Value Added Catalogs

The large-scale kinematics of young stars in the Milky Way disc

Abstract

This Value Added Catalog (VAC) provides the OB-star sample analyzed in Zari et al. (2025), including spectroscopic line-of-sight velocities, Galactocentric radial velocities and positions, and stellar ages. The catalog is constructed from Milky Way Mapper targets selected through the mwm_ob cartons. We apply quality and astrophysical cuts based on the median signal-to-noise ratio of the single-epoch BOSS spectra, Gaia parallax precision, Gaia RUWE, and BOSSNet effective temperature. These criteria select hot stars with reliable spectroscopic parameters, well-determined distances, and robust Gaia astrometry. The VAC includes line-of-sight velocity estimates for all targets. For stars with XCSAO_RXC > 6, we adopt velocities from the XCSAO pipeline; otherwise, we use the BOSSNet velocity estimates. For targets with multi-epoch observations, the reported velocity is the average over all available epochs, with uncertainties estimated from the scatter among epochs. The VAC also provides BOSSNet estimates of Teff, logg, and [Fe/H]. For targets with multi-epoch observations, these are the averages over all epochs. The catalog additionally includes Gaia DR3 source identifiers, coordinates, proper motions, and Bailer-Jones photo-geometric distances. These quantities are used to compute Galactocentric Cartesian coordinates, Galactocentric distances, and Galactocentric radial velocities following the method described in Section 3.1 of Zari et al. (2025). Stellar ages, together with their 16th and 84th percentile uncertainties, are derived as described in Section 3.2 of Zari et al. (2025).

Catalog last modified: 2026-07-30 12:12:10