Virac2: NIR Astrometry and Time Series Photometry for 500M+ Stars from the VVV and VVVX Surveys

Abstract

We present VIRAC2, a catalogue of positions, proper motions, parallaxes and Z, Y, J, H, and K_s near-infrared photometric time series of 545 346 537 unique stars. The catalogue is based on a point spread function fitting reduction of nearly a decade of VISTA VVV and VVVX images, which cover 560 deg^2 of the Southern Galactic plane and bulge. The catalogue is complete at the >90 per cent level for <Ks mag<1 11<Ks<16 sources, but extends to Ks≈17.5 mag in most fields. Astrometric performance for 11<Ks mag<14 sources is typically ≈0.37 mas yr−1per dimension for proper motion, and 1 mas for parallax. At Ks=16 the equivalent values are around 1.5 mas yr−1and 5 mas. These uncertainties are validated against Gaia DR3 and Hubble Space Telescope astrometry. The complete catalogues are available via the ESO archive. We perform an initial search of the catalogue for nearby ultracool dwarf candidates. In total we find 26 new sources whose parallaxes place them within 50 parsecs of the Sun. Among them we find two high-confidence T dwarfs and a number of other sources that appear to lie close to the L/T transition.