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A Nonuniform Dark Energy Fluid: Perturbation Equations

Halle, A.; Zhao, H.; Li, B.

A Nonuniform Dark Energy Fluid: Perturbation Equations Thumbnail


A. Halle

H. Zhao


We propose that galactic dark matter can be described by a nonuniform dark energy fluid. The underlying field is a decaying vector field, which might corresponds to a photon-like but massive particle of 4 degrees of dynamical freedom. We propose a very general Lagrangian for this vector field. The model includes a continuous spectrum of plausible gravity theories, for example, quintessence, f(R), Einstein-Aether, MOND, TeVeS, BSTV, V-Λ theories, and the inflaton scalar field as special cases. We study in detail a special class of models with a fixed norm of the timelike vector field in the physical metric, which includes a nonlinear K4 term and a Ricci scalar term. We derive the Einstein equations in the perturbed form, which are needed for simulating structure growth in an FRW universe to test such theories. A special case of the model V-Λ shows promise of resembling the ΛCDM cosmology. We show that the vector field has the effect of a nonuniform dark fluid, which resembles dark matter in galaxies and dark energy in the late universe.

Journal Article Type Article
Publication Date Jul 1, 2008
Deposit Date Jan 20, 2012
Publicly Available Date May 1, 2014
Journal Astrophysical Journal Supplement
Print ISSN 0067-0049
Electronic ISSN 1538-4365
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 177
Issue 1
Pages 1-13
Keywords Cosmology: theory, Dark matter, Gravitation.
Public URL


Published Journal Article (189 Kb)

Copyright Statement
© 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.

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