initial-mass-function 2025.1.20a0

Tools for sampling from and working with functional forms of the initial mass fuctino

IMF

Simple tools to work with the Initial Mass Function

Some basic examples below.

1. Make a simple 1000 Msun cluster sampled from the default Kroupa IMF:

   cluster = imf.make_cluster(1000)
   

   or from a Salpeter IMF::

   cluster = imf.make_cluster(1000, massfunc='salpeter')
   

2. Create a sample of clusters to do some analysis of later. This will make clusters with masses Gaussian-distributed around a given mean mass in the list of cluster_masses, so that you could then do things like estimate the typical luminosity of a cluster for a given mass:

   from imf import imf
   from astropy.utils.console import ProgressBar
   cluster_masses = [100, 1000, 10000]
   nclusters_per_bin = 30
   clusters = np.array([[imf.make_cluster(mass*(np.random.randn()/20.+1.), silent=True)
                        for ii in range(nclusters_per_bin)]
                        for mass in ProgressBar(cluster_masses)])
   

3. Calculate the mass fraction represented by M>8 Msun stars in a Kroupa IMF when the maximum mass is 200 Msun:

     kroupa = imf.Kroupa()
   
     mmax = 200
     cutoff1 = 8
   
     over8fraction = (kroupa.m_integrate(cutoff1, mmax)[0] /
                      kroupa.m_integrate(kroupa.mmin, mmax)[0])
   

4. This figure was made with examples/imf_figure.py

   

Credits

• Adam Ginsburg (@keflavich, wrote most of this)
• Sergey Koposov (@segasai, majorly refactored the distribution functions)
• Tiffany Christian (@teachristian, made some small corrections)
• Theo Richardson (@richardson-t, refactored optimal sampling)

No formal citation is available yet; please just reference the repository (https://github.com/keflavich/imf) if you use this.