This collage shows images of six different galaxy clusters taken with NASA's Hubble Space Telescope and Chandra X-ray Observatory. The clusters were observed in a study of how dark matter in clusters of galaxies behaves when the clusters collide. ... Using visible-light images from Hubble, the team was able to map the post-collision distribution of stars and also of the dark matter (colored in blue), which was traced through its gravitational lensing effects on background light. ...

... 2000 January 12 . NGC 6791: An Old, Large Open Cluster . ... Explanation: NGC 6791 is one of the oldest and largest open clusters of stars known. ... Open star cluster NGC 6791 , however, contains thousands of stars recently measured to be about 8 billion years old. ... This enigma makes NGC 6791, pictured above , one of the most studied open clusters and a possible example of how stars might evolve in the centers of galaxies. ... About APOD | ...

... This represents the first HI selected sample covering the core and the outskirts of a local cluster of galaxies. ... Optically selected samples miss a considerable number of low luminosity, low surface brightness galaxies underestimating by almost a factor 2 the number of HI rich galaxies present in the cluster volume. ... Right: The g band luminosity function for galaxies in the A1367 volume as obtained from the optically (circles) and HI (histogram) selected sample. ...

... The study of the Large-scale structure of the Universe and measurements of the Dark Energy equation of state; The exploration of the growth and cosmological evolution of supermassive Black holes in the Universe. ... In course of the all sky survey SRG will discover about 100 000 galaxy clusters and 3 million AGNs. Galaxy clusters are the largest gravitationally bounded objects in the Universe and are best explored through the study of X-ray emission from the hot intergalactic gas. ... 2016 IKI RAN ...

Armed with these assumptions, observations, and laws, cosmologists try to build a theory of the development, or evolution, of the universe. ... Over the past 70 years, they have constructed and tested a theory that seems to explain the major properties of the universe: the Big Bang theory. ... This is an important point: The Big Bang theory allows for many different scenarios of the detailed evolution and composition of the universe. ... Because of a theory called nucleosynthesis. ...

Next: Star Formation Rate and Up: No Title Previous: Calculation of Evolutionary Tracks . To start calculations, we choose the distributions of the initial binary parameters: the mass of the primary ZAMS component, , binary mass ratio, , orbital separation a . ... whereas the mass ratio distribution is not. ... The zero assumption often made is that the mass ratio distribution has a flat shape, that is binaries with a high mass ratio occur as frequently as those with equal masses. ...

... We cannot use for this purpose equivalent widths and profiles of HI lines (well known criteria of atmospheric conditions for normal supergiants), since these lines are strongly distorted in the spectrum of IRAS04296 as seen in Fig. ... Figure: Upper: iron abundance FeI (circles) and FeII (crosses) calculated for IRAS04296+3429 with model parameters , and using lines with different excitation potentials EP of a low level; bottom: the same as a function of the equivalent width W . ...

Teaching courses . for student of the Department of Astrophysics and Stellar Astronomy . ... Geophysics and physics of the planets (Kurt, Panteleev) . ... Close Binary Stars . ... Solar Physics . ... This is introductory course for students of the third year of education which are familiar with elementary astronomy and general physics. ... The one-year course includes theory of radiation transfer, theory of internal stellar structure with account of binary systems with compact comapnions. ...

... LEFT?, expression, RIGHT?, %math? . where expression is %math or %math tag %math, see below. The BOX element is used for a variety of purposes: . ... The BOX element can be used with the LEFT and RIGHT tags for delimiters that stretch to match the size of the enclosed expression. ... Left delimiters should be given before the LEFT tag, while right delimiters should be given following the RIGHT tag, for instance: ( 1 + x ) f(x) = {(<left> f(x) = ( ----- ) 1+x<over> sin x ( sin x ) <right>)} . ...

ABSOLUTE PROPER MOTIONS OF 331 OPEN CLUSTERS . ... The proper motions of stars in the fields of 331 open clusters were taken from Four-Million Star Catalog (4M-catalog) of positions and proper motions (Volchkov et al. ... The absolute proper motions for 21 young open clusters have been derived by comparison of precise relative proper motions of individual stars and their corresponding absolute proper motions. ... Sign of proper motions in RA . ... 0.0001 arcsec/yr . ... rms error in RA proper motion . ...

