RR Lyrae stars as tracers of bulge globular clusters and accretion remnants

The inner Galaxy is a combination of different stellar populations and structures, each with its own characteristics and history. RR Lyrae stars are widely adopted distance indicators with which to study components composed of old stellar populations. Here we use RR stars as tracers of the inner Galaxy to (1) quantify the RR Lyrae stars with accreted properties, as well as quantify the fraction of RR Lyrae stars in the inner Galaxy consistent with the “Gaia-Enceladus-Sausage” merger, and (2) use RR Lyrae stars identifying stripped globular cluster stars from inner Galaxy globular clusters. We present the first evidence for the “Gaia-Enceladus-Sausage” merger in the inner Galaxy and find it is not as prominent in the solar vicinity. Drawing from the Milky Way-like zoom-in cosmological simulation Auriga, we find this is because of a declining contribution of “Gaia-Enceladus-Sausage” as a function of galactocentric radius. We spectroscopically confirm RR Lyrae Stars in new inner bulge globular clusters that are tidally disintegrating and find a connection between stripped stars from globular clusters and the inner Galaxy field population. Milky Way Bulge extra-tidal star survey (MWBest) is a spectroscopic survey with the goal of identifying stripped globular cluster stars from inner Galaxy clusters. We present a view of the stellar halo in the inner-central regions of the Milky Way ($R\rm \lesssim 10~kpc$) mapped by RR Lyrae stars.