Abstract This study explores the density profile of the stellar disk, radially and azimuthally, based on approximately 8.4 million red clump stars selected from Gaia Bp/Rp spectra. After correcting for selection effects and distance uncertainties, we fit the vertical stellar density profile of the Galactic disk with a two-component model consisting of geometrically thin and thick disks. Our derived density profile shows several breaks radially: (1) a steep exponent inside R ∼ 3 kpc; (2) a nearly flat plateau from R ∼ 3 to ∼7 kpc; (3) an exponential decline beyond the solar radius to around 13 kpc; (4) a sharper exponential drop-off beyond R ∼ 13 kpc. The parameters of these four main components depend on ϕ to some extent. The variation of the termination radius of the first component suggests an interaction with the bar/bulge. Besides the typical flaring at R > 6.4 kpc, we find that the thin disk also exhibits a similar and smooth thickening/flaring feature toward the Galactic center at R < 6.4 kpc. The observed inner flaring may indicate heating effects introduced by the Galactic bar, since R = 6.4 kpc lies close to the corotation radius where the bar’s dynamical influence becomes significant. Additionally, we identify a localized density bump in the region 5 < R < 7 kpc and −30° < ϕ < 15°, where a corresponding metallicity bump is also visible near the Galactic plane. This density/metallicity bump may be related to the recently reported bimodal distribution of the guiding radius of super metal-rich stars in the solar vicinity through radial migration.
Wu et al. (Fri,) studied this question.