LoCuSS: A COMPARISON OF CLUSTER MASS MEASUREMENTS FROM XMM-NEWTON AND SUBARU—TESTING DEVIATION FROM HYDROSTATIC EQUILIBRIUM AND NON-THERMAL PRESSURE SUPPORT
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Smith, Graham P.
Evrard, August E.
Sanderson, Alastair J. R.
Marrone, Daniel P.
cosmology: observations – galaxies: clusters: general – galaxies: clusters: individual (Abell 1914) – gravitational lensing: weak – surveys – X-rays: galaxies: clusters
We compare X-ray hydrostatic and weak-lensing mass estimates for a sample of 12 clusters that have been observed with both XMM-Newton and Subaru. At an over-density of Δ = 500, we obtain 1 − MX/MWL = 0.01 ± 0.07 for the whole sample. We also divided the sample into undisturbed and disturbed sub-samples based on quantitative X-ray morphologies using asymmetry and fluctuation parameters, obtaining 1 − MX/MWL = 0.09 ± 0.06 and −0.06 ± 0.12 for the undisturbed and disturbed clusters, respectively. In addition to non-thermal pressure support, there may be a competing effect associated with adiabatic compression and/or shock heating which leads to overestimate of X-ray hydrostatic masses for disturbed clusters, for example, in the famous merging cluster A1914. Despite the modest statistical significance of the mass discrepancy, on average, in the undisturbed clusters, we detect a clear trend of improving agreement between MX and MWL as a function of increasing overdensity, MX/MWL = (0.908 ± 0.004) + (0.187 ± 0.010) · log10(Δ/500). We also examine the gas mass fractions, fgas = Mgas/MWL, finding that they are an increasing function of cluster radius, with no dependence on dynamical state, in agreement with predictions from numerical simulations.Overall, our results demonstrate that XMM-Newton and Subaru are a powerful combination for calibrating systematic uncertainties in cluster mass measurements.
We acknowledge support from KICP in Chicago for hospitality, and thank our LoCuSS collaborators, especially Masahiro Takada and Keiichi Umetsu, for helpful comments on the
manuscript. Y.Y.Z. thanks Massimo Meneghetti and Gabriel Pratt for useful discussion. Y.Y.Z. acknowledges support by the DFG through Emmy Noether Research Grant RE 1462/ 2, through Schwerpunkt Program 1177, and through project B6 “Gravitational Lensing and X-ray Emission by Non-Linear Structures” of Transregional Collaborative Research Centre
TRR 33 The Dark Universe, and support by the German BMBF through the Verbundforschung under grant 50 OR 0601. This work is supported by a Grant-in-Aid for the COE Program “Exploring New Science by Bridging Particle-Matter Hierarchy” and G-COE Program “Weaving Science Web beyond Particle-Matter Hierarchy” in Tohoku University, funded by theMinistry of Education, Science, Sports and Culture of Japan. This work is, in part, supported by a Grant-in-Aid for Science Research in a Priority Area “Probing the Dark Energy through an Extremely Wide and Deep Survey with Subaru Telescope” (18072001) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. N.O. is, in part, supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science,
and Technology of Japan (20740099). A.F. acknowledges support from BMBF/DLR under grant 50 OR 0207 and MPG, and was partially supported by a NASA grant NNX08AX46G to
UMBC. G.P.S. acknowledges support from the Royal Society and STFC. D.P.M. acknowledges support provided by NASA through Hubble Fellowship grant HF-51259.01 awarded by the Space Telescope Science Institute, which is operated by the Association
of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555.
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