norashipp / ugali

Ultra-faint galaxy likelihood toolkit

Overview

The ultra-faint galaxy likelihood (UGaLi) toolkit provides a set of python classes and functions developed for maximum-likelihood-based studies of Milky Way satellite galaxies. The primary inputs are stellar object catalogs derived from optical photometric surveys and the coverage masks of those surveys.

Keith Bechtol & Alex Drlica-Wagner

Installation

There are several ways to install ugali and it's complimentary isochrone library.

The easiest way to install ugali is through PyPi using pip:

# To install just the source code
pip install ugali

# To install source code and isochrone library
pip install ugali --install-option "--isochrones"

# To specify a path for the isochrone library
pip install ugali --install-option "--isochrones" --install-option "--isochrones-path <PATH>"

The isochrone library is a ~100 MB tarball. The default isochrone installation location is set by the UGALIDIR environment variable and defaults to $HOME/.ugali. The download and unpacking of the isochrone files might make it appear that your pip installation has stalled. Unfortunately, pip will not display a progress bar during this delay.

To get the most up-to-date version of ugali, you can download the source code from github and install it using setup.py:

# Clone source code from the parent repository
git clone https://github.com/DarkEnergySurvey/ugali.git
cd ugali

# Install the python source code
python setup.py install

# Also install the isochrone library
python setup.py install --isochrones

# Specify the isochrone install path
python setup.py install --isochrones --isochrones-path=<PATH>

The code uses the UGALIDIR environment variable to find the isochrones (defaults to $HOME/.ugali). If you install the isochrones in a non-standard location be sure to set UGALIDIR so ugali can find them:

export UGALIDIR=<PATH>

If all else fails, check out the automated build installation procedure using conda in .travis.yml.

Usage Examples

Examples go here...

Dependencies

These should mostly be taken care of by PyPi with a pip install.

Python packages:

• numpy
• scipy
• matplotlib
• pyfits
• healpy
• astropy
• emcee
• pyyaml

Mangle:

Not a strict dependency. Used to interface with masks produced by the Dark Energy Survey Data Mangement group. Download and documentation available at http://space.mit.edu/~molly/mangle/

Isochrones:

The ugali uses a library of stellar isochrones packaged with ugali releases. These isochrones come dominantly from two different groups:

• Padova isochrones (http://stev.oapd.inaf.it/cgi-bin/cmd)
• Dartmouth isochrones (http://stellar.dartmouth.edu/models/isolf_new.html)

Conventions

Indexing:

array[index_z][index_y][index_x]

Naming:

• package_name
• module_name.py
• ClassName
• functionName
• variable_name

ABBREVIATIONS

• IMF: initial mass function
• CMD: color-magnitude diagram
• ROI: region of interest
• PDF: probability distribution function
• LUT: look-up table
• LKHD: likelihood