The Local Perspective on the Hubble Tension: Local Structure Does Not Impact Measurement of the Hubble Constant

Kenworthy, W. D.; Scolnic, Dan; Riess, Adam G.

doi:10.3847/1538-4357/ab0ebf

Cited by 165 publications

(113 citation statements)

References 40 publications

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“…The expected magnitude of such a shift in a standard ΛCDM model given expected density fluctuations is on the order of ∼ 10 −5 (see Wojtak et al 2015 , Figs 1-3). Kenworthy et al (2019) summarise the recent evidence for a local overdensity or void from the supernova data, concluding that there is no evidence for a significant local void, and any local density fluctuation on scales larger than 69 Mpc h −1 must have a density contrast δ = (ρ −ρ)/ρ within |δ| < 27%.…”

Section: Density Fluctuationsmentioning

confidence: 95%

Can redshift errors bias measurements of the Hubble Constant?

Davis

Hinton

Howlett

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Redshifts have been so easy to measure for so long that we tend to neglect the fact that they too have uncertainties and are susceptible to systematic error. As we strive to measure cosmological parameters to better than 1% it is worth reviewing the accuracy of our redshift measurements. Surprisingly small systematic redshift errors, as low as 10 −4 , can have a significant impact on the cosmological parameters we infer, such as H 0 . Here we investigate an extensive (but not exhaustive) list of ways in which redshift estimation can go systematically astray. We review common theoretical errors, such as adding redshifts instead of multiplying by (1 + z); using v = cz; and using only cosmological redshift in the estimates of luminosity and angular-diameter distances. We consider potential observational errors, such as rest wavelength precision, air to vacuum conversion, and spectrograph wavelength calibration. Finally, we explore physical effects, such as peculiar velocity corrections, galaxy internal velocities, gravitational redshifts, and overcorrecting within a bulk flow. We conclude that it would be quite easy for small systematic redshift errors to have infiltrated our data and be impacting our cosmological results. While it is unlikely that these errors are large enough to resolve the current H 0 tension, it remains possible, and redshift accuracy may become a limiting factor in near future experiments. With the enormous efforts going into calibrating the vertical axis of our plots (standard candles, rulers, clocks, and sirens) we argue that it is now worth paying a little more attention to the horizontal axis (redshifts).

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Section: Density Fluctuationsmentioning

confidence: 95%

Can redshift errors bias measurements of the Hubble Constant?

Davis

Hinton

Howlett

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…uncertainty of the locally determined H 0 to the point that the tension is alleviated [106][107][108][109][110], or that local measurements might be biased by the presence of a local void [111][112][113][114][115] (see however e.g. [116,117] for criticisms on both these possibilities). [134]:…”

Section: Extended Interacting Dark Energy Modelsmentioning

confidence: 99%

Nonminimal dark sector physics and cosmological tensions

et al. 2020

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We explore whether non-standard dark sector physics might be required to solve the existing cosmological tensions. The properties we consider in combination are: (a) an interaction between the dark matter and dark energy components, and (b) a dark energy equation of state w different from that of the canonical cosmological constant w = −1. In principle, these two parameters are independent. In practice, to avoid early-time, superhorizon instabilities, their allowed parameter spaces are correlated. Moreover, a clear degeneracy exists between these two parameters in the case of Cosmic Microwave Background (CMB) data. We analyze three classes of extended interacting dark energy models in light of the 2019 Planck CMB results and Cepheid-calibrated local distance ladder H0 measurements of Riess et al. (R19), as well as recent Baryon Acoustic Oscillation (BAO) and Type Ia Supernovae (SNeIa) distance data. We find that in quintessence coupled dark energy models, where w > −1, the evidence for a non-zero coupling between the two dark sectors can surpass the 5σ significance. Moreover, for both Planck+BAO or Planck+SNeIa, we found a preference for w > −1 at about three standard deviations. Quintessence models are, therefore, in excellent agreement with current data when an interaction is considered. On the other hand, in phantom coupled dark energy models, there is no such preference for a non-zero dark sector coupling. All the models we consider significantly raise the value of the Hubble constant easing the H0 tension. In the interacting scenario, the disagreement between Planck+BAO and R19 is considerably reduced from 4.3σ in the case of ΛCDM to about 2.5σ. The addition of low-redshift BAO and SNeIa measurements leaves, therefore, some residual tension with R19 but at a level that could be justified by a statistical fluctuation. We conclude that non-minimal dark energy cosmologies, such as coupled quintessence or phantom models, may soften the existing cosmological tensions. * eleonora.divalentino@manchester.ac.uk † alessandro.melchiorri@roma1.infn.it ‡ omena@ific.uv.es § sunny.vagnozzi@ast.cam.ac.uk 1 In Ref. [15,16] the reader can find complete reviews comparing the CMB and local determinations of H 0 .

