# # Program information file # PROGRAM_ID 2021A023 PROGRAM_TITLE Constraining ultra-cool dwarf formation throughout the history of the Galaxy using the 30pc sample. PROGRAM_INV1 Richard Smart PROGRAM_INV2 William Cooper PROGRAM_INV3 Federico Marocco PROGRAM_INV4 Adam Burgasser PROGRAM_INV5 J. Davy Kirkpatrick PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We will constrain the formation processes of ultra-cool dwarfs [UCDs] using the local sample of all UCDs within 30pc of the sun. We will derive space densities to compare to simulations of different mass functions to probe the low mass star/brown dwarf formation history of the Galaxy. The large statistical weight of this sample and the reliability of the Gaia astrometry makes this sample the calibration point for other programs that investigate the birth rate in the L/T boundary. The spectra will be used to calibrate correlations of physical characteristics with spectral diagnostics, confirm moving group members, identify common-proper-motion companions to more massive stars, and to search for spectroscopic binaries. To accurately measure and characterise the UCDs population we will spectroscopically characterise candidates identified using multi-band photometry and Gaia astrometry and find the corresponding space densities. In Gaia we have found 585 UCDs wihtin 30pc of which 51 have been spectroscopically confirmed by this team, 382 are published in the literature and 152 are new candidates, half of which we propose to observe with SPEX/IRTF. This is part of a large, ongoing, international collaboration, that is using southern telescopes to complete an all-sky census. The spectra are also being used to improve the training set of the UCD work-package of the Gaia Data Processing and Analysis Consortium pipeline to improve the procedures for generating a complete UCD sample to the Gaia detection limit. This dataset, simply because it will be complete, homogenous and local, will remain the authoritative sample of ultra-cool dwarfs, bridging the stellar to sub-stellar boundary, for the foreseeable future. This is the followup submission of the successful proposal 2020B057 to cover the full 24h RA range. These nights will suffice to complete the program. PROGRAM_ABSTRACT_END