Physical properties of RR Lyrae variables in Galactic globular clusters and dwarf spheroidal galaxies

We propose a tool to distinguish between Galactic globular clusters (GCs) and dwarf galaxies based on physical properties of RR Lyrae (RRL) variables in the systems. Normally, these two systems show various distinctive properties; for instance, mass, size, and luminosity. Nevertheless, these properties overlap each other in recently discovered systems. The subsequent classification between GCs and dwarf spheroidal (dSph) galaxy is ambiguous. An RRL variable is a pulsating variable star with a short period of 0.2-1 days. It is relatively easy to observe the complete period of its light curve. The age of RRL stars is typically more than 10 Gyr; therefore, they can provide information of the host system at its early stage. In this study, we provide an extensive data collection of RRLs in 96 GCs, 23 dSphs, and 10 dwarf irregular (dIrr) galaxies. Based on public catalogs, we analyze various RRL properties such as Oosterhoff dichotomy, fraction of high amplitude short period (HASP) variables, metallicity, and specific frequency of RRLs (SRR). We examine correlations among all properties in an attempt to distinguish between GCs and dSphs.