Python package to read in a star formation history file, input galaxy parameters and run a chemical evolution model to determine the evolution of gas, metals and dust in galaxies.

Running the script following the instructions below will produce:

1. a results data file with galaxy parameters in (filename.dat with name provided by user from inits file - see instructions below)

The code is based on Morgan & Edmunds 2003 (MNRAS, 343, 427) and described in detail in Rowlands et al 2014 (MNRAS, 441, 1040), with latest features discussed in De Vis et al (submitted 2016).

If you use this code, please do cite the above papers. The license is provided with this package.

Download this repository and do the following:

python setup.py install

• numpy
• astropy
• matplotlib [Not a strict requirement]

The code reads in a star formation history from a file called filename.sfh. This needs to be in the form: time (yr), SFR (Msolar/yr) and in the directory where you are running the code. An example is provided with this code Milkyway.sfh based on the SFH for the Milky Way in Yin et al 2009 (A & A, 505, 497).

The code also requires a dictionary of initial parameters. This can be done by providing a .json or .csv file and using the package installed, or by running the example python script provided with this package.

There are example data files in the folder <Download Dir>/chemevol/chemevol/examples/ which show the correct format of each type of file. Feel free to copy these example data files into the directory where you wish to run the code and follow the instructions. A detailed breakdown of the parameter files and inputs needed are found at the bottom of this readme.

There are helper functions for loading batch files in CSV and valid JSON format. Note: Valid JSON uses double quotes for definitions and lower case for booleans, e.g. "myvalue" : false

import chemevol as ch
galaxies = ch.BulkEvolve('<File directory>/data.json')
galaxies.upload_json()
galaxies.evolve_all()

Or for CSV files:

import chemevol as ch
galaxies = ch.BulkEvolve('<File directory>/data.csv')
galaxies.upload_csv()
galaxies.evolve_all()

See the files in <Download Dir>/chemevol/chemevol/examples/ for the correct format of each type of file (.py, .json, .csv examples are provided).

Once the code is run you will have an array called galaxies.results with all the parameters in. To look at this data try:

[g['dust_all'] for g in galaxies.results] #will print out the dust_all
[g['mgas'] for g in galaxies.results] #will print out all the gasmasses
gasmass  = galaxies.results[0]['mgas'] #etc

The code writes data to a file (if you use the example in <Download Dir>/chemevol/chemevol/examples/data.json the code writes out two files called Model_I.dat and Model_VI.dat). To read in this data for plotting or playing with you can use astropy.table:

from astropy.table import Table
import matplotlib.pyplot as plt

t = Table.read('Model_VI.dat', format='ascii')
plt.semilogy(t['fg'],t['dustmass']/(t['mgas']+t['mstars']))

Alternatively you can run the code without the bulkevolve class above:

Copy the example_multi.py file to the desired directory (where your .sfh file is and where you want to have your results). Then edit the parameters in the init dictionaries within this script.

python example_multi.py