A SUNYAEV-ZEL'DOVICH-SELECTED SAMPLE OF THE MOST MASSIVE GALAXY CLUSTERS IN THE 2500 deg²SOUTH POLE TELESCOPE SURVEY

Abstract

The South Pole Telescope (SPT) is currently surveying 2500 deg 2 of the southern sky to detect massive galaxy clusters out to the epoch of their formation using the Sunyaev-Zel'dovich (SZ) effect. This paper presents a catalog of the 26 most significant SZ cluster detections in the full survey region. The catalog includes 14 clusters which have been previously identified and 12 that are new discoveries. These clusters were identified in fields observed to two differing noise depths: 1500 deg 2 at the final SPT survey depth of 18 μK arcmin at 150 GHz and 1000 deg 2 at a depth of 54 μK arcmin. Clusters were selected on the basis of their SZ signal-to-noise ratio (S/N) in SPT maps, a quantity which has been demonstrated to correlate tightly with cluster mass. The S/N thresholds were chosen to achieve a comparable mass selection across survey fields of both depths. Cluster redshifts were obtained with optical and infrared imaging and spectroscopy from a variety of ground-and space-based facilities. The redshifts range from 0.098 z 1.132 with a median of z med = 0.40. The measured SZ S/N and redshifts lead to unbiased mass estimates ranging from 9.8 × 10 14 M h −1 70 M 200 (ρ mean) 3.1 × 10 15 M h −1 70. Based on the SZ mass estimates, we find that none of the clusters are individually in significant tension with the ΛCDM cosmological model. We also test for evidence of non-Gaussianity based on the cluster sample and find the data show no preference for non-Gaussian perturbations.

Observational probes of cosmic acceleration

“…The first three successful cluster SZ surveys -using the South Pole Telescope (SPT), the Atacama Cosmology Telescope (ACT), and the Planck satellite -are all currently ongoing. All three projects have released SZ-selected cluster samples (Vanderlinde et al, 2010;Marriage et al, 2011;Planck Collaboration et al, 2011a;Williamson et al, 2011;Reichardt et al, 2013). These samples tend to be of very massive clusters (see Figure 27) and, in the case of ACT and SPT, extend to z ≈ 2, with the upper limit set by the lack of massive galaxy clusters above this redshift.…”

Constraints on the duality relation from ACT cluster data

“…For this, data from optical and X-ray cluster surveys are currently used to constrain cosmological parameters. Recently, however, a new window of information regarding galaxy cluster physics has opened with the release of cluster surveys (e.g., Staniszewski et al 2009;Marriage et al 2011;Williamson et al 2011;Planck Collaboration VIII 2011;Reichardt et al 2013) that make use of the SZ effect, which is a signature that does not diminish with luminosity distance because it is nearly independent of redshift. In fact, thermal SZ signal is a tracer of the total thermal energy of the hot (∼10 7 K) intracluster gas, therefore it is correlated to the mass of the cluster.…”

DISCOVERY OF A SUPERCLUSTER AT z ∼ 0.91 AND TESTING THE ΛCDM COSMOLOGICAL MODEL

“…So far, high-redshift LSS studies have been limited mostly to galaxy-cluster-scale structures (1-2 Mpc), with mixed results. Some results show agreements with the ΛCDM cosmology models (Williamson et al 2011;Bayliss et al 2014), but others suggest too many massive clusters at z1 (Jee et al 2009;Gonzalez et al 2012;Kang & Im 2015).…”

“…The ΛCDM cosmological model has been successful in reproducing the LSS at z;0, showing the promise of the ΛCDM cosmology to explain our universe (e.g., Bahcall et al 2003;Williamson et al 2011;Benson et al 2013).…”