Computing the halo mass function and the SFH

AI Thread Summary
To compute the halo mass function, it's essential to determine the volume of the catalog, as this will allow for accurate density calculations. Dark matter halos can be characterized using Navarro-Frenk-White (NFW) profiles, which require knowledge of mass and concentration to derive the density profile and virial radius. For the star formation history (SFH), converting stellar positions and birthdates into a rate per volume also hinges on understanding the catalog's volume. The discussion highlights the importance of these calculations for accurate astrophysical modeling. Resources such as the NFW profile Wikipedia page and the original Navarro, Frenk, and White paper are recommended for further guidance.
matteo86bo
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Hi,
I have a catalog of dark matter halos, which consists of their COM positions and their masses.
I need to determine the halo mass function. How can I do? I mean, it is easy to plot the number of halos between mass M and M+dM, but how can I have information on the volume? I don't get it.

Similarly, how can I determine the SFH in terms of solar masses per year per volume, when my stellar catalog contains only stars positions and their birthdate? I mean the problem it is alway the volume.

I know it is a stupid question but I really don't get it.


Thanks in advance
 
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Well... how big is the volume of the catalog?
 

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