Direct detection of the cosmic expansion: the redshift drift and the flux drift

Chengyi Wang; Geraint F. Lewis; Krzysztof Bolejko

arxiv: 1907.04495 · v1 · pith:P6AYJFJNnew · submitted 2019-07-10 · 🌌 astro-ph.CO · gr-qc

Direct detection of the cosmic expansion: the redshift drift and the flux drift

Krzysztof Bolejko , Chengyi Wang , Geraint F. Lewis This is my paper

Pith reviewed 2026-05-24 23:52 UTC · model grok-4.3

classification 🌌 astro-ph.CO gr-qc

keywords redshift driftflux driftcosmic expansionSKAdirect detectioncosmologyaccelerating universe

0 comments

The pith

Redshift drift and flux drift can directly detect cosmic expansion and acceleration with SKA1-mid by the mid-2030s if flux stability reaches 10^{-6}.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that the redshift drift, the slow change in observed redshift of distant sources over years, follows directly from the expansion of space and therefore tests cosmological models without intermediate distance indicators. It shows that the same expansion also produces a measurable flux drift in the received light, so the two effects can be combined to strengthen the signal. Strategies are outlined to separate this cosmological signal from the much larger but random motions of individual galaxies. The analysis concludes that if flux can be measured stably to one part in a million, the SKA1-mid Array can register both drifts before the ELT or the completed SKA, yielding direct evidence of expansion including its accelerating phase by the mid-2030s.

Core claim

The redshift drift is a direct consequence of the expansion of the Universe. The redshift drift directly impacts the change of flux, so measurements of the flux drift provide an additional tool for detecting the expansion of the universe, including its acceleration. With flux stability at the level of ΔF/F ∼ 10^{-6}, the SKA1-mid Array should be able to detect these effects before the ELT and the full SKA, providing by mid-2030s a direct evidence of the expansion of the universe including its accelerating phase.

What carries the argument

The redshift drift (change in cosmological redshift with time) together with the linked flux drift, which together encode the time evolution of the scale factor.

If this is right

Direct measurement of expansion becomes possible without distance-ladder calibrations.
The accelerating phase can be confirmed by the sign of the measured drift.
SKA1-mid can reach the required sensitivity earlier than the ELT or full SKA.
Adding the flux-drift channel increases the overall detection significance.
Kinematic contamination can be mitigated by multi-epoch and multi-object strategies.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The same stability requirement would also allow cross-checks against independent expansion-rate probes such as baryon acoustic oscillations.
Extending the time baseline beyond a decade would tighten constraints on the deceleration parameter.
Other radio arrays reaching comparable flux stability could provide an independent confirmation route.

Load-bearing premise

Kinematic contamination from galaxy motions can be separated from the cosmological redshift and flux drift signals using the outlined strategies, and the required flux stability of 10^{-6} is achievable with SKA1-mid instrumentation.

What would settle it

A decade-long monitoring campaign with SKA1-mid that finds no net redshift or flux change at the level predicted by standard expanding models, after subtracting galaxy peculiar velocities, would falsify the claim.

read the original abstract

The redshift drift, the change of cosmological redshift with time, is a direct consequence of the expansion of the Universe. Thus the measurement of the cosmological redshift drift will offer a direct test of our models of cosmology. The magnitude of the effect is very small, i.e. the spectral shift is of order of $10^{-10} - 10^{-9}$ over the period of a decade, but the next generation facilities such as ELT and SKA will be able to directly detect the expansion of our Universe by the year 2040. In this paper we focus on detectebility of this effect, including strategies of overcoming the kinematic contamination of the cosmological signal. We also show that the redshift drift directly impacts the change of flux. Thus apart from the redshift drift, measurements of the flux drift will provide an additional tool of detecting the expansion of the universe, including its acceleration. We discuss the strategies of detecting the flux drift and show that by including the flux drift signal to the redshift drift signal we boost the chances of a direct detection of the expansion of the Universe. We show that if only the stability of flux is at the level of $\Delta F/F \sim 10^{-6}$ then the SKA1-mid Array should be able to detect these effects, before the ETL and the full SKA. Thus, by including the flux drift into the SKA1-mid Array's analysis pipeline, we could be able to provide by mid-2030s a direct evidence of the expansion of the universe including its accelerating phase.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

