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Can we distinguish early dark energy from a cosmological constant?

Shi, D.; Baugh, C.M.

Can we distinguish early dark energy from a cosmological constant? Thumbnail


D. Shi


Early dark energy (EDE) models are a class of quintessence dark energy with a dynamically evolving scalar field which display a small but non-negligible amount of dark energy at the epoch of matter-radiation equality. Compared with a cosmological constant, the presence of dark energy at early times changes the cosmic expansion history and consequently the shape of the linear theory power spectrum and potentially other observables. We constrain the cosmological parameters in the EDE cosmology using recent measurements of the cosmic microwave background and baryon acoustic oscillations. The best-fitting models favour no EDE; here we consider extreme examples which are in mild tension with current observations in order to explore the observational consequences of a maximally allowed amount of EDE. We study the non-linear evolution of cosmic structure in EDE cosmologies using large-volume N-body simulations. Many large-scale structure statistics are found to be very similar between the Λ cold dark matter (ΛCDM) and EDE models. We find that EDE cosmologies predict fewer massive haloes in comparison to ΛCDM, particularly at high redshifts. The most promising way to distinguish EDE from ΛCDM is to measure the power spectrum on large scales, where differences of up to 15 per cent are expected.


Shi, D., & Baugh, C. (2016). Can we distinguish early dark energy from a cosmological constant?. Monthly Notices of the Royal Astronomical Society, 459(4), 3540-3550.

Journal Article Type Article
Acceptance Date Apr 12, 2016
Online Publication Date Apr 15, 2016
Publication Date Jul 11, 2016
Deposit Date May 24, 2016
Publicly Available Date Jun 16, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 459
Issue 4
Pages 3540-3550


Published Journal Article (1.1 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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