On the other hand I find in Nelson et al. 2018: "the first simulation, TNG100 … the gravitational softening length of the dark matter and stars is 0.7 kpc at z=0, and the gas component has an adaptive softening with a minimum of 185 comoving parsecs…."
Sorry if I am missing an obvious point here but could you please help me understanding how these numbers relate to each other? What is the minimum comoving softening length and how can I get the softening length in physical units as a function of redshift?
And is the softening length for stellar particles the same as for gas particles?
Hi,
I have a question about the softening lengths. Using the api to access the data I find for example for TNG100-1
softening_dm_comoving = 1.0
softening_stars_comoving = 1.0.
On the other hand I find in Nelson et al. 2018:
"the first simulation, TNG100 … the gravitational softening length of the dark matter and stars is 0.7 kpc at z=0, and the gas component has an adaptive softening with a minimum of 185 comoving parsecs…."
Sorry if I am missing an obvious point here but could you please help me understanding how these numbers relate to each other? What is the minimum comoving softening length and how can I get the softening length in physical units as a function of redshift?
And is the softening length for stellar particles the same as for gas particles?
Thanks a lot in advance,
Peter
Hi Peter,
The values
are in "code length units" of
ckpc/h. So dividing byhgives 0.7 ckpc, or 0.7 pkpc at z=0.Stars and DM have similar softenings, while for gas it is quite different (adaptive). This should be well described in Pillepich+ (2018).