RR Lyrae Stars in the Inner Galactic Globular Clusters

The innermost Galactic globular clusters are poorly known. Strong reddening in the line of sight and high stellar densities in the surrounding fields are among the main drawbacks to study these type of objects when we look at low latitudes. The Vista Variables in the Via Lactea (VVV) survey is contributing to solve the situation. Covering most of the Galactic Bulge and providing high-resolution images in the near infrared, the VVV survey successfully helps to overcome the difficulties we face when observing these clusters of stars. Not only that, but VVV multi-epoch observations enable us to look for variable stars in the sampled globular clusters. Paramount among these variable stars are the RR Lyrae, because they are frequent in globular clusters and their tight period-luminosity relation has promoted their use as standard candles. We are searching for the presence of RR Lyrae variable stars in the inner Galactic globular clusters that lie inside the area surveyed by the VVV. The newly detected RR Lyrae stars, along with the ones reported in other previous studies and surveys, are then used to learn about these inner Galactic globular clusters and to more properly constrain the physical parameters of these poorly known sample of stellar aggregates.