IllustrisTNG 50 - Formation of a small galaxy cluster

The motion of cosmic gas in a small region of TNG50, color encoding velocity from at rest (black) to 1000 km/s (bright red and white). At early times, accretion and infall from the intergalactic medium coallesces in the centers of many small halos. Stellar feedback produces slow galactic winds which gradually push mass outwards, until several central blackholes become sufficiently massive to launch high-velocity outflows to large distance. Past redshift one, we switch to a view of the stellar distribution of this forming protocluster, revealing the process of the hierarchical assembly of structure and its signatures: stellar streams, shells, tidal tails, and merging galaxies. The binary coallesence of the two galactic nuclei occurs at z=0.15, sending spiral waves outwards into the ICL. --- z = redshift