Or at least the start of it. Last time I described the results of a set of simulations exploring what happens to a gas stream that's dropped into the chaotic gravitational field of a galaxy cluster. The idea was to see if the stream would get torn apart and produce clouds similar to what we see in real clusters. It didn't.
The advantage of only simulating a stream of gas is that it's computationally cheap - a batch of 27 simulations can run in an afternoon. The problem is that you have to make up some model for what the stream should be like and the gravity of the parent galaxy is missing. So for the sequel we're correcting that, modelling a galaxy with full particles for the gas, stars, and dark matter. That's a lot more computational expensive (these 27 will probably take 1-2 weeks) but quite a lot more accurate. Now the streams form by themselves so we don't have to worry about setting them up correctly.
Initially I was worried that streams didn't seem to be forming at all. The gravity of 400 other galaxies buzzing around seemed to bother the target galaxies not a jot. Oh dear, there go a whole bunch of theories... fortunately I just hadn't waited long enough.
This very preliminary result shows the formation of a long, one-sided tail. So far (AFAIK) that's only been shown in one other paper, which I have a lot of problems with because their modelled galaxy isn't very realistic. It seems that isn't such a big problem after all, and what our simulations will be able to show is how common such features might be. Still no sign of any isolated clouds though, which was the interesting result of the first paper. So it looks like this should keep everybody happy. Hurrah !
No comments:
Post a Comment