نتایج جستجو برای: cmb model
تعداد نتایج: 2108334 فیلتر نتایج به سال:
We present cosmological parameters derived from the angular power spectrum of the cosmic microwave background (CMB) radiation observed at 148 GHz and 218 GHz over 296 deg2 with the Atacama Cosmology Telescope (ACT) during its 2008 season. ACT measures fluctuations at scales 500 < < 10,000. We fit a model for the lensed CMB, Sunyaev–Zel’dovich (SZ), and foreground contribution to the 148 GHz and...
The Atacama Cosmology Telescope has measured the angular power spectra of microwave fluctuations to arcminute scales at frequencies of 148 and 218 GHz, from three seasons of data. At small scales the fluctuations in the primordial Cosmic Microwave Background (CMB) become increasingly obscured by extragalactic foregounds and secondary CMB signals. We present results from a nine-parameter model d...
We conduct waveform inversion to infer the three-dimensional (3-D) S-velocity structure in the lowermost 400 km of the mantle (the D′′ region) beneath the Northern Pacific region. Our dataset consists of about 20,000 transverse component broadband body-wave seismograms observed at North American stations for 131 intermediate and deep earthquakes which occurred beneath the western Pacific subduc...
In this paper, we examine the “urban legend” of CMB and question the impact of nine common errors that researchers make when designing survey instrument. We define the nine most common errors and implement these errors in an empirical study of 537 undergraduate students enrolled in an Introductory Psychology course at a large southeastern university. By analyzing this data in PLS, we discover t...
The energy content in radiation from beyond our Galaxy is dominated by the Cosmic Microwave Background (CMB), discovered in 1965 [1]. The spectrum of the CMB is well described by a blackbody function with T = 2.725 K. This spectral form is one of the main pillars of the hot Big Bang model for the early Universe. The lack of any observed deviations from a blackbody spectrum constrains physical p...
This is a course on cosmic microwave background (CMB) anisotropies in the standard cosmological model, designed for beginning graduate students and advanced undergraduates. “Standard cosmological model” in this context means a Universe dominated by some form of cold dark matter (CDM) with adiabatic perturbations generated at some initial epoch, e.g., Inflation, and left to evolve under gravity ...
We present preliminary results of an analysis into the effects of primordial voids on the cosmic microwave background (CMB). We show that an inflationary bubble model of void formation predicts excess power in the CMB angular power spectrum that peaks between 2000 < < 3000. Therefore, voids that exist on or close to the last scattering surface at the epoch of decoupling can contribute significa...
Cosmic strings are a well-motivated extension to the standard cosmological model and could induce a subdominant component in the anisotropies of the cosmic microwave background (CMB), in addition to the standard inflationary component. The detection of strings, while observationally challenging, would provide a direct probe of physics at very high-energy scales. We develop a framework for cosmi...
We consider a specific dark energy model, which only includes the Lagrangian up to cubic order in terms of vector field self-interactions generalized Proca theory. examine cosmological parameters model by using data sets CMB and CMB+HST, respectively. In particular, Hubble constant is found be H0=71.80?0.72+1.07 (72.48?0.60+0.72) kms?1Mpc?1 at 68% C.L. with (CMB+HST), would alleviate tension. a...
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...
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