I will present theresults from a deep, extended, planetary nebulae survey in a 0.5 sqdeg region centered on the brightest cluster galaxy NGC 4486 (M87) in the Virgo cluster core, carried out with SuprimeCam@Subaru and FLAMES-GIRAFFE@VLT. ... A substructure detected in the projected phase-space of the line-of-sight velocity vs. major axis distance for the M87 halo planetary nebulae provides evidence for the recent accretion event of a satellite galaxy with luminosity twice that of M33. ...

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. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2011 June 29 . Abell 2744: Pandora's Cluster of Galaxies . Image Credit: NASA , ESA , J. Merten ( ITA , AOB ), D. Coe ( STScI ) . ... 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 . ... About APOD | ...

... 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 . ...

... Science . ... The goal is to bring together two communitities: the one working on star formation (mostly galactic) and the one working on the formation of young massive clusters (mostly extra-galactic). We will link galactic with extra-galactic work, optical/NIR techniques with sub-mm/mm/radio ones, the formation of stars with the one of massive star clusters - observations and theory. ... Coordinated by Marina Rejkuba (abstract) . ... How did star formation proceed in Globular Clusters? ...

Last time we saw that flat rotation curves for galaxies, when measured in galaxies with extended gas distributions, provides unambiguous data that shows the mass distribution is dominated by an unseen, spherical halo. ... Perhaps only galaxies with extended dark matter halos are capable of retaining large gaseous extents? . ... Clusters of Galaxies: . ... The case of the Cancer cluster: . ... Below is the velocity distribution of galaxies in the Cancer cluster: . ... What's going on in Cancer? ...

... Authors: Arunav Kundu 1,2 , Bradley C. Whitmore 1 Using the WFPC2 on-board the HST we have identified 144 globular cluster candidates in the inner region of the S0 galaxy NGC 3115. The color distribution of the globular clusters is bimodal, with a blue peak at V-I = 0.96 mag and a red peak at V-I = 1.17 mag. ... While the red clusters follow the thick disk component of the galaxy, the blue cluster distribution is less flattened and mimics the bulge/halo light distribution. ... huizinga@stsci.edu . ...

Authors: V.A. Marsakov , T.V. Borkova , . ... It is shown that general populations of globular clusters and metal-poor field stars are components at least of three subsystems occupying different volumes in the Galaxy. The thick disk and proto-disk subsystems are genetically associated with the Galaxy. ... It is argued that heavy-element enrichment and the collapse of the proto-galactic medium occurred mainly in the period between the formation of the proto-disk halo and thick disk subsystems. ...

... 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. ...

... 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. ...

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. ...

Figure 1. ... Scattering geometry illustration. ... Maps of scattering angle in the cluster core for standard GCW grains and a Model A nebula (left) and UV-altered GCW grains in the same model (right). ... Degrees of consistency between the scattering angles of different models at different wavelengths. ... Schmidt scattering angles over a wider area. ... Schmidt line-of-sight separations over the same area, derived for two different simplified geometric models. ...

... Why Lyman Limit Systems (a.k.a LLSs)? ... 2014; MF et al. 2015 in prep Method #2: LLS autocorrelation The basic idea behind the experiment is to probe the correlation length of LLSs , which should correspond to the size of halos Dark matter halos NH N H Projected Separation NHI UVB Redshift Method #2: LLS autocorrelation The basic idea behind the experiment is to probe the correlation length of LLSs , which should correspond to the size of ...

... 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 . ...

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? ...

... Up: Surveys & Large Scale Data Management . ... The CoCat (Co-processor Catalogue) project main goal is to parallelize the VizieR large catalogue treatments (data extraction, cross-matching) for reducing the response time. ... Figure 2: The CoCat cluster. As the Sun server is becoming overloaded we decided to move the set of large catalogues to a Linux cluster (the CoCat cluster). ... The CoCat cluster involves one master node and five slave nodes (Fig 2 ). ...

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 ). ...

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. ...

FAMILIES AND SCATTERING . ... An important observation on the orbital distribution of irregular satellites is that satellite families at Saturn, Uranus and Neptune are not well defined. At Jupiter one finds 3-4 reasonably compact retrograde families, corresponding to each of the previously known retrograde irregulars and one prograde family. ... That is contrary to the current doctrine that very little has happened to these irregular satellite families following their collisional formation. ...