This paper recycles the established redshift-drift idea, adds a flux-drift link, and claims SKA1-mid could detect both by the mid-2030s, but the detection timeline rests on unshown flux-stability and kinematic-separation performance.

read the letter

The paper's main move is to note that redshift drift implies a corresponding flux drift and to argue that folding the flux signal into SKA1-mid analysis could let that array beat ELT and full SKA to a direct detection of expansion and acceleration. Redshift drift itself is not new; the text treats it as known and focuses on practical detection strategies plus the flux extension. The linkage between the two drifts is direct from the same expansion kinematics and is presented clearly enough to be useful as an extra handle. The discussion of kinematic contamination from galaxy motions and possible separation methods is also straightforward and worth having on the table for observers planning long-baseline programs. The soft spot is exactly where the stress-test flagged it: the headline claim that SKA1-mid can reach the required signals if flux stability hits 10^{-6} is stated without an error budget, integration-time estimate, or simulation showing that the stability and separation are realistic after calibration and source variability. The abstract gives order-of-magnitude numbers but no propagated uncertainties or Monte-Carlo tests, so the mid-2030s timeline stays conditional rather than demonstrated. This is a short feasibility sketch aimed at people already thinking about SKA science cases or drift experiments. It does not introduce new derivations or data, but the combined-signal suggestion is a reasonable incremental point that some readers might want to follow up. I would send it to referees so they can judge whether the instrumental assumptions need tightening or can be left as stated.

Referee Report

2 major / 2 minor

Summary. The paper claims that the cosmological redshift drift (spectral shift ~10^{-9} over a decade) and the associated flux drift provide a direct probe of cosmic expansion, including acceleration. It outlines strategies to mitigate kinematic contamination from galaxy motions and argues that flux stability of ΔF/F ∼ 10^{-6} would allow the SKA1-mid Array to detect these signals by the mid-2030s—earlier than the ELT or full SKA—by adding flux-drift measurements to the analysis pipeline.

Significance. If the stated instrumental stability and kinematic-separation performance can be demonstrated, the work would offer a novel radio-based route to direct detection of expansion that complements optical redshift-drift efforts. The suggestion to combine redshift and flux drifts is a potentially useful strengthening of the signal. The manuscript supplies only order-of-magnitude estimates and high-level strategies, however, so its immediate scientific impact is limited until quantitative support is added.

major comments (2)

[Abstract] Abstract: the central claim that SKA1-mid can detect the redshift and flux drifts with ΔF/F ∼ 10^{-6} before ELT/full SKA rests on an unverified threshold. No section, equation, or table supplies the required error budget, integration-time calculation, or Monte-Carlo simulation that propagates instrumental, calibration, and source-variability contributions to show that 10^{-6} stability is sufficient to reach the cosmological signal amplitude.
[Abstract] Abstract and discussion of kinematic strategies: the assertion that galaxy-motion contamination can be separated from the cosmological flux-drift signal (itself ~10^{-9} in relative terms) is presented without a quantitative residual-noise estimate. No calculation demonstrates that the outlined separation reduces the kinematic term below the target cosmological amplitude after realistic velocity dispersions and survey selection.

minor comments (2)

[Abstract] Abstract contains the typo 'detectebility' (should be 'detectability') and 'ETL' (should be 'ELT').
The manuscript would benefit from explicit references to prior redshift-drift literature and from a clear definition of the flux-drift quantity (e.g., whether it is derived directly from the redshift-drift formula or treated as an independent observable).

