### Unit of the HI mass given by Diemer et al.

Zhixing Li
• 1
• 17 Sep '20

When I was using the HI mass data in [Supplementary Data Catalogs - (i) Molecular and atomic hydrogen (HI+H2) galaxy contents], I found that the HI abundance in my results, which was obtained using this data, is much smaller than the HI abundance in published papers. It seems the unit of the HI mass should be Msun/h rather than Msun, or the HI abundance in published papers must be wrong. Can you just check again the unit of HI mass for me? That will be really helpful.

Benedikt Diemer
• 18 Sep '20

Hi Zhixing, the masses should be in solar masses (no h). Can you point to exactly the published plots that you think are wrong?

Zhixing Li
• 10
• 21 Sep '20

Hi Diemer,

The figure 2 in 'Ingredients for 21cm Intensity Mapping', which is published by Navarro et al. in 2018, demonstrates the HI abundance. In this figure, the HI abundance of z=0 seems to be larger than $0.7 \times 10^{-3}$. In addition, the figure 1 in 'Atomic and molecular gas in IllustrisTNG galaxies at low redshift', which is your paper published in 2019, also show the same thing. But I found this value to be around $0.55 \times 10^{-3}$ using your HI mass data (sorry for my poor English)

I feel so confused why the data and the figures show such a large difference in HI abundance of z=0.

Zhixing

Benedikt Diemer
• 21 Sep '20

Hi Zhixing,

I think you're right! I just went over my old code and it seems like there is an h missing in one place -- that's very annoying, but I'm glad you found it. It brings the TNG data into better agreement with observations at low redshift, but worse agreement at high z. Here's the corrected figure:

Zhixing Li
• 22 Sep '20

That makes sense！Thanks a lot :D

Benedikt Diemer
• 31 Mar

Hi Zhixing, not sure whether you're still working with the HI/H2 catalogs, but I wanted to let you know that the files have been updated to fix a few minor bugs. The overall results shouldn't change much.

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