Welcome to VAST’s documentation!
The Void Analysis Software Toolkit, or VAST, provides Python implementations of two popular classes of void-finding algorithms in galaxy catalogs:
Void identification by growing spherical voids.
Void identification using watershed algorithms.
Voids are expansive regions in the universe containing significantly fewer galaxies than surrounding galaxy clusters and filaments. They are a fundamental feature of the cosmic web and provide important information about galaxy physics and cosmology. For example, correlations between voids and luminous tracers of large-scale structure improve constraints on the expansion of the universe as compared to using tracers alone. However, what constitutes a void is vague and formulating a concrete definition to use in a void-finding algorithm is not trivial. As a result, several different algorithms exist to identify these cosmic underdensities. VAST provides Python 3 implementations of two such algorithms: VoidFinder and V2.
VAST also contains an implementation called VoidRender which utilizes OpenGL to create interactive 3D visualizations of the output of the void-finding algorithms overlaid on top of the reference galaxy survey. Each of the void-finding algorithms in VAST provides its own visualization class.
VAST
VoidFinder
V²