نتایج جستجو برای: cmb
تعداد نتایج: 5818 فیلتر نتایج به سال:
We discuss two new observational techniques that use observations of the cosmic microwave background (CMB) to place constraints on the mass, distance, and size distribution of small objects in the Kuiper Belt and inner Oort Cloud, collectively known as trans-Neptunian objects (TNOs). The first new technique considers the spectral distortion of the isotropic, ormonopole, CMBbyTNOs that have been...
Observations of the Cosmic Microwave Background (CMB) are discussed, with particular emphasis on current ground-based experiments and on future satellite, balloon and interferometer experiments. Observational techniques and the effects of contaminating foregrounds are highlighted. Recent CMB data is used with large scale structure (LSS) data to constrain cosmological parameters and the compleme...
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...
The polarization of the cosmic microwave background (CMB) is encoded with exactly the same cosmic information as the CMB’s temperature anisotropy. However, polarization has the additional promise of accurately probing the reionization history of the universe and potentially constraining, or detecting, the primordial background of gravitational waves produced by inflation. We demonstrate that th...
In this paper we compare data to theory. We use a compilation of the most recent cosmic microwave background (CMB) measurements to constrain Hubble’s constant h, the baryon fraction Ωb, and the cosmological constant λo. We fit h-, Ωband λo-dependent power spectra to the data. The models we consider are flat cold dark matter (CDM) dominated universes with flat (ns = 1) power spectra, thus the re...
We review present understanding of Galactic free–free emission and its possible importance to CMB fluctuation measurements. Current results, from both " direct " observations in the microwave band and from Hα studies, suggest that this foreground does not represent a serious obstacle to mapping the CMB; however, this is based on limited information and we emphasize the need for more exhaustive ...
We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 deg region of the sky with 10 resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements o...
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