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“…A recent work of Shanks et al (2019) argues that the combination of local inhomogeneity effect together with the re-calibration of Cepheids and local SN Ia distances using the recent parallax measurements from Gaia mission, is sufficient to completely remove the tension. Kenworthy et al (2019) (hereafter KSR19) find that any inhomogeneity with contrast > 20% is strongly inconsistent with SN Ia data, consequently reassuring the ability to measure the distance and Hubble constant with locally calibrated SN Ia to a 1% precision.…”

Section: Introductionmentioning

confidence: 98%

“…The results of KBC13 and WH14 go against the standard cosmological paradigm and the assumption of large-scale homogeneity. In fact, indications for a few hundred Mpc large local underdensity encouraged renewed popularity of void models based on Lemaître-Tolman-Bondi (LTB) metric, also motivated as a remedy for the H 0 tension (Moffat 2016; Tokutake et al 2018;Hoscheit & Barger 2017;Shanks et al 2019;Kenworthy et al 2019) and even as a possible explanation for the CMB cold spot (Szapudi et al 2015). Contrasting the homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker (FLRW) models, the LTB metric (Lemaître 1927(Lemaître , 1933Tolman 1934;Bondi 1947) describes an isotropic but inhomogeneous dust system, which on cosmological scales can be used for studying cold dark matter density distribution.…”

Section: Introductionmentioning

confidence: 99%

Exploring the evidence for a large local void with supernovae Ia data

Luković

Haridasu

Vittorio

2019

Monthly Notices of the Royal Astronomical Society

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In the present work we utilise the most recent publicly available SN Ia compilations and implement a well formulated cosmological model based on LTB metric in presence of cosmological constant Λ (ΛLTB) to test for signatures of large local inhomogeneities at z ≤ 0.15. Local underdensities in this redshift range have been previously found based on luminosity density data and galaxy number counts. Our main constraints on the possible local void using the Pantheon SN Ia dataset are -redshift size of z size = 0.068 +0.021 −0.030 and density contrast of δΩ 0 /Ω 0 = −10.5 +9.3 −7.4 % in 68% confidence intervals. Investigating the possibility to alleviate the tension between the measurements of present expansion rate H 0 , coming from calibrated local SN Ia and high-z CMB data, we confirm previous findings that large local void alone is a very unlikely explanation for the ∼ 9% disagreement between the two estimates. However, constraints from our SN Ia analysis inside 1σ confidence regions of z size − δΩ 0 /Ω 0 plane allow a void of e.g. z size = 0.075 (320 h 70 −1 Mpc) and δΩ 0 /Ω 0 = −20%. Fitting Pantheon SN Ia from 0.023 < z < 0.15 range, we find a 1.1% shift towards lower H 0 value for ΛLTB model compared to model-independent method with Taylor expanded distance formula. Analysing luminosity density data with ΛLTB model yields constraint on contrast of large isotropic void δΩ 0 /Ω 0 = −51.9 ± 6.3%, which is in ∼ 4σ tension with SN Ia results. More data is necessary to better constrain the local matter density profile and understand the disagreement between SN Ia and luminosity density samples.

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The Local Perspective on the Hubble Tension: Local Structure Does Not Impact Measurement of the Hubble Constant

Cited by 165 publications

References 40 publications

Can redshift errors bias measurements of the Hubble Constant?

Can redshift errors bias measurements of the Hubble Constant?

Nonminimal dark sector physics and cosmological tensions

Exploring the evidence for a large local void with supernovae Ia data

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