... Posts tagged ?PDF? ... Probability density functions are another way of summarizing the consequences of assuming a Gaussian error distribution when the true distribution is Poisson. ... The figure below ( AAS 472.09 ) compares the pdfs for the Poisson intensity (red curves) and the Gaussian equivalent (black curves) for two cases: when the number of counts in the source region is 50 (top) and 8 (bottom) respectively. ... Tags: background , gaussian , PDF , Poisson . ... ArXiv] 4th week, Nov. 2007? ...

... casa::Normal . ... Normal ( RNG *gen, Double mean=0.0, Double variance=1.0) . Construct a random number generator for a normal distribution. virtual . ... Returns a value from the normal distribution. virtual Double . ... These function allow you to manipulate the parameters (mean & variance) described above through the base class. virtual Vector < Double > . ... The second and third arguments define the parameters for this distribution as described in the synopsis. virtual casa::Normal::~Normal . ...

... Using the central limit theorem, the total noise can be approximated by a Gaussian or normal distribution which has the frequency function : . ... where is the mean intensity of the source. ... In the statistical analysis of the probability distribution of data several estimators based on moments are used. ... For a normal distribution, these moments are and while for a Poisson distribution are and . Besides these moments other estimators are used to describe a distribution e.g. median and mode . ...

... 2002 August 20 . The Universe in Hot Gas . ... Explanation: Where is most of the normal matter in the Universe? ... The above image derives from a computer simulation showing an expected typical distribution of hot gas in a huge slice of the universe 2.7 billion light-years across and 0.3 billion light years thick. The distribution of much more abundant dark matter likely mimics the normal matter, although the composition of the dark matter remains mysterious. ... About APOD | ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Quasi-stationary electron distributions for the different values of the particle escape time. ... The electron-cyclotron maser instability is widespread in the Universe, producing, e.g., radio emission of the magnetized planets and cool substellar objects. ... The model used takes into account the radiation escape from the source region and the particle flow through this region. ...

ST ScI Preprint #1364 . Authors: H. R. Schmitt Spectral energy distributions (SEDs) are some of the most important sources of information for galaxies, especially for high redshift ones. ... We discuss the integrated spectra of galaxies of different morphological and activity type, their application to derive K-corrections and classification of high redshift objects. ... Appeared in: Building Galaxies: from the Primordial Universe to the Present . ... Last updated: September 26, 2000 . ...

... We have assumed a constant in time star formation rate and the total number of stars in the Galaxy, , to be such that the total mass of the galaxy is ; assuming the Salpeter mass function   , we get . ... This number agrees with a standard estimation of the galactic star formation rate of order of per year. In each run of calculations, we trace the evolution of binaries with initial parameters randomly distributed according to the chosen initial laws. ...

Authors: Yu.G. Shevelev , V.A. Marsakov , . ... We have constructed and investigated properties of metallicity function of disk stars with different ages, proceeding from the statistically restored real altitude distributions of stars at the solar galactocentric distance. It is shown that the metallicity distribution of stars in each age range is not of Gaussian form, but it may be considered as a superposition of two normal distributions centered at -0.2 and 0.0 dex. ...

Next: Introduction . ... A spike immunity method of digital integrating radiometer signals in the jamming environment is described. ... The purpose of the method is real-time signal processing, and the basic is an alternative selection of the least offset signal estimation using nonparametric "Nearest Neighbor" rule. ... The additive spike-like jam makes the "tails" of the distribution "heavier" which leads to different offsets for linear and rank mean estimation on the integrating interval. ...

Chair of solid state physics . ... The Physics of Phonons . ... In the first part of the course “The Physics of Phonons” the dynamics of atoms in one- and three- dimensional crystalline lattices is considered in detail. The quasiparticle conception in solids, taking phonons as an example, is discussed; creation and annihilation operators of phonons, main properties of acoustic and optical phonons dispersion laws, density of phonon states. ... Crystalline state. ... Acoustic and optical phonons. ...

