From left to right: HST/WFC3 image in the filter F140W, ALMA [C ii] 158 μm integrated map not corrected for primary beam attenuation, and Spitzer map with IRAC at 3.6 μm. Contours in the middle and right panel show the HST flux. The colour scale of the ALMA map is shown at the bottom in Jy km s^-1. To emphasize the emission from the arc, the ALMA data were tapered and the resolution is 0.5′′ (represented by the black circle at the bottom left). The red circle represents the ALMA primary beam at half its maximum; its diameter is 9.5′′. The white box delineates the region over which the continuum and the spectra have been integrated. The images are 9′′ by 18′′ side with a standard orientation (N up, E left).