Resolving Cosmic Structure Formation with the Millennium-II Simulation

(1) MPA, (2) Durham, (3) ARI-ZAH, (4) MPE
Mon. Not. Roy. Astron. Soc., 398, 1150 (2009); arXiv:0903.3041 [astro-ph]
Abstract and paper (NASA ADS)

The Millennium-II Simulation is a very large N-body simulation of dark matter evolution in the concordance ΛCDM cosmology. It uses the same cosmological parameters and number of particles as the Millennium Simulation in a cube one-fifth the size (100 Mpc/h), resulting in 5 times better spatial resolution (1 kpc/h) and 125 times better mass resolution (6.89 x 10⁶ M_sun/h). The combination of the Millennium and Millennium-II Simulations provides precise results over an unprecedented range of scales. Furthermore, the six Milky Way-mass halos resimulated in the Aquarius Project were selected from a lower resolution version of the Millennium-II Simulation. The Aquarius halos, and several thousands of other halos with similar masses, are therefore present in the Millennium-II Simulation.

Dark matter halo catalogs, merger trees, and galaxy catalogs (based on the semi-analytic model described in Guo et al. 2011) from the Millennium-II Simulation are publicly available (registration required).

Visualization

Movies

Movie credits: Boylan-Kolchin et al. (2009)

Fast fly-through: low resolution (512 x 384, 51 MB): Unix / Mac or Windows high resolution (1024 x 768, 204 MB): Unix / Mac or Windows Slow fly-through: low resolution (512 x 384, 82 MB): Unix / Mac or Windows high resolution (1024 x 768, 345 MB): Unix / Mac or Windows

In this movie, the viewer flies through the dark matter distribution of the Millennium-II Simulation at redshift zero towards the most massive dark matter halo in the simulation. After pausing at 2.5 Mpc/h from the center of the cluster, the camera rotates around this halo, revealing its three dimensional structure. A final rotation and zoom to 1 Mpc/h from the halo center shows the richness of substructure on even smaller scales.

Note on formats: Both versions are encoded using MPEG-4.   The Unix / Mac version should play on mplayer or xine (Unix) and Quicktime (Mac) without any additional plug-ins; the same is true on Windows Media Player for the Windows version.

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Composite images (click to enlarge)

Image credits: Boylan-Kolchin et al. (2009)

Zoom sequence from 100 to 0.5 Mpc/h into the most massive halo in the simulation at redshift zero. [text-free version]	Time evolution of the formation of the most massive halo. From left to right: 100, 40, and 15 Mpc/h (all in comoving units). From top to bottom: z=6, 2, 1, and 0.

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Individual images (click any image to enlarge):
Image credits: Boylan-Kolchin et al. (2009)

Redshift zero

This set of 6 images starts at the full scale of the simlation (100 Mpc/h) and zooms into the largest halo at redshift zero, ending up at a scale of 0.5 Mpc/h.   (These are the images that compose the zoom sequence above.)

100 Mpc/h	40 Mpc/h	15 Mpc/h

5 Mpc/h	2 Mpc/h	0.5 Mpc/h

Time Evolution

This set of 12 images shows the growth of the most massive halo over cosmic time. The left column is 100 x 100 Mpc/h, the center column is 40 x 40 Mpc/h, and the right is 15 x 15 Mpc/h (in comoving units). From top to bottom, the regions are plotted at redshift 6, 2, 1, and 0.   (This is the set of images that composes the time evolution sequence shown near the top of this page on the right.)

			z=6.2
			z=2.07
			z=0.99
			z=0
100 Mpc/h	40 Mpc/h	15 Mpc/h