Journal Article

The Milky Way rotation curve in Horava–Lifshitz theory

V. F. Cardone, N. Radicella, M. L. Ruggiero and M. Capone

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 406, issue 3, pages 1821-1829
Published in print August 2010 | ISSN: 0035-8711
Published online August 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.16657.x
The Milky Way rotation curve in Horava–Lifshitz theory

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The Horava–Lifshitz (HL) theory has recently attracted a lot of interest as a viable solution to some quantum gravity related problems and the presence of an effective cosmological constant able to drive the cosmic speed up. We show here that, in the weak field limit, the HL proposal leads to a modification of the gravitational potential because of two additive terms (scaling, respectively, as r2 and r−4) to the Newtonian 1/r potential. We then derive a general expression to compute the rotation curve of an extended system under the assumption that the mass density only depends on the cylindrical coordinates (R, z) showing that the HL modification induces a dependence of the circular velocity on the mass function which is a new feature of the theory. As a first exploratory analysis, we then try fitting the Milky Way rotation curve using its visible components only in order to see whether the HL modified potential can be an alternative to the dark matter framework. This turns out not to be the case so that we argue that dark matter is still needed, but the amount of dark matter and the dark halo density profile have to be revised according to the new HL potential.

Keywords: gravitation; Galaxy: kinematics and dynamics; dark matter

Journal Article.  7125 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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