. F IGURE . 13. The (a) metallicity and (b) age distributions of the globular clusters of Galactic origin. Different shadings are used to show the thick-disk and old-halo clusters. The curves are Gaussian fits to the corresponding histograms. discussion in the text | privious figure | next figure .

To construct two-dimension distribution of minor planets user should specify elements/ parameters/ function that will be plotted as abscissas and ordinates. In three-dimension case one should add to them the element plotted on Z axis. ... Though you may choose elements plotted along different axes at will, often there is good reason to plot such elements as a, n, or n" along X axis (two-dimension distributions) and to plot them along Y axis in three-dimension case. ...

Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

The radial distribution of metallicity of star-forming galaxies in a galaxy cluster can inform us about the mass assembly and enrichment history of the galaxy cluster. ... Both galaxy clusters are cool-core clusters at redshift z т?? ... The gas-phase metallicity of star- forming galaxies in MACS1115+01 exhibit anti-correlation with projected distance т??0.15 ТБ 0.08 dex/Mpc, whereas the radial metallicity distribution of RXJ1532+30 is statistically flat (т??0.09 ТБ 0.12 dex/Mpc). ...

... We address a question if globular clusters (GC) in a protogalaxy could for some time evolve chemically as isolated systems, enriching themselves with heavy elements produced in first supernova events that follow initial star formation. We determine both the critical mass of a protoglobular cluster that is needed to retain the ejecta of the very first supernova, and the critical energy (i.e., number of supernovae) that is needed to expel the residual gas from a cluster of a given mass. ...

... Archives . ... my first AAS. ... I was questioned by two attendees, acquainted before the AAS, if I can suggest them clustering methods relevant to their projects. ... classification vs. clustering or supervised learning vs. unsupervised learning : the former terms from the pairs indicate the fact that the scientist already knows types of objects in his hands. ... Tags: Classification , clustering , cosmology , spatial statistics , supervised learning , test , unsupervised learning . ...

... Resolved Stellar Populations Globular Clusters . Galaxies are made of stars, gas and the illusive dark matter. ... Star clusters are the simplest form of the stellar population. ... Old globular clusters are easily observed at great distances and can be used as probes of the early stages of star formation history in galaxies where individual stars cannot be resolved. My research interests are centered on the studies of resolved stellar populations and (old) star clusters in nearby galaxies. ...

... We present V and I photometry for a sample of globular cluster candidates in the Virgo galaxy M87. ... A comparison with the color distribution of globular clusters in the Milky Way shows that M87 contains a large population of red clusters that is virtually absent in our Galaxy. ... Increasingly accurate measurements of the colors and metallicities of globular clusters in distant galaxies are beginning to shed new light on, and provoke new questions about, the origin of globular cluster systems. ...

J/AstL/vol/page SAI Open Clusters Catalog (Glushkova+, 2009) ================================================================================ Automated search for star clusters in large multiband surveys. ... Color excesses E(B-V), distance moduli and ages were determined for 141 new and 27 known, but poorly studied clusters. We present the Sternberg Astronomical Institute Open Clusters Catalog (SAI OCL Catalog) of coordinates, diameters and main physical parameters of these clusters. ...

... Bisnovatyi-Kogan, Gennady S.; Merafina , Marco; Vaccarelli , Maria Rosaria; Spherically Symmetric Stellar Clusters with Anisotropy and Cutoff Energy in Momentum Distribution. ... We construct numerical models of spherically symmetric Newtonian stellar clusters with anisotropic distribution functions. ... Models of spherically symmetric relativistic stellar clusters with anisotropic distribution functions in relativistic regime are described by using Maxwellian distribution function with energy...

... 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. ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

... 2006 August 10 . Galactic Center Star Clusters . ... CXC , NASA . Explanation: If you had x-ray vision , the central regions of our Galaxy would not be hidden from view by cosmic dust clouds. ... Pleasing to look at, the gorgeous false-color representation of x-ray data from the Chandra Observatory shows high energies in blue, medium in green, and low energy x-rays in red. ... It reveals massive, x-ray emitting star clusters in a crowded environment. ... About APOD | ...

There are at least 3 ways that the age of the Universe can be estimated. ... The age of the oldest star clusters. The age of the oldest white dwarf stars. ... When a rock solidifies, the chemical elements often get separated into different crystalline grains in the rock. ... But if the elements are made continuously at a constant rate, then the mean age of stuff in the Solar System is (t o + t SS )/2 = 8-11 Gyr which we can solve for the age of the Universe giving t o = 11.5-17.5 Gyr . ... Age | ...

... Abell 2744: Pandoras Cluster of Galaxies . ... Credit Copyright: NASA , ESA , J. Merten ( ITA , AOB ), D. Coe ( STScI ) Explanation: Why is this cluster of galaxies so jumbled? Far from a smooth distribution, Abell 2744 not only has knots of galaxies, but the X-ray emitting hot gas (colored red) in the cluster appears distributed differently than the dark matter . ... Publications with keywords: galaxy cluster - dark matter - hot gas . ... The Hydra Cluster of Galaxies . ...

... The perceptron structure, on the basis of which the database is built, is defined by a number of the input and output parameters and a required accuracy. ... The output perceptron data are the expansion coefficients of the scattering matrix elements in series of the generalized spherical functions. ... As the cluster structure depends on the generation conditions the expansion coefficients were averaged over 5--7 realizations of the clusters (for N . ... is the coefficient number. ...

Formation of intra-group HI gas through multiple galaxy encounters and ram pressure stripping Kenji Bekki (ICRAR at UWA, Australia) (Figures from APOD) Physical processes that drive galaxy evolution in different environments. (a) Ram pressure stripping due to hot intergalactic medium in clusters. ... Ram pressure of warm/hot intra-group gas on extended gaseous (HI) disks of galaxies in small groups and filaments (with Westmeier T. et al. ... 2011) Gas kinematics of disk galaxies under ram pressure. ...

... The distribution of galactic RCB stars is controversial. Several authors have argued that they belong to a thick galactic disk, and are thus old Population I stars. However, they may alternatively belong to the even older galactic bulge (Population II). ... In either case, the populations are sufficiently old that RCB stars must have relatively low masses ( ). ... These are the only RCB stars for which a distance is known and hence for which an absolute magnitude can be deduced. ...

... 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. ...

The new view on the population of Galactic open clusters A.E.Piskunov1, N.V.Kharchenko2, S.RЖser3, E.Schilbach3, R.-D.Scholz4 1 2 3 4 Institute of Astronomy, Moscow, Russia Main Astronomical ... Observatory, Kiev, Ukraine Astronomisches Rechen-Institut, Heidelberg, Germany Astrophysikalisches Institut Potsdam, Germany What are open clusters and what do they teach us Groups of Population I ... Cluster complexes: OCC-1 = Gould's Belt cluster complex? ...