Your description of our problem is correct. We use the setup “galaxy_merger_star_formation_3d” as a template. In the “param.txt” file we only edit the BoxSize, ReferenceGasPartMass, and MeanVolume parameters according to our ICs, so probably we’re missing something important here. On the other hand, for the files related to “ADDBACKGROUNDGRID” we didn’t change anything. You can find the “Setup.sh”, “param.txt”, and the ICs files in this link:
For the moment, the ICs file only contains gas particles as we want to characterize the Arepo’s HD. The next step is adding collisionless particles (DM halo, stellar disk, and bulge) trying to reproduce a MW-type galaxy.
Best regards and thanks a lot for your kind help.