Me and my group have been doing some galaxy colisions simulations in Gadget-4. After testing many initial condition codes. We found some troubles in a few of them, so we thought "Maybe we can use a galaxy taken from another big simulation as a Initial condition". I try to do this, but the simulation of just one galaxy taked from TNG it is not stable. So my question. Is this possible ? Anyone have been try too ?
Thanks in advance,
In theory it may be possible, but I think you might also find stability problems.
I know of one case where this was attempted - if you want to try it, I would excise a large cutout around the galaxy of interest, at least 3 times the virial radius of the parent halo. Then, I would delete all other particles/cells in the box, and replace them with a coarse (i.e. very low resolution / very high mass) "background grid" of gas cells and dark matter particles, which together sum up to all the mass removed. The background gas should be hot and low density so it doesn't really evolve.
In such a setup, I think it would be possible to use a TNG galaxy as an initial condition.
However, I think a more idealized setup (i.e. using GalIC) might be simpler to get working.