Galaxy Clusters Selected via the Sunyaev-Zel'dovich Effect in the SPTpol 100-Square-Degree Survey

Abstract

We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev-Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional 2 galaxy clusters are confirmed using the overdensity of near-infrared galaxies only, and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift of $z\ge 1.0$, with a maximum confirmed redshift of $z_{\max }=1.38\pm 0.10$. We expect this catalog to contain every galaxy cluster with $M_{500c}>2.6\times 10^{14}{M}_{\odot }{h}_{70}^{-1}$ and $z>0.25$ in the survey area. The mass threshold is approximately constant above $z=0.25$, and the complete catalog has a median mass of approximately $M_{500c}=2.7\times 10^{14}{M}_{\odot }{h}_{70}^{-1}$. Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 $\hat{I}¼$K-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass.

21 pages, 7 figures, associated data available at http://pole.uchicago.edu/public/data/sptsz-clusters. V2 was accepted to the AJ, and includes minor changes requested by the reviewer