Spatially-resolved SFHs of dwarf galaxies in the HLWAS
| Program ID | 19022 |
|---|---|
| Science Category | Stellar Populations |
| Program Type | Analysis |
| Category | Small |
| Principal Investigator | Christopher Garling |
| PI Institution | University of Virginia |
| Co-Investigators |
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| Abstract | We propose to utilize the medium tier of the Roman HLWAS to measure the first spatially-resolved star formation histories of five nearby dwarf galaxies. We target the Fornax, Sculptor, and Sextans Milky Way satellites along with the Local Field systems Sextans A and B. These galaxies are both close enough to resolve their stellar populations into individual stars and massive enough to have well-populated color magnitude diagrams enabling us to measure their lifetime star formation histories over 13 Gyr of cosmic time. With transformative spatially-resolved star formation histories from the Roman HLWAS we will measure stellar age gradients and determine if the stellar populations vary as a function of projected radius in our targets. Cosmological hydrodynamical simulations predict “U-shaped” age gradients where both galaxies quenched early and actively forming stars have minimal age gradients, whereas intermediately quenched galaxies have steep negative age gradients (i.e., young stars are more centrally concentrated than old stars). This trend is caused by dynamical heating resulting from vigorous stellar feedback; our measurements therefore provide an innovative new test of subgrid stellar feedback models with wide-reaching astrophysical impact. To enable our program, we will produce catalogs of photometry and artificial star tests optimized for the high-density cores of these galaxies. By releasing these products to the community, we will enable a plethora of additional scientific investigations of the stellar populations of these galaxies. In summary, our program will measure the first resolved star formation histories and age gradients of dwarf galaxies with Roman imaging, directly testing theoretical predictions, and will provide an invaluable community resource in the form of high-level photometric data products to enable additional community analyses. |