Beschreibung
Galaxy clusters are sensitive probes of the growth of cosmic structure, but their cosmological power depends on clean samples with well-characterized selection, accurate redshifts, and controlled contamination. I will discuss recent progress and challenges in turning large samples of more than 10,000 ICM-selected candidates into well-controlled galaxy cluster catalogs using multi-wavelength optical and infrared data. The talk will focus on methods to quantify and validate sample quality, selection effects, and systematics, while also highlighting limitations set by the depth, wavelength coverage, and resolution of currently available datasets.
As a key example, I will present recent results from the SPT-3G Main Survey, covering about 1,600 deg² and reaching cluster masses of M₅₀₀c ≈ 10¹⁴ M⊙ at z>1. This high sensitivity at high redshift pushes existing large-area optical and infrared surveys to their limits. Ongoing and recently started surveys such as Euclid and the Rubin Observatory’s LSST will therefore be essential for fully exploiting the next generation of SZ-selected cluster samples. I will conclude with first insights into cluster confirmation with Euclid.