Monika Biernacka Włodzimierz Godłowski Teresa Juszczyk Paulina Piwowarska Elena Panko

1. Some properties of galaxy clusters Piotr Flin Monika Biernacka Włodzimierz Godłowski Teresa Juszczyk Paulina Piwowarska Elena Panko

2. The organisation of the talk • Observational data • Numerical simulation • PF catalogue of structure • Shape of structures • e-z relation • Binggeli effect • richness vs alignment • Tully’s group alignment • Conclusions

3. Motivation of study

5. Large scale distribution of matter in the Universe(cosmic web) long structures ( filaments) flat structures (sheets, walls) dense, compact regions (galaxy clusters ) surrounded by depopulated regions (voids)

8. Observational data • The Muenster Red Sky Survey is a large-sky galaxy catalogue covering an area of about 5000 square degrees on the southern hemisphere. The catalogue includes 5.5 millions galaxies and is complete till photo-graphic magnitude rF=18m.3 (Ungruhe 2003). • 217 ESO Southern Sky Atlas R Schmidt plates with galactic latitudes b<-45 were digitized with the two PDS microdensitometers of the Astronomisches Institut at Muenster. The classification of objects into stars, galaxies and perturbed objects was done with an automatic procedure with a posterior visual check of the automatic classification. The external calibration of the photographic magnitudes was carried out by means of CCD sequences obtained with three telescopes in Chile and South Africa. The MRSS contains positions, red magnitudes, radii, ellipticities and position angles of about 5.5 million galaxies and it is complete down to rF=18m.3.

9. Distribution of galaxies of Muenster Red Sky Survey. Blue color indicates low galaxy densities, green and yellow high galaxy densities. White spot is the region around the SMC.

10. Structure finding • We selected the Voronoi tessellation technique (VTT hereafter)for cluster detection. • This technique is completely non-parametric, and therefore sensitive to both symmetric and elongated clusters, allowingcorrect studies of non-spherically symmetric structures. For adistribution of seeds, the VTT creates polygonal cellscontainingone seed each and enclosing the whole area closest to the seed.This is the definition of a Voronoi cell in 2D.

11. Voronoi cells for PF 2243-4774 region (left panel) and the found cluster members as black dots with non-clustered galaxies as open symbols (right panel). PJF 2009, AJ 138, 1709

12. Structure ellipticity determination Using standard covariance ellipse method for galaxies in the considered region within the magnitude limit m3, m3+3m, we determined the moments of the distribution: The semiaxes in arcsec for the best-fitting ellipse were calculated from: Position angle: Ellipticity:

13. Structures PF 0364-3272 and PF 2243-4774 in tangential coordinates, north is up. Open dots represented the structure members, black symbols corresponded to brightest galaxy in cluster, and line notes the direction of fitted ellipse major axe. Ellipticity and major axis position angle are shown in the right corner for each structure. PJF 2009, AJ 138, 1709

15. N Identification for input data a b Number SD R 1 ACO (0.5r) -3.895 (±0.210) 0.1737 (±0.012) 455 0.17 0.56 2 ACO (0.3r) -3.771 (±0.242) 0.1660 (±0.015) 290 0.17 0.55 3 APM (0.5r) -3.813 (±0.148) 0.1684 (±0.009) 372 0.11 0.65 4 ACO (m10<19m.3) -3.767 (±0.195) 0.1641 (±0.0116) 519 0.18 0.28 Table 1. The result of the statistical analysis of m10 - z relation BFJP, 2009, ApJ 696, 1689

16. Recent dynamical evolution Plionis (2002)

17. 6068 struktur PF

18. The distribution of estimated z and the limits of the division into groups BFJP 2009, ApJ 696, 1689

19. BFJP 2009, ApJ 696, 1689

20. BFJP 2009, ApJ 696, 1689

21. The frequency distributions of structure ellipticities in four classes with richness identified in the upper right portion of each section (left panel all data, right panel 457 structures with m3+3m18m.3). PJBF 2009, ApJ 700, 1686

22. The frequency distribution of structure redshifts for samples containing different number of galaxies in the structure (left panel all data, right panel 457 points) PJBF 2009, ApJ 700, 1686