... Главная . ... Новости . ... Проекты . Любителям астрономии . Проект ISON . ... Подробнее . ... Категория: Новости проекта ISON . ... Метки: Космический мусор ,љ Астероиды ,љ Гамма-всплески ,љ Любителям астрономии ,љ Кометы љ . ... Метки: Космический мусор ,љ Астероиды ,љ Любителям астрономии љ . ... Новости обсерваторий проекта] - Обсерватория Кубанского государственного университета от Иванов А - 09.04.2016 11:08:49 . ... 1999-2013 Copyright "Астрономия и Телескопостроение" . ...

... Should be broken out by telescope within a facility.) ... Should be broken out by telescope within a facility.) - # programs allocated time ­ number of programs with non- staff PI's ­ number of programs with observatory staff as PI's ­ number of thesis programs ­ number with U.S. PI's ­ number with foreign PI's ­ information on geographic distribution - # states, # institutions, characterization of institution (R1, PUI, etc), if information ...

Median Twilight Image . all frames normalized by their median before averaging and corrected for 4-port structure) . Median of Normalized Twilight Images at Rotator Angle 0 . Median of Normalized Twilight Images at Random Rotator Angle . Time Frame and Rotator Angle Distribution . B_UT2_2CCD: 134 frames . ... distribution of rotator angles) . U_UT2_2CCD: 106 frames . ... uncorrected median twilight image) . B_UT2: 298 frames . ... U_UT2: 246 frames . ... B_UT3: 266 frames . ...

... Fitting the observed dependence includes calculations of the polarization cross-sections averaged over particles orientation and size distribution, their normalization and the comparison of obtained dependencies with Serkowski's curve representing observational data for a chosen star. ... Variations of the polarization factors with wavelength are shown in Fig. 16 for homogeneous spheroidal particles with PF orientation. ... The distinction between prolate and oblate spheroids is also clearly seen. ...

... Within SAS, a tool is available to check the pile-up fraction in the pn data: epatplot . This tool compares the observed pattern distributions (derived from a pn calibrated and concatenated even list) with the calibrated models. ... The lower panel is the key element for the evaluation of the pile-up fraction: it shows the observed distribution of pattern as a function of energy (PI channel in Analog-Digital Units ), using the same color code. ... Pages maintained by SAS librarian . ...

Next: Data reduction: moments Up: No Title Previous: Feature enhancement: local . ... When this is done for the energy map, with the energy scale distributed logarithmically, the result is shown on Fig. ... It can be shown that the mean magnitude at each duration reproduces the mean power spectrum in log-log coordinates. Therefore, this particular presentation of the probability density function shows graphically the scale-dependent scatter around the mean energy spectrum. ...

... STScI-PRC01-04 HUBBLE'S ULTRAVIOLET VIEWS OF NEARBY GALAXIES YIELD CLUES TO EARLY UNIVERSE Astronomers are using these three NASA Hubble Space Telescope images to help tackle the question of why distant galaxies have such odd shapes, appearing markedly different from the typical elliptical and spiral galaxies seen in the nearby universe. ... Light from these galaxies travels great distances (billions of light-years) to reach Earth. ... These stars emit mostly ultraviolet light. ...

... Bad Astronomy . ... Mad Science . ... Site Info . ... Public Talks . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... Who is this guy who calls himself "The Bad Astronomer?" ... First, yes, I am a real live astronomer (when people ask me what astronomers do, I tell them "They astronom !" ... These are emitted by powerful objects like black holes, exploding stars, and super-dense neutrons stars. ... Finally, am I really a bad astronomer? ... 2008 Phil Plait. ...

... 1) Studying distributions of stars of different ages in irregular and spiral galaxies we found for each galaxy a clear correlation between the age of stars and the spatial size of the subsystems of stars of this age. ... We made a stellar photometry of eight NGC 1313 fields and of its dwarf companion AM 0319-662 and studied the visible distribution of stars of different ages and of metallicity in the galaxy. ... This disappeared galaxy was the cause of the gravitational deformation of NGC 1313. ...

Next: Identification and Analysis of Binary Star Systems using Probability Theory . ... We present a computing code for modelling energy flux distributions, photometric indices and spectral line profiles of (non-)radially pulsating Main-Sequence stars. ... In the case of slowly rotating stars one can use the zero-rotation approximation to describe stellar pulsations. Such a model was used already by Cugier, Dziembowski & Pamyatnykh (1994) to study nonadiabatic observables of Cephei stars. ...