The origin of cosmological density fluctuations
نویسندگان
چکیده
منابع مشابه
Nonlinear Effects in the Amplitude of Cosmological Density Fluctuations
The amplitude of cosmological density fluctuations, σ8, has been studied and estimated by analysing many cosmological observations. The values of the estimates vary considerably between the various probes. However, different estimators probe the value of σ8 in different cosmological scales and do not take into account the nonlinear evolution of the parameter at late times. We relate the linear ...
متن کاملthe effect of traffic density on the accident externality from driving the case study of tehran
در این پژوهش به بررسی اثر افزایش ترافیک بر روی تعداد تصادفات پرداخته شده است. به این منظور 30 تقاطع در شهر تهران بطور تصادفی انتخاب گردید و تعداد تصادفات ماهیانه در این تقاطعات در طول سالهای 89-90 از سازمان کنترل ترافیک شهر تهران استخراج گردید و با استفاده از مدل داده های تابلویی و نرم افزار eviews مدل خطی و درجه دوم تخمین زده شد و در نهایت این نتیجه حاصل شد که تقاطعات پر ترافیک تر تعداد تصادفا...
15 صفحه اولAmplitude of Primeval Fluctuations from Cosmological Mass Density Reconstructions
We use the POTENT reconstruction of the mass density field in the nearby universe to estimate the amplitude of the density fluctuation power spectrum for various cosmological models. We find σ8 Ω 0.6 m = 1.3 +0.4 −0.3, almost independently of the power spectrum. This value agrees well with the COBE normalization for the standard CDM model, while some alternative models predict an excessive ampl...
متن کاملWavelet Analysis of One-Dimensional Cosmological Density Fluctuations
Wavelet analysis is proposed as a new tool for studying the large-scale structure formation of the universe. To reveal its usefulness, the wavelet decomposition of one-dimensional cosmological density fluctuations is performed. In contrast with the Fourier analysis, the wavelet analysis has advantage of its ability to keep the information for location of local density peaks in addition to that ...
متن کاملGreen function for metric perturbations due to cosmological density fluctuations.
We study scalar perturbations to a Robertson-Walker cosmological metric in terms of a pseudo-Newtonian potential, which emerges naturally from the solution of the field equations. This potential is given in terms of a Green function for matter density fluctuations of arbitrary amplitude whose time and spatial dependence are assumed known. The results obtained span both the linearized and Newton...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nuclear Physics B
سال: 1985
ISSN: 0550-3213
DOI: 10.1016/0550-3213(85)90427-4