Precision Distances to Dwarf Galaxies and Globular Clusters from Pan-STARRS1 3π RR Lyrae

Abstract

We present new spatial models and distance estimates for globular clusters and dwarf spheroidals orbiting our Galaxy based on RR Lyrae (RRab) stars in the Pan-STARRS1 (PS1) 3 π survey. Using the PS1 sample of RRab stars from Sesar et al. in 16 globular clusters and 5 dwarf galaxies, we fit structural models in ( l , b , D ) space; for 13 globular clusters and 6 dwarf galaxies, we give only their mean heliocentric distance D . We verify the accuracy of the period–luminosity relations used in Sesar et al. to constrain the distance to those stars, and compare them to period–luminosity–metallicity relations using metallicities from Carretta et al. We compare our Sesar et al. distances to the parallax-based Gaia DR2 distance estimates from Bailer-Jones et al. and find our distances to be consistent and considerably more precise.