  We introduce IGM-Vis, a novel astrophysics visualization and data analysis
application for investigating galaxies and the gas that surrounds them in
context with their larger scale environment, the Cosmic Web. Environment is an
important factor in the evolution of galaxies from actively forming stars to
quiescent states with little, if any, discernible star formation activity. The
gaseous halos of galaxies (the circumgalactic medium, or CGM) play a critical
role in their evolution, because the gas necessary to fuel star formation and
any gas expelled from widely observed galactic winds must encounter this
interface region between galaxies and the intergalactic medium (IGM). We
present a taxonomy of tasks typically employed in IGM/CGM studies informed by a
survey of astrophysicists at various career levels, and demonstrate how these
tasks are facilitated via the use of our visualization software. Finally, we
evaluate the effectiveness of IGM-Vis through two in-depth use cases that
depict real-world analysis sessions that use IGM/CGM data.
