galaxies.

We also note that the SED fitting procedure implies uncertanties as high as $\sim50$ per cent of the stellar mass, and systematic errors can be due to the uncertain separation between lens and source and can provide up to an additional factor $\sim2$, but these are not crucial to our following findings.

Emission from the region of the two targets is present in the FIRST[^1] maps at 1.4 GHz at levels of $1.21\pm0.14$ and $0.72\pm0.12$mJy respectively for SDP.9 and SDP.11. The presence of emission from stronger sources within a few arcmin does not allow us to fully discard the possibility of a small spurios contamination, at least for SDP.9. The conversion of the SFR, as estimated form the Herschel maps, into radio signal at this frequency using the Bonzini et al. (2015) relation after scaling for the magnification factor does not discard the possibility of an AGN contribution responsible for the remaining emission.

![HST/WFC3 lens-subtracted F160W images (brightness scale in $\mu$Jy/arcsec$^2$, left panel) and 0.5/7keV images (right panel) of SDP.9 and SDP.11, overlaid with signal-to-noise ratio contours at 880 $\mu$m from the SMA (in steps of 3,6,9, Bussmann et al. 2013, Negrello et al. 2014).[]{data-label="fig:chandra_im"}](sdp9.png "fig:"){width="50.00000%"} ![HST/WFC3 lens-subtracted F160W 