Trident [@doi:10.3847/1538-4357/aa7e2d] is a Python-based open-source tool for
post-processing hydrodynamical simulations to produce synthetic absorption
spectra and related data. In many ways, Trident is the first external package
that utilizes yt to provide data access and numerical operations, but then
builds on those to develop detailed, astrophysically-aware systems for
processing and analyzing that data.
[@doi:10.1038/nature15383]
Building on yt for access to halo catalogs, and implementing a similar system
for derived fields as applied to graph datasets, ytree
[@doi:10.5281/zenodo.1174374] is a system for analyzing merger trees from
analysis of dark matter halos in cosmological simulations.
ytree provides flexibility in determining the path that a given analysis takes through the graph of merger trees; for instance, it enables the user to select if they wish to follow the "most massive" progenitor halo backwards in time, or even to set their own criteria for this. Connecting this to the raw, unprocessed data from the simulation (such as the unsampled particle or cell content that comprises the halos) allows researchers to deepen and guide their analysis based on the physical characteristics of the merger history.