2026/07/01 by L. E. Bleem, M. Klein, K. Kornoelje +148 · 2 voices
#astro-ph.CO #astro-ph.GA
We report a new galaxy cluster catalog, selected using the thermal Sunyaev-Zel'dovich (SZ) effect, from 5 years of observations of the SPT-3G Main field. Drawn from arcminute-resolution data with white noise levels of 3.2, 2.5, and 8.9 μK-arcmin at 95, 150, and 220 GHz, respectively, the sample consists of 8,892 cluster candidates detected above significance ξ=4, with an expected purity of >82% (4,480 at ξ≥5 with purity >99%). Using optical and infrared data we have confirmed 7,190 candidates as clusters. The sample spans a mass range 7.9 × 1013 M_\odot/h70 < M_\textrm500c < 1.6 × 1015 M_\odot/h70 with a median mass of 1.65 × 1014 M_\odot/h70, and a redshift range of 0.037<z\lesssim 2 with a median redshift of z_\textrmmed = 0.73; 1,780 clusters are at z>1 and 271 at z>1.5. Compared to previous SZ cluster samples from South Pole Telescope and Atacama Cosmology Telescope data, the SPT-3G sample is highly consistent in mass and redshift but is significantly deeper, with per-cluster detection signal-to-noise 2-4 times higher and a cluster density of 4.5 confirmed clusters/deg2. We cross match with eRASS1 cluster and point source catalogs, finding 1,279 and 1,319 matches, respectively. The SPT and eROSITA cluster mass estimates are in relatively good agreement. We perform a series of validation checks using both internal data splits and comparisons to external samples. These tests show increasing correlated (dusty) emission with redshift, with a ∼17× larger 220 GHz temperature increment for clusters at z∼1.5 than z∼0.25, but only weak evidence for correlated synchrotron emission. Finally, a number of clusters are flagged as candidate strong gravitational lenses.