Searching for dark energy in the matter-dominated era

Abstract

Most efforts to detect signatures of dynamical dark energy are focused on late times, $z\lesssim 2$, where the dark energy component begins to dominate the cosmic energy density. Many theoretical models involving dynamical dark energy exhibit a 'freezing' equation of state however, where $w\to -1$ at late times, with a transition to a 'tracking' behaviour at earlier times (with $w\gg -1$ at sufficiently high redshift). In this paper, we study whether large-scale structure surveys in the post-reionisation matter-dominated regime, $2\lesssim z\lesssim 6$, are sensitive to this behaviour, on the basis that the dark energy component should remain detectable (despite being strongly subdominant) in this redshift range given sufficiently precise observations. Using phenomenological models inspired by parameter space studies of Horndeski (generalised scalar-tensor) theories, we show how existing CMB and large-scale structure measurements constrain the dark energy equation of state in the matter-dominated era, and examine how forthcoming galaxy surveys and 21cm intensity mapping instruments can improve constraints in this regime. We also find that the combination of existing CMB and LSS constraints with DESI will already come close to offering the best possible constraints on $H_0$ using BAO/galaxy power spectrum measurements, and that either a spectroscopic follow-up of the LSST galaxy sample (e.g. along the lines of MegaMapper or SpecTel) or a Stage 2/PUMA-like intensity mapping survey, both at $z\gtrsim 2$, would offer better constraints on the class of dark energy models considered here than a comparable cosmic variance-limited galaxy survey at $z\lesssim 1.5$.

13 pages, 10 figures; comments welcome

References in corpus (21)

• The NumPy array: a structure for efficient numerical computation
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity
• Early dark energy, the Hubble-parameter tension, and the string axiverse
• Early Dark Energy Does Not Restore Cosmological Concordance
• Late-time cosmology with 21cm intensity mapping experiments
• A unifying description of dark energy
• The Parameterized Post-Friedmann Framework for Theories of Modified Gravity: Concepts, Formalism and Examples
• Blinded challenge for precision cosmology with large-scale structure: results from effective field theory for the redshift-space galaxy power spectrum
• On the way from matter-dominated era to dark energy universe
• Gravity in the Era of Equality: Towards solutions to the Hubble problem without fine-tuned initial conditions
• Limits on Dark Radiation, Early Dark Energy, and Relativistic Degrees of Freedom
• Mitigating Internal Instrument Coupling for 21 cm Cosmology I: Temporal and Spectral Modeling in Simulations
• Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
• Modeling the neutral hydrogen distribution in the post-reionization Universe: intensity mapping
• A test of the CPL parameterization for rapid dark energy equation of state transitions
• Predicting Hα emission line galaxy counts for future galaxy redshift surveys
• Early Dark Energy at High Redshifts: Status and Perspectives
• Narrowing down the possible explanations of cosmic acceleration with geometric probes
• FOBOS: A Next-Generation Spectroscopic Facility at the W. M. Keck Observatory
• Inflation and Dark Energy from spectroscopy at $z>2$

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