... Archives . ... Poisson vs Gaussian . ... Probability density functions are another way of summarizing the consequences of assuming a Gaussian error distribution when the true distribution is Poisson. We can compute the posterior probability of the intensity of a source , when some number of counts are observed in a source region, and the background is estimated using counts observed in a different region. ... Tags: background , gaussian , PDF , Poisson . ... Chandra Blog . ...

... Dept. for Physics of Stars&Galaxies . ... Using a database view Sloan Digital Sky Survey (SDSS), containing almost a million spectra created 15,000 sample galaxies with active star formation, which is used for various studies and physical state of evolution of galaxies. ... Star clusters of the Galaxy . The project MWSC (Milky Way Star Clusters) directory using 2MASS, which includes nearly 500 million vision to the limit Ks = 15.3, analyzed more than 4,000 cluster-like objects in the galaxy. ...

... Galaxy clusters in presence of dark energy: a kinetic approach . ... The external regions of galaxy clusters may be under strong influence of the dark energy, which was discovered by observations of supernovae Ia at redshift z < 1. The presence of the dark energy in the gravitational equilibrium equation, with the Einstein ? ... diagram where equilibrium solutions are not possible. ... Galactic Cluster in the Presence of Dark Energy . ...

Astronotes Armagh Planetarium's Stellar Blog! ... Planets . ... Of the worlds in our Solar System (gas giants excluded) only Venus has a completely ice-free surface. ... The continued melting of polar ice and consequent freshening of the waters of the Arctic Ocean might stop some ocean currents €аaffecting the lives of hundreds of millions of people.€а Studying the ice worlds of space helps us understand the part that ice has played in the history of our own planet and our present day existence on it. ...

... О Далекой Галактике . ... Теперь в Далекой Галактике вы всегда можете увидеть свежие фотографии Солнца. ... Форум . Форум "Далекой Галактики" - прекрасное место для общения всех астрономов. ... Новости из космоса . ... Подписаться на новости Далекой Галактики Вы можете здесь: . ... Новости из Далекой Галактики - популярно об Астрономии . ... Если вы хотите выразить свое мнение о сайте "Далекая Галактика", или просто почитать мнения других посетителей - пожалуйста, заходите в Гостевую книгу . ...

... The presence of small scale fluctuations of density (or of optical properties) in the spatial distribution of the dust would have important consequences for the modelling of molecular clouds because the UV light penetration and therefore the physical and chemical processes depend strongly on their structure (cf Boiss? ... We have developed methods to study in a direct way the amplitude of small scale variations of the extinction throughout translucent clouds ( mag). ...

... FTP access the basic models is here . ... Below, we put short descriptions of the used SED models for the photometric redshifts providing by the current server . ... The uniqueness of this model consists in expanding to the near IR (NIR) of Rocca-Volmerange and Guiderdoni's (1988) atlas of synthetic spectra with a revised stellar library, which includes parameters of cool stars. ... Homepage of the GISSEL model). ... Another model used earlier is the model of synthetic spectra of Poggianti (1997). ...

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... OGIP spectrum for selected source region . OGIP spectrum for selected background region . ... The primary input to especget is an image data set and two spatial selection expressions which need to mark an extraction region around a point source and a source-free background region. ... All regions will be deleted from the image - new initial selections for source and background regions must be made In the first and second case especget is eventually invoked with the appropriate input. ...

... Sternberg Astronomical Institute , Moscow University . ... Present edition unites two parts of Catalogue of interacting galaxies by B.A.Vorontsov-Velyaminov: the first part (Part 1) containing 355 systems was published in 1959 [1] and the second one (Part 2) with 497 objects - in 1976 [2].Thus two published parts of Catalogue include 852 interacting systems. ... All new of them (1162 by number) were taken from the comments to the galaxies in Morphological catalogue by Vorontsov-Velyaminov et al.[ ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

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... Distribution of orbital elements for the RR Lyrae stars. Results for stars with [Fe/H ] > -0.95 (left column), [Fe/H ] < 0.95 and V res < 290 km/s (middle column), and [Fe/H] < -0.95 and V res > 290 km/s (right column) are shown separately. In the top row, we have plotted normal curves fitting the distributions. ... next figure | privious figure . ...

... S.P. KOROLEV ROCKET AND SPACE CORPORATION ENERGIA . ... OAO RSC "Energia" . ... Company's History . ... News . ... S.P. Korolev Rocket and Space Corporation Energia takes part in the 10th International Aerospace Show. ... S.P. Korolev RSC Energia's stand presents the company's work on manned spacecraft and space stations, space launchers and unmanned spacecraft in the past and at present, as well as its proposals for the future. ... Contribution of RSC Energia to the Russian Rocket-Space Technology ...

... We consider the astrophysical evolution of the Galaxy over large time scales, from early stages (an age of ~10 8 yrs) to the end of traditional stellar evolution (~10 11 yrs). ... In the model considered, the basic stages of Galactic evolution are as follows. ... Essentially all other basic parameters of the Galaxy vary little. ... The final "stellar epoch" in the life of the Galaxy is completed ~10 13 yrs after its formation, when the evolution of the least massive stars comes to an end. ...

... Session 1 - Stars, star formation, stellar populations and planets . 9.20 10.00 . ... HST Spectroscopy of the Hottest White Dwarfs . ... Coffee break . ... Lunch break . ... A (long) look at neutron stars with HST . ... Session 2 - Nearby galaxies, bulges, spheroids, galaxy formation . ... New HST/ACS Insights into the Evolution of Star-Forming Dwarf Galaxies with Extreme Properties of Cosmological Relevance . ... Deriving properties of Lyman-break galaxies at z~3-5 using HST/VLT/Spitzer data . ...

... For us to see them from such great distances, quasars must be producing enormous energy -- they are about 1000 times brighter than an average galaxy! ... One of their choices for the energy source of quasars was a black hole. ... On the one hand, it may seem difficult to think that mere friction between bits of matter could account for the energy of a quasar, but, on the other hand, gravity is unimaginably strong near a black hole. ... How does matter actually rush towards the black hole? ...

Class 1 Introduction, Background History of Modern Astronomy The Night Sky, Eclipses and the Seasons Kepler's Laws Newtonian Gravity General Relativity Matter and Light Telescopes Class 2 Solar System Characteristics Formation Exosolar Planets Class 3 Stars The Sun Stellar Evolution of Low and High Mass Stars Deaths of Stars Class 4 Galaxies Galaxy Classification Formation of Galaxies Galactic Evolution Large-Scale Structure of the Universe Big Bang Cosmology Why is Pluto no longer a planet? ...

STAR FORMATION EFFICIENCY AND GRAVITATIONAL STABILITY OF GASEOUS DISKS IN GALAXIES In summary, gravitational instability is the essential factor of promoting SF in spiral galaxies. ... Becoming overstable, gas layer slows down its SFE, especially for the regions where the volume gas density is low, however the formation of stars still continues at the rate which is much lower now than in the past. ...

SPECTRAL FEATURES OF THE AVALANCHE DEPOSITS IN LUNAR CRATER REINER. ... Crater Reiner. ... 5 Immature soils (coded in green, box 3) occupy most areas of the inner wall slopes of the crater. ... Distribution of the immature soils shown in Fig. 5 correlates with distribution of the bright materials on the wall slope of the crater as it is seen in Fig. ... The presence of very immature soils on the inner wall slopes and on the central peak of the crater Reiner suggests recent intensive slope processes. ...