


Ciaran A.?J. O�Hare


It has been shown that the presence of nonminimally coupled scalar fields giving rise to a fifth force can noticeably alter dynamics on galactic scales. Such a fifth force must be screened in the Solar System but if unscreened it can have similar observational effects as a component of nonbaryonic matter. We consider this possibility in the context of the vertical motions of local stars in the Milky Way disk by reframing a methodology used to measure the local density of dark matter. By attempting to measure the properties of the symmetron field required to support vertical velocities we can test it as a theory of modified gravity and understand the behavior of screened scalar fields in galaxies. In particular, this relatively simple setup allows the symmetron field profile to be solved for model parameters where the equation of motion becomes highly nonlinear and difficult to solve in other contexts. We update the existing Solar System constraints for this scenario and find a region of parameter space not already excluded that can explain the vertical motions of local stars out to heights of 1 kpc. At larger heights the force due to the symmetron field profile exhibits a characteristic turn over which would allow the model to be distinguished from a dark matter halo.

Journal Article Type Article
Acceptance Date Aug 31, 2018
Online Publication Date Sep 12, 2018
Publication Date Sep 15, 2018
Deposit Date Jan 16, 2019
Publicly Available Date Jan 16, 2019
Journal Physical Review D
Print ISSN 2470-0010
Electronic ISSN 2470-0029
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 98
Issue 6
Article Number 064019
Keywords Physics and Astronomy (miscellaneous)
Public URL
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