Spatial distribution of the sources from this work (red dots) and N11 (yellow dots), plotted over the CO emission (integrated in the range 0 < v_LSR < 130 km s^-1, the tangent point along the line of sight) taken from the Galactic Ring Survey (Jackson et al. 2006). The yellow dashed circle represents the position of RSGC3 (assuming a radius for the cluster of 7′), and the red dashed circle follows the almost circular shell of the HII region N49 (Watson et al. 2008).