Abstract

Using a complete sample of about 330,000 dwarf stars, well measured by Gaia DR3, limited to the galactic north and south solid angles vertical bar b vertical bar 75 degrees and up to a vertical distance of 2 kpc, we analyze the vertical structure of the Milky Way stellar disks, based on projected tangential velocities. From selected subsamples dominated by their corresponding population, we obtain the thin and thick disk scale heights as h(Z) = 279.76 +/- 12.49 pc and H-Z = 797.23 +/- 12.34 pc, respectively. Then from the simultaneous fitting of the sum of two populations over the whole sample, assuming these scale heights, we estimate the thick-to-thin disk number density ratio at the galactic plane to be rho(T)/rho(t) = 0.750 +/- 0.049, which is consistent with a previous result by the authors: in the galactic plane there is a significant number of thick disk stars, possibly as many as thin disk ones, which also points to the existence of more thick disk stars than generally thought. The overall fit does not closely follow the data for vertical bar Z broken vertical bar > 700 pc and points to the presence of more stars beyond the thin disk that cannot be accounted for by the two-disk model.