The VISTA variables in the vía láctea survey: A first glance on stellar variability

Abstract

VISTA Variables in the Vía Láctea (VVV) is an ESO public near-infrared variability survey of the Galactic bulge and an adjacent area of the southern mid-plane. It will produce a deep atlas in the ZYJHKs filters, and a Ks-band time-series database of ~ 109 point sources, among which ≳ 106 are expected to be variable. One of VVV’s immediate scientific goals is to provide accurate light curves of primary distance indicators, such as RR Lyrae stars, and utilize these data to produce a 3-D map of the surveyed area and, ultimately, trace the structure of the inner Galaxy. We give, based on the first ~ 1:5 years of the 5-year-long survey, an early assessment on the basic properties and the overall quality of the VVV photometric time-series, and use these data to put an estimate of the fraction of variable stellar sources.