The Ara OB1 Association and its Molecular Complex

摘要

The results of low (HPBW~1=8!7) and intermediate (HPBW=-2!angular resolution carbon monoxide (~(12)C0J=1 →0) line observations towardthe OB association Ara OB1 are reported. The molecular features that arelikely to be associated with the OB-association span a velocity range from -28to -20 km s~(-1). The most negative radial velocities are observed along NGC 6188(also known as the Rim Nebula). The main CO structures, labeled E and Fin Fig. 2, have radial velocities of about -23.5 and -21.8 km s~(-1), respectively.The former harbors the IRAS source IRAS 16362-4845 and the infrared clus-ter RCW 108-IR. The observations at intermediate resolution show noticeablechanges in shape, peak intensity and full width at half maximum in the line pro-files observed toward structures E and F. The large line widths, about 7.5 km s~(-1),found toward structure E very likely reflect the interaction of RCW 108-IR withits surrounding molecular gas. A scale down version of this phenomenon is alsofound toward structure F. The total amount of molecular gas related to struc-tures E and Fin NGC 6188 is about 8.2x 10~3 M_⊙.