Kinematics, metallicities, and stellar distributions in the inner disk andbulge of the Milky Way

We present the results of a photometric and spectroscopic study of stars in four fields toward the inner disk and Galactic bulge. The fields are locat ed symmetrically about the minor axis of the Milky Way at (l,b)=(-24.degree s 8,-6.degrees 0), (-8.degrees 7,-6.degrees 0), (+8.degrees 4,-6.degrees 0) , and (+24.degrees 4,-6.degrees 1). We measured radial velocities and stren gths of selected absorption-line indexes and derived the average reddening to each field, individual metallicities and photometric parallaxes for each star, and mean azimuthal rotation velocities and velocity dispersions for each field. We found that the stars are not strongly peaked in distribution at the tangent point or at bulgelike distances along any of the lines of s ight. In each field, we find that velocity dispersion decreases as [Fe/H] i ncreases, a correlation noted in many previous works. We also find that bot h velocity dispersion and [Fe/H] vary along each line of sight in a manner consistent with progressively sampling different populations (thin disk, bu lge, thick disk, halo) at increasing distance; hence, the observed metallic ity-velocity dispersion correlation is likely the result, at least in part, of the superposition of multiple populations viewed along the line of sigh t. We find that the disk stars in the (-24.degrees 8, -6.degrees 0) field a re approaching the solar position at similar to 50 km s(-1) faster than the stars in the (+24.degrees 4, -6.degrees 1) field are moving away. Similarl y, inner disk stars from the two inner fields have a velocity asymmetry of similar to 35 km s(-1). The velocity dispersions in these fields are also a symmetric; the -l fields have lower values than predicted for a circularly rotating exponential disk, while the +l fields have higher values. These ki nematic asymmetries suggest that a barlike asymmetry exists in the inner di sk of similar geometric positioning as the bar detected in the Galactic bul ge. Comparison of the line-of-sight kinematics in our (+8.degrees 4, -6.deg rees 0) field with the values of Minniti for a field at (+8 degrees, +7 deg rees) indicates that the kinematics of the outer bulge is symmetric about t he Galactic major axis. From the stars at bulgelike distances in our inner fields, we calculated a rotational velocity, and azimuthal velocity dispers ion for the bulge. By linearly interpolating the values in the two fields, we found the projected mean rotation of the bulge to be 53.3 +/- 0.3 km s(- 1) kpc(-1), or 9.0 +/- 0.5 km s(-1) deg(-1), in general agreement with othe r values from the literature.