Detection of the large-scale tidal field with galaxy multiplet alignment in the DESI Y1 spectroscopic survey

Understand

We explore correlations between the orientations of small galaxy groups, or "multiplets", and the large-scale gravitational tidal field.

• Using data from the Dark Energy Spectroscopic Instrument (DESI) Y1 survey, we detect the intrinsic alignment (IA) of multiplets to the galaxy-traced matter field out to separations of 100 Mpc/h.
• Unlike traditional IA measurements of individual galaxies, this estimator is not limited by imaging of galaxy shapes and allows for direct IA detection beyond redshift z = 1.
• Multiplet alignment is a form of higher-order clustering, for which the scale-dependence traces the underlying tidal field and amplitude is a result of small-scale (< 1 Mpc/h) dynamics.