The SPTpol Extended Cluster Survey
Abstract
We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 < ξ < 5. The confirmed sample has a median mass of M_500c∼ 4.4×1014 M_{⊙} h70-1 and a median redshift of z = 0.49, and we have identified 44 strong gravitational lenses in the sample thus far. Radio data are used to characterize contamination to the SZ signal; the median contamination for confirmed clusters is predicted to be ∼1% of the SZ signal at the ξ > 4 threshold, and <4% of clusters have a predicted contamination >10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (λ-M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data - a difference significant at the 4σ level - with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- March 2020
- DOI:
- 10.3847/1538-4365/ab6993
- arXiv:
- arXiv:1910.04121
- Bibcode:
- 2020ApJS..247...25B
- Keywords:
-
- Galaxy clusters;
- Strong gravitational lensing;
- Large-scale structure of the universe;
- 584;
- 1643;
- 902;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 49 pages, 14 figures, 10 tables. Minor changes to match accepted version in ApJS
