Program: GS-2022B-Q-108

Galactic outflows play a key role in regulating the stellar build up and metal distribution in the galaxy ecosystem, and hence are critical to galaxy evolution. Since the outflows from low-mass galaxies (M* < 10^10 M_solar) are more likely to escape the galaxy's potential well and enrich the universe, it is crucial to study the link between the outflows and galaxy's properties (SFR, M*, size, morphology) and thus infer the outflow mechanisms. The outflow-galaxy link is poorly understood for these low-mass galaxies at cosmic noon (z ~ 2- 3). To address this critical issue, we employ a novel approach of using high-z GRB hosts as represtative lowmass star-forming galaxies. Due to their narrow beams, GRB afterglow spectra can be used to measure the outflows in the host galaxy. The late-time imaging is then used to measure the host galaxy's SFR (ground + AO), M* (Spitzer), size (AO) and GRB offset (AO). A sub-sample of 9 GRBs at z = 2-3 is selected, for which high-resolution and high-SNR afterglow spectra have already been analyzed, and have prior Spitzer + ground observations of the hosts. We propose single-band, rest-frame UV imaging with WFC3 to unambiguously identify and resolve the host galaxy and its star formation (SFR surface density), measure the GRB offsets, and estimate the dust extinction (by adding ground data). This program will build an exquisite sample with afterglow spectra to probe the outflows, and GSAOI + Spitzer + anciliary ground imaging to measure the host galaxy properties, ultimately constraining key outflow-galaxy correlations (eg: Outflow rate - SFR surface density) for low-mass high-z galaxies. Such a study is extremely difficult by any other method.