This is a single output of a cosmological simulation of a volume a little more than 1 billion light years across, simulated with 1 billion dark matter particles and over 10 billion resolution elements. Dark matter dominates the matter content and, as can be seen in the video, has collapsed into the filamentary structure known as the cosmic web. The bright points that lie at the intersection of these filaments are the sites of galaxy and galaxy cluster formation. The simulated volume is sufficiently large to contain hundreds of rare massive clusters and was used, for example, to study how differences in the formation history of these objects affect their structure.

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This video shows the complicated formation of a single galaxy cluster. The dark matter (top left) and gas (top right) collapse early into small clumps or halos, and the gas is converted into stars (top middle). Some of those stars end their lives in supernovae and enrich the gas around them with heavy elements and metals (bottom right). As gas falls into the large scale filaments, strong accretion shocks form (most easily seen in entropy, bottom middle). This heats the gas to temperatures above 10 million degrees (bottom left), so hot that it emits x-rays. The final galaxy cluster forms at z ~ 0.5 from the massive collision between two equal-sized projenitors. Download full-size video

This video zooms in on the final merger of the previous video for two simulations which follow slightly different physics. The right-hand panels show the rate of mixing between gas in the two halos; blue shows gas that has not mixed and red shows where the gas is well mixed. In the top simulation the gas mixes all the way to the center, causing a flat entropy profile on the left. The bottom simulation, on the other hand, has higher pressure at the center, which prevents the gas from fully mixing, and which protects the low-entropy cusp at the cluster center.

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This is a visualization of a simulated galaxy provided by Nick Gnedin. I created this video with his IFrIT visualzation tool to demonstrate the 3-d projector at the UChicago Research Computing Center (this is only a 2-d version). The dense gas in the galaxy's disk is shown in pink and stars are shown in orgnge. Note the strong warp in the gaseous disk and spiral arms in the stars. Download full-size video