This repository contains the code and most of the data required to reproduce the analysis presented in Krumholz, Lada, & Forbrich (2025), and provides instructions for obtaining the remaining data.
This repository contains five Python routines. The files with names of the form plot_*.py are plotting routines to produce the figures in the paper. Specifically:
plot_polytropes.pyproduces figures 1 and 2, which show virial diagrams computed for polytropesplot_avir_sim.pyproduces figures 3 and 4, which show an example contour on a simulation and virial diagrams derived from that contour anlaysisplot_m31_obs.pyproduces figures 5, 6, and 7, which show virial diagrams for the giant molecular clouds of M31 computed using 12CO and 13CO data, and a comparison between the two.
The remaining two Python files, avir_sim_tools.py and polytrope_tools.py, containg calculation routines used by the plotting files.
The scripts plot_avir_sim.py and plot_m31_obs.py require data from a simulation and from observations of M31, respectively. The M31 data are included in the repository, in the file m31gmcs.csv. For details on how these data are derived and an explanation of the content and form of this file, see Lada, Forbrich, Krumholz, & Keto (2025, submitted).
The simulation data required are not included in this repository due to their large size, but can be downloaded from the Catalogue of Astrophysical Turbulence Simulations (CATS). The required files are four HDF5 files containing the outputs of an enzo simulation by Collins et al. (2012). The files required are the MHD Gravo-turbulence Simulations for the case Beta0.2, and have names of the form C12_Beta0.2_256_NNNN.h5, where NNNN is a four-digit number. The files must be placed in the same directory as plot_avir_sim.py for the script to function properly.
The Python code provided has the following dependencies:
The figures in the paper were generated using NumPy 2.1.1, SciPy 1.14.1, Matplotlib 3.9.2, AstroPy 7.0.0, and scikit-image 0.25.0. Earlier versions may work, but have not been tested.