title: 'Gala: A Python package for galactic dynamics' tags:
- Python
- astronomy
- dynamics
- galactic dynamics
- milky way authors:
- name: Adrian M. Price-Whelan^[co-first author] # note this makes a footnote saying 'co-first author' orcid: 0000-0003-0872-7098 affiliation: "1, 2" # (Multiple affiliations must be quoted)
- name: Author Without ORCID^[co-first author] # note this makes a footnote saying 'co-first author' affiliation: 2
- name: Author with no affiliation^[corresponding author] affiliation: 3 affiliations:
- name: Lyman Spitzer, Jr. Fellow, Princeton University index: 1
- name: Institution Name index: 2
- name: Independent Researcher index: 3 date: 13 August 2017 bibliography: paper.bib
aas-doi: 10.3847/xxxxx <- update this with the DOI from AAS once you know it. aas-journal: Astrophysical Journal <- The name of the AAS journal.
The forces on stars, galaxies, and dark matter under external gravitational fields lead to the dynamical evolution of structures in the universe. The orbits of these bodies are therefore key to understanding the formation, history, and future state of galaxies. The field of "galactic dynamics," which aims to model the gravitating components of galaxies to study their structure and evolution, is now well-established, commonly taught, and frequently used in astronomy. Aside from toy problems and demonstrations, the majority of problems require efficient numerical tools, many of which require the same base code (e.g., for performing numerical orbit integration).
Gala
is an Astropy-affiliated Python package for galactic dynamics. Python
enables wrapping low-level languages (e.g., C) for speed without losing
flexibility or ease-of-use in the user-interface. The API for Gala
was
designed to provide a class-based and user-friendly interface to fast (C or
Cython-optimized) implementations of common operations such as gravitational
potential and force evaluation, orbit integration, dynamical transformations,
and chaos indicators for nonlinear dynamics. Gala
also relies heavily on and
interfaces well with the implementations of physical units and astronomical
coordinate systems in the Astropy
package [@astropy] (astropy.units
and
astropy.coordinates
).
Gala
was designed to be used by both astronomical researchers and by
students in courses on gravitational dynamics or astronomy. It has already been
used in a number of scientific publications [@Pearson:2017] and has also been
used in graduate courses on Galactic dynamics to, e.g., provide interactive
visualizations of textbook material [@Binney:2008]. The combination of speed,
design, and support for Astropy functionality in Gala
will enable exciting
scientific explorations of forthcoming data releases from the Gaia mission
[@gaia] by students and experts alike.
Single dollars ($) are required for inline mathematics e.g.
Double dollars make self-standing equations:
You can also use plain \LaTeX for equations \begin{equation}\label{eq:fourier} \hat f(\omega) = \int_{-\infty}^{\infty} f(x) e^{i\omega x} dx \end{equation} and refer to \autoref{eq:fourier} from text.
Citations to entries in paper.bib should be in rMarkdown format.
If you want to cite a software repository URL (e.g. something on GitHub without a preferred citation) then you can do it with the example BibTeX entry below for @fidgit.
For a quick reference, the following citation commands can be used:
@author:2001
-> "Author et al. (2001)"[@author:2001]
-> "(Author et al., 2001)"[@author1:2001; @author2:2001]
-> "(Author1 et al., 2001; Author2 et al., 2002)"
Figures can be included like this: and referenced from text using \autoref{fig:example}.
Figure sizes can be customized by adding an optional second parameter: { width=20% }
We acknowledge contributions from Brigitta Sipocz, Syrtis Major, and Semyeong Oh, and support from Kathryn Johnston during the genesis of this project.