THE COLUMN DENSITY VARIANCE-${\cal M}_s$ RELATIONSHIP
نویسندگان
چکیده
منابع مشابه
The Low Column Density Lyman-alpha Forest
We develop an analytical method based on the lognormal approximation to compute the column density distribution of the Lyman-alpha forest in the low column density limit. We compute the column density distributions for six different cosmological models and found that the standard, COBE -normalized CDM model cannot fit the observations of the Lyman-alpha forest at z = 3. The amplitude of the flu...
متن کاملAtmospheric Sodium Column Density Monitoring
In Laser Guide Star Adaptive Optics (AO), a laser is used to excite the mesospheric (90km altitude) sodium (Na) layer and thereby creates an artiicial star that can be used as reference for the AO wavefront sensor. The intensity of the created star depends strongly on the amount of Na present in the atmosphere. Experiences to measure the column density and details of excitation of scattering pr...
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 اولThe Statistics of Density Peaks and the Column Density Distribution of the Lyman - Alpha Forest
We develop a method to calculate the column density distribution of the Lyα forest for column densities in the range 10 − 10 cm. The Zel’dovich approximation, with appropriate smoothing, is used to compute the density and peculiar velocity fields. The effect of the latter on absorption profiles is discussed and it is shown to have little effect on the column density distribution. An approximati...
متن کاملThe +CAL Algorithm Language
Algorithms are different from programs and should not be described with programming languages. Until now, the only simple alternative to programming languages has been pseudo-code. Based on the TLA+ specification language, +cal is an algorithm language that is designed to replace pseudocode. A +cal algorithm is automatically translated to a TLA+ specification that can be checked with the TLC mo...
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: The Astrophysical Journal
سال: 2012
ISSN: 2041-8205,2041-8213
DOI: 10.1088/2041-8205/755/1/l19