Comparison of the ALMA coverage (red isocontours at primary beam attenuation levels of 0.8, 0.6, 0.4, and 0.2) with those of HDFS (WFPC2/F814W; background grey map) and MUSE3D (1 × 1 arcmin² blue region). The blue stars and circles indicate the positions of the group members at z_spec = 1.284 and 4.699, respectively (two of the high-redshift members lie too close to each other for their two circles to be distinguished). The HDFS imaging was aligned with Gaia-DR3 reference (Gaia Collaboration 2023) making use of three stars in the field (black diamonds) at RA, Dec = 22:32:50.513, −60:34:00.94 (used for the MUSE Slow Guiding System); 22:32:56.999, −60:34:05.82 (brightest star in the field); and 22:32:50.513, −60:32:18.83. The image is oriented such that north is up, and west is to the right.