Kernel density estimate plots of (a) SCUBA-2 850 μm and (b) 850 μm sources with photo-z close to 4C 23.56 (Δz < 1), with 10% as the contour step. The direction of the radio jet is shown as dotted red lines. The FoV is indicated as a dotted circle. Bright and faint SCUBA-2 sources are color-coded by red and blue, respectively. After the redshift selection, the SMGs still show the angular preference.