Evolution of structure in the UniverseEvolution of structure in the Universe

Galaxy Superclusters Detected Galaxy Superclusters Detected in the MPF-Catalogue Using the in the MPF-Catalogue Using the FoFFoF

MethodMethod

Elena PankoElena Panko

Nikolaev National UniversityNikolaev National University

Input dataInput dataPFPF cataloguecatalogue (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

RichnessRichness Number of PF Number of PF clustersclusters

50-10050-100 12501250

101011--200200 362362

201-300201-300 7171

301-400301-400 1919

>400>400 99

AllAll 17117111

1711711 PF galaxy clusters 1 PF galaxy clusters have mhave more, than

50 members

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

The estimated redshifts for 1711 input galaxy clusters.

log log z z = −3= −3..771 + 0771 + 0..1660 1660 mm1010

Since the Muenster Red Sky Survey does not contain galaxy redshifts, the

distances to galaxy clusters were estimated using the (logz)–m10 relation:

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.

SuperclustersSuperclusters

Using Friend-of-Friend method with Using Friend-of-Friend method with critical distance critical distance DD  = 24 = 24 hh-1-1MpcMpc

were found 111 superclusters with were found 111 superclusters with richness from 3 to 9.richness from 3 to 9.

Supercluster shapes were estimated Supercluster shapes were estimated under the assumption of thee-axial under the assumption of thee-axial

ellipsoid. ellipsoid.

The positions of supercluster The positions of supercluster components were respected to the components were respected to the supercluster centroid and then the supercluster centroid and then the

matrix was diagonalized. The matrix was diagonalized. The diagonal elements are proportional diagonal elements are proportional to the best-fit ellipsoid semi-axes. to the best-fit ellipsoid semi-axes.

N clusters N clusters N super-N super-

clustersclusters

33 6262

44 3030

55 1010

66 55

77 11

88 22

9 1

The ellipticities of the 62 3-member superclustersThe ellipticities of the 62 3-member superclusters

3-memebr galaxy superclusters are elongate. It is not random shape. It is 3-memebr galaxy superclusters are elongate. It is not random shape. It is shown in comparison with simulated 3-memebr structures. Kolmogorov-shown in comparison with simulated 3-memebr structures. Kolmogorov-Smirnov has corresponding valuesSmirnov has corresponding values =0.05=0.05 = 1.385 and = 1.385 and =0.01=0.01 = 1.627 = 1.627..

D = 0.323 = 1.798

D = 0.387 = 2.155

E=1-b/a E=1-b/a

The shape of 49 superclusters with richness 4 -9.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

ConclusionsConclusions

We found 49 superclusters with richness from 4 to 9 in We found 49 superclusters with richness from 4 to 9 in

with estimated redshifts in limits 0.068 with estimated redshifts in limits 0.068 0.117. 0.117.

Typical size of these structures is about Typical size of these structures is about 55 55 hh-1-1 Mpc, Mpc,

and they are flat and elongated structures. and they are flat and elongated structures.

Typical Typical bb//aa 0.47 and 0.47 and cc//aa 0.15 exclude 2 superclusters 0.15 exclude 2 superclusters

with with bb//aa>0.75 and >0.75 and cc//aa>0.5>0.5

69 superclusters with richness 3 are 69 superclusters with richness 3 are elongated too. elongated too.

Thank you!