Results 1  10
of
251
ThreeYear 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 ..."
Abstract

Cited by 379 (7 self)
 Add to MetaCart
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 modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, ScalarTensor, EinsteinAether, and Bimetric theories, as well as TeVeS, f(R), general higherorder theo ..."
Abstract

Cited by 28 (0 self)
 Add to MetaCart
In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, ScalarTensor, EinsteinAether, and Bimetric theories, as well as TeVeS, f(R), general higherorder theories, HořavaLifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including KaluzaKlein, RandallSundrum, DGP, and higher codimension braneworlds. We also review attempts to construct a Parameterised PostFriedmannian 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 students in cosmology and gravitational physics, as well as a selfcontained, comprehensive and uptodate introduction to the subject as a whole.
High Resolution Asymptotics for the Angular Bispectrum”, Annals of Statistics, forthcoming Park, C.G. (2004) “NonGaussian 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 fixedradius fields, which are observed with increasing resolution as the sample size grows. The results we present are then exploited i ..."
Abstract

Cited by 24 (13 self)
 Add to MetaCart
(Show Context)
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 fixedradius 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 nonGaussianity; 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 nonGaussian alternatives. The issue of testing for nonGaussianity 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
"... ar ..."
(Show Context)
Scale Dependent Local NonGaussianity from Loops, arXiv:0909.2040 [astroph.CO
"... Abstract: We analyze multifield inflationary systems which yield strongly scale dependent nonGaussianity with a shape that is very close to the local shape. As in usual multifield models, the nonGaussianity arises from the nonlinear transfer of scalar field fluctuations to curvature perturbatio ..."
Abstract

Cited by 16 (1 self)
 Add to MetaCart
(Show Context)
Abstract: We analyze multifield inflationary systems which yield strongly scale dependent nonGaussianity with a shape that is very close to the local shape. As in usual multifield models, the nonGaussianity arises from the nonlinear 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 nonGaussianity depends on an infrared cutoff which is determined by our observational probes measuring nonGaussianity. 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, [hepph/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 ..."
Abstract

Cited by 16 (7 self)
 Add to MetaCart
(Show Context)
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 slowroll 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 lowredshift 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 ..."
Abstract

Cited by 15 (1 self)
 Add to MetaCart
(Show Context)
Abstract. We illustrate how recently improved lowredshift 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
Quasisingle field inflation and nonGaussianities
 JCAP 1009, 027 (2010) [arXiv:0911.3380 [hepth
"... ar ..."
Constraining dark energy anisotropic stress. arXiv:0708.0830 [astroph
, 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 ..."
Abstract

Cited by 13 (7 self)
 Add to MetaCart
(Show Context)
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.