I am wondering if there is a way to get the box's dimension of the halo/subhalo. Specifically, when using the data from TNG100, each snapshot's dimension would be approximately 100x100 Mpc. But when downloading the data of the Halo/Subhalo, the box's dimensions would be smaller, so how could I get the size of that box? Or is there a way that I can calculate the dimension of the smallest box that completely contains the central galaxy of a Halo or the galaxy of the corresponding Subhalo?

Thank you in advance,
Thang

Dylan Nelson

8 Feb

I believe you are referring to "snapshot cutouts" (of particle data).

They do not have any box size - their extent is set by the distribution of particles in that (sub)halo. Computing the min/max of all the Coordinates, along each direction, will give you that extent.

"The dimension of the smallest box that completely contains the (particles of) a galaxy/halo/subhalo" is not information available in any catalog, but you can compute it exactly as described above.

Dear all,

I am wondering if there is a way to get the box's dimension of the halo/subhalo. Specifically, when using the data from TNG100, each snapshot's dimension would be approximately 100x100 Mpc. But when downloading the data of the Halo/Subhalo, the box's dimensions would be smaller, so how could I get the size of that box? Or is there a way that I can calculate the dimension of the smallest box that completely contains the central galaxy of a Halo or the galaxy of the corresponding Subhalo?

Thank you in advance,

Thang

I believe you are referring to "snapshot cutouts" (of particle data).

They do not have any box size - their extent is set by the distribution of particles in that (sub)halo. Computing the min/max of all the

`Coordinates`

, along each direction, will give you that extent."The dimension of the smallest box that completely contains the (particles of) a galaxy/halo/subhalo" is not information available in any catalog, but you can compute it exactly as described above.