Forming new generations of stars in galaxies critically depends on gas flows that can both fuel and deprive galaxies of their precious gas supply. Fresh cold gas must flow in to form new stars, while the explosive deaths of stars and supermassive black holes eject cold and hot gas into a galaxy’s surroundings. All of this is compounded by the fact that galaxies do not live in isolation; they form a veritable ecosystem, exchanging matter and energy, which dramatically impacts the evolution of galaxies therein. I will present observations of gaseous galaxy environments on both small and large scales that reveal this evolution in action, from dwarf galaxies to galaxy groups and clusters to the Cosmic Web. In the immediate vicinity of galaxies, the gaseous halo, or circumgalactic medium (CGM), serves as both a gas reservoir and mediator of all interactions between galaxies and their environments. On the largest scales, the intergalactic medium (IGM) filling the Cosmic Web is the Universe’s storehouse of gas that can feed the CGM and galaxies themselves. With a little help from slime mold, I will present our novel Cosmic Web reconstruction framework and show how we are beginning to reveal how galaxies, their CGM, and the IGM are intimately connected to the Cosmic Web and evolve within an ecosystem context.
Slicing through the density field reconstructed from the most massive 456 k halos (≥1011 M⊙) of the BP simulation volume. Top: false-color visualization of the mapped overdensity. Bottom: spatial distribution of the trace density values, divided into three intervals.