The local hole: a galaxy underdensity covering 90 per cent of sky to ≈200 Mpc

Wong, Jonathan; Shanks, T.; Metcalfe, N.; Whitbourn, J. R.

doi:10.1093/mnras/stac396

Cited by 21 publications

(12 citation statements)

References 49 publications

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“…Another possibility is that we are located in an underdense region of the Universe. This is (at least to some degree) supported by data (Keenan et al 2013;Frith et al 2003;Whitbourn & Shanks 2014;Böhringer et al 2020;Wong et al 2022) and would result in a locally increased expansion rate compared with the cosmological background (see e.g. Sundell et al 2015), potentially explaining the higher value for H 0 obtained from local observations by the SH0ES team.…”

Section: Introductionmentioning

confidence: 58%

Impact of symmetron screening on the Hubble tension: new constraints using cosmic distance ladder data

Högås¹,

Mörtsell²

2023

Preprint

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Fifth forces are ubiquitous in modified theories of gravity. To be compatible with observations, such a force must be screened on solar-system scales but may still give a significant contribution on galactic scales. If this is the case, the fifth force can influence the calibration of the cosmic distance ladder, hence changing the inferred value of the Hubble constant H 0 . In this paper, we analyze symmetron screening and show that it generally increases the Hubble tension. On the other hand, by doing a full statistical analysis, we show that cosmic distance ladder data are able to constrain the theory to a level competitive with solar-system tests -currently the most constraining tests of the theory. For the standard coupling case, the constraint on the symmetron Compton wavelength is λ C 2.5 Mpc. Thus, distance ladder data constitutes a novel and powerful way of testing this, and similar, types of theories.

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Section: Introductionmentioning

confidence: 58%

Impact of symmetron screening on the Hubble tension: new constraints using cosmic distance ladder data

Högås¹,

Mörtsell²

2023

Preprint

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“…1 and allow for underdensities and mild overdensities up to |δ 0 | = 1. Since galaxy surveys indicate the potential presence of a local void [11,[13][14][15], more pronounced overdensities are disfavoured on the scales of interest, as the results in C21 also indicate.…”

Section: Numerical Investigationmentioning

confidence: 83%

A Cosmological Underdensity Does Not Solve the Hubble Tension

Castello,

Högås,

Mörtsell

2021

Preprint

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A potential solution to the Hubble tension is the hypothesis that the Milky Way is located near the center of a matter underdensity. We model this scenario through the Lemaître-Tolman-Bondi formalism with the inclusion of a cosmological constant (ΛLTB) and consider a generalized Gaussian parametrization for the matter density profile. We constrain the underdensity and the background cosmology with a combination of data sets: the Pantheon Sample of type Ia supernovae (both the full catalogue and a redshift-binned version of it), a collection of baryon acoustic oscillations data points and the distance priors extracted from the latest Planck data release. The analysis with the binned supernovae suggests a preference for a −13% density drop with a size of approximately 300 Mpc, interestingly matching the prediction for the so-called KBC void already identified on the basis of independent analyses using galaxy distributions. The constraints obtained with the full Pantheon Sample are instead compatible with a homogeneous cosmology and we interpret this radically different result as a cautionary tale about the potential bias introduced by employing a binned supernova data set. We quantify the level of improvement on the Hubble tension by analyzing the constraints on the B-band absolute magnitude of the supernovae, which provides the calibration for the local measurements of H 0 . Since no significant difference is observed with respect to an analogous fit performed with a standard ΛCDM cosmology, we conclude that the potential presence of a local underdensity does not resolve the tension and does not significantly degrade current supernova constraints on H 0 .

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“…The KBC void (discussed also in [716]) rules out ΛCDM cosmology at 6.04σ [93] based on a comparison to the Millennium XXL (MXXL) simulation [717]. This conclusion is very robust because the length scale corresponds to the linear regime of ΛCDM, where the density fluctuations are expected to be only a few percent.…”

Section: The Kbc Void and Hubble Tensionmentioning

confidence: 92%

“…This would still not explain the KBC void, but in principle we do not expect a correct theory to explain all the data as some of the many published observational results are very likely incorrect. While the detection of the KBC void seems very secure [716], its exact properties are somewhat uncertain. It could be argued that slightly increasing the uncertainties would reduce the 6.04σ tension with ΛCDM [93] to < 5σ, thereby gaining consistency with any theory that has the same predictions as ΛCDM at scales 100 Mpc.…”

Section: Towards a Relativistic Modelmentioning

confidence: 99%

From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity

Banik

Zhao

2022

Symmetry

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Astronomical observations reveal a major deficiency in our understanding of physics—the detectable mass is insufficient to explain the observed motions in a huge variety of systems given our current understanding of gravity, Einstein’s General theory of Relativity (GR). This missing gravity problem may indicate a breakdown of GR at low accelerations, as postulated by Milgromian dynamics (MOND). We review the MOND theory and its consequences, including in a cosmological context where we advocate a hybrid approach involving light sterile neutrinos to address MOND’s cluster-scale issues. We then test the novel predictions of MOND using evidence from galaxies, galaxy groups, galaxy clusters, and the large-scale structure of the universe. We also consider whether the standard cosmological paradigm (LCDM) can explain the observations and review several previously published highly significant falsifications of it. Our overall assessment considers both the extent to which the data agree with each theory and how much flexibility each has when accommodating the data, with the gold standard being a clear a priori prediction not informed by the data in question. Our conclusion is that MOND is favoured by a wealth of data across a huge range of astrophysical scales, ranging from the kpc scales of galactic bars to the Gpc scale of the local supervoid and the Hubble tension, which is alleviated in MOND through enhanced cosmic variance. We also consider several future tests, mostly at scales much smaller than galaxies.

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The local hole: a galaxy underdensity covering 90 per cent of sky to ≈200 Mpc

Cited by 21 publications

References 49 publications

Impact of symmetron screening on the Hubble tension: new constraints using cosmic distance ladder data

Impact of symmetron screening on the Hubble tension: new constraints using cosmic distance ladder data

A Cosmological Underdensity Does Not Solve the Hubble Tension

From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity

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