CluMPR: A new galaxy cluster-finding algorithm

Michael Barth ( Université de Montréal )

The Dark Energy Spectroscopic Instrument (DESI) Legacy Survey has produced multi-band images of 14,000 square degrees. The DESI Legacy Survey photometry has enabled a search for galaxy clusters up to z=1 using a new algorithm optimized to exploit photometric redshifts (photo-z's) and stellar masses. This algorithm, which we call CluMPR (Clusters from Masses and Photometric Redshifts), uses a 2-dimensional binary search tree to search for overdensities in the sky plane and determines cluster membership statistically along the line-of-sight (redshift) direction. The final catalog contains cluster stellar mass estimates and member galaxies for over 300,000 galaxy cluster candidates from z=0.1 to z=1. This catalog will be made publicly available and may be used for searches for gravitationally-lensed transients and hosts of gravitational wave sources, as well as for galaxy evolution studies and to calibrate redshifts for Sunyaev-Zel’dovich selected clusters.