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments. The points raised correctly identify areas where the manuscript would benefit from additional quantitative analysis. We will revise the paper accordingly to include the requested error budgets and calculations.

read point-by-point responses

Referee: [Abstract] Abstract: the central claim that SKA1-mid can detect the redshift and flux drifts with ΔF/F ∼ 10^{-6} before ELT/full SKA rests on an unverified threshold. No section, equation, or table supplies the required error budget, integration-time calculation, or Monte-Carlo simulation that propagates instrumental, calibration, and source-variability contributions to show that 10^{-6} stability is sufficient to reach the cosmological signal amplitude.

Authors: We agree that a more detailed error budget is necessary to substantiate the central claim. In the revised manuscript, we will add integration-time calculations and Monte-Carlo simulations that incorporate instrumental noise, calibration uncertainties, and source variability. These additions will show that the 10^{-6} flux stability is sufficient for detection, supporting the statements in the abstract. We will also ensure the abstract accurately reflects the new quantitative results. revision: yes
Referee: [Abstract] Abstract and discussion of kinematic strategies: the assertion that galaxy-motion contamination can be separated from the cosmological flux-drift signal (itself ~10^{-9} in relative terms) is presented without a quantitative residual-noise estimate. No calculation demonstrates that the outlined separation reduces the kinematic term below the target cosmological amplitude after realistic velocity dispersions and survey selection.

Authors: The referee is correct that the kinematic separation is discussed at a high level without quantitative residual estimates. We will include in the revision explicit calculations of the residual noise after applying the separation strategies, using realistic velocity dispersions and survey selections. This will demonstrate that the kinematic contamination can be reduced below the cosmological signal level of ~10^{-9}. revision: yes

Circularity Check

0 steps flagged

No significant circularity; claims are conditional proposals, not self-referential derivations.

full rationale

The paper's core content is a forward-looking proposal for observational detection of redshift and flux drift with instruments such as SKA1-mid, conditional on stated instrumental stability (ΔF/F ∼ 10^{-6}) and kinematic separation strategies. These are presented as external requirements rather than quantities derived from or fitted to the paper's own equations. No load-bearing step reduces by construction to a self-definition, a fitted input renamed as prediction, or a self-citation chain; the relation between redshift drift and flux drift follows from standard cosmological kinematics without circular closure. The detectability timeline claims rest on unverified technical premises but do not exhibit the enumerated circularity patterns.

Axiom & Free-Parameter Ledger

0 free parameters · 3 axioms · 0 invented entities

The central claims rest on the standard cosmological model predicting the drift magnitudes and on assumptions about future instrument performance and contamination removal, none of which are independently verified in the abstract.

axioms (3)

domain assumption The universe expands according to the standard FLRW model, producing redshift drift of order 10^{-10} to 10^{-9} per decade
Stated as direct consequence of expansion without derivation in the abstract.
domain assumption Kinematic contamination from peculiar velocities can be overcome with the proposed strategies
Mentioned as focus but no details or validation provided.
domain assumption SKA1-mid can achieve flux stability of 10^{-6}
Conditional claim for earlier detection.

pith-pipeline@v0.9.0 · 5817 in / 1478 out tokens · 27559 ms · 2026-05-24T23:52:10.598473+00:00 · methodology

discussion (0)

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

IndisputableMonolith/Cost/FunctionalEquation.lean washburn_uniqueness_aczel unclear

?

unclear
Relation between the paper passage and the cited Recognition theorem.

The redshift drift for FLRW models is given by ż = H0(1+z)−H(z) (eq. 2.1) … ΔFν/Fν = −α Δz/(1+z) (eq. 4.5)
IndisputableMonolith/Foundation/RealityFromDistinction.lean reality_from_one_distinction unclear

?

unclear
Relation between the paper passage and the cited Recognition theorem.

