UHS DR3, PS1 DR2, Gaia DR3: High proper motion stars

We identify a total of 127 new discoveries with total proper motions >=300mas/yr. A significant fraction of these sources with counterparts in the Gaia DR3 catalog are found to be distant (>100pc) low-mass stars, where their large tangential velocities and placement on color-magnitude diagrams suggest that they are likely low-metallicity M-type subdwarfs.

Optical spectroscopy is used to confirm the low mass and low metallicity for two such sources. Using available optical and infrared photometry, we estimate the spectral type for all non-Gaia sources and find 10 likely late-M dwarfs, 15 objects with colors most consistent with L-type dwarfs, and nine possible T-type dwarfs. Follow-up spectroscopy is needed to confirm spectral types and further characterize these new discoveries.