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Constraining the dark fluid

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journal contribution
posted on 2023-06-07, 23:04 authored by Martin Kunz, Andrew R Liddle, David Parkinson, Changjun Gao
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.

History

Publication status

  • Published

File Version

  • Published version

Journal

Physical Review D

ISSN

1550-7998

Publisher

American Physical Society

Issue

8

Volume

80

Department affiliated with

  • Physics and Astronomy Publications

Notes

Article Number: 083533

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

First Open Access (FOA) Date

2016-03-22

First Compliant Deposit (FCD) Date

2016-11-10

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