0 Assigned ID: 595 ----- Attempting Submission 1 (Fri Mar 06 17:51:01 GMT 2020) ----- HST Phase I Proposal 595 successfully submitted. Receipt: # 595-1 ----- Attempting Submission 2 (Fri Mar 06 20:16:06 GMT 2020) ----- HST Phase I Proposal 595 successfully submitted. Receipt: # 595-2 ----- Attempting Submission 3 (Fri Mar 06 21:55:04 GMT 2020) ----- It is widely accepted that starbursts can dramatically affect their host galaxies via feedback-driven outflows, especially for gas-rich dwarfs with shallow potential wells. The removal of gas from a galaxy's center is predicted to change the gravitational potential, causing "cuspy" cold dark matter (CDM) density profiles to transform into constant-density "cores." Recent hydrodynamical simulations have identified this mechanism as a potential solution to the long-standing core-cusp problem in CDM cosmology, and further predict that cusps can reform within a few 100 Myr post-burst as gas cools and collects in the galaxy center, creating the conditions for another starburst. We propose a novel, direct test of how feedback from starbursts impacts dwarf galaxy dynamics. We have assembled a sample of nearby dwarf galaxies spanning a range of central density profiles from cuspy to cored, determined from high-quality HI rotation curves, that have archival HST imaging of resolved stars suitable for deriving recent star formation histories (SFHs). We will identify current and recent starbursts and measure their timing, duration, energetics, and spatial extent across our sample, which is large enough to include diverse recent SFHs. With galaxies at a range of times post-burst, we will statistically sample the time evolution of central density profiles following a starburst and test the hypotheses that (1) cored galaxies are post-starburst, and (2) cusps reform on timescales comparable to the dynamical time. This study will probe the fundamental connection between starbursts, gas, and dark matter and provide an observational test of the favored solution to the core-cusp problem. Dr. Grace Telford will lead the star formation history (SFH) derivation with MATCH, analysis of results, and writing the paper(s) presenting the findings of this work. Telford has led multiple projects based on MATCH SFHs (Telford et al. 2019, 2020). Our team includes Drs. Kristen McQuinn and Federico Lelli, the lead researchers from both the study of the SFHs in starburst dwarf galaxies (McQuinn et al. (2010a,b, 2015) and the study of the HI rotation curves in gas- rich dwarf galaxies (Lelli et al. 2014a). McQuinn has deep experience working with HST imaging data with several published papers on SFHs from resolved stars, ensuring the data will be processed carefully and efficiently. Lelli has analyzed all the HI data for the sample and will lead the mass modeling of the LITTLE-THINGS galaxies, as well as any new analysis with the HI data that might be needed to compare with simulations. Dr. Evan Skillman brings extensive expertise on the star formation histories, evolution, and kinematics of low- mass galaxies. Dr. Andrew Dolphin is the developer of the DOLPHOT photometry package and the CMD fitting technique MATCH to be used in the analysis. Drs. Chris Brook and Arianna Di Cinto are leaders in galaxy simulations and have worked specifically on the theoretical density profiles of dwarfs (e.g., Di Cinto et al. 2014a). They will provide comparisons from simulations. Our team is highly productive and we bring significant expertise to the analysis and interpretation of the proposed data. Stellar Populations and the Interstellar Medium 0 Regular false false false false false SUPPORTED