星系模拟中的气体
Gas in simulations
The gas in the Universe is in multi-phase. Some gas dissipates its internal energy through various cooling processes and eventually forms stars, while some is hotter than 10^7 K and remain in the surrounding of galaxies. Gas not only interacts with itself, but also with gravity, radiation, stars, AGN, and magnetic field. To deal with the gas component in simulation is thus challenging both to our understanding of the underlying physical processes on different scales, and to the computational techniques. In this talk, I will briefly summarize various approaches used in simulations to handle gas in different phases, including the cold gas, CGM and ICM. I will show some results from different simulations. By making comparisons between them, we can see where the current hydrodynamical simulations really help, and what difficulties we still need to be aware of.
