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, B. A., Dodelson, S., Rykoff, E. S., Bleem, L., Abbott, T. M. C., Abdalla, F. B., Allen, S., Annis, J., Benoit-Levy, A., Brooks, D., Burke, D. L., Capasso, R., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Chiu, I., Crawford, T. M., Cunha, C. E., D'Andrea, C. B., da Costa, L. N., Desai, S., Dietrich, J. P., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Frieman, J., Gangkofner, C., Gaztanaga, E., Gerdes, D. W., Giannantonio, T., Grandis, S., Gruen, D., Gruendl, R. A., Gupta, N., Gutierrez, G., Holzapfel, W. L., James, D. J., Kuehn, K., Kuropatkin, N., Lima, M., Marshall, J. L., McDonald, M., Melchior, P., Menanteau, F., Miquel, R., Ogando, R., Plazas, A. A., Rapetti, D., Reichardt, C. L., Reil, K., Romer, A. K., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Soergel, B., Strazzullo, V., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Vikram, V., Walker, A. R., Zenteno, A.
• Format: Text
• Language: unknown
• Published: arXiv 2016
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; FOS Physical sciences; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1605.08770; https://arxiv.org/abs/1605.08770

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 $λ\sim20$. 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 $ζ$-$λ$, relation and two integrated Compton-$y$ $Y_\textrm{500}$-$λ$ relations for the DES-selected clusters and compare these to model expectations accounting for the SZE-optical center offset distribution. For clusters with $λ> 80$, 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 $20 < λ< 80$, the measured SZE signal is smaller by a factor of $\sim$0.20-0.80 (between 2.3 and 10~$σ$ significance) compared to the prediction, with the SPT calibrated scaling relations and larger $λ$ 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 $λ$-mass relation at lower richnesses.