0 Assigned ID: 4988 ----- Attempting Submission 1 (Thu Mar 14 21:56:18 GMT 2024) ----- HST Phase I Proposal 4988 successfully submitted. Receipt: # 4988-1 ----- Attempting Submission 2 (Mon Mar 25 15:26:17 GMT 2024) ----- Galactic winds, driven by intense star formation and supernovae, are essential for regulating galaxy growth and evolution. However, the mechanisms behind these outflows remain uncertain, leading to questions about whether they act by heating gas to prevent further accretion, or by expelling the fuel needed for star formation. We propose a new technique for constraining feedback from galactic winds, using semi-numerical models to create mock UV spectra. We will use high-resolution simulations of cool clouds interacting with a hot wind, post processing each cloud with radiation transport to build a library of absorption line spectra. The individual cloud spectra will be combined according to a flexible, physically motivated model, thereby simulating galaxy-wide outflows. With this new strategy, we can investigate how spectra are influenced by changes in physical parameters like the wind energy and mass loading, cloud sizes, and wind geometry. We will compare our simulated spectra with observations of nearby star-forming galaxies obtained with the Cosmic Origins Spectrograph. Through this method of forward-modeling galactic winds and analyzing their spectra, we aim to provide the most accurate constraints yet into the physics of outflows and their impact on the evolution of galaxies. This innovative approach represents a new way of bridging theory and observation to enhance our understanding of star formation feedback. Our hybrid team of theorists, observers, and radiation transport experts has been specially built to have the skill sets needed for this investigation. From the top down, the Co-PI team comprises a theorist (Fielding), a radiation transport expert (Smith), and an observer (Henry), ensuring investment in the success of the project from all sides. In detail: Co-PI Henry is an expert in UV spectroscopy of star-forming galaxies. She is a Co-I on two large COS programs that have been carried out in recent years: the COS Legacy Archive Spectroscopic Survey (CLASSY) and the Low Redshift Lyman Continuum Survey (LzLCS). With an interest in Lyman Alpha and Lyman Continuum escape in reionization-epoch analogs, Henry has been trying to understand the clumpy or patchy nature of the ISM and CGM. This proposed investigation into outflows and feedback is a natural extension of that work. Co-PI Fielding is an expert in theoretical modeling of galaxy outflows, both analytically and in simulations. In collaboration with Co-Is Abruzzo and Bryan, their recent simulations of individual clouds entrained in a hot wind represent the state-of-the art. With exceptional resolution, they are some of the only simulations to model the turbulent radiative mixing layers that are necessary for the survival of cold clouds in a hot wind. Likewise, their derivation of a semi-analytical model for the hot wind when it is coupled with cold clouds is a fundamental advancement in the field, and a key component of our proposed analysis. Co-PI Smith is the author of the COsmic Lyman-Alpha Transfer code (COLT), which we will use to model the resonant and fluorescent metal absorption and emission lines. He has extensive experience developing and applying Monte Carlo radiative transfer (MCRT) algorithms to study observable signatures of local and high-redshift galaxies from hydrodynamical simulations. Also critical to this investigation: Co-I Jennings is the JHU graduate student who will carry out this project. He has background in models for cloud formation via simulations of thermal instabilities as in the case of the turbulent radiative mixing layers that are the critical component of our cloud simulations. More recently, Jennings has been working on mock observations of UV spectroscopic lines simulated with RAMSES + the RT code RASCAS. These two investigations provide the perfect background for Jennings to move into the research in this proposal. Importantly, Henry, Fielding and Smith are committed to co-advising Jennings through this project and the completion of his PhD. Furthermore: Co-Is Scarlata and Carr are the developers of the SALT model for predicting emission and absorption line profiles using analytical prescriptions. They have published numerous papers on this topic, including a generalization to biconical models. Their expertise will be essential for the stage of the project where we account for geometry and viewing angles as we combine spectra. Additionally, Co-Is Scarlata, Rubin, Hayes, Xu, Heckman, and Roy are all experts on observations of outflows in the UV and optical spectra of galaxies. They form a key sub-group of the team for advice on how to observe and interpret the model spectra. Furthermore, Xu & Heckman led the outflow studies in the CLASSY survey, and will provide measurements from these COS spectra when we compare our models to observations. Lastly, Co-Is Schneider is leading complementary simulations. She is the author of the GPU-based hydrodynamical simulation code Cholla, and the PI of the Cholla Galactic OutfLow Simulations (CGOLS). Her expertise will provide an important viewpoint as we interpret the models and develop intuition about how wind physics impacts the observed spectra. Galaxies Intergalactic Medium and the Circumgalactic Medium 0 false false true true true false false SUPPORTED