Welcome to GSnap


The foreground and background are fully-synthetic. All galaxies in the background are from the same simulation as the foreground galaxies.

GSnap is a tool for analyzing, viewing, and manipulating snapshots from galaxy simulations. It is currently under development and is licensed under the GNU General Public License 3.0, so you can freely access the code and become a contributor. The code is written in C++11 and currently depends only upon the Qt Framework, the standard C++ library, and (optionally) OpenMP. It is compatible with GNU/Linux, Mac OS, and Windows operating systems. In principle, it should work on any OS supported by Qt, but GNU/Linux is the main target.

GSnap was initially written to measure the velocity dispersion of particles in galaxy simulations, but it is now useful for interactively rotating and zooming snapshots, measuring distances between objects (and sizes of objects), interpolating between snapshots, manipulating / editing snapshots, and creating high quality visualizations of the stars and gas in galaxy simulation snapshots. In addition to a GUI, GSnap offers a powerful command line interface, which allows the user to operate the program from a script, and a built-in ECMAScript interpreter, which allows the user to potentially extend GSnap’s functionality. Currently, only very specialized GADGET-2 and GADGET-3, type 1 snapshots are supported, however, adding a new file format is a fairly straightforward task.

Since the code is undergoing development, much of the documentation on this page is obsolete. Several features have been added and the command line interface and parameter file keywords and syntax have changed significantly. Updated documentation will be posted when the user interface reaches a more stable state.

GSnap was developed by Nathaniel Stickley as part of his Ph.D. research project at the University of California, Riverside. He has continued to work on the project after graduating and he encourages others to join the project. Financial support for GSnap was provided by NASA through a grant from the Space Telescope Science Institute (Program AR-12626), which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Additional funding was also provided by NSF under grant number AST-0507450.