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.
|Keywords:||Cosmology: theory, Dark matter, Gravitation.|
|Full text:||(VoR) Version of Record|
Download PDF (185Kb)
|Publisher Web site:||http://dx.doi.org/10.1086/587744|
|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|
Save or Share this output
|Look up in GoogleScholar|