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For many students assignments connecting chemistry to sustainability are outside of their prior experience, and helpful resources such as a curated chatbot can provide directed assistance even when instructors are unavailable. 

The circumgalactic medium (CGM) is a known reservoir of metals and star forming fuel. Most baryons in the universe are in the CGM or ICM. The baryon cycle- how metals reach the CGM from the inner regions of the galaxy and how gas from the CGM replenishes star forming activity in the inner regions- is an essential question in galaxy evolution. We seek to illuminate these processes by analyzing 2770 isolated halos in the IllustrisTNG simulation. This sample is divided into different classes of galaxy based star forming and AGN feedback, and morphology. By stacking halos of similar mass and history, we can identify correlations between galaxy history and the properties and dynamics of the surrounding gas. 

Antarctic ice cores provide a unique archive of Earth’s atmosphere and its largest extant ice sheet. The oldest continuous ice core extends back 800 ky, though discontinuous ice cores from the Allan Hills blue ice area (BIA) have been shown to preserve snapshots of ice and air back to at least 2.7 million years ago (Ma). Here, we provide snapshots of putatively Miocene and Pliocene ice and air from shallow ice cores drilled in the Allan Hills BIA. The ice, dated using the deficit in⁴⁰Ar in ancient air compared to the modern atmosphere, is stratigraphically complex. Nevertheless, surface temperatures inferred from water isotopes correlate with sample age and indicate 12 ± 2 °C of cooling in Antarctica between 6 Ma and the late Pleistocene. Basal ice is nearly devoid of gases and remains to be dated with existing methods. This undated ice is characterized by an isotopic temperature 5 ± 1 °C warmer than the oldest dated (6 million year old) sample. We speculate that this ice reflects surface snowpack or permafrost that was preserved by the growth of the East Antarctic ice sheet in the Middle to Late Miocene. 

IllustrisTNG is a widely used suite of hydrodynamical simulations, but we found that most users are likely missing up to 5% of the gas mass within the virial radius of halos generated by TNG. An FoF (“friend of friends”) algorithm determines what gas in the simulation is assigned to each halo. Approximately one third of gas cells are not in any halo: this gas is called “fuzz”. However, at certain densities, temperatures, and halo-centric distances this decision becomes (perhaps necessarily) arbitrary for individual gas cells. We use a method of loading gas data that avoids this issue, and instead loads all gas in a given volume of the simulation. Preliminary findings suggest the FoF algorithm functions as a permeable, stochastic density threshold which preferentially misses low density gas. At the same time, the fuzz does not match gas of similar densities in the same region. In this poster, we compare fuzz gas and halo gas at similar radii and densities to explore the implications of this omission. 

The circumgalactic medium (CGM) is a critical repository for metals around galaxies, and serves as the meeting ground for galactic outflows and infalling material from the intergalactic medium. We study the net flow of metals through the CGM in the IllustrisTNG galaxy formation simulations, with a particular focus on the geometry and radial distribution of metal flows. Special care is taken to account for “fuzz” particles, which are often missed by traditional methods of selecting CGM particles in the Illustris simulations, but dominate the net outflow of gas around massive galaxies near the virial radius.