We demonstrate that measurements of the gravitational tidal field made with spectroscopic redshifts can be improved with information from imaging surveys. The average orientation of small groups of galaxies, or "multiplets" is correlated with large-scale structure and is used to measure the direction of tidal forces. Previously, multiplet intrinsic alignment has been measured in DESI using galaxies that have spectroscopic redshifts. The DESI Legacy Imaging catalog can be used to supplement multiplet catalogs. Our findings show that galaxy positions from the imaging catalog produce a measurement similar to the measurements made with only spectroscopic data. This demonstrates that imaging can improve our signal-to-noise ratio for multiplet alignment in DESI.
@article{arxiv.2510.08353,
title = {Enhancing Multiplet Alignment Measurements with Imaging},
author = {Alexus Annika Kumwembe and Claire Lamman and Daniel Eisenstein and Jessica Nicole Aguilar and Steven Ahlen and Davide Bianchi and David Brooks and Todd Claybaugh and Andrei Cuceu and Axel de la Macorra and Biprateep Dey and Peter Doel and Andreu Font-Ribera and Jaime E. Forero-Romero and Enrique Gaztanaga and Satya Gontcho A Gontcho and Gaston Gutierrez and Mustapha Ishak and Jorge Jimenez and Dick Joyce and Robert Kehoe and Theodore Kisner and Ofer Lahav and Martin Landriau and Marc Manera and Ramon Miquel and Seshadri Nadathur and Nathalie Palanque-Delabrouille and Ignasi Perez-Rafols and Francisco Prada and Graziano Rossi and Eusebio Sanchez and David Schlegel and Hee-Jong Seo and Joseph Harry Silber and David Sprayberry and Gregory Tarle and Benjamin Alan Weaver},
journal= {arXiv preprint arXiv:2510.08353},
year = {2025}
}