SPHEREx Ultracool Dwarf spectrophotometric Atlas (SUDA): Atmospheric and Fundamental Parameters of Ultracool Dwarfs

This archive contains the data products used for the SUDA analysis (Tu et al. 2026, submitted to ApJ). It includes the SPHEREx 102-channel spectrophotometric products for the final analysed sources, the empirical spectrophotometric atlas, the electronic source catalog, and the XGBoost model used to estimate bolometric luminosities for sources without parallaxes. Contents source_spectra/ Per-source 102-channel SPHEREx spectrophotometry in CSV format. File names use the source coordinate (J2000): RA_Dec.csv. atlas/ spectra/: empirical atlas spectra, one file per adopted (Teff, logg) bin. atlas_figure.pdf: PDF rendering of the atlas figure. catalog/suda_catalog.csv Full electronic catalog for the SUDA sources, see catalog/README.md for more details. model/ lbol_model.joblib: serialized XGBoost model pipeline for estimating log(Lbol/Lsun). SPHEREx 102-channel products The per-source CSV files include one row per nominal SPHEREx channel and contain spectrophotometry: wavelength_um: channel wavelength in microns. flux_ujy: flux density in micro-Jy. flux_err_ujy: flux-density uncertainty in micro-Jy. Empirical atlas products The atlas was constructed from sources with parallaxes by grouping the SPHEREx spectrophotometric measurements in bins of atmospheric-model Teff and evolutionary-model logg. The atlas contains 57 bins constructed from 986 spectrophotometric measurements. Each atlas spectrum contains: wave_um: wavelength in microns. normalized_flux: median normalized flux in the atlas bin. normalized_flux_err: uncertainty on the normalized flux estimate. n_contrib: number of contributing sources at that wavelength. XGBoost luminosity model The model predicts log(Lbol/Lsun) for sources without parallaxes using Teff, logg, and MH.