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

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Grandis, S., Klein, M., Mohr, J., Bocquet, S., Paulus, M., Abbott, T., Aguena, M., Allam, S., Annis, J., Benson, B., Bertin, E., Bhargava, S., Brooks, D., Burke, D., Rosell, A., Kind, M., Carretero, J., Capasso, R., Costanzi, M., da Costa, L., Vicente, J., Desai, S., Dietrich, J., Doel, P., Eifler, T., Evrard, A., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R., Gschwend, J., Gutierrez, G., Hartley, W., Hinton, S., Hollowood, D., Honscheid, K., James, D., Jeltema, T., Kuehn, K., Kuropatkin, N., Lima, M., Maia, M., Marshall, J., Melchior, P., Menanteau, F., Miquel, R., Ogando, R., Palmese, A., Paz-Chinchon, F., Plazas, A., Romer, A., Roodman, A., Sanchez, E., Saro, A., Scarpine, V., Schubnell, M., Serrano, S., Sheldon, E., Smith, M., Stark, A., Suchyta, E., Swanson, M., Tarle, G., Thomas, D., Tucker, D., Varga, T., Weller, J., Wilkinson, R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2020
• Subjects: South Pole; South pole
• Online Access: http://hdl.handle.net/21.11116/0000-0007-FCCF-5; http://hdl.handle.net/21.11116/0000-0007-FCD1-1

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.