VISTA variability survey of Local Group Galaxies

The primary aim of this survey is to observe 4 Local Group Galaxies (Fornax, NGC 6822, IC 1613 and WLM) 50 times over a 3 year period down to point-source magnitudes of about K= 18.8 and Z= 21.5 (15sigma, Vega system) in a single observation. This will enable the detection of all cepheids and AGB Mira variables in those galaxies (and RR Lyrae in Fornax). In addition, the brightest variable main-sequence stars and eclipsing binaries will be detected. This survey will provide a unique database of variable objects. The primary science driver is to understand the pulsational properties of the RR Lyrae, cepheids and AGB variables and to link these to the (spatially resolved) Star Formation History of these galaxies. The secondary science goals include the analysis of other classes of pulsational variables and the selection of detached eclipsing binaries for follow-up studies.

Other uses include the analysis of the galaxies' colour-magnitude diagram (the co-added data with reach 5sigma limiting magnitudes of about K= 22.1 and Z= 24.6), study of the galactic foreground population, including proper motion studies, and quasar variability.