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A nonuniform dark energy fluid : perturbation equations.

Halle, A. and Zhao, H. and Li, B. (2008) 'A nonuniform dark energy fluid : perturbation equations.', Astrophysical journal : supplement series., 177 (1). pp. 1-13.


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.

Item Type:Article
Keywords:Cosmology: theory, Dark matter, Gravitation.
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Publisher statement:© 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.
Date accepted:No date available
Date deposited:01 May 2014
Date of first online publication:July 2008
Date first made open access:No date available

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