Cloudy as a Shock Modeling Code: Utility for HST, & Looking Out to JWST

Title: Cloudy as a Shock Modeling Code: Utility for HST, & Looking out to JWST Abstract: Shocks are a ubiquitous heating mechanism that produces non-equilibrium spectral emission. Their interpretation influences our understanding of a diverse set of astrophysical processes, such as supernova remnants (SNRs), molecular emission from external galaxies, AGN, and, most recently, the transition of starburst to red-and-dead galaxies. In the most recent (from the mid-90s) code comparison project for steady shocks into ionized gas, the competing codes varied in their predictions for key observational signatures by factors of a few. Unfortunately, at the moment only two publicly-available shock-modeling codes exist: one for SNR-type shocks, and onAe for continuous shocks in molecular gas. Clearly, independent predictions for key observables are a much-needed asset for current and future observational programs in the optical and the infrared. We request funding for a three (3) year Legacy Archival Theory program to upgrade Cloudy, a state-of-the-art microphysics code, to model shocks. This will double the number of publicly available shock codes, and will complement existing shock code predictions. The basis for achieving the goals of this program is already laid in Cloudy in its treatment of advective ionization fronts. In the first two years, we will focus on adapting the existing infrastructure to model shocks, and on faithfully representing the physics for each shock class. In the third year, we will focus on producing predictions for key observables for the benefit of the observing community. Our work will have an immediate impact on the interpretation of HST observations of a variety of objects, and a lasting impact through our JWST-tailored predictions.