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Hi Dylan,

I am using the merger tree of Subhalo1031479 (at z=0) from TNG300-1. I found that sometimes the stellar half mass radius is zero while there is nonzero stellar mass. Is it a resolution issue or any other reason?

Also, I found that there is nonzero SFR when the gas mass within stellar half mass radius is zero. However, it makes no sense to form starts while there is no gas around. Perhaps it is due to resolution limit?

Thanks in advance,
Yu-Hsiu

Hi Yu-Hsiu,

For this subhalo I see that SubhaloHalfmassRadType[4] = 3.8, and likewise SubhaloMassInRadType[0] = 0.5. Are we talking about the same object?

Hi Dylan,

I mean along the merger tree of this subhalo. Some progenitors in this merger tree have zero stellar half mass radius but nonzero stellar mass, such as subhalo 1019315 at snapshot 25.

Hi Dylan,

I mean along the merger tree of this subhalo. Some progenitors in this merger tree have zero stellar half mass radius but nonzero stellar mass, such as subhalo 1019315 at snapshot 25.

Hi,

Yes I see, it has 1 star, and SubhaloHalfmassRadType[4] = 0. I think it's a fair statement to say that with one star, the stellar half mass radius is not defined. I guess you could define it as half the radial distance to this star, but I would consider this a very uncertain/unresolved value.

I see, thanks