Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters
Smith, M.; Annis, J.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Doel, P.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Menanteau, F.; Miquel, R.; Ogando, R. L. C.; Plazas, A. A.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Walker, A. R.; DES Collaboration; Mann, R. G.; Zhang, Y.; Vergara Cervantes, C.; Hollowood, D. L.; Bhargava, S.; Jeltema, T.; Avila, S.; Buckley-Geer, E.; Costanzi, M.; De Vicente, J.; Evrard, A. E.; Melchior, P.; Serrano, S.; Thomas, D.; Giles, P.; Weller, J.; Dietrich, J. P.; Chen, X.; Krause, E.; Liddle, A. R.; Vikram, V.; Everett, S.; Tucker, D. L.; Hilton, M.; Farahi, A.; Rooney, P.; Rozo, E.; Mantz, A.; Viana, P. T. P.; Collins, C.; Wilkinson, R.; Sahlen, M.; Bermeo, A.; Mayers, J.; Stott, J.
United States, United Kingdom, South Africa, Germany, Portugal, Canada, Sweden, Spain, Brazil, India, Australia, Chile
Abstract
Using archival X-ray observations and a lognormal population model, we estimate constraints on the intrinsic scatter in halo mass at fixed optical richness for a galaxy cluster sample identified in Dark Energy Survey Year-One (DES-Y1) data with the redMaPPer algorithm. We examine the scaling behaviour of X-ray temperatures, TX, with optical richness, λRM, for clusters in the redshift range 0.2 < z < 0.7. X-ray temperatures are obtained from Chandra and XMM observations for 58 and 110 redMaPPer systems, respectively. Despite non-uniform sky coverage, the TX measurements are > 50{{ per cent}} complete for clusters with λRM > 130. Regression analysis on the two samples produces consistent posterior scaling parameters, from which we derive a combined constraint on the residual scatter, σ _{ln T | λ }= 0.275 ± 0.019. Joined with constraints for TX scaling with halo mass from the Weighing the Giants program and richness-temperature covariance estimates from the LoCuSS sample, we derive the richness-conditioned scatter in mass, σ _{ln M | λ }= 0.30 ± 0.04 _{(stat)} ± 0.09 _{(sys)}, at an optical richness of approximately 100. Uncertainties in external parameters, particularly the slope and variance of the TX-mass relation and the covariance of TX and λRM at fixed mass, dominate the systematic error. The 95{{ per cent}} confidence region from joint sample analysis is relatively broad, σ _{ln M | λ }\in [0.14, 0.55], or a factor 10 in variance.