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. ...

... 145Slee,Roy Savage We present detailed radio and optical parameters for the stronger radio sources in 58 Abell cluster fields observed with the Very Large Array (VLA) using scaled arrays at 1.5 and 4.9 GHz. ... The cluster fields were distributed over 24 h of RA and between declinations +35 deg and -30 deg. ... Optical identifications Cluster Source Radio Centroid Optical Position EF Ang. ...

... Two Start of the data set. touch each other and cancellation big cluster of negative fragment at southwest also at the edge of at the northeast, and it The emerging positive negative fragments at its continues at the previous During the cancellation at the bipolar region, although there are short-living X-ray flashing sometimes, it is hardly to see any clear bright structure. ... 03:29 The negative fragments in the previous bipolar region become less, smaller and weaker. ... Cancellation continues. ...

... Authors: Marc Postman 1 , Lori M. Lubin 2,3,4 , J. B. Oke 5,6 We present an extensive photometric and spectroscopic study of two high-redshift clusters of galaxies based on data obtained from the Keck 10m telescopes and the Hubble Space Telescope. The clusters CL0023+0423 (z=0.84) and CL1604+4304 (z=0.90) are part of a multi-wavelength program to study nine candidate clusters at z 0.6 (Oke, Postman & Lubin 1998). ... We also observe many old, red galaxies. ... huizinga@stsci.edu . ...

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). ...

... The large body of near infrared observations presented in Testi et al. (1997; 1998) are analysed with the aim of characterizing the young stellar clusters surrounding Herbig Ae/Be stars. The results confirm the tendency of early Be stars to be surrounded by dense clusters of lower mass "companions", while Ae stars are never found to be associated with conspicuous groups. ... Only the most massive stars (10-20Msun) are found to be associated with dense (10^3 pc^-3) stellar clusters. ...

... Meta Index / Home Page This section documents warnings and errors generated by this task (if any). ... The Keyword TIMEDEL should be present in the input file . ... corrective action: CONTENT keyword should be present in the input file header . ... Count rate errors negative . ... corrective action: Count rate errors must be positive . ... corrective action: TSTART keyword should be present in header of GTI file . ... corrective action: TSTOP keyword should be present in header of GTI file . ...

... 3C294: Distant X Ray Galaxy Cluster . ... Astronomers now realize that a hallmark of these cosmic behemoths are gas clouds with temperatures of tens of millions of degrees that pervade the clusters and radiate strongly in x-rays. This Chandra Observatory image centered on a radio galaxy cataloged as 3C294 indeed reveals the telltale hot x-ray gas in an hourglass shaped region surrounding the dominant galaxy and shows the presence of a massive galaxy cluster in the distant universe . ...

... Editor's choices for the most educational Astronomy Pictures of the Day about clusters of galaxies: . APOD: 2006 March 21 - The Coma Cluster of Galaxies . ... APOD: 2005 November 22 - A Galactic Collision in Cluster Abell 1185 . ... A prominent example occurs on the left of the above image of the rich cluster of galaxies Abell 1185. ... Recent observations of Abell 1185 have found unusual globular clusters of stars that appear to belong only to the galaxy cluster and not to any individual galaxy. ...

... 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 . ...

... Structure of Data . ... Catalog . ... In SAI OCL Catalog, we introduce our work on investigation of the Milky Way system of open star clusters. The main goal of our study is a search for new clusters using huge surveys. 168 new clusters have been already discovered by us using J,H,Ks data from 2MASS point source catalog. ... For 141 new clusters, we found their physical parameters using J,H,Ks data from 2MASS catalog and, for a number of clusters, our UBVRI CCD observational magnitudes. ...

... In 1930, Trumpler noticed that linear diameters (LD) of open clusters increase with distance (D) from the Sun. ... Since that time, the interstellar absorption has become one of the best studied factor in astrophysics, and we may hope that current OCL distance scales are free from this LD-D correlation. To verify if this is the case we have chosen several modern OCL distance scales and test them with the same clusters and the same angular diameters that Trumpler had used back in 1930. ...

... The most powerful and widely used methods to calculate the scattering matrix of a fractal cluster are based on the coupled dipoles methods (e.g. the Discrete Dipole Approximation, DDA) and the theory of light scattering by a cluster of spherical particles [2-4]. ... At present the procedure of calculation of the scattering matrix is well developed for both an oriented cluster of spherical particles and for chaotically oriented clusters of such particles [4]. ...

... The Astronomical Society of the Pacific (ASP) presented Priscilla and Bart Bok Awards to two high School Seniors at the Intel International Science and Engineering Fair held May 10 to 15 in Reno this year. ... The Bok prize is named for Bart and Priscilla Bok. ... About 10 years ago, at the suggestion of the American Astronomical Society, the activities supported by the Bok Fund were expanded to include the joint sponsorship of an astronomy award at Intel Science and Education Fair. ...

. N OTE: . Only clusters with R<60 kpc were used to compute the spatial parameters and metallicity gradients for all subsystems except the corona. The numbers in parantheses give the number of clusters for which the corresponding parameter is known. The X O scale length of the old halo is strongly distorted by the observed asymmetry of the distribution of the corresponding clusters projected onto the XY plane ( Fig. 4А ) . discussion in the text | previous table .

not-minutes' for second E-ALFA LOC Meeting Tuesday, April 13th Present: Chris S., A. Desh, Carmen S., Jose A. Erik M. Telecon: Bob B., Karen O. Items outstanding or pending items from last meetings action list: ACTION - Karen O: Update w/site to include a strong recommendation for all visitors to use calling cards. ... ACTION - Chris S.: Check the price of telecon with Jill. ... Deferred to Lister Staveley-Smith (ATNF) ACTION: Karen O. to arrange for Info Handouts Pending actual content of handouts. ...

... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... ESO . ... Survey Telescopes . ... ESO Supernova . ... Star Clusters . ... Stars@ESO . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... ESO 1-metre Schmidt telescope . ... Future Projects . ... This NASA/ESA Hubble Space Telescope image shows the positions of the past, present and predicted future appearances of the Refsdal supernova behind the galaxy cluster€а MACS J1149+2223 . ...

... 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 . ...

IFP gallery SCORPIO (since 2000). Here some data observed on the 6m telescope with IFP installed in the SCORPIO focal reducer are presented. ... Velocity field . Mkn 1157 was observed 1 Sep. 2002 in the Ha emission line. Texp =32x240 sec, seeing 1.5", IFP260. ... This galaxy was observed September, 23 2000 in the Ha emission line, Texp=32x120 sec, seeing 2.5", IFP260. ... PV Cep was observed at the 6m telescope in May, 25 2003 in the [SII] 6716A with IFP501, Texp=36x200 sec, seeing 1.0". ...

... For this paper: postscript PPEUC CMB index 1 Introduction.. ... We present a new model for the formation of spherically symmetric clusters in an expanding Universe. Both the Universe and the collapsing cluster are governed by the same pressure less fluid equations for which a uniform initial density profile is assumed. ... The computation of photon paths allows us to evaluate the gravitational effects imprinted on a Cosmic Microwave Background (CMB) photon passing through such an evolving mass. ...