Kunz, Martin, Liddle, Andrew R, Parkinson, David and Gao, Changjun (2009) Constraining the dark fluid. Physical Review D, 80 (8). ISSN 1550-7998

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Abstract

Cosmological observations are normally fit under the assumption that the dark sector can be decomposed into dark matter and dark energy components. However, as long as the probes remain purely gravitational, there is no unique decomposition and observations can only constrain a single dark fluid; this is known as the dark degeneracy. We use observations to directly constrain this dark fluid in a model-independent way, demonstrating, in particular, that the data cannot be fit by a dark fluid with a single constant equation of state. Parametrizing the dark fluid equation of state by a variety of polynomials in the scale factor a, we use current kinematical data to constrain the parameters. While the simplest interpretation of the dark fluid remains that it is comprised of separate dark matter and cosmological constant contributions, our results cover other model types including unified dark energy/matter scenarios.

Item Type:	Article
Additional Information:	Article Number: 083533
Schools and Departments:	School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User:	Andrew Liddle
Date Deposited:	06 Feb 2012 19:29
Last Modified:	02 Jul 2019 20:48
URI:	http://sro.sussex.ac.uk/id/eprint/20830

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