Galaxy cluster mass reconstruction project - I. Methods and first results on galaxy-based techniques

Old, L. and Skibba, R.A. and Pearce, Frazer R. and Croton, D. and Muldrew, Stuart I. and Muñoz-Cuartas, J.C. and Gifford, D. and Gray, M and der Linden, A. von and Mamon, G.A. and Merrifield, Michael R. and Müller, V. and Pearson, R.J. and Ponman, T.J. and Saro, Alexandro and Sepp, T. and Sifón, C. and Tempel, E. and Tundo, E. and Wang, Y.O. and Wojtak, R. (2014) Galaxy cluster mass reconstruction project - I. Methods and first results on galaxy-based techniques. Monthly Notices of the Royal Astronomical Society, 441 (2). pp. 1513-1536. ISSN 1365-2966

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This paper is the first in a series in which we perform an extensive comparison of various galaxy-based cluster mass estimation techniques that utilize the positions, velocities and colours of galaxies. Our primary aim is to test the performance of these cluster mass estimation techniques on a diverse set of models that will increase in complexity. We begin by providing participating methods with data from a simple model that delivers idealized clusters, enabling us to quantify the underlying scatter intrinsic to these mass estimation techniques. The mock catalogue is based on a Halo Occupation Distribution (HOD) model that assumes spherical Navarro, Frenk and White (NFW) haloes truncated at R₂₀₀, with no substructure nor colour segregation, and with isotropic, isothermal Maxwellian velocities. We find that, above 1014Mʘ, recovered cluster masses are correlated with the true underlying cluster mass with an intrinsic scatter of typically a factor of 2. Below 1014Mʘ, the scatter rises as the number of member galaxies drops and rapidly approaches an order of magnitude. We find that richness-based methods deliver the lowest scatter, but it is not clear whether such accuracy may simply be the result of using an over-simplistic model to populate the galaxies in their haloes. Even when given the true cluster membership, large scatter is observed for the majority non-richness-based approaches, suggesting that mass reconstruction with a low number of dynamical tracers is inherently problematic.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Keywords: Methods: numerical - methods: statistical - galaxies: clusters: general - galaxies: haloes - galaxies: kinematics and dynamics - cosmology: observations
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Physics and Astronomy
Identification Number:
Depositing User: Eprints, Support
Date Deposited: 08 Sep 2016 08:32
Last Modified: 20 Sep 2016 16:10

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