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Varying alpha from N-body simulations

Li, B.; Mota, D.F.; Barrow, J.D.

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D.F. Mota

J.D. Barrow


We have studied the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) model for the spatial and temporal variations of the fine structure constant, α, with the aid of full N-body simulations that explicitly and self-consistently solve for the scalar field driving the α-evolution. We focus on the scalar field (or equivalently α) inside the dark matter halos and find that the profile of the scalar field is essentially independent of the BSBM model parameter. This means that given the density profile of an isolated halo and the background value of the scalar field, we can accurately determine the scalar-field perturbation in that halo. We also derive an analytic expression for the scalar-field perturbation using the Navarro-Frenk-White halo profile and show that it agrees well with numerical results, at least for isolated halos; for non-isolated halos, this prediction differs from numerical result by a (nearly) constant offset, which depends on the environment of the halo.

Journal Article Type Article
Publication Date Feb 20, 2011
Deposit Date Jan 20, 2012
Publicly Available Date May 1, 2014
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 728
Issue 2
Article Number 108
Keywords Cosmology: miscellaneous, Dark matter, Large-scale structure of universe, Methods: numerical.
Public URL


Published Journal Article (705 Kb)

Copyright Statement
© 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A

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