First Cospatial Mapping of H2O, CO2 and CO Ices Across a Molecular Cloud with JWST NIRCam WFSS

In the coldest regions of molecular clouds, carbon and oxygen are incorporated into icy dust grains. Ices play an essential role in star and planet formation where they set the initial chemical composition for future protoplanetary disks and chemical complexity. Despite this, ice's sequential formation is poorly constrained. Infrared spectroscopy probes ice chemistry, but previous telescopes observed insufficient sightlines to map a single cloud. JWST NIRCam Wide-Field Slitless Spectroscopy (WFSS) provides an excellent opportunity to do this. I present the first cospatial <1000AU-scale maps of H2O, CO2 and CO ice over the central region of the Chamaeleon I molecular cloud, using 44 sightlines along with the novel data reduction pipeline written to make WFSS a viable observing option. These observations show that ice species correlations, at densities ten times larger than previous work, suggest additional CO2 ice formation in CO ice for the densest sightlines. This large statistical sampling within a single cloud represents a step-change in constraining ice chemistry, eliminating averaging over clouds with different intrinsic chemical environments. This dataset adds a wealth of chemically-consistent observational constraints that can now be applied to pre-stellar phase astrochemical models. Mapping opens the door to probing gas-grain exchanges, snowlines, chemical evolution in the densest regions, and drawing conclusions on the impact of ice chemistry on wider astrophysics.