Results 61 to 70 of about 777,610 (246)
GALAXY CLUSTERS AT HIGH REDSHIFT AND EVOLUTION OF BRIGHTEST CLUSTER GALAXIES [PDF]
The Astrophysical Journal, 2011 Identification of high redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada-France-Hawaii Telescope (CFHT) Wide field, 202 clusters from the CHFT Deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) and 737 clusters from the Spitzer
Wen, Z. L., Han, J. L.
openaire +2 more sources
Principal Component‐Based Classification of Blazar Candidates of Uncertain Type in the 4FGL/LAT
Astronomische Nachrichten, EarlyView.ABSTRACT We adopted principal component analysis (PCA), linear discriminant analysis (LDA), and support vector machines (SVM), to study classification for a sample of 2708 Fermi blazars: 1142 BL Lac objects (BLLs), 759 flat spectrum radio quasars (FSRQs), and 807 blazar candidates of uncertain type (BCUs).
Wen‐Xin Yang +13 more
wiley +1 more source
The “Sausage” and “Toothbrush” clusters of galaxies and the prospects of LOFAR observations of clusters of galaxies [PDF]
Astronomische Nachrichten, 2013 AbstractLOFAR, the Low Frequency Radio Array, is a new pan‐European radio telescope that is almost fully operational. One of its main drivers is to make deep images of the low frequency radio sky. To be able to do this a number of challenges need to be addressed. These include the high data rates, removal of radio frequency interference, calibration of
Jackson, Neal +30 more
openaire +7 more sources
Influence of Dynamical Friction on the Unstable Manifolds of Lagrange Points in Barred Galaxies
Astronomische Nachrichten, EarlyView.ABSTRACT Some time ago the idea has been proposed that rings and spirals in barred galaxies are shaped by the unstable manifolds of the Lagrange points sitting near the ends of the bar. The topic of the present article is an investigation of whether the numerical support for this suggestion can be improved by the inclusion of dynamical friction into ...
Christof Jung
wiley +1 more source
Gravitational lensing and galaxy clusters [PDF]
, 1995 Kaiser & Squires have proposed a technique for mapping the dark matter in galaxy clusters using the coherent weak distortion of background galaxy images caused by gravitational lensing.
Wilson, Gillian, Wilson, G
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Evolution of clusters of galaxies
The Astrophysical Journal, 1991 In hierarchical models for structure formation like CDM, the mass scale of clustering evolves rapidly and clusters in the past are predicted to be less massive, but denser and more numerous. The indication from optical searches is that the cluster population is roughly stable in that high velocity dispersion clusters seem to be about as abundant at z ~
openaire +1 more source
Statistics of Galaxy Clustering [PDF]
, 2006 In this introductory talk we will establish connections between the statistical analysis of galaxy clustering in cosmology and recent work in mainstream spatial statistics. The lecture will review the methods of spatial statistics used by both sets of scholars, having in mind the cross-fertilizing purpose of the meeting series.
Martinez, Vicent J., Saar, Enn
openaire +2 more sources
Secondary evolution of galaxies investigated by N-body simulations [PDF]
, 2008 In the ΛCDM cosmology, merging is one of the most important physical processes that drives the formation and evolution of galaxies. In the present work, we use N-body techniques to investigate some of currently open issues related to the formation and ...
Coppola, Giuseppina
core +1 more source
Direct SMBH Formation Driven by Runaway Stellar Collisions in Globally Unstable Stellar Systems
Astronomische Nachrichten, EarlyView.ABSTRACT The fueling problem addresses the ultimate fate of the reservoirs of gas and stars driven into the deepest gravitational potential wells of galaxies, thus it may contain the Universe's densest concentrations of gas and stars. This raises a key question: does the infalling material collapse directly into a supermassive black hole, or can it ...
Marcelo C. Vergara, Andrés Escala
wiley +1 more source
Towards AMR Simulations of Galaxy Formation [PDF]
, 2010 Numerical simulations present a fundamental building block of our modern theoretical understanding of the Universe. As such the work in this thesis is primarily concerned with understanding fundamental differences that lie between the different ...
MITCHELL, NIGEL,LEWIS +1 more
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