Simulation of an isolated disc galaxy, looking at the disc of the galaxy face on (top panels) and edge on (bottom panels). The left-hand panels show images of the stellar light, and is what we would see if we viewed this galaxy with a telescope such as Hubble. The right-hand panels show the gas in the simulation, colour-coded according to the temperature, from cold (100 K) gas in blue to hot (10^7 K) gas in yellow.
Credit: Alex Richings / Northwestern