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Evolution of structure in the Universe

Evolution of structure in the Universe. Galaxy Superclusters Detected in the MPF-Catalogue Using the FoF Method Elena Panko Nikolaev National University. Input data.

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Evolution of structure in the Universe

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  1. Evolution of structure in the Universe Galaxy Superclusters Detected in the MPF-Catalogue Using the FoF Method Elena Panko Nikolaev National University

  2. Input data PFcatalogue (Panko, E., Flin,P. A Catalogue of Galaxy Clusters and Groups Based on the Muenster Red Sky Survey. // 2006. - J. Astron. Data.– V. 12. – Р.1.) This catalogue was created on statistically completed data by making use of galaxy positions and magnitudes given in the Muenster Red Sky Survey (MRSS). Limit magnitude rF= 18m.3 1711 PF galaxy clusters have more, than 50 members

  3. The distribution of PF galaxy clusters on celestial sphere. The size of symbol illustrates the richness. P' notes the South Pole.

  4. Since the Muenster Red Sky Survey does not contain galaxy redshifts, the distances to galaxy clusters were estimated using the (logz)–m10 relation: log z = −3.771 + 0.1660 m10 The estimated redshifts for 1711 input galaxy clusters.

  5. Superclusters search The distances to nearest neighbour for all 1711 clusters are in the limits between 4.6 to 173.7 h-1 Mpc, but only for 20 structures neighbour places farther than 68.5 h-1 Mpc. Value 24 h-1 Mpc for simulated random distances combines 20% of objects. We used it for clusterization.

  6. Superclusters Using Friend-of-Friend method with critical distance D= 24 h-1Mpc were found 111 superclusters with richness from 3 to 9. Supercluster shapes were estimated under the assumption of thee-axial ellipsoid. The positions of supercluster components were respected to the supercluster centroid and then the matrix was diagonalized. The diagonal elements are proportional to the best-fit ellipsoid semi-axes.

  7. The ellipticities of the 62 3-member superclusters D = 0.387  = 2.155 D =0.323  = 1.798 E=1-b/a E=1-b/a 3-memebr galaxy superclusters are elongate. It is not random shape. It is shown in comparison with simulated 3-memebr structures. Kolmogorov-Smirnov has corresponding values=0.05 = 1.385 and =0.01 = 1.627.

  8. The shape of 49 superclusters with richness 4 -9. 20 superclusters are flat elongated structures (c/a  0.1 and for 19 from this 20 ones b/a<0.5). Their richness is 4 and 5, and only one 6-member cluster is plane structure. From all list only 2 supercluster (with N=4 and N=8) has c/a>0.5 and b/a>0.75 (noted by arrows). Other superclusters have maximal c/a=0.38 and the shape of supercluster did not show significant dependence form richness. c/a

  9. Conclusions • We found 49 superclusters with richness from 4 to 9 in with estimated redshifts in limits 0.068  0.117. • Typical size of these structures is about 55 h-1 Mpc, and they are flat and elongated structures. • Typical b/a 0.47 and c/a 0.15 exclude 2 superclusters with b/a>0.75 and c/a>0.5 • 69 superclusters with richness 3 are elongated too.

  10. Thank you!

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