The SPTpol Extended Cluster Survey
Abstract
We describe the observations and resultant galaxy cluster catalog from the 2770 deg^{2} SPTpol Extended Cluster Survey (SPTECS). Clusters are identified via the SunyaevZel'dovich (SZ) effect and confirmed with a combination of archival and targeted followup data, making particular use of data from the Dark Energy Survey (DES). With incomplete followup 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∼ 4.4×10^{14} M_{⊙} h_{70}^{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 SZselected clusters, from both SPTECS and the SPTSZ 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 Plancklike cosmology, we measure the optical richnessSZ mass (λM) relation and find it to be 28% shallower than that from a weaklensing analysis of the DES data  a difference significant at the 4σ level  with the relations intersecting at λ = 60. The SPTECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPTSZ cluster sample, will be an important component of future cosmological analyses.
 Publication:

The Astrophysical Journal Supplement Series
 Pub Date:
 March 2020
 DOI:
 10.3847/15384365/ab6993
 arXiv:
 arXiv:1910.04121
 Bibcode:
 2020ApJS..247...25B
 Keywords:

 Galaxy clusters;
 Strong gravitational lensing;
 Largescale structure of the universe;
 584;
 1643;
 902;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 49 pages, 14 figures, 10 tables. Minor changes to match accepted version in ApJS