the map coincide in position with one or several Class I sources. Those peaks are likely related to the most recent episodes of formation in the complex. Notice how none of the peaks near the center, corresponding to IC 1795, are associated with Class I sources, possibly indicating an absence of current formation. We also show the positions of O and B type stars listed by @Ogura:1976aa, @Navarete:2011ys and @Bik:2012aa.

The largest concentration of massive stars (6 O-type stars, 7 B-type stars) is located at W3-Main, along with a noticeable concentration of protostars, associated with at least four YSO surface density sub-structures. In IC 1795 there are two O-type stars and one B-type star identified. The central O star in IC 1795 (No. 89 in the @Ogura:1976aa list) is associated with the highest surface density peak. In the W3(OH) region, two sub-structures define the positions of groups B and C in W3(OH), and both are associated with B type stars. It is interesting that the main cluster (group A) in W3(OH) is not associated with any identified massive source.

[lcccc]{}

1 & 02:27:33.29 & 61:56:24.2 & $\dots$ & $\dots$\
2 & 02:27:21.43 & 61:54:57.4 & $\dots$ & W3(OH)-C\
3 & 