23. The dependence of group richness on redshift z.(left panel all data, right 457points) PJBF 2009, ApJ 700, 1686

24. The ellipticity-redshift relation for galaxy group samples,with the galaxy populations of each structure noted in the upper right hand corners. The fitted linear relationstogether with their = 0.95 confidence intervals are also plotted. PJBF 2009, ApJ 700, 1686

25. The cluster ellipticity e (left panel) and cluster ellipticity evolution rate de/dz (right panel) versus redshift for four samples of different richness. Error bars correspond to  = 0.95 confidence intervals. (upper panel all data, lower 457 points) PJBF 2009, ApJ 700, 1686

26. The distribution of structure ellipticity is identical for structures with N>50 members • Less populated structures are more elongated than rich ones.  • The small groups are forming on the filament and later on, due to hierarchical clustering, greater, more spherical structures are formed. The additional argument for this picture: the mean group redshift is greater than clusters. • The elipticity – redshift realtion depends on the structure richness. The difference between ellipticity and evolution rate de/dz for small groups are at the 3level different from rich ones. • Only groups with 10-30 member galaxies exhibit the strong e-z correlation. • Numerical simulations show that in ΛCDM for z <3.0 ellipticity increases with z, as well as the structure mass. We support the first point, but our redshits are small. In simulations: very massive structures were considered (21013h-1 Msun ).

28. The frequency distribution of position angles for the two brightest galaxies PA1 and PA2 in the structure and structure position angle PAs. Dotted lines refer to an isotropic distribution, and a 1 error bar is also shown. PJF 2009, AJ 138, 1709

29. The frequency distribution of the angle θ1 between the brightest galaxy and parent cluster for groups of BM type I and I-II. Dotted lines show the isotropic distribution, together with a 1 error bar. PJF 2009, AJ 138, 1709

30. The lack of galaxy orientation is in agreement with CDM The physical processes in the filament: Either: (anisotropic merging of structures + infall of matter) orientation of galaxies or: (tidal torque) lack of orientation Our result: lack of orientation Angular momenta of galaxies are due to tidal interaction of neighbours in the early Universe. The flow of matter along the filament causes the co-linearity of the brightest galaxy with the structure great semi-axis.

31. Binggelieffect structure is pointing toward neighbours

33. Only in the case of BM I type clusters the effect is observed, and also BM II-III

35. The orientation of galaxies in clusters • rich clusters having at least 100 members each. The relation between • parameters describing galaxy orientation (position angle p, the angles: δDand η) • and value of statistics, used for anisotropy calculation Value of statistics increase with the amount of the galaxy members, which is equivalent tothe existance of a relation between anisotropy and the number of galaxies in a cluster. GPPF 2010, ApJ 723. 985

36. Local Supercluster Investigation of Tully’s group (NGC) alignment

37. LSC GF ApJ 708,.920 (2010)

38. Position angles: Pag group position angle Pabm PA of the brightest galaxy Pal PA of the line joining two brightest galaxies in group Pav Virgo PA (direction toward Virgo ) The distribution of the four PA were checked as well the differences between: Pag – Pav Pal – PaV Pag – Pal Pabm – Pag Pabm – Pal Pabm – Pav

39. GF ApJ 708,.920 (2010)

40. Angle difference GF ApJ 708,.920 (2010)

41. Binggeli effect for Tully’s group GF ApJ 708,.920 (2010)

42. Conclusions Two brightest galaxies are formed on the filament directed toward LSC centre. The gravitational interaction of groups originates on the line joining these two brightest galaxies. Therfore we observed the alignment of the structure position angle and line joining two brightest galaxies

43. Conclusions • The distribution of structure ellipticities depends on the structure richness. Richer are more spherical. • The e – z dependence shows that in the past the interactions were stronger. • The distribution of the position angles of the 10 brightest galaxies are random ones. • The differences between structure position angle and brightest galaxies are random. • Only in the case of cD galaxies the alignment is observed; the special evolution of such clusters. • Structures are formed on the filament • Richer groups exhibit bigger alignment

44. Thank you

46. Struktury PF 6068 struktur przedział jasności: m3 – m3+3m

47. Contingency table 0.05=1, 358 0.01=1.627

48. PA Distribution The division of ACO clusters corresponding to PF structures according to structure richness and B-M morphological types