Visualizations of the 6dF Galaxy Survey Some highlights Fairall / University of Cape Town / November 2007
6dF reveals the bubbly texture of the Cosmos (seen here in cross section) Almost all galaxies (white dots) conglomerate into a network of large-scale structures, shown here as three-dimensional bodies, generated by ‘Labyrinth’ Software (which wraps surfaces around ‘minimal spanning trees’) Only about 1% of galaxies appear to lie in the voids. The void in the centre is about 60 Mpc (200 million light years across) Data used here are between and km/s in Supergalactic Z coordinates
Sometimes the structures seem almost orthogonal Data used here are between and km/s in Supergalactic Z coordinates Data absent in middle due to obscuration by the Milky Way, and top right due to northern Declinations.
The 6dF Galaxy Survey finds ‘cratons’ of high density (percolated by small voids) separated by low-density regions with anaemic structures. ‘Labyrinth’ software is used here to isolate the high-density regions. Data used here are between and km/s in Supergalactic X coordinates
The ‘craton’ in the preceding slide is the previously unrecognised ‘Horologium-Canis Major’ Concentration. It is 250 Mpc (800 million light years) long Its lower end links to the Horologium Concentration
The Horologium-Pictor ‘craton’ (on the right) forms a parallel structure to Horologium-Canis major Note the void in the centre, with an empty core 100 Mpc (300 million light years) across. The data used here are between and km/s in Supergalactic X coordinates. Its lower end also links to Horologium
The Horologium concentration (enlarged here) links the ‘vertical’ structures in the two previous slides Data here are between and km/s in Supergalactic X coordinates The width of the slide is about 100 Mpc (300 million light years)
Here is the more distant Telescopium Concentration Data here are between and km/s In Supergalactic X coordinates The width of this slide is about 150 Mpc (500 million light years)
A void with ‘tessellated’ sides, seen in cross section The void is about 65 Mpc (200 million light years) across. Data shown here lie between and km/s in Supergalactic X coordinates
Aquarius Void Canis Major Void Eridanus Void Sculptor Void Hydra Void e n t C a u r u s W a l l Sculptor Wall Approx 50 Mpc (150 million light years) Pavo-Indus-Telescopium Centaurus (C8) Virgo Hydra C4 (C2) C3 (N1600) Cetus V16 V31 V17 Micoscopium Void (continuation of Local Void) A3627 LMC SMC Alternatively the entire southern sky can be seen as a sequence of redshift shells. This sample shell shows relatively nearby structures The data used here has all 6dF redshifts between 4000 and 4999 km/s
The data used here has redshifts between and km/s V245 V127 V287 V389 Shapley (b) Part of Horologium- Canis Major V Mpc (150 million light years) Shapley AS0757 C29 (C30) C28 Abell 3376 Leo V88 V87 V404 V411 V415 V463 V477V465 V391 V410 V440 V441 V365 V386 V341 V301 V264 V303 V232 V277 V230 V194 V131 V129 V272 V234 V270 V200 V149 V111 V169 V217 V36 V313 V164 V138 V85 V529 V84 V226 V243 V125 V355 V371 V LMC SMC Whereas this distant shell shows part of the Shapley Concentration The Shapley Concentration is by far the greatest over-density in the 6dF volume. Note also the huge voids Obscured by the foreground Milky Way
FRONT BACK LEFT SIDE RIGHT SIDE “Top” (looking -SGZ) Shapley (a) Shapley (b) To Earth A 6dF Data cube showing the Shapley Concentration Data ‘cube’ Centred at SGX = SGY=7500, SGZ= Mpc front to back 100 Mpc left to right 70 Mpc top to bottom
“Bottom” (looking +SGZ) FRONT BACK LEFT SIDE RIGHT SIDE Shapley (a) Shapley (b) 6dF Data cube showing the Shapley Concentration
“Front” (looking –SGX) 6dF Data cube showing the Shapley Concentration
“Right-hand side” (looking –SGY) FRONT 6dF Data cube showing the Shapley Concentration
“Back” (looking +SGX) 6dF Data cube showing the Shapley Concentration
“Left-hand side” (looking +SGY) FRONT 6dF Data cube showing the Shapley Concentration