... Запорожский клуб АЛЬТАИР > . Catalogue of 109 new Galactic open clusters, for Cartes du Ciel . ... Cartes du Ciel - Sky Charts . ... Этот каталог является версией части каталога "J/A+A/440/403 109 new Galactic open clusters (Kharchenko+, 2005) ", а именно файла stars.dat, содержащего информацию о 26778 звездах до 14.627m , находящихся в 130 рассеяных скоплениях района Млечного Пути (Galactic Open Cluster). ... We present a list of 130 Galactic Open Clusters, found in the All-Sky . ...

Distribution of the analyzed SEPs with different >100 MeV proton fluxes ( J 100 ) at the microwave flux density plane ' S 9 vs. ... 1) General correspondence takes place between intensities of microwave bursts and proton fluxes - J 100 increases when S 9 and S 15 rise. ... 3) Powerful microwave bursts ( S 9 , S 15 >3000-10000 sfu ) with hard radio spectra ( S 9 < S 15 ) correspond to majority of powerful proton fluxes ( J 100 >10 pfu ). ...

... Next: Unsupervised Catalog Classification Up: Object Detection and Previous: Classification of Objects . ... Multi-resolution allows for image analysis in terms of different scales. ... This approach is used for the detection (and subsequent analysis) of globular cluster systems around elliptical galaxies, and for image characterization and object trawling in large image databases. ... The applicability of this approach to object detection in large image collections has been investigated. ...

The Mass-Density of the Universe and the Distribution of Dark Matter Neta A. Bahcall Princeton University, USA One of the most fundamental questions of cosmology is: How much matter is there in the Universe and how is it distributed? Here we show that several independent measures - including those utilizing clusters of galaxies - all indicate that the mass-density of the Universe is low: only 20-30% of the critical density. ... The results reveal a low den- sity of 0.16+-0.05. ...

... For an input list of EBOXDETECT source locations, simultaneous maximum likelihood PSF fits to the source count distribution are performed in all energy bands of each EPIC telescope. A description of the main properties of the detection algorithm may be found in Cruddace, Hasinger, Schmitt (1988). ... Note, that =1 in the case of the individual energy band detection likelihoods listed in source table rows with ID_BAND 0 and is equal to the total number of energy bands in the ID_BAND=0 summary rows. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Comets and Asteroids . ... Image credit:ESO/J.Emerson/VISTA. ... However others are less pessimistic and it has even been claimed that the mysterious ?Wow! signal? received in 1977 originated from the direction M55.б  Sadly, this still unexplained pulse of radio energy originated from a location rather to the northwest of M55 so I doubt if the source was this cluster (if indeed the signal was genuinely of extraterrestrial origin). ... Mysterious Wow! ...

FEATURES OF THE HYDROGEN DISTRIBUTION AROUND LUNAR CRATERS PROCLUS AND KEPLER. ... In result of analysis of the data Lawrence and Feldman constructed the hydrogen distribution on the lunar surface [1]. ... However, the authors shown, that EN flux data features may be explained by other element abundance in the lunar soils, namely: Si, Ca, Gadolinium (Gd), Samarium (Sm) and Fe. ... Using of the Feldman's interpretation of the Lunar Prospector data [8], we constructed hydrogen distribution map (Fig.1). ...

... Chubukova I. - Data Mining (2007) PDF Data Mining . Hand D. Mannila H. Smyth P. - Principles of data mining (2001) DJVU Data Mining . Mitra S. Acharya T. - Data mining (2003) (In Russian) DJVU Data Mining . Abbass H. Sarker R. Newton C. - Data Mining Heuristic Approach (2002) PDF Data Mining . Rao C. Wegman E. Solka J. - Handbook of Statistics Data Mining and Data Visualization (2004) PDF Data Mining . ... Whittet D. - Dust in galaxies (2003) PDF Межзвездная среда . ...

ATMoB "Open Cluster Observing Award " Guidelines Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston through participation in the Open Clusters Observing Awards program. Introduction: This awards program is oriented towards visually observing open clusters above magnitude 9.9. ... It turns out that a very unprejudiced and convenient method to dermine the limiting magnitude is to count the number of visible stars in certain areas on the sky. ...

... Variation of systematic errors for USNO A2 (in mas per year) 23 .914 0.082 0.250 0.418 0.586 0.753 0.921 1.089 1.257 1.425 1.593 4 4. 3. 3. 3. 3. 3. 3. 3. 3. 3. 15 ± 7± 1± 3± 3± 10 ± 10 ± 11 ± 6± 10 ± 12 ± and their errors USNO UCAC USNO UCAC A2.0 2 3 B1.0 4 (1998) (2006) (2003) (2012) 37 27 11 4 732 529 778 501 050 078 775 387 (34 610 829) (17 209 447) (9 744 401) () Distribution of observations ( ...