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

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.; Rosell, A. Carnero; Kind, M. Carrasco; 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.; Garcia-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.; Menantcau, F.; Miquel, R.; Ogando, R. L. C.; Palmese, A.; Paz-Chinchon, E.; 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. (2020): Validation of selection function, sample contamination and mass calibration in galaxy cluster samples. In: Monthly Notices of the Royal Astronomical Society, Vol. 498, No. 1: pp. 771-798

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.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 0035-8711
• Language: English