Kinematic contamination … flux stability ΔF/F ∼ 10^{-6}

What do these tags mean?

matches: The paper's claim is directly supported by a theorem in the formal canon.
supports: The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends: The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses: The paper appears to rely on the theorem as machinery.
contradicts: The paper's claim conflicts with a theorem or certificate in the canon.
unclear: Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

24 extracted references · 24 canonical work pages · 17 internal anchors

[1]

Sandage, The Change of Redshift and Apparent Luminosity of Galaxies d ue to the Deceleration of Selected Expanding Universes

A. Sandage, The Change of Redshift and Apparent Luminosity of Galaxies d ue to the Deceleration of Selected Expanding Universes. , Astroph. J. 136 (1962) 319

work page 1962
[2]

Direct Measurement of Cosmological Parameters from the Cosmic Deceleration of Extragalactic Objects

A. Loeb, Direct Measurement of Cosmological Parameters from the Cosm ic Deceleration of Extragalactic Objects, Astroph. J. 499 (1998) L111 [astro-ph/9802122]

work page internal anchor Pith review Pith/arXiv arXiv 1998
[3]

G. C. McVittie, Appendix to The Change of Redshift and Apparent Luminosity o f Galaxies due to the Deceleration of Selected Expanding Universes. , Astroph. J. 136 (1962) 334

work page 1962
[4]

The time evolution of cosmological redshift as a test of dark energy

A. Balbi and C. Quercellini, The time evolution of cosmological redshift as a test of dark energy, Mon. Not. Roy. Astron. Soc. 382 (2007) 1623 [0704.2350]

work page internal anchor Pith review Pith/arXiv arXiv 2007
[5]

Lyman alpha absorbers in motion: consequences of gravitational lensing for the cosmological redshift drift experiment

M. Killedar and G. F. Lewis, Lyα absorbers in motion: consequences of gravitational lensing for the cosmological redshift drift experiment , Mon. Not. Roy. Astron. Soc. 402 (2010) 650 [0910.4580]

work page internal anchor Pith review Pith/arXiv arXiv 2010
[6]

J.-P. Uzan, F. Bernardeau and Y. Mellier, Time drift of cosmological redshifts and its variance , Phys. Rev. D 77 (2008) 021301 [0711.1950]

work page internal anchor Pith review Pith/arXiv arXiv 2008
[7]

Distinguishing Between Void Models and Dark Energy with Cosmic Parallax and Redshift Drift

M. Quartin and L. Amendola, Distinguishing between void models and dark energy with cosm ic parallax and redshift drift , Phys. Rev. D 81 (2010) 043522 [0909.4954]. 1http://gnuplot.info/ 2https://matplotlib.org/ 3https://healpy.readthedocs.io 4https://samreay.github.io/ChainConsumer/ [24] – 12 –

work page internal anchor Pith review Pith/arXiv arXiv 2010
[8]

Redshift propagation equations in the $\beta' \neq 0$ Szekeres models

A. Krasiński and K. Bolejko, Redshift propagation equations in the β ′ ̸=0 Szekeres models , Phys. Rev. D 83 (2011) 083503 [1007.2083]

work page internal anchor Pith review Pith/arXiv arXiv 2011
[9]

Optical drift effects in general relativity

M. Korzyński and J. Kopiński, Optical drift eﬀects in general relativity , Journal of Cosmology and Astro-Particle Physics 2018 (2018) 012 [1711.00584]

work page internal anchor Pith review Pith/arXiv arXiv 2018
[10]

Geometric optics in general relativity using bilocal operators

M. Grasso, M. Korzyński and J. Serbenta, Geometric optics in general relativity using bilocal operators, Phys. Rev. D 99 (2019) 064038 [1811.10284]

work page internal anchor Pith review Pith/arXiv arXiv 2019
[11]

A. G. Kim, E. V. Linder, J. Edelstein and D. Erskine, Giving cosmic redshift drift a whirl , Astroparticle Physics 62 (2015) 195 [1402.6614]

work page internal anchor Pith review Pith/arXiv arXiv 2015
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Haehnelt, S

