Modeling Asteroseismic Yields of the Roman Galactic Bulge Time-Domain Survey

In addition to its core cosmology and exoplanet science goals, the Nancy Grace Roman Space Telescope's cadence and precision in the infrared will enable asteroseismology of red giant branch stars in the Galactic bulge for the first time. Asteroseismology has proven to be revolutionary in the fields of stellar physics and Galactic archaeology thanks to its precise ages, which in the context of the bulge could contribute meaningfully to the debate regarding a young stellar population in the bulge. Here, we describe expected yields for the upcoming Galactic Bulge Time-Domain Survey, which will image the bulge over the course of the nominal five-year mission. A nominal 15-minute cadence survey yields ~300k detections in total, 200k of which are bulge stars. We investigate the effects on the asteroseismic yields from the assumed survey strategy, noise properties, extinction choices, and assumed bulge stellar population. We find that cadence significantly impacts the yields, as does varying Roman's noise properties from the literature. By comparison, field placement and extinction choice is less important. By varying the fraction of the young-to-old bulge stars, we find that the asteroseismic yield is sensitive to the age distribution of the bulge at the 10% level, which indicates that even the asteroseismology yields themselves may place constraints on the bulge age distribution. The resulting asteroseismic ages also promise to enable tests of planet formation and evolution when combined with Roman’s expected microlensing planet yields.