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

• Main Authors: Grandis, S, Klein, M, Mohr, JJ, Bocquet, S, Paulus, M, Abbott, TMC, Aguena, M, Allam, S, Annis, J, Benson, BA, Bertin, E, Bhargava, S, Brooks, D, Burke, DL, Rosell, AC, Kind, MC, Carretero, J, Capasso, R, Costanzi, M, da Costa, LN, De Vicente, J, Desai, S, Dietrich, JP, Doel, P, Eifler, TF, Evrard, AE, Flaugher, B, Fosalba, P, Frieman, J, Garcia-Bellido, J, Gaztanaga, E, Gerdes, DW, Gruen, D, Gruendl, RA, Gschwend, J, Gutierrez, G, Hartley, WG, Hinton, SR, Hollowood, DL, Honscheid, K, James, DJ, Jeltema, T, Kuehn, K, Kuropatkin, N, Lima, M, Maia, MAG, Marshall, JL, Melchior, P, Menantcau, F, Miquel, R, Ogando, RLC, Palmese, A, Paz-Chinchon, E, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Saro, A, Scarpine, V, Schubnell, M, Serrano, S, Sheldon, E, Smith, M, Stark, AA, Suchyta, E, Swanson, MEC, Tarle, G, Thomas, D, Tucker, DL, Varga, TN, Weller, J, Wilkinson, R
• Format: Article in Journal/Newspaper
• Language: English
• Published: OXFORD UNIV PRESS 2020
• Subjects: methods: statistical; galaxies: clusters: general; large-scale structure of Universe; X-rays: galaxies: clusters; SOUTH-POLE TELESCOPE; DARK ENERGY SURVEY; WEAK-LENSING ANALYSIS; X-RAY; SCALING RELATIONS; COSMOLOGICAL PARAMETERS; CATALOG; XMM; CONSTRAINTS; GIANTS; South Pole; South pole
• Online Access: https://discovery.ucl.ac.uk/id/eprint/10117092/1/staa2333.pdf; https://discovery.ucl.ac.uk/id/eprint/10117092/

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.