40′ × 40′ map centered on G237 showing the significance of the flux-weighted density contrast of the red SPIRE sources based on the distance distribution to the 10th nearest neighbors. White contours represent the Planck signal in the 550 μm red-excess map at 50, 62.5, 75, and 87.5% of the peak value. The yellow ellipse represents the double Gaussian fit (solid: full axis equal to FWHM, dashed: half axis equal to 3σ^pos) obtained when measuring the position and extent of G237 in the Planck maps. The map and the contours have been smoothed with a 3′ Gaussian filter.