Searching for variable stars in the VVV globular clusters

TL;DR

This study utilizes near-infrared data from the VVV survey to identify and analyze variable stars, especially RR Lyrae, in three Galactic globular clusters to improve distance and reddening estimates.

Contribution

It presents a preliminary analysis of variable stars in three globular clusters using VVV near-infrared data, focusing on RR Lyrae stars for distance measurements.

Findings

Identification of candidate variable stars in the clusters

Potential for improved distance and reddening estimates

Foundation for future detailed variability studies

Abstract

The VVV is currently surveying the central regions of the Milky Way at near-infrared wavelengths, including 36 known Galactic globular clusters. We already have data in several filters to generate their color-magnitude diagrams. We also have enough epochs to begin producing the light-curves of the cluster stars and look for any possible member variable stars. We are especially interested in RR Lyrae stars, since they are abundant in Galactic globular clusters, and the period-luminosity relation they show at near-infrared wavelengths, can help enormously in providing accurate distances and reddenings for the most extincted and poorly studied inner Galactic globular clusters. We center our attention here in the preliminary analysis of three of these clusters: NGC 6441, Terzan 10 and 2MASS-GC02.