The richest superclusters:SCL126 and SCL9

Maret Einasto,

J. Einasto, E. Saar, E. Tago, L.J. Liivamägi, and others

Tartu Observatory

SCL9 – 2dF Southern slice SCL126 - 2dF Northern slice

SCL126 and SCL9 in the 2dF Redshift Survey

Supercluster data

Center: 196h, -1.75 deg, 250 Mpc 10h, -29 deg, 326 Mpc N(2dFgroups) 42 26 N(Abell clusters) 9 12(25)N(X-ray clusters) 4 2(6)N(galaxies) 3591 3175δ(mean) 7.7 8.1L(tot) 0.4x1014Lsun mass > 2 x 1016 Msun 0.5x1014Lsun Length 70 Mpc 150 Mpc

For comparison:The Shapley Supercluster: N(Ab) = 28, N(X)= 8, length > 100 Mpc, mass > 2 x 1016 Msun

The Horologium-Reticulum Supercluster: N(Ab) = 35, N(X)= 10, length > 100 Mpc, mass > 2 x 1016 Msun

A1750A1651, 1650, A1663:Very compact high-density core region(~10 Mpc)

Multiple mergersEvidence of a filament with X-ray clusters(Belsole etal 2004, Donelly etal 2001)

Imprints of such superclusters on CMB maps(SZ, RS effects, Rubino-Martin etal 2004)

SCL126 in 2dFSupercluster SCL126

A2811, A2829

Supercluster SCL9

Substructures in superclusters

SCL126 SCL9

P – passive, non-star-forming, red galaxies (early type)A – actively star forming, blue galaxies (late type)

Galaxy populations in superclusters:luminosity

Luminosity functions of galaxies in groups.

G10: rich groups (Ngal >= 10), G2: poor groups (Ngal < 10), IG: isolated galaxies (those not in groups)

SCL126 SCL9

Galaxy populations in superclusters:colours

Colour index col: col > 1.07 – red, passive galaxies (P)

col < 1.07 – blue, actively star-forming galaxies (A)

blue red blue red

P/ASCL126: 2.77SCL9: 2.45

Quantifying morphology with Minkowski functional V3 (Euler characteristic)

V3 – the number of isolated clumps, mf – mass fraction: the ratio of the mass in regions with density lower than the density on the surface, to the total mass of the supercluster

Rich superclusters – a challenge for cosmological models

There are too many of them.

Galaxy formation and evolution depend on both local and global environment.

Richness of groups and their galaxy content depend of environment.

Bright/faint galaxy distribution more clumpy than in models.

Rich superclusters – a challenge for cosmological models

There are large differences between the richest superclusters:1. SCL126 contains very compact core with X-ray clusters. Collapsing core? In models such cores are very rare (Gramann and Suhhonenko 2002)2. Structure SCL9 more similar to model superclusters than SCL126.3. Galaxy populations and distribution/clumpiness in SCL126 the fraction of red galaxies higher than in SCL9 – SCL126 – older? One of the first superclusters?

z=2 z=0