0 Assigned ID: 4441 ----- Attempting Submission 1 (Wed May 24 17:23:16 GMT 2023) ----- HST Phase I Proposal 4441 successfully submitted. Receipt: # 4441-1 ----- Attempting Submission 2 (Wed May 24 18:58:55 GMT 2023) ----- HST Phase I Proposal 4441 successfully submitted. Receipt: # 4441-2 ----- Attempting Submission 3 (Wed May 24 20:53:00 GMT 2023) ----- Stellar feedback is a multi-scale process that originates from individual star-formation sites and propagates through a galaxy's interstellar medium and into the circumgalactic medium. However, the delicate process of stellar feedback coupling to the gas within and around galaxies remains poorly understood. We propose a spatially resolved analysis of localized outflows down to ~pc scales in the nearby galaxy Sextans A using an unusually large sample of COS spectra of 8 massive O stars from the HST archive. The proximity and low inclination angle of Sextans A present a unique opportunity to quantify feedback efficiency in the low-mass, low-metallicity galaxy regime where this analysis has never before been possible. We will measure the physical properties of localized outflows in Sextans A (e.g., speed, ionization structure, outflow rate, and mass loading factor) and compare them with the galaxy's current and past star formation activity to construct a complete picture of how stellar feedback drives outflows on ~pc scales. This proposal will provide a timely constraint for galaxy formation simulations that aim to determine how feedback injection at local scales regulates star formation and drives large-scale outflows of gas and metals. The PI, Dr. Yong Zheng, is an expert in the circumgalactic medium and gas flows of the Milky Way and nearby galaxies. Dr. Zheng is experienced in COS data reduction and HI 21cm data reduction (e.g., Zheng+2017, 2020). Telford (co-PI) is an expert in FUV spectroscopy of metal-poor O stars in nearby dwarf galaxies (Telford+ 2021, 2023) and an experienced COS observer (PI of GO-16767, 16920). She also has an extensive background in the chemical evolution of galaxies and using the metal content of galaxies to constrain their past metal loss (Telford+ 2019). CoI Chisholm has deep expertise measuring the metal outflow rate from FUV observations of distant galaxies (Chisholm+ 2017). CoI McQuinn is an expert on the stellar populations, star formation histories, and galactic winds of nearby dwarf galaxies (e.g., McQuinn+ 2019). CoI Carr is an expert in modeling outflows and built the semi-analytical line transfer (SALT) code for galactic outflows (Carr & Scarlata 2022). CoI Berg has extensive experience working with COS spectra and is the PI of the CLASSY program (PID 15840, Berg+2022) to create a treasury of COS spectra of metal-poor, star-forming galaxies in the local universe. Stellar Populations and the Interstellar Medium Intergalactic Medium and the Circumgalactic Medium 0 Regular false false false false false false SUPPORTED