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Lensing and x-ray mass estimates of clusters (simulations)

Rasia, E. and Meneghetti, M. and Martino, R. and Borgani, S. and Bonafede, A. and Dolag, K. and Ettori, S. and Fabjan, D. and Giocoli, C. and Mazzotta, P. and Merten, J. and Radovich, M. and Tornatore, L. (2012) Lensing and x-ray mass estimates of clusters (simulations). New Journal of Physics, 14 . Art. No. 055018. ISSN 1367-2630.

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We present a comparison between weak-lensing and x-ray mass estimates of a sample of numerically simulated clusters. The sample consists of the 20 most massive objects at redshift z = 0.25 and M_vir > 5 × 10^(14) M_☉ h^(−1). They were found in a cosmological simulation of volume 1 h^(−3) Gpc^3, evolved in the framework of a WMAP-7 normalized cosmology. Each cluster has been resimulated at higher resolution and with more complex gas physics. We processed it through Skylens and X-MAS to generate optical and x-ray mock observations along three orthogonal projections. The final sample consists of 60 cluster realizations. The optical simulations include lensing effects on background sources. Standard observational tools and methods of analysis are used to recover the mass profiles of each cluster projection from the mock catalogue. The resulting mass profiles from lensing and x-ray are individually compared to the input mass distributions. Given the size of our sample, we could also investigate the dependence of the results on cluster morphology, environment, temperature inhomogeneity and mass. We confirm previous results showing that lensing masses obtained from the fit of the cluster tangential shear profiles with Navarro–Frenk–White functionals are biased low by ~5–10% with a large scatter (~10–25%). We show that scatter could be reduced by optimally selecting clusters either having regular morphology or living in substructure-poor environment. The x-ray masses are biased low by a large amount (~25–35%), evidencing the presence of both non-thermal sources of pressure in the intra-cluster medium (ICM) and temperature inhomogeneity, but they show a significantly lower scatter than weak-lensing-derived masses. The x-ray mass bias grows from the inner to the outer regions of the clusters. We find that both biases are weakly correlated with the third-order power ratio, while a stronger correlation exists with the centroid shift. Finally, the x-ray bias is strongly connected with temperature inhomogeneities. Comparison with a previous analysis of simulations leads to the conclusion that the values of x-ray mass bias from simulations are still uncertain, showing dependences on the ICM physical treatment and, possibly, on the hydrodynamical scheme adopted.

Item Type:Article
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Meneghetti, M.0000-0003-1225-7084
Ettori, S.0000-0003-4117-8617
Additional Information:© 2012 Institute of Physics. Authors, their institutions and third parties all have the same rights to reuse articles published in New Journal of Physics in accordance with the Creative Commons Attribution 3.0 Unported (CC-BY) license. Received 26 August 2011; Published 17 May 2012. We acknowledge financial support from contracts ASI-INAF I/023/05/0, ASI-INAF I/088/06/0, PRIN-INAF-2009 grant ‘Towards an Italian Network for Computational Cosmology’ and INFN PD51. This work has been performed under the HPC-EUROPA2 project (project number 228398) with the support of the European Commission—Capacities Area—Research Infrastructures. ER acknowledges the support of the Michigan Society of Fellows. MM, ER, PM, SB and SE thank the organizers of the workshop ‘Galaxy cluster at the crossroads between astrophysics and cosmology’, the KITP for hospitality and the National Science Foundation for financial support under grant no. PHY05-51164. SB acknowledges partial support from the European Commissions FP7 Marie Curie Initial Training Network CosmoComp (PITNGA- 2009-238356). DF acknowledges support by the European Union and the Ministry of Higher Education, Science and Technology of Slovenia. This research was supported in part by the Michigan Center for Theoretical Physics. Simulations have been carried out at CINECA (Bologna, Italy), with CPU time allocated through an Italian SuperComputing Resource Allocation (ISCRA) project.
Funding AgencyGrant Number
European CommissionUNSPECIFIED
Michigan Society of FellowsUNSPECIFIED
European Commissions FP7 Marie Curie Initial Training Network CosmoCompPITNGA-2009-238356
Ministry of Higher Education, Science and Technology (Slovenia)UNSPECIFIED
Michigan Center for Theoretical PhysicsUNSPECIFIED
Subject Keywords:Fluid dynamics; Gravitation and cosmology; Astrophysics and astroparticles
Classification Code:PACS: 98.62.Sb; 98.65.Cw; 98.70.Qy; 98.80.Cq; 95.30.Lz
Record Number:CaltechAUTHORS:20120705-092629110
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Official Citation:Lensing and x-ray mass estimates of clusters (simulations) E Rasia et al 2012 New J. Phys. 14 055018
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32260
Deposited By: Jason Perez
Deposited On:06 Jul 2012 14:58
Last Modified:03 Oct 2019 03:59

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