Today's APOD | ... Galaxies rotate and move in clusters as if a tremendous amount of unseen matter is present. ... Specifically, present analyses of above WMAP all-sky image indicate that the universe is 13.7 billion years old (accurate to 1 percent), composed of 73 percent dark energy , 23 percent cold dark matter , and only 4 percent atoms , is currently expanding at the rate of 71 km/sec/ Mpc (accurate to 5 percent), underwent episodes of rapid expansion called inflation , and will expand forever . ...

... Galaxies rotate and move in clusters as if a tremendous amount of unseen matter is present. But does dark matter exist in the greater universe too -- and if so, where? ... In the above frame from a computer simulation of our universe , a 300 million light-year slice shows dark matter in gray and galaxies as colored circles. ... Publications with keywords: universe - dark matter - 2dF survey - simulation . Publications with words: universe - dark matter - 2dF survey - simulation . ...

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). ...

... 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. ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

... Australia Telescope Compact Array . ... Compact Stellar Systems in the Fornax Cluster: Super-massive Star Clusters or Extremely Compact Dwarf Galaxies? ... We suggest that these objects are either super-massive star clusters (intra-cluster globular clusters or tidally stripped nuclei of dwarf galaxies) or a new type of low-luminosity compact elliptical dwarf (``M32-type'') galaxy. ... Keywords: galaxies: star clusters -- galaxies: dwarf -- galaxies: formation . ... Properties of the compact objects ...

... The sample of the Local Volume galaxies (distance smaller than 10 Mpc) gives a unique opportunity to study the properties of galaxies including the weakest objects: the absolute magnitude M B -10 and the virial mass M vir 10 9 M x263C;. ... Luminosity function of the Local Volume galaxies. ... The luminosity functions for galaxies are presented: red dashed line - from the 2dFGRS survey (Norberg et al. 2002); blue dash-dotted line - from the SDSS survey (Blanton et al. ...

... 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 . ...

... December 13, 1997 . The Coma Cluster of Galaxies . ... The Coma Cluster of Galaxies pictured is one of the densest clusters known - it contains thousands of galaxies . Each of these galaxies house billions of stars - just as our own Milky Way Galaxy does. ... In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! Most galaxies in Coma and other clusters are ellipticals , while most galaxies outside of clusters are spirals . ...

The above image is a computer simulation of the distribution of mass in a Dark Matter dominated Universe. ... What is Dark Matter? ... Theory: if the Universe is critical then all the luminous matter seen in galaxies contributes only 0.5% of the mass required to eventually halt the expansion (note that the recent WMAP results have substantially lowered the amount of dark matter required to reach a flat/critical Universe). ... Below is the velocity distribution of galaxies in the Cancer cluster: . ...

... Gravitational wave search provides insights into galaxy evolution and mergers . ... galaxies . ... Globular cluster NGC 2808, elliptical galaxy NGC 2986, and the Sextans Dwarf . ... Open cluster NGC 2818, spiral galaxy NGC 2964, and spiral galaxy NGC 2976 . ... What are typical star-to-star distances in globular clusters compared to stellar distances in our region of the galaxy? ... RELATED TOPICS: GLOBULAR CLUSTERS . ... Get instant access to subscriber content on Astronomy.com! ...

Next: SMUDGES Up: Minutes of the 1st Previous: Pilot Survey . ... The Jodrell Virgo survey is part of HIJASS and encompasses 4 X 8 degrees, fully sampled. ... This indicates that we should perhaps survey the outskirts of the cluster to look for low mass clouds. In the survey, objects were detected using a combination of by-eye method and automated routine. 28 detections of well known galaxies . ... Velocity distribution suggests infall or extension along the line of sight. ... Jon . ...

home publications > mercury . ... Big Clusters, Tiny Galaxies . ... Astronomers struggle to understand why giant star clusters form in the tiniest of galaxies . ... These clusters are probably young versions of globular clusters, but they are commonly called super star clusters. Seven dwarf galaxies within 16 million light-years have formed super star clusters, with one of these galaxies, NGC 1569, possessing two young clusters. ... Super star clusters have a lot to tell us about star formation. ...

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Astronotes Armagh Planetarium's Stellar Blog! ... Stars . ... Starbursts are short-lived events, stars are forming so quickly that the reservoirs of interstellar gas from which stars are coalescing would be used up on a timescale much shorter than the age of the galaxy . ... Strong stellar winds from giant new stars in the starburst region combine with the blasts of supernovae to push a mighty flood of extremely hot gas, a ?superwind? from the galaxy thousands of light years into intergalactic space. ...

... Visible Distribution of Galaxies. ... Features of Elliptical, Lens-Shaped, Spiral and Irregular Galaxies. Galaxies with Bar. ... Distribution of Surface Brightness of Surface and Spiral Galaxies. ... Color Characteristics of Galaxies. ... Methods of Galaxies' Mass Determination. ... Hidden Mass of Spiral Galaxies. ... Features of Dark Matter Distribution in E and SO Galaxies. ... The Whole Number of Galaxies and Their Density by the Results of Observation on the 'Hubble' Space Telescope. ...

The LCDM paradigm: successes and challenges on scales of galaxies Anatoly Klypin (NMSU) LCDM · · · · DM profiles, concentrations, .. Clustering of galaxies: P(k) and correlation functions Satellites: abundance, number-density profiles Galaxies and Dark Matter: abundances Dwarfs. ... Springel et al 2008. ... Klypin et al 2010. ... Observations - LCDM: just enough Magellanic Clouds Observations LCDM Vmax > 50 km/s Busha et al 2010 Dark matter profiles: standard LCDM Aquarius simulation. ...

... 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 ...

... The obtained results lead to the following conclusions: a) the heavy element enrichment had taken place in the Galaxy in a few bursts of its activity rether than in a continuons manner; b) these bursts occured during the callapse of the early Galaxy; c) the star formation had been inhibited in the time of the bursts; d) the metal enrichment did not proceed in the periods of star formation, between these bursts of activity. ...

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. ...