Dust and gas correlations in the region of the South Celestial Pole

A high-resolution 21-cm survey of the South Celestial polar region is being conducted to determine the relationship between the visible nebulosity, the local neutral hydrogen, and the overlying Carina spiral arm. In the region studied (9h to 16h, -82 deg to -88 deg) there is a good correlation between the neutral hydrogen column density and the brightest nebulae (about 25 mag per square arcsec). This suggests that the brightest nebulae are associated with a mass of infalling neutral hydrogen. The presence of a narrow and distinct boundary between the approximately 0 km/s gas and the higher negative velocity components suggests that the infalling material is fairly localized and is 'falling through' the local gas in toward the galactic plane.