. 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 .

... 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. ...

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). ...

... Compact Binaries . ... Globular Clusters . ... Ultra-Compact binaries in globular clusters . ... It is known that UC X-ray binaries are more abundant in globular clusters compared to that found in Galactic fields (eg van der Sluys, Verbunt \ Pols 2005 and references therein). On the other hand no AM CVn systems have been found in globular clusters, while 20 are known in the Galactic field (for a review of AM CVn systems see Nelemans 2005). ...

... Archives . ... ArXiv] SVM and galaxy morphological classification, Sept. 10, 2007 . ... On the Metallicity-Color Relations and Bimodal Color Distributions in Extragalactic Globular Cluster Systems by M. Cantiello and J. P. Blakeslee . Many observations on globular cluster systems (GCS) show bimodal distributions in color and metallicity space. ... Based on their simulation study, (V-H) and (V-K) are confirmed to be good colors for revealing unbiased bimodal metallicity distributions in GCS. ...

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...

... 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. ...

... The Hydra Cluster of Galaxies . ... 16.04.2001 . ... Most of a cluster's mass , however, appears to be in a form too dark to see , as analyses of the distribution of X-ray light , gravitational lensing , and internal motions indicate. Abell 1060, as the above cluster is also known, appears to have an even higher fraction of dark matter than seen in a similar cluster, a situation astronomers cannot easily reconcile with both clusters forming solely from gravitational attraction. ... April 2001 . ...

... 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. ...

Today's APOD | ... Editor's choices for the most educational Astronomy Pictures of the Day about globular clusters: . ... Explanation: Globular clusters once ruled the Milky Way . Back in the old days , back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy . ... APOD: 2002 July 30 - A Star Cluster in Motion . ... Globular star clusters normally roam the halo of the Milky Way, ancient relics of our galaxy's formative years. ... Index | ... About APOD | ...