Although multiplets are tiny by cosmologists' standards (~1 Mpc), their orientations are aligned with large-scale structure. Out to 150 Mpc/h! We detect a signal in all our galaxy samples: bright galaxies (BGS), luminous red galaxies (LRG) and emission-line galaxies (ELG).

This is similar to the intrinsic alignment (IA) of individual galaxies, except: 1) does not rely on imaging 2) can be used to measure the IA blue galaxies. This has allowed us to measure alignment even with faint, blue ELGs which are beyond z=1 (shown in last plot).