نتایج جستجو برای: cmb
تعداد نتایج: 5818 فیلتر نتایج به سال:
We provide computationally convenient expressions for all marginal distributions of the polarization CMB power spectrum distribution P (Cl|σl), where Cl = {CTT l , C l , C l , C l } denotes the set of ensemble averaged polarization CMB power spectra, and σl = {σTT l , σ l , σ l , σ l } the set of the realization specific polarization CMB power spectra. This distribution describes the CMB power ...
BACKGROUND AND PURPOSE Cerebral microbleeds (CMB) represent a common magnetic resonance imaging marker of cerebral small vessel disease, increasingly recognized as a subclinical marker of stroke and dementia risk. CMB detection may reflect the cumulative effect of vascular risk burden and be a marker of higher mortality. We investigated the relation of CMB to risk of death in community dwelling...
Images of dust continuum and carbon monoxide (CO) line emission are powerful tools for deducing structural characteristics of galaxies, such as disc sizes, H2 gas velocity fields and enclosed H2 and dynamical masses. We report on a fundamental constraint set by the cosmic microwave background (CMB) on the observed structural and dynamical characteristics of galaxies, as deduced from dust contin...
this study assesses the air quality of two urban localities, fahaheel and al-rabia city, to assistlocal authorities to generate information supporting the planning of pollution control strategies to keeppollutants within safe limits in the long run. in terms of diurnal and seasonal variations, almost all measured pollutants exhibited two peaks: one in the morning and another in the afternoon. t...
The last years have been an exciting period for the field of the Cosmic Microwave Background (CMB) research. With recent CMB balloon-borne and ground-based experiments we are entering a new era of ’precision’ cosmology that enables us to use the CMB anisotropy measurements to constrain the cosmological parameters and test new theoretical scenarios.
Cosmic Microwave Background (CMB) anisotropies have been recognized as one of the most important observational quantities to understand the early stage of our universe. In this paper, recent development of theoretical works on CMB anisotropies are summarized and it is shown that temperature uctuations of CMB contain rich information, i.e., cosmological parameters, geometry of the universe, init...
Secondary anisotropies of the cosmic microwave background (CMB) can be detected by using the cross-correlation between the large-scale structure (LSS) and the CMB temperature fluctuations. In such studies, chance correlations of primordial CMB fluctuations with the LSS are the main source of uncertainty. We present a method for reducing this noise by exploiting information contained in the pola...
These lectures introduce some of the basic theory of cosmic microwave background (CMB) polarization with the primary aim of developing the theory of CMB polarization from inflationary gravitational waves, as well as some of the related theory of weak gravitational lensing (cosmic shear) of CMB polarization. We begin with production of polarization by Thomson scattering. We then discuss tensor-h...
Spectroscopic studies of high-redshift objects combined with increasingly precise data on the cosmic microwave background (CMB) are beginning to place strong bounds on the epoch of hydrogen reionization. Parameter estimation from current CMB data continues, however, to be subject to several degeneracies. Here, we focus on those degeneracies in CMB parameter forecasts related to the optical dept...
The CMB angular temperature fluctuations observed by Cobe and Wmap enable us to place a lower limit on the spectral distortions of the CMB at any angular scale. These distortions are connected with the simple fact, that the superposition of blackbodies with different temperatures in general is not a blackbody. We show, that in the limit of small temperature fluctuations, the superposition of bl...
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