The SPT-Deep Cluster Catalog: Sunyaev-Zel'dovich Selected Clusters from Combined SPT-3G and SPTpol Measurements over 100 Square Degrees

Abstract

We present a catalog of 500 galaxy cluster candidates in the SPT-Deep field: a 100 deg${}^2$ field that combines data from the SPT-3G and SPTpol surveys to reach noise levels of 3.0, 2.2, and 9.0 $\hat{I}¼$K-arcmin at 95, 150, and 220 GHz, respectively. This is comparable to noise levels expected for the wide field survey of CMB-S4, a next-generation CMB experiment. Candidates are selected via the thermal Sunyaev-Zel'dovich (SZ) effect with a minimum significance of $\hat{I}¾=4.0$, resulting in a catalog of purity $\sim 89\%$. Optical data from the Dark Energy Survey and infrared data from the Spitzer Space Telescope are used to confirm 442 cluster candidates. The clusters span $0.12<z\lesssim 1.8$ and $1.0\times 10^{14}{M}_{\odot }/h_{70}<M_{500c}<8.7\times 10^{14}{M}_{\odot }/h_{70}$. The sample's median redshift is 0.74 and the median mass is $1.7\times 10^{14}{M}_{\odot }/h_{70}$; these are the lowest median mass and highest median redshift of any SZ-selected sample to date. We assess the effect of infrared emission from cluster member galaxies on cluster selection by performing a joint fit to the infrared dust and tSZ signals by combining measurements from SPT and overlapping submillimeter data from Herschel/SPIRE. We find that at high redshift ($z>1)$, the tSZ signal is reduced by $17.4_{-2.9}^{+3.1}\%$ ($3.7_{-0.7}^{+0.7}\%$) at 150 GHz (95 GHz) due to dust contamination. We repeat our cluster finding method on dust-nulled SPT maps and find the resulting catalog is consistent with the nominal SPT-Deep catalog, demonstrating dust contamination does not significantly impact the SPT-Deep selection function; we attribute this lack of bias to the inclusion of the SPT 220 GHz band.

Submitted to ApJ, 20 pages, 9 figures, affiliations at end of document, cluster catalog available at https://pole.uchicago.edu/public/data/spt3g_deep_cluster_sample/