Density distribution of the cosmological matter field

The cosmological matter density

The status of observational cosmology is a subject that David Schramm followed intently. As spokesman for the entire "eld of particle astrophysics, David was interested in the full picture. He was always conversant with the latest developments in observations of the light elements, as they directly impacted his work on primordial nucleosynthesis and the resulting predicted abundances of deuteri...

Evolution of the cosmological density distribution function

We present a new calculation for the evolution of the 1-point Probability Distribution Function (PDF) of the cosmological density field based on an exact statistical treatment. Using the Chapman–Kolmogorov equation and second–order Eulerian perturbation theory we propagate the initial density distribution into the nonlinear regime. Our calculations yield the moment generating function, allowing...

the 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...

Perturbation Theory of the Cosmological Log-Density Field

Estimating Cosmological Parameters from the Dark Matter Distribution

A grand challenge of the 21 century cosmology is to accurately estimate the cosmological parameters of our Universe. A major approach in estimating the cosmological parameters is to use the large scale matter distribution of the Universe. Galaxy surveys provide the means to map out cosmic large-scale structure in three dimensions. Information about galaxy locations is typically summarized in a ...