The molecular complex associated with RCW 121 and RCW 122

Abstract

The distribution of the molecular gas towards the region containing the open cluster HM 1, the Wolf-Rayet stars WR 87, WR 89, and WR 91, and the star forming regions RCW 121 and RCW 122 is analyzed with the aim of looking for a possible physical relationship among these objects. Using ^{12}CO observations carried out at λ ? 2.6 mm with the 4 m NANTEN radiotelescope, and adopting a distance of 5 kpc for RCW 121 and RCW 122, a giant molecular cloud (GMC) having a lineal extent of ? 100×20 pc is found to be associated with these galactic star-forming regions. The total mass of this GMC is of the order of 1.2×10^6 solar masses and its mean radial velocity is about -15 km s^{-1}.