I would like to calculate the inflow and outflow rates of galaxies in the TNG300-1 simulation. In this context, what choice of radius is typically adopted for measuring these rates? Should the radius be fixed for all galaxies, or should it vary with galaxy mass (for example, scaled to the virial radius)? I would appreciate guidance on which approach is more appropriate and why.
Dylan Nelson
3 Feb
You will see many analyses along these lines in Nelson+19, as well as references to other simulation papers that have studied outflows.
In short, I would say there is no true answer: it is up to the science question that you wish to answer.
In general, fixed apertures (i.e. in kpc) applied to galaxies/halos with extremely different sizes rarely make sense. For "galaxy-scale outflows" or "halo-scale outflows" I would suggest to use the flow across the corresponding radius, i.e. the radius must change for different mass galaxies/halos.
I would like to calculate the inflow and outflow rates of galaxies in the TNG300-1 simulation. In this context, what choice of radius is typically adopted for measuring these rates? Should the radius be fixed for all galaxies, or should it vary with galaxy mass (for example, scaled to the virial radius)? I would appreciate guidance on which approach is more appropriate and why.
You will see many analyses along these lines in Nelson+19, as well as references to other simulation papers that have studied outflows.
In short, I would say there is no true answer: it is up to the science question that you wish to answer.
In general, fixed apertures (i.e. in kpc) applied to galaxies/halos with extremely different sizes rarely make sense. For "galaxy-scale outflows" or "halo-scale outflows" I would suggest to use the flow across the corresponding radius, i.e. the radius must change for different mass galaxies/halos.