Validation of selection function, sample contamination and mass calibration in galaxy cluster samples

• Published in: Monthly notices of the Royal Astronomical Society 2020-10, Vol.498 (1), p.771-798
• Main Authors: Grandis, S, Klein, M, Mohr, J J, Bocquet, S, Paulus, M, Abbott, T M C, Aguena, M, Allam, S, Annis, J, Benson, B A, Bertin, E, Bhargava, S, Brooks, D, Burke, D L, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Capasso, R, Costanzi, M, da Costa, L N, De Vicente, J, Desai, S, Dietrich, J P, Doel, P, Eifler, T F, Evrard, A E, Flaugher, B, Fosalba, P, Frieman, J, García-Bellido, J, Gaztanaga, E, Gerdes, D W, Gruen, D, Gruendl, R A, Gschwend, J, Gutierrez, G, Hartley, W G, Hinton, S R, Hollowood, D L, Honscheid, K, James, D J, Jeltema, T, Kuehn, K, Kuropatkin, N, Lima, M, Maia, M A G, Marshall, J L, Melchior, P, Menanteau, F, Miquel, R, Ogando, R L C, Palmese, A, Paz-Chinchón, F, Plazas, A A, Romer, A K, Roodman, A, Sanchez, E, Saro, A, Scarpine, V, Schubnell, M, Serrano, S, Sheldon, E, Smith, M, Stark, A A, Suchyta, E, Swanson, M E C, Tarle, G, Thomas, D, Tucker, D L, Varga, T N, Weller, J, Wilkinson, R
• Format: Article
• Language: English
• Subjects: galaxies: clusters: general; large-scale structure of Universe; methods: statistical; X-rays: galaxies: clusters
• ISSN: 0035-8711; 1365-2966; 1365-2966
• DOI: 10.1093/mnras/staa2333

ABSTRACT We construct and validate the selection function of the MARD-Y3 galaxy cluster sample. This sample was selected through optical follow-up of the 2nd ROSAT faint source catalogue with Dark Energy Survey year 3 data. The selection function is modelled by combining an empirically constructed X-ray selection function with an incompleteness model for the optical follow-up. We validate the joint selection function by testing the consistency of the constraints on the X-ray flux–mass and richness–mass scaling relation parameters derived from different sources of mass information: (1) cross-calibration using South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) clusters, (2) calibration using number counts in X-ray, in optical and in both X-ray and optical while marginalizing over cosmological parameters, and (3) other published analyses. We find that the constraints on the scaling relation from the number counts and SPT-SZ cross-calibration agree, indicating that our modelling of the selection function is adequate. Furthermore, we apply a largely cosmology independent method to validate selection functions via the computation of the probability of finding each cluster in the SPT-SZ sample in the MARD-Y3 sample and vice versa. This test reveals no clear evidence for MARD-Y3 contamination, SPT-SZ incompleteness or outlier fraction. Finally, we discuss the prospects of the techniques presented here to limit systematic selection effects in future cluster cosmological studies.