Simulating Solar Neighborhood Brown Dwarfs: A Guide for Upcoming Surveys

Major upcoming digital sky surveys will reveal unprecedented numbers of brown dwarfs, among even greater numbers of stellar objects, enabling the statistical study of brown dwarfs. To effectively parse these massive datasets and extract the comparatively rare brown dwarfs, we must understand how brown dwarfs will look in upcoming databases. To explore the photometric properties and spread of brown dwarfs, we construct a synthetic population of brown dwarfs in the Solar Neighborhood using Gaia-derived star formation rate histories and Galactic thin disk scale heights alongside observational mass, metallicity, and age relationships. We apply the Sonora Bobcat and the 2008 Saumon and Marley hybrid (SM08) evolutionary models to assign temperatures, luminosities, and radii to the sample. We present luminosity, temperature, age, and metallicity functions varying with height above the Galactic thin disk. These models predict significant differences in the brown dwarf population as a function of distance from the Galactic plane, which can be tested with future JWST, Rubin Observatory LSST, and Roman surveys.