Forecasts of redshift drift constraints on cosmological parameters

Abstract

Cosmological observations usually map our present-day past light cone. However, it is also possible to compare different past light cones. This is the concept behind the redshift drift, a model-independent probe of fundamental cosmology. In simple physical terms, this effectively allows us to watch the Universe expand in real time. While current facilities only allow sensitivities several orders of magnitude worse than the expected signal, it should be possible to detect it with forthcoming ones. Here we discuss the potential impact of measurements by three such facilities: the Extremely Large Telescope (the subject of most existing redshift drift forecasts), but also the Square Kilometre Array and intensity mapping experiments. For each of these we assume the measurement sensitivities estimated respectively in Liske {\it et al.} (2008), Klockner {\it et al.} (2015) and Yu {\it et al.} (2014). We focus on the role of these measurements in constraining dark energy scenarios, highlighting the fact that although on their own they yield comparatively weak constraints, they do probe regions of parameter space that are typically different from those probed by other experiments, as well as being redshift-dependent. Specifically, we quantify how combinations of several redshift drift measurements at different redshifts, or combinations of redshift drift measurements with those from other canonical cosmological probes, can constrain some representative dark energy models. Our conclusion is that a model-independent mapping of the expansion of the universe from redshift $z=0$ to $z=4$---a challenging but feasible goal for the next generation of astrophysical facilities---can have a significant impact on fundamental cosmology.

19 pages, 10 figures, 4+2 tables; to appear in MNRAS

References in corpus (9)

• Cosmic dynamics in the era of Extremely Large Telescopes
• Time drift of cosmological redshifts as a test of the Copernican principle
• Exploring the Dark Energy Redshift Desert with the Sandage-Loeb Test
• The time evolution of cosmological redshift as a test of dark energy
• Time drift of cosmological redshifts and its variance
• Testing the LCDM model (and more) with the time evolution of the redshift
• Parameter estimation with Sandage-Loeb test
• Measuring the Expansion of the Universe Through Changes in the CMB Photosphere
• Measuring Space-Time Geometry over the Ages

Cited by in corpus (4)

• The ACCELERATION programme: I. Cosmology with the redshift drift
• Redshift Drift in $f(R,T)$ Gravity
• Low-redshift constraints on homogeneous and isotropic universes with torsion
• Testing the Equivalence Principle with Strong Lensing Time Delay Variations