I want to study the filaments in TNG. Could you provide the filaments catalogue?
Dylan Nelson
10 Sep '19
Hello,
We don't have any such data available at the moment for TNG.
There are two possible things in progress: (i) from Davide Martizzi based on the usual Hessian of the density field, i.e. this paper, and (ii) from Chris Duckworth, finding filaments based on the DISPERSE algorithm (in prep).
If you'd like to use either of these, you should contact these authors directly and inquire. Otherwise you'd be welcome to run your own filament finder-type algorithm.
I have checked the Cosmic Web Distances identified by the DisPerSE code. I note that subhalos with a minimum stellar mass of 10^8.5 solar mass are used to define the cosmic web. However, the code given by Duckworth is
def return_stel_tracers(basepath, snapnum, blen, min_mass=10**8.5):
'''
returns stellar tracer positions for all objects with a defined minimum mass at a
defined snapshot. basepath should direct to /output directory of chosen simulation
and blen should be the corresponding box side length.
'''
# Subhalo fields
sfields = ['SubhaloMassType','SubhaloPos']
subhalos = gc.loadSubhalos(basepath, snapnum, fields=sfields)
# selecting based on total mass within the subhalo.
return subhalos['SubhaloPos'][()][subhalos['SubhaloMassType'][()][:,4]*10**10 > min_mass]
Maybe he did not consider dividing by h.
Dylan Nelson
25 Mar '23
Yes you are probably right, that the minimum mass is therefore 1e8.5/h. I will update the documentation with this note.
Hi, Dylan,
I want to study the filaments in TNG. Could you provide the filaments catalogue?
Hello,
We don't have any such data available at the moment for TNG.
There are two possible things in progress: (i) from Davide Martizzi based on the usual Hessian of the density field, i.e. this paper, and (ii) from Chris Duckworth, finding filaments based on the DISPERSE algorithm (in prep).
If you'd like to use either of these, you should contact these authors directly and inquire. Otherwise you'd be welcome to run your own filament finder-type algorithm.
As a follow-up, this data catalog has now been released as Cosmic Web Distances (Disperse).
Hi Dylan,
I have checked the Cosmic Web Distances identified by the DisPerSE code. I note that subhalos with a minimum stellar mass of 10^8.5 solar mass are used to define the cosmic web. However, the code given by Duckworth is
def return_stel_tracers(basepath, snapnum, blen, min_mass=10**8.5):
'''
returns stellar tracer positions for all objects with a defined minimum mass at a
defined snapshot. basepath should direct to /output directory of chosen simulation
and blen should be the corresponding box side length.
'''
Maybe he did not consider dividing by h.
Yes you are probably right, that the minimum mass is therefore 1e8.5/h. I will update the documentation with this note.