M. Haehnelt, S. Cristiani, V. D’Odorico, P. Molaro, M. V iel, E. Vanzella et al., CODEX Phase A Science Case . E-ELT PROGRAMME, E-TRE-IOA-573-0001, 2010

work page 2010
[13]

Peculiar velocity effects in high-resolution microwave background experiments

A. Challinor and F. van Leeuwen, Peculiar velocity eﬀects in high-resolution microwave background experiments, Phys. Rev. D 65 (2002) 103001 [astro-ph/0112457]

work page internal anchor Pith review Pith/arXiv arXiv 2002
[14]

Liske, A

J. Liske, A. Grazian, E. Vanzella, M. Dessauges, M. Viel , L. Pasquini et al., E-ELT and the Cosmic Expansion History - A Far Stretch? , The Messenger 133 (2008) 10

work page 2008
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P. E. Dewdney, W. Turner, R. Millenaar, R. McCool, J. Laz io and T. J. Cornwell, SKA1 System baseline design . SKA Oﬃce, 2013

work page 2013
[16]

An Australia telescope survey for CMB anisotropies

R. Subrahmanyan, M. J. Kesteven, R. D. Ekers, M. Sinclai r and J. Silk, An Australia Telescope survey for CMB anisotropies , Mon. Not. Roy. Astron. Soc. 315 (2000) 808 [astro-ph/0002467]

work page internal anchor Pith review Pith/arXiv arXiv 2000
[17]

H. R. Kloeckner, D. Obreschkow, C. Martins, A. Raccanel li, D. Champion, A. L. Roy et al., Real time cosmology - A direct measure of the expansion rate o f the Universe with the SKA , in Advancing Astrophysics with the Square Kilometre Array (AAS KA14), p. 27, Apr, 2015, 1501.03822

work page internal anchor Pith review Pith/arXiv arXiv 2015
[18]

A Virtual Sky with Extragalactic HI and CO Lines for the SKA and ALMA

D. Obreschkow, H. R. Klöckner, I. Heywood, F. Levrier an d S. Rawlings, A Virtual Sky with Extragalactic H I and CO Lines for the Square Kilometre Array a nd the Atacama Large Millimeter/Submillimeter Array , Astroph. J. 703 (2009) 1890 [0908.0983]

work page internal anchor Pith review Pith/arXiv arXiv 2009
[19]

G. F. R. Ellis, Republication of: Relativistic cosmology , General Relativity and Gravitation 41 (2009) 581

work page 2009
[20]

E. V. Linder, Exploring the Expansion History of the Universe , Phys. Rev. Lett. 90 (2003) 091301 [astro-ph/0208512]

work page internal anchor Pith review Pith/arXiv arXiv 2003
[21]

Report of the Dark Energy Task Force

A. Albrecht, G. Bernstein, R. Cahn, W. L. Freedman, J. He witt, W. Hu et al., Report of the Dark Energy Task Force , arXiv e-prints (2006) astro [ astro-ph/0609591]

work page internal anchor Pith review Pith/arXiv arXiv 2006
[22]

Planck Collaboration, P. A. R. Ade, N. Aghanim, M. Arnau d, M. Ashdown, J. Aumont et al., Planck 2015 results. XIII. Cosmological parameters , Astron. Astroph. 594 (2016) A13 [1502.01589]

work page internal anchor Pith review Pith/arXiv arXiv 2015
[23]

Forecast and analysis of the cosmological redshift drift

R. Lazkoz, I. Leanizbarrutia and V. Salzano, Forecast and analysis of the cosmological redshift drift, European Physical Journal C 78 (2018) 11 [1712.07555]

work page internal anchor Pith review Pith/arXiv arXiv 2018
[24]

