Presentation #301.02 in the session “How Gaia Reveals the Galaxy’s Secrets: Results Local to the Sun”.
The coldest brown dwarfs are invisible to Gaia because of their intrinsic faintness shortward of 1 micron. Nonetheless, Gaia astrometry is vital to the success of ongoing astrometric follow-up of L, T, and Y dwarfs. In this talk, I discuss our use of astrometry obtained from a variety of different spacecraft — the Spitzer Space Telescope, the Wide-field Infrared Survey Explorer (WISE), and the Hubble Space Telescope — to measure accurate parallaxes, with Gaia positions of random field stars anchoring the common reference frame. A couple of science highlights include the identification of the most enigmatic brown dwarf discovered so far, along with the measurement of the substellar mass function using the 20-pc census.