Radius between Subhalos and Distance between them

Bhuvan Manojh
  • 16 Nov

Hi, I wanted to know if the radius of the subhalos are taken into account when I calculate the distance between two subhalos. I made a function to calculate the distance between the central subhalo of a halo and some satellite given. Let's say I find a distance of about 20 kpc, how do I know if this is within the radius of the central or satellite halo? I used the 'SubhaloHalfmassRad' field to get an approximate radius for the central and it gives around ~ 186kpc. So in this case, would the satellite be "contained" in the central? I might be misunderstanding how these radii are defined perhaps...

Dylan Nelson
  • 17 Nov

If you are considering two satellite subhalos, then everything you say makes sense and is rather well posed.

However, the situation for the central subhalo is somewhat different: you should really think of a "central subhalo" as, in fact, the halo. So the radius/size of a central is essentially the size of the halo, and then by definition, many (although not all) satellites will be within this radius.

Bhuvan Manojh
  • 23 Nov

This really helps, thank you!

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