OBSERVATIONS OF INTERSTELLAR GAS TOWARDS OMEGA-CENTAURI AND THE CARINA-SAGITTARIUS SPIRAL ARM

Interstellar Na D and K i line spectra are reported for three stars which lie within 5-degrees of the omega Cen cluster. These new data have enabled us to complete the identification of the absorption components which are observed in the gas foreground to this cluster. In particular, we discuss a component at velocity v(lsr) almost-equal-to -15 km s-1 which is produced by gas beyond almost-equal-to 1 kpc and at a distance greater than or similar 175 pc above the Galactic plane. We suggest that this feature originates in the gas of the Carina spiral arm. Weaker components having negative peculiar velocities appear to lie beyond the bulk of the -15 km s-1 gas. A comparison of these new observations with similar studies made towards M4 and M22 provides a further indication of the complex structure of the gas over part of the Carina-Sagittarius arm region.