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251
Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for . . .
, 2007
"... A simple cosmological model with only six parameters (matter density, Ωmh 2, baryon density, Ωbh 2, Hubble Constant, H0, amplitude of fluctuations, σ8, optical ..."
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Cited by 379 (7 self)
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A simple cosmological model with only six parameters (matter density, Ωmh 2, baryon density, Ωbh 2, Hubble Constant, H0, amplitude of fluctuations, σ8, optical
Modified Gravity and Cosmology
, 2012
"... In this review we present a thoroughly comprehensive survey of recent work on modi-fied theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f(R), general higher-order theo ..."
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Cited by 28 (0 self)
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In this review we present a thoroughly comprehensive survey of recent work on modi-fied theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f(R), general higher-order theories, Hořava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Pa-rameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and stu-dents in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.
High Resolution Asymptotics for the Angular Bispectrum”, Annals of Statistics, forthcoming Park, C.-G. (2004) “Non-Gaussian Signatures in the Temperature Fluctuation Observed by the Wilkinson Microwave Anisotropy Probe
- Cosmological Physics, Cambridge University
, 2005
"... In this paper, we study the asymptotic behaviour of the angular bispectrum of spherical random fields. Here, the asymptotic theory is developed in the framework of fixed-radius fields, which are observed with increasing resolution as the sample size grows. The results we present are then exploited i ..."
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Cited by 24 (13 self)
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In this paper, we study the asymptotic behaviour of the angular bispectrum of spherical random fields. Here, the asymptotic theory is developed in the framework of fixed-radius fields, which are observed with increasing resolution as the sample size grows. The results we present are then exploited in a set of procedures aimed at testing non-Gaussianity; for these statistics, we are able to show convergence to functionals of standard Brownian motion under the null hypothesis. Analytic results are also presented on the behaviour of the tests in the presence of a broad class of non-Gaussian alternatives. The issue of testing for non-Gaussianity on spherical random fields has recently gained an enormous empirical importance, especially in connection with the statistical analysis of Cosmic Microwave Background radiation.
Modified Newtonian dynamics (MOND): Observational phenomenology and relativistic extensions
- Living Reviews in Relativity
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Scale Dependent Local Non-Gaussianity from Loops, arXiv:0909.2040 [astro-ph.CO
"... Abstract: We analyze multi-field inflationary systems which yield strongly scale dependent non-Gaussianity with a shape that is very close to the local shape. As in usual multi-field models, the non-Gaussianity arises from the non-linear transfer of scalar field fluctuations to curvature perturbatio ..."
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Abstract: We analyze multi-field inflationary systems which yield strongly scale dependent non-Gaussianity with a shape that is very close to the local shape. As in usual multi-field models, the non-Gaussianity arises from the non-linear transfer of scalar field fluctuations to curvature perturbations. Here we consider models in which higher order terms (loops) dominate over the lowest order source of nonlinearity. The magnitude of non-Gaussianity depends on an infrared cutoff which is determined by our observational probes measuring non-Gaussianity. In our models, the running is positive and large (nNG ∼ 0.2) on CMB scales. The magnitude of the bispectrum is maximally of order O(100), and grows on small scales. This can lead
Exploring the superimposed oscillations parameter space
- JCAP 0501 (2005) 007, [hep-ph/0405249
"... The space of parameters characterizing an inflationary primordial power spectrum with small superimposed oscillations is explored using Monte Carlo methods. The most interesting region corresponding to high frequency oscillations is included in the analysis. The oscillations originate from some new ..."
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Cited by 16 (7 self)
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The space of parameters characterizing an inflationary primordial power spectrum with small superimposed oscillations is explored using Monte Carlo methods. The most interesting region corresponding to high frequency oscillations is included in the analysis. The oscillations originate from some new physics taking place at the beginning of the inflationary phase and characterized by the new energy scale Mc. It is found that the standard slow-roll model remains the most probable one given the first year WMAP data. At the same time, the oscillatory models better fit the data on average, which is consistent with previous works on the subject. This is typical of a situation where volume effects in the parameter space play a significant role. Then, we find the amplitude of the oscillations to be less than 22 % of the mean amplitude and the new scale Mc to be such that H/Mc < 6.6 × 10 −4 at 1σ level, where H is the scale of inflation. PACS numbers: 98.80.Cq, 98.70.VcExploring the Superimposed Oscillations Parameter Space 2 1.
Robust Neutrino Constraints by Combining Low Redshift Observations with the CMB
, 910
"... Abstract. We illustrate how recently improved low-redshift cosmological measurements can tighten constraints on neutrino properties. In particular we examine the impact of the assumed cosmological model on the constraints. We first consider the new HST H0 = 74.2±3.6 measurement by Riess et al. (2009 ..."
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Cited by 15 (1 self)
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Abstract. We illustrate how recently improved low-redshift cosmological measurements can tighten constraints on neutrino properties. In particular we examine the impact of the assumed cosmological model on the constraints. We first consider the new HST H0 = 74.2±3.6 measurement by Riess et al. (2009) and
Quasi-single field inflation and non-Gaussianities
- JCAP 1009, 027 (2010) [arXiv:0911.3380 [hep-th
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Constraining dark energy anisotropic stress. arXiv:0708.0830 [astro-ph
, 2007
"... Abstract. We investigate the possibility of using cosmological observations to probe and constrain an imperfect dark energy fluid. We consider a general parameterization of the dark energy component accounting for an equation of state, speed of sound and viscosity. We use present and future data fro ..."
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Cited by 13 (7 self)
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Abstract. We investigate the possibility of using cosmological observations to probe and constrain an imperfect dark energy fluid. We consider a general parameterization of the dark energy component accounting for an equation of state, speed of sound and viscosity. We use present and future data from the cosmic microwave background radiation (CMB), large scale structures and supernovae type Ia. We find that both the speed of sound and viscosity parameters are difficult to nail down with the present cosmological data. Also, we argue that it will be hard to improve the constraints significantly with future CMB data sets. The implication is that a perfect fluid description might ultimately turn out to be a phenomenologically sufficient description of all the observational consequences of dark energy. The fundamental lesson is however that even then one cannot exclude, by appealing to observational evidence alone, the possibility of imperfectness in dark energy. PACS numbers: 98.80.-k,98.80.JkConstraining Dark Energy Anisotropic Stress 2 1.
