0 Assigned ID: 4536 ----- Attempting Submission 1 (Wed May 24 19:45:54 GMT 2023) ----- HST Phase I Proposal 4536 successfully submitted. Receipt: # 4536-1 ----- Attempting Submission 2 (Wed May 24 22:39:27 GMT 2023) ----- Galactic winds, driven by intense star formation and supernova explosions, are crucial for regulating galaxy growth and evolution. However, the physics that governs these outflows remains uncertain, with open questions about whether they are primarily ejective, removing large amounts of mass, or preventive, heating circumgalactic gas to suppress further accretion. We propose a new method for constraining wind models using simulated galaxy spectra. We will model individual cool clouds as they interact with a hot wind, using high-resolution simulations that we will post-process with radiative transfer to build a library of mock absorption-line spectra. We will then combine these cloud spectra into galactic-scale outflows based on a flexible, physically consistent model. With this approach, we can explore how changes to physical parameters like the wind energy and mass loading, cloud sizes, and wind geometry impact the resulting spectrum. We will compare our mock spectra to observations of local star-forming galaxies obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. By forward-modeling galactic winds and directly fitting their spectra, we aim to provide the most robust constraints to date on the physics of these multiphase outflows and their role in shaping galaxy evolution. Our method constitutes a new approach for understanding astrophysical phenomena through synthesis of theory and observation. 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 Legacy false false true true false false SUPPORTED