Optical and X-ray images of SPT0615. Top left: HST/ACS image in the F814W filter of SPT0615. Spectroscopically confirmed member galaxies are indicated by green circles. Top right: Chandra image of the same region. The alignment seen in the galaxy distribution coincides with the major axis of the surface brightness distribution in X-rays at the inclination of ∼22° shown in the bottom figure. Bottom: X-ray isocontours of SPT0615, which show a similar elongation as the galaxy distribution and critical lensing curves (Fig. 6 of Paterno-Mahler et al. 2018). Excess X-ray emission can be seen clearly east and south, and it is marked by green arrows. North is up. East is left.