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Evidence for anisotropy of cosmic acceleration

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arxiv 1808.04597 v3 pith:CMLZMTFU submitted 2018-08-14 astro-ph.CO

Jacques Colin , Roya Mohayaee , Mohamed Rameez , Subir Sarkar This is my paper · ORCID
classification astro-ph.CO
keywords mathrmaccelerationanalysisbulkcomponentcosmicdipoleevidence
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abstract

Observations reveal a `bulk flow' in the local Universe which is faster and extends to much larger scales than is expected around a typical observer in the standard $\Lambda$CDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred from observations of objects within the bulk flow. From a maximum-likelihood analysis of the Joint Lightcurve Analysis (JLA) catalogue of Type Ia supernovae we find that the deceleration parameter, in addition to a small monopole, indeed has a much bigger dipole component aligned with the CMB dipole which falls exponentially with redshift $z$: $q_0 = q_\mathrm{m} + \vec{q}_\mathrm{d}.\hat{n}\exp(-z/S)$. The best fit to data yields $q_\mathrm{d} = -8.03$ and $S = 0.0262~(\Rightarrow d \sim 100~\mathrm{Mpc})$, rejecting isotropy ($q_\mathrm{d} = 0$) with $3.9\sigma$ statistical significance, while $q_\mathrm{m} = -0.157$ and consistent with no acceleration ($q_\mathrm{m} = 0$) at $1.4\sigma$. Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of `dark energy' in the Universe.

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Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. A Quantitative Framework for Testing the Hubble Tension in a Bianchi Type I Cosmological Background

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    gr-qc 2025-01 conditional novelty 5.0 of 10

    A constant correlation between external and internal expansion rates yields exact Bianchi type-I solutions whose effective dark energy mimics a cosmological constant at late times and a steady-state universe for negat...

  3. Hubble tension: a short review of theoretical explanations

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    A comprehensive review finds no theoretical Hubble-tension solution yet passes all consistency tests; new early-dark-energy chains reach high H0 only when the SH0ES calibration is added.

  4. Anisotropic power-law inflation for the S\'aez-Ballester theory non-minimally coupled to a vector field

    gr-qc 2025-02 conditional novelty 4.0 of 10

    A stable anisotropic inflationary solution exists in the Saez-Ballester theory, but it is equivalent to the known Kanno-Soda-Watanabe solution and has a too-large tensor-to-scalar ratio.

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