S. R. Hinton, ChainConsumer, The Journal of Open Source Software 1 (2016) 00045 . – 13 –

work page 2016

[1] [1]

Sandage, The Change of Redshift and Apparent Luminosity of Galaxies d ue to the Deceleration of Selected Expanding Universes

A. Sandage, The Change of Redshift and Apparent Luminosity of Galaxies d ue to the Deceleration of Selected Expanding Universes. , Astroph. J. 136 (1962) 319

work page 1962

[2] [2]

Direct Measurement of Cosmological Parameters from the Cosmic Deceleration of Extragalactic Objects

A. Loeb, Direct Measurement of Cosmological Parameters from the Cosm ic Deceleration of Extragalactic Objects, Astroph. J. 499 (1998) L111 [astro-ph/9802122]

work page internal anchor Pith review Pith/arXiv arXiv 1998

[3] [3]

G. C. McVittie, Appendix to The Change of Redshift and Apparent Luminosity o f Galaxies due to the Deceleration of Selected Expanding Universes. , Astroph. J. 136 (1962) 334

work page 1962

[4] [4]

The time evolution of cosmological redshift as a test of dark energy

A. Balbi and C. Quercellini, The time evolution of cosmological redshift as a test of dark energy, Mon. Not. Roy. Astron. Soc. 382 (2007) 1623 [0704.2350]

work page internal anchor Pith review Pith/arXiv arXiv 2007

[5] [5]

Lyman alpha absorbers in motion: consequences of gravitational lensing for the cosmological redshift drift experiment

M. Killedar and G. F. Lewis, Lyα absorbers in motion: consequences of gravitational lensing for the cosmological redshift drift experiment , Mon. Not. Roy. Astron. Soc. 402 (2010) 650 [0910.4580]

work page internal anchor Pith review Pith/arXiv arXiv 2010

[6] [6]

J.-P. Uzan, F. Bernardeau and Y. Mellier, Time drift of cosmological redshifts and its variance , Phys. Rev. D 77 (2008) 021301 [0711.1950]

work page internal anchor Pith review Pith/arXiv arXiv 2008

[7] [7]

Distinguishing Between Void Models and Dark Energy with Cosmic Parallax and Redshift Drift

M. Quartin and L. Amendola, Distinguishing between void models and dark energy with cosm ic parallax and redshift drift , Phys. Rev. D 81 (2010) 043522 [0909.4954]. 1http://gnuplot.info/ 2https://matplotlib.org/ 3https://healpy.readthedocs.io 4https://samreay.github.io/ChainConsumer/ [24] – 12 –

work page internal anchor Pith review Pith/arXiv arXiv 2010

[8] [8]

Redshift propagation equations in the $\beta' \neq 0$ Szekeres models

A. Krasiński and K. Bolejko, Redshift propagation equations in the β ′ ̸=0 Szekeres models , Phys. Rev. D 83 (2011) 083503 [1007.2083]

work page internal anchor Pith review Pith/arXiv arXiv 2011

[9] [9]

Optical drift effects in general relativity

M. Korzyński and J. Kopiński, Optical drift eﬀects in general relativity , Journal of Cosmology and Astro-Particle Physics 2018 (2018) 012 [1711.00584]

work page internal anchor Pith review Pith/arXiv arXiv 2018

[10] [10]

Geometric optics in general relativity using bilocal operators

M. Grasso, M. Korzyński and J. Serbenta, Geometric optics in general relativity using bilocal operators, Phys. Rev. D 99 (2019) 064038 [1811.10284]

work page internal anchor Pith review Pith/arXiv arXiv 2019

[11] [11]

A. G. Kim, E. V. Linder, J. Edelstein and D. Erskine, Giving cosmic redshift drift a whirl , Astroparticle Physics 62 (2015) 195 [1402.6614]

work page internal anchor Pith review Pith/arXiv arXiv 2015

[12] [12]

