SPITZER IRAC 4.5 μm image (Chavarría et al. 2008) overlaid with SCUBA 850 μm contours (Di Francesco et al. 2008; Klein et al. 2005). In the upper panel, the gray scale is the SPITZER IRAC 4.5 μm image, the black contours are the NVSS 1.4 GHz emission and the green contours are the SCUBA 850 μm continuum. In the bottom left panel, the gray scale is the SPITZER MIPS 24 μm image, the contours are the SCUBA 850 μm continuum, the three dashed circles mark the primary beam of our SMA observations. In the bottom right panel, the gray scale is the SPITZER MIPS 70 μm image, the contours and the circles are the same as the ones in the left panel. The contour levels of the NVSS start at 10σ (1σ = 0.6 mJy beam^-1) in steps of 5σ. For the SCUBA 850 μm, the contour levels start at 10σ (1σ = 0.1 Jy beam^-1) with a step of 10σ. The SPITZER/IRAC post-bcd data processed with pipeline version S18.7.0 and the MIPS post-bcd data processed with pipeline version S17.2.0 have been downloaded from the SPITZER archive to create these images.