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Title: Optical–SZE scaling relations for DES optically selected clusters within the SPT-SZ Survey

We study the Sunyaev-Zel'dovich effect (SZE) signature in South Pole Telescope (SPT) data for an ensemble of 719 optically identified galaxy clusters selected from 124.6 deg$^2$ of the Dark Energy Survey (DES) science verification data, detecting a stacked SZE signal down to richness $$\lambda\sim20$$. The SZE signature is measured using matched-filtered maps of the 2500 deg$^2$ SPT-SZ survey at the positions of the DES clusters, and the degeneracy between SZE observable and matched-filter size is broken by adopting as priors SZE and optical mass-observable relations that are either calibrated using SPT selected clusters or through the Arnaud et al. (2010, A10) X-ray analysis. We measure the SPT signal to noise $$\zeta$$-$$\lambda$$, relation and two integrated Compton-$y$ $$Y_\textrm{500}$$-$$\lambda$$ relations for the DES-selected clusters and compare these to model expectations accounting for the SZE-optical center offset distribution. For clusters with $$\lambda > 80$$, the two SPT calibrated scaling relations are consistent with the measurements, while for the A10-calibrated relation the measured SZE signal is smaller by a factor of $$0.61 \pm 0.12$$ compared to the prediction. For clusters at $$20 < \lambda < 80$$, the measured SZE signal is smaller by a factor of $$\sim$$0.20-0.80 (between 2.3 and 10~$$\sigma$$ significance) compared to the prediction, with the SPT calibrated scaling relations and larger $$\lambda$$ clusters showing generally better agreement. We quantify the required corrections to achieve consistency, showing that there is a richness dependent bias that can be explained by some combination of contamination of the observables and biases in the estimated masses. We discuss possible physical effects, as contamination from line-of-sight projections or from point sources, larger offsets in the SZE-optical centering or larger scatter in the $$\lambda$$-mass relation at lower richnesses.
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Publication Date:
Report Number(s):
DES-2014-0015; FERMILAB-PUB-16-132-E; arXiv:1605.08770; DES-2014-0015-FERMILAB-PUB-16-132-E
Journal ID: ISSN 0035-8711; 1466121
Grant/Contract Number:
AC02-07CH11359; AC02-76SF00515
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 468; Journal Issue: 3; Journal ID: ISSN 0035-8711
Royal Astronomical Society
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; methods: observational; methods: statistical; galaxies: abundances; galaxies: clusters: general; large-scale structure of Universe
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1294435