1995BaltA...4....1B

A new homogeneous catalog of photographic RGU star count and color data in seven high-galactic latitude fields has been used to determine the best-fitting structural parameter values from a large number of multi-component population models of the Galaxy. We confirm the presence of a prominent thick disk component coexisting with a canonical thin disk and a low-density spheroidal halo. to 6mm We find that the thick disk has an exponential scale length of 4.25±1.5 kpc, exponential scale height of 1.15±0.25 kpc, and a local density of 5.4±1.5 % relative to the (old) thin disk population. to 6mm For the thick disk, our best model fitting to the observed color distributions provide a mean metallicity <[M/H]> = -0.6±0.1 dex and a minor vertical metallicity gradient of the order of d[M/H]/dz = -0.1 dex/kpc. The observed color distributions are consistent with the (old) thin disk having mean abundance <[M/H]> and dispersion σ_<[M/H]> of -0.32±0.24 dex and vertical metallicity gradient d[M/H]/dz = -0.6 dex/kpc. to 6mm These results are in good agreement with recent evidence from detailed studies of kinematic and chemical data for smaller, and more local, stellar samples.