Cosmological Observations in a Local Void

Moffat, J. W.; Tatarski, D. C.

doi:10.1086/176365

Cited by 56 publications

(90 citation statements)

References 27 publications

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“…As above, on taking the curl of the resulting equation we obtain a simple constraint which can generically only be satisfied if a 1 vanishes. Another way to prove that necessarily a 1 = 0, is to check that there is no combination of the two possible nontrivial terms in a cubic action, 20) which can compensate the change of (3.1) under δ 1 B µν = H λ µν ǫ λ , i.e., which solves δ 1 L 2 = −δ 0 L 3 . Having proven the triviality of all possible first order deformations, an inductive argument using (3.16) exactly as in [15] shows that…”

Section: Geometric Theoriesmentioning

confidence: 99%

“…Equation (5.14) can formally be solved by successive iterations in powers of κ 2 , 19) where, for simplicity, we shall consider a flat background metric, G 20) one gets To quote some numbers, the dimensionless quantity α 5 = g 2 5 /(κ 2 m 2 N ) (where m N denotes, say, one atomic mass unit) was found to be bounded by < ∼ 10 −3 when µ −1 = 1 m, < ∼ 10 −5 when µ −1 = 1 km, and < ∼ 10 −8 for µ −1 > 10 4 km (assuming a coupling to baryon number, i.e. θ 5 = 0 in (5.2); see [27] for precise numbers, the dependence on the mixing angle and further references).…”

Section: )mentioning

confidence: 99%

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Nonsymmetric gravity theories: Inconsistencies and a cure

1993

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Motivated by the apparent dependence of string σ-models on the sum of spacetime metric and antisymmetric tensor fields, we reconsider gravity theories constructed from a nonsymmetric metric. We first show that all such "geometrical" theories homogeneous in second derivatives violate standard physical requirements: ghost-freedom, absence of algebraic inconsistencies or continuity of degree-of-freedom content. This no-go result applies in particular to the old unified theory of Einstein and its recent avatars. However, we find that the addition of nonderivative, "cosmological" terms formally restores consistency by giving a mass to the antisymmetric tensor field, thereby transmuting it into a fifth-force-like massive vector but with novel possible matter couplings. The resulting macroscopic models also exhibit "van der Waals"-type gravitational effects, and may provide useful phenomenological foils to general relativity.

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Section: Geometric Theoriesmentioning

confidence: 99%

Section: )mentioning

confidence: 99%

Nonsymmetric gravity theories: Inconsistencies and a cure

1993

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“…These models require an as yet unknown mechanism for their formation, probably requiring something unusual at the start of inflation to create a model close to spherically symmetric on Hubble scales. They also are in (dire) need of an explanation for the antiCopernican fine tuning that exists: we have to be within tens of Mpc of the centre of spherical symmetry of the 1 We have in mind the 'very big void models' which vary gently over Gpc scales (e.g., [2,13,48]). The density profile reaches full width at half maximum around the Hubble scale.…”

Section: Introductionmentioning

confidence: 99%

The cosmic microwave background in an inhomogeneous universe

Clarkson¹,

Regis²

2011

J. Cosmol. Astropart. Phys.

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The dimming of Type Ia supernovae could be the result of Hubble-scale inhomogeneity in the matter and spatial curvature, rather than signaling the presence of a dark energy component. A key challenge for such models is to fit the detailed spectrum of the cosmic microwave background (CMB). We present a detailed discussion of the small-scale CMB in an inhomogeneous universe, focusing on spherically symmetric 'void' models. We allow for the dynamical effects of radiation while analyzing the problem, in contrast to other work which inadvertently fine tunes its spatial profile. This is a surprisingly important effect and we reach substantially different conclusions. Models which are open at CMB distances fit the CMB power spectrum without fine tuning; these models also fit the supernovae and local Hubble rate data which favour a high expansion rate. Asymptotically flat models may fit the CMB, but require some extra assumptions. We argue that a full treatment of the radiation in these models is necessary if we are to understand the correct constraints from the CMB, as well as other observations which rely on it, such as spectral distortions of the black body spectrum, the kinematic Sunyaev-Zeldovich effect or the Baryon Acoustic Oscillations.

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“…The existence of the Universe's large-scale structure of voids and superclusters suggests the voids are underdense regions that have been decelerated less due to gravity so they have ballooned up into roughly spherical regions without undergoing structure formation, while the superclusters are overdense regions where gravity has overcome the Universe's expansion such that they have reached turnaround and collapsed in their densest regions. Moffat and Tatarski (1995) looked at what observational effects we would theoretically observe if we were to inhabit a local void. Via comparison of their theoretical curves with a survey of redshift-distance determinations, they found the data were better fit by a model with a local void than by a homogeneous universe.…”

Section: Introductionmentioning

confidence: 99%

Anisotropy in the Hubble constant as observed in the HST extragalactic distance scale key project results

McClure

Dyer

2007

New Astronomy

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Based on general relativity, it can be argued that deviations from a uniform Hubble flow should be thought of as variations in the Universe's expansion velocity field, rather than being thought of as peculiar velocities with respect to a uniformly expanding space. The aim of this paper is to use the observed motions of galaxies to map out variations in the Universe's expansion, and more importantly, to investigate whether real variations in the Hubble expansion are detectable given the observational uncertainties. All-sky maps of the observed variation in the expansion are produced using measurements obtained along specific lines-of-sight and smearing them across the sky using a Gaussian profile. A map is produced for the final results of the HST Extragalactic Distance Scale Key Project for the Hubble constant, a comparison map is produced from a set of essentially independent data, and Monte Carlo techniques are used to analyse the statistical significance of the variation in the maps. A statistically significant difference in expansion rate of 9 km s −1 Mpc −1 is found to occur across the sky. Comparing maps of the sky at different distances appears to indicate two distinct sets of extrema with even stronger statistically significant variations. Within our supercluster, variations tend to occur near the supergalactic plane, and beyond our supercluster, variations tend to occur away from the supergalactic plane. Comparison with bulk flow studies shows some concordance, yet also suggests the bulk flow studies may suffer confusion, failing to discern the influence of multiple perturbations.

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Cosmological Observations in a Local Void

Cited by 56 publications

References 27 publications

Nonsymmetric gravity theories: Inconsistencies and a cure

Nonsymmetric gravity theories: Inconsistencies and a cure

The cosmic microwave background in an inhomogeneous universe

Anisotropy in the Hubble constant as observed in the HST extragalactic distance scale key project results

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