evstats

A python module for calculating extreme value statistics of the halo and galaxy stellar mass distributions. Full details provided in Lovell et al. 2023.

Installation

pip install evstats

or, from a clone of this repository, pip install .. You can then use evstats as so:

from evstats import evs
from evstats import stats
from evstats import stellar

evstats requires Python 3.12 or newer. The core package needs only numpy, scipy, astropy and hmf. hmf is held at 3.6, since other versions shift the halo mass function and the tabulated EVS in example/data/ were computed with it.

Optional dependencies are installed as extras:

pip install "evstats[examples]"     # matplotlib and h5py: plotting, and the scripts in example/
pip install "evstats[observables]"  # also Synthesizer and unyt: the photometry in example/observables/

The star-formation-history module (evstats.sfr) provides mass_growth_track / plot_mass_growth_track, which project an observed stellar mass back in redshift for an assumed (parametric or binned) star formation history, for comparison against the EVS contours. Plotting needs the examples extra, and average_sfr_over_window needs the observables extra.

An example

A notebook showing a simple example of how to create contours in the stellar mass -- redshift plane, for arbitrary survey areas, is available here.

Observables

The scripts in example/observables/ turn the stellar mass EVS into JWST fluxes using Synthesizer, so need the observables extra. They read flux tables that are not distributed with this repository; to make them:

1. Get the Synthesizer grid for the fiducial model, bpass-2.2.1-bin_chabrier03-0.1,300.0_cloudy-c23.01-sps, and set GRID_DIR in evs_file_generator.py to the directory containing it.
2. From example/observables/, generate the flux tables for every star formation history with that grid, at the fiducial metallicity:

   python evs_file_generator.py "" bpass-2.2.1-bin_chabrier03-0.1,300.0_cloudy 0.01
   

3. Plot the EVS flux predictions for each star formation history:

   python evs_sfh.py
   

Running evs_file_generator.py with no arguments makes the tables for every SFH, SPS model and metallicity, which the other scripts need; this is slow.

The paper

All of the plots and analysis in Lovell et al. 2023 can be recreated using the scripts in example/paper/.