Haehnelt, S

M. Haehnelt, S. Cristiani, V. D’Odorico, P. Molaro, M. V iel, E. Vanzella et al., CODEX Phase A Science Case . E-ELT PROGRAMME, E-TRE-IOA-573-0001, 2010

work page 2010

[13] [13]

Peculiar velocity effects in high-resolution microwave background experiments

A. Challinor and F. van Leeuwen, Peculiar velocity eﬀects in high-resolution microwave background experiments, Phys. Rev. D 65 (2002) 103001 [astro-ph/0112457]

work page internal anchor Pith review Pith/arXiv arXiv 2002

[14] [14]

Liske, A

J. Liske, A. Grazian, E. Vanzella, M. Dessauges, M. Viel , L. Pasquini et al., E-ELT and the Cosmic Expansion History - A Far Stretch? , The Messenger 133 (2008) 10

work page 2008

[15] [15]

P. E. Dewdney, W. Turner, R. Millenaar, R. McCool, J. Laz io and T. J. Cornwell, SKA1 System baseline design . SKA Oﬃce, 2013

work page 2013

[16] [16]

An Australia telescope survey for CMB anisotropies

R. Subrahmanyan, M. J. Kesteven, R. D. Ekers, M. Sinclai r and J. Silk, An Australia Telescope survey for CMB anisotropies , Mon. Not. Roy. Astron. Soc. 315 (2000) 808 [astro-ph/0002467]

work page internal anchor Pith review Pith/arXiv arXiv 2000

[17] [17]

H. R. Kloeckner, D. Obreschkow, C. Martins, A. Raccanel li, D. Champion, A. L. Roy et al., Real time cosmology - A direct measure of the expansion rate o f the Universe with the SKA , in Advancing Astrophysics with the Square Kilometre Array (AAS KA14), p. 27, Apr, 2015, 1501.03822

work page internal anchor Pith review Pith/arXiv arXiv 2015

[18] [18]

A Virtual Sky with Extragalactic HI and CO Lines for the SKA and ALMA

D. Obreschkow, H. R. Klöckner, I. Heywood, F. Levrier an d S. Rawlings, A Virtual Sky with Extragalactic H I and CO Lines for the Square Kilometre Array a nd the Atacama Large Millimeter/Submillimeter Array , Astroph. J. 703 (2009) 1890 [0908.0983]

work page internal anchor Pith review Pith/arXiv arXiv 2009

[19] [19]

G. F. R. Ellis, Republication of: Relativistic cosmology , General Relativity and Gravitation 41 (2009) 581

work page 2009

[20] [20]

E. V. Linder, Exploring the Expansion History of the Universe , Phys. Rev. Lett. 90 (2003) 091301 [astro-ph/0208512]

work page internal anchor Pith review Pith/arXiv arXiv 2003

[21] [21]

Report of the Dark Energy Task Force

A. Albrecht, G. Bernstein, R. Cahn, W. L. Freedman, J. He witt, W. Hu et al., Report of the Dark Energy Task Force , arXiv e-prints (2006) astro [ astro-ph/0609591]

work page internal anchor Pith review Pith/arXiv arXiv 2006

[22] [22]

Planck Collaboration, P. A. R. Ade, N. Aghanim, M. Arnau d, M. Ashdown, J. Aumont et al., Planck 2015 results. XIII. Cosmological parameters , Astron. Astroph. 594 (2016) A13 [1502.01589]

work page internal anchor Pith review Pith/arXiv arXiv 2015

[23] [23]

Forecast and analysis of the cosmological redshift drift

R. Lazkoz, I. Leanizbarrutia and V. Salzano, Forecast and analysis of the cosmological redshift drift, European Physical Journal C 78 (2018) 11 [1712.07555]

work page internal anchor Pith review Pith/arXiv arXiv 2018

[24] [24]

S. R. Hinton, ChainConsumer, The Journal of Open Source Software 1 (2016) 00045 . – 13 –

work page 2016