Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters

Farahi, A. and Chen, X. and Evrard, A.E. and Hollowood, D.L. and Wilkinson, R. and Bhargava, S. and Giles, P. and Romer, A.K. and Jeltema, T. and Hilton, M. and Bermeo, A. and Mayers, J. and Vergara Cervantes, C. and Rozo, E. and Rykoff, E.S. and Collins, C. and Costanzi, M. and Everett, S. and Liddle, A.R. and Mann, R.G. and Mantz, A. and Rooney, P. and Sahlen, M. and Stott, J. and Viana, P.T.P. and Zhang, Y. and Annis, J. and Avila, S. and Brooks, D. and Buckley-Geer, E. and Burke, D.L. and Carnero Rosell, A. and Carrasco Kind, M. and Carretero, J. and Castander, F.J. and da Costa, L.N. and de Vicente, J. and Desai, S. and Diehl, H.T. and Dietrich, J.P. and Doel, P. and Flaugher, B. and Fosalba, P. and Frieman, J. and García-Bellido, J. and Gaztanaga, E. and Gerdes, D.W. and Gruen, D. and Gruendl, R.A. and Gschwend, J. and Gutierrez, G. and Honscheid, K. and James, D.J. and Krause, E. and Kuehn, K. and Kuropatkin, N. and Lima, M. and Maia, M.A.G. and Marshall, J.L. and Melchior, P. and Menanteau, F. and Miquel, R. and Ogando, R.L.C. and Plazas, A.A. and Sanchez, E. and Scarpine, V. and Schubnell, M. and Serrano, S. and Sevilla-Noarbe, I. and Smith, M. and Sobreira, F. and Suchyta, E. and Swanson, M.E.C. and Tarle, G. and Thomas, D. and Tucker, D.L. and Vikram, V. and Walker, A.R. and Weller, J. (2019) Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters. Monthly Notices of the Royal Astronomical Society, 490 (3). pp. 3341-3354. ISSN 0035-8711

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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, T-X, with optical richness, lambda(RM), 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 T-X measurements are > 50 per cent complete for clusters with lambda(RM) > 130. Regression analysis on the two samples produces consistent posterior scaling parameters, from which we derive a combined constraint on the residual scatter, sigma(ln) (T) (vertical bar) (lambda) = 0.275 +/- 0.019. Joined with constraints for T-X 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, sigma(ln) (M) (vertical bar) (lambda) = 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 T-X-mass relation and the covariance of T-X and lambda(RM) at fixed mass, dominate the systematic error. The 95 per cent confidence region from joint sample analysis is relatively broad, sigma(ln) (M) (vertical bar) (lambda) is an element of [0.14, 0.55], or a factor 10 in variance.