is frequently observed in this kind of sources (Dye et al. 2015, Fu et al. 2012), and reflects the intrinsic nature of the observations. The near-IR emission traces the direct light of stars that are partially or not at all obscured by dust, while the sub-mm emission traces directly the dust-reprocessed photons from the UV radiation field of newborn stars, that is completely or almost completely obscured. This displacement is then reproduced on the reconstructed source plane, with a distance between the two emission peaks of $\sim0.9$ kpc.

A first order lens modeling with the previously found HST parameter set has also been performed on available X-ray data, in order to simply constrain the position of the peak signal, since any further analysis needs data at higher resolution. This is cospatial with the sub-mm signal, and along with the mid-IR excess observed in the source SED, suggests the presence of an obscured AGN in the galaxy.

![image](CPmass_z2_massardi.eps){height="6cm" width="45.00000%"} ![image](MS_z2_Massardi.eps){width="50.00000%"}

Discussion
==========

Our -ACIS observations confirmed that by observing strongly-lensed submm-bright galaxies we can access earlier stages of the co-evolutionary scenario than previously possible. So far, in fact, available X-ray data allowed to test the in-situ coevolution scenario only at relatively 