Optical-SZE Scaling Relations for DES Optically Selected Clusters within the SPT-SZ Survey

• Main Authors: Saro, A, Bocquet, S, Mohr, J, Rozo, E, Benson, BA, Dodelson, S, Rykoff, ES, Bleem, L, Abbott, TMC, Abdalla, FB, Allen, S, Annis, J, Benoit-Levy, A, Brooks, D, Burke, DL, Capasso, R, Rosell, AC, Kind, MC, Carretero, J, Chiu, I, Crawford, TM, Cunha, CE, D'Andrea, CB, Costa, LND, Desai, S, Dietrich, JP, Evrard, AE, Neto, AF, Flaugher, B, Fosalba, P, Frieman, J, Gangkofner, C, Gaztanaga, E, Gerdes, DW, Giannantonio, T, Grandis, S, Gruen, D, Gruendl, RA, Gupta, N, Gutierrez, G, Holzapfel, WL, James, DJ, Kuehn, K, Kuropatkin, N, Lima, M, Marshall, JL, McDonald, M, Melchior, P, Menanteau, F, Miquel, R, Ogando, R, Plazas, AA, Rapetti, D, Reichardt, CL, Reil, K, Romer, AK, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Soergel, B, Strazzullo, V, Suchyta, E, Swanson, MEC, Tarle, G, Thomas, D, Vikram, V, Walker, AR, Zenteno, A
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Methods: observational; methods: statistical; galaxies: abundances; galaxies: clusters: general; large-scale structure of Universe; Lambda; South Pole; South pole
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1540495/1/Abdalla_stx594.pdf; https://discovery.ucl.ac.uk/id/eprint/1540495/

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.