Physical Properties of 6.7 Million Galaxies from the DESI Bright Galaxy Survey

Similar trends are observed for stellar population parameters, while emission-line fluxes are recovered with high accuracy and minimal bias. We further validate our stellar mass estimates by comparison with independent measurements from photometric spectral energy distribution fitting, finding good overall consistency within the expected systematic uncertainties. The value-added catalog presented in this work enables a wide range of statistical studies of galaxy evolution with DESI, and provides a foundation for future analyses based on stacked spectra and improved modeling of dust attenuation.This dataset contains two main data files:（1）zall-pix-iron-bgs.fits.gz: The official DESI DR1 spectroscopic catalog, restricted to BGS targets.

It includes basic observational metadata, such as the unique target identifier (TARGETID), redshift (Z) from the Redrock pipeline, redshift uncertainty (ZERR), target bitmasks (DESI_TARGET, BGS_TARGET), and photometric fluxes in the g and r bands (FLUX_G, FLUX_R). （2）BGS_catalog.fits.gz: The value-added catalog derived from full spectral fitting. This file contains three FITS extensions: (a) FIT_RES: Stores the stellar continuum fitting results and derived stellar population properties.

Key parameters include the signal-to-noise ratio (snr), stellar velocity dispersion (vd), dust attenuation (ebv), stellar mass (M in units of M⊙​), light-weighted and mass-weighted ages (age_L, age_M in log(yr)), metallicities (z_L, z_M), and various spectral indices (e.g., D4000, Mgb, Fe5270). (b) FIT_EMLINES: Provides measurements for 18 optical emission lines. For each line (e.g., Hα, [O III], [N II]), the extension includes the line flux, equivalent width, central wavelength, Gaussian line width, and their corresponding uncertainties.

(c) ZCAT: Contains the cross-matching identifiers (e.g., TARGETID, SURVEY, HEALPIX) that link each fitted spectrum in the value-added catalog back to the original DESI DR1 catalog. The ordering of sources is consistent across extensions, enabling unambiguous cross-matching. Detailed data models for all extensions are provided in the corresponding tables of the associated paper.