Modeling the WMAP large-angle anomalies as an effect of a local density inhomogeneity

He, Liping; Guo, Qi

doi:10.1088/1674-4527/10/2/002

Cited by 7 publications

(3 citation statements)

References 38 publications

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“…phase [33]), etc. There have also been attempts at providing various other explanations such as nonprimordial causes [34][35][36][37][38] and those based on systematic effects [39,40] as well as attempts to relate this low power to other anomalies in the CMB (see e.g. [41]).…”

Section: Introductionmentioning

confidence: 99%

“…hybrid models of inflation[25], multi-field inflation[26], inflation which takes place in two stages[27][28][29] just enough inflation[30,31] which could take place in modified gravity theories[32] or preceded by a fast roll phase[33]), etc. There have also been attempts at providing various other explanations such as non-primordial causes[34][35][36][37][38] and those based on systematic effects[39,40] as well as attempts to relate this low power to other anomalies in the CMB (see e.g [41]…”

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confidence: 99%

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Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum

Das

Goswami

Prasad

et al. 2015

J. Cosmol. Astropart. Phys.

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We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a pre-inflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We initially discuss in detail the issues relevant to our scenario of a pre-inflationary radiation dominated era and then obtain the scalar power spectrum for this scenario. We find that the power spectrum is free from infrared divergences. We then use the WMAP and Planck data to determine the constraints on the inflaton comoving 'temperature' and on the duration of inflation. We find that the best fit value of the duration of inflation is less than 1 e-folding more than what is required to solve cosmological problems, while only an upper bound on the inflaton temperature can be obtained.1 Other attempts to explain the low power at low CMB multipoles involve non-trivial topologies of the universe [14][15][16][17][18][19][20][21][22], bouncing cosmologies [23,24], various inflationary scenarios (e.g. hybrid models of inflation [25], multi-field inflation [26], inflation which takes place in two stages [27][28][29] just enough inflation [30,31] which could take place in modified gravity theories [32] or preceded by a fast roll

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum

Das

Goswami

Prasad

et al. 2015

J. Cosmol. Astropart. Phys.

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show abstract

“…Measurements of polarization provide possible indications on signatures of cosmological anisotropy (see [15], [16] and [17]). Also, it may be signal of a nontrivial topology (see [18], [19], [20] and [21]). In the literature, several proposals are advanced to account for those anomalies (see [13], [22] and [23]).…”

Section: Introductionmentioning

confidence: 99%

Improved solution to CMB quadrupole problem using ellipsoidal Universes with Chaplygin gas

Lamine¹,

Mebarki²

2020

Preprint

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A Universe containing uniform magnetic fields, strings, or domain walls is shown to have an ellipsoidal expansion. This case has motivations from observational cosmology especially the anomaly concerning the low quadrupole amplitude compared to the best-fit ΛCDM prediction in Planck data. It is shown that a Universe with eccentricity at decoupling of order 10 −2 can reduce the quadrupole amplitude without affecting higher multipoles of the angular power spectrum of the temperature anisotropy. We study the evolution of ellipsoidal Universes using dynamical system techniques for the first time. The determined critical points vary between saddle and past attractors depending on dark energy state equation parameter wΛ, with no future attractors. Important results are shown with numerical integrations of this dynamical system done using several initial conditions. For instance, a tendency for high expansion differences between planar and perpendicular axes is observed which contradicts previous assumption on the evolution behaviour of ellipsoid Universes. Considering dark energy as a Chaplygin gas solves this contradiction by controlling cosmic shear evolution.

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Light propagation in statistically homogeneous and isotropic universes with general matter content

Räsänen

2010

J. Cosmol. Astropart. Phys.

211

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We derive the relationship of the redshift and the angular diameter distance to the average expansion rate for universes which are statistically homogeneous and isotropic and where the distribution evolves slowly, but which have otherwise arbitrary geometry and matter content. The relevant average expansion rate is selected by the observable redshift and the assumed symmetry properties of the spacetime. We show why light deflection and shear remain small. We write down the evolution equations for the average expansion rate and discuss the validity of the dust approximation.

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Modeling the WMAP large-angle anomalies as an effect of a local density inhomogeneity

Cited by 7 publications

References 38 publications

Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum

Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum

Improved solution to CMB quadrupole problem using ellipsoidal Universes with Chaplygin gas

Light propagation in statistically homogeneous and isotropic universes with general matter content

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