Brown dwarfs from JWST NIRSpec observations

The James Webb Space Telescope (JWST), with its unprecedented near-infrared sensitivity, enables the discovery and characterization of distant substellar objects, including those in the Milky Way's thick disk and halo. We conducted a systematic search using over 40,000 publicly available JWST/NIRSpec PRISM/CLEAR spectra and identified 68 brown dwarfs through spectral template matching and visual inspection.

Among them, 12 are newly identified candidates, including eight T dwarfs and four M/L dwarfs, most at distances exceeding 1 kpc. Remarkably, two sources-JWST J001418.22-302223.2 and JWST J033240.07-274907.8-are found at distances greater than 5kpc, making them the most distant brown dwarfs within the Milky Way. Spectral fits were performed using a nested sampling Monte Carlo algorithm with three model grids: Sonora Elf Owl, LOWZ, and SAND.