Star formation in IR dust bubbles: the S21 - S24 complex

We present an analysis of YSOs linked to the IR dust bubble complex S21-S22-S23-S24 of about 12 arcmin in size, which also includes infrared dark clouds and EGOS. The study reveals the presence of many YSOs and their correlation with molecular gas (CO data from APEX) and dust. The YSOs identified in IR point source catalogs indicate that the complex is a very active star forming region with sources in different evolutionary states. Outflow signatures is also investigated. We compare the main parameters of the different sections of the complex in order to characterize the star forming process