نتایج جستجو برای: cosmic microwave background cmb
تعداد نتایج: 905952 فیلتر نتایج به سال:
We review the theory of the temperature anisotropy and polarization of the cosmic microwave background (CMB) radiation, and describe what we have learned from current CMB observations. In particular, we discuss how the CMB is being used to provide precise measurements of the composition and geometry of the observable universe, and to constrain the physics of the early universe. We also briefly ...
The improved data on the cosmic microwave background (CMB) anisotropy allows a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that the CMB favors a significant contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and has a large spectral index (niso ∼ 3)....
Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We deve...
We review the role of the temperature anisotropies and polarization of the cosmic microwave background (CMB) radiation in constraining the cosmological model. We put particular emphasis on the major milestones that have been passed, and CMB constraints on early-universe physics. We also look ahead, surveying what we hope to learn from the next generation of instruments targeting the small-scale...
4 1 Standard framework 5 1.1 Big bang models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 The cosmic microwave background . . . . . . . . . . . . . . . . . . 10 2 Characterizing early Universe fluctuations 15 2.1 Density fluctuations . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2 CMB temperature fluctuations . . . . . . . . . . . . . . . . . . . . . 18 2.3 Fluctua...
I’m a third year Ph.D. student in the Physics department working for Adrian Lee. I work on the data analysis pipeline for the POLARBEAR Cosmic Microwave Background (CMB) experiment and I am interested in the computational problems posed by the size and complexity of the datasets that will be produced by the next generation of CMB experiments. I’m also willing to work on something completely unr...
I review the general aspects of cosmological parameter estimation from observations of the cosmic microwave background (CMB) temperature anisotropies in the framework of inflationary adiabatic models. The most recent CMB datasets are starting to give good constraints on the relevant parameters of inflationary adiabatic models. They point toward a model consistent with the basic predictions of i...
We consider the problem of the interpolation of irregularly spaced spatial data, applied to observation of Cosmic Microwave Background (CMB) anisotropies. The well-known interpolation methods and kriging are compared to the binning method which serves as a reference approach. We analyse kriging versus binning results for different resolutions and noise level in the original data. Most of the ti...
Wilkinson Microwave Anisotropy Probe (WMAP) has provided us with the highest resolution all-sky maps of the Cosmic Microwave Background. As a result of thermal Sunyaev-Zel’dovich effect, clusters of galaxies are imprinted as tiny, poorly resolved dips on top of primary CMB anisotropies in these maps. Here, I describe different efforts to extract the physics of Intracluster Medium (ICM) from the...
Fluctuations in the cosmic microwave background (CMB) temperature are being studied with ever increasing precision. Two competing types of theories might describe the origins of these fluctuations: “inflation” and “defects”. Here we show how the differences between these two scenarios can give rise to striking signatures in the microwave fluctuations on small scales, assuming a standard recombi...
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