Redshift drift cosmography with ELT and SKAO measurements

Abstract

Mapping the expansion history of the universe is a compelling task of physical cosmology, especially in the context of the observational evidence for the recent acceleration of the universe, which demonstrates that canonical theories of cosmology and particle physics are incomplete and that there is new physics still to be discovered. Cosmography is a phenomenological approach to cosmology, where (with some caveats) physical quantities are expanded as a Taylor series in the cosmological redshift $z$, or analogous parameters such as the rescaled redshift $y=z/(1+z)$ or the logarithmic redshift $x=\ln (1+z)$. Moreover, the redshift drift of objects following cosmological expansion provides a model-independent observable, detectable by facilities currently under construction, {\it viz.} the Extremely Large Telescope and the Square Kilometre Array Observatory (at least in its full configuration). Here we use simulated redshift drift measurements from the two facilities to carry out an assessment of the cosmological impact and model discriminating power of redshift drift cosmography. We find that the combination of measurements from the two facilities can provide a stringent test of the $\Lambda$CDM paradigm, and that overall the logarithmic based expansions of the spectroscopic velocity drift are the most reliable ones, performing better than analogous expansions in the redshift or the rescaled redshift: the former nominally gives the smaller error bars for the cosmographic coefficients but is vulnerable to biases in the higher order terms (in other words, it is only reliable at low redshifts), while the latter always performs poorly.

18 pages, 5 figures, 5 tables; in press at MNRAS

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Cited by in corpus (16)

• Cosmographic Footprints of Dynamical Dark Energy
• Constraining minimally extended varying speed of light by cosmological chronometers
• Cosmography from well-localized Fast Radio Bursts
• Perturbations of Cosmological Redshift Drift
• Revisiting model-independent constraints on spatial curvature and cosmic ladders calibration: updated and forecast analyses
• Toward a direct measurement of the cosmic acceleration: The pilot observation of H I 21cm absorption line at FAST
• Cosmography of the minimally extended Varying Speed of Light Model
• The ESPRESSO Redshift Drift Experiment I -- High-resolution spectra of the Lyman-$\alpha$ forest of QSO J052915.80-435152.0
• Fundamental cosmology from ANDES precision spectroscopy
• Redshift drift in a universe with structure III: Numerical relativity
• Algebraic symmetries of the observables on the sky: Variable emitters and observers
• Redshift drift effect through the observation of HI 21cm signal with SKA
• Varying fundamental constants cosmography
• Estimating constraints on cosmological parameters via the canonical and the differential redshift drift with SKA HI 21-cm observations
• Safely simplifying redshift drift computations in inhomogeneous cosmologies: Insights from LTB Swiss-cheese models
• Cosmic microwave background temperature cosmography