VIRAC2: NIR Astrometry and Time Series Photometry for 500M+ Stars from the VVV and VVVX Surveys

TL;DR

VIRAC2 is a comprehensive near-infrared astrometric and photometric catalogue of over 545 million stars from the VVV and VVVX surveys, providing precise measurements and discovering new nearby ultracool dwarfs.

Contribution

This work introduces VIRAC2, a large-scale, high-precision near-infrared star catalogue with proper motions and parallaxes, extending previous surveys and enabling new nearby star discoveries.

Findings

Identified 26 new stars within 50 parsecs of the Sun.

Detected two high-confidence T dwarfs.

Validated astrometric accuracy against Gaia DR3 and HST data.

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 $560~{\rm deg}^2$ of the Southern Galactic plane and bulge. The catalogue is complete at the $>90$ per cent level for $11<K_s~{\rm mag}<16$ sources, but extends to $K_s\approx{}17.5$ mag in most fields. Astrometric performance for $11<K_s~{\rm mag}<14$ sources is typically $\approx{}0.37~{\rm mas~yr}^{-1}$ per dimension for proper motion, and $1~{\rm mas}$ for parallax. At $K_s=16$ the equivalent values are around $1.5~{\rm mas~yr}^{-1}$ and $5~{\rm mas}$. 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.