Oxford University Press (OUP), Monthly Notices of the Royal Astronomical Society, 2(449), p. 1897-1920
DOI: 10.1093/mnras/stv421
Full text: Download
This article is the second in a series in which we perform an extensive comparison of various galaxy-based cluster mass estimation techniques that utilise the positions, velocities and colours of galaxies. Our aim is to quantify the scatter, systematic bias and completeness of cluster masses derived from a diverse set of 25 galaxy-based methods using two contrasting mock galaxy catalogues based on a sophisticated halo occupation model and a semi-analytic model. Analysing 968 clusters, we find a wide range in the RMS errors in log M200c delivered by the different methods (0.18 to 1.08 dex, i.e., a factor of ∼1.5 to 12), with abundance matching and richness methods providing the best results, irrespective of the input model assumptions. In addition, certain methods produce a significant number of catastrophic cases where the mass is under- or over-estimated by a factor greater than 10. Given the steeply falling high-mass end of the cluster mass function, we recommend that richness or abundance matching-based methods are used in conjunction with these methods as a sanity check for studies selecting high mass clusters. We see a stronger correlation of the recovered to input number of galaxies for both catalogues in comparison with the group/cluster mass, however, this does not guarantee that the correct member galaxies are being selected. We do not observe significantly higher scatter for either mock galaxy catalogues. Our results have implications for cosmological analyses that utilise the masses, richnesses, or abundances of clusters, which have different uncertainties when different methods are used. ; We would like to acknowledge funding from the Science and Technology Facilities Council (STFC). DC would like to thank the Australian Research Council for receipt of a QEII Research Fellowship. The Dark Cosmology Centre is funded by the Danish National Research Foundation. The authors would like to express special thanks to the Instituto de Fisica Teorica (IFT-UAM/CSIC in Madrid) for its hospitality and support, via the Centro de Excelencia Severo Ochoa Program under Grant No. SEV-2012-0249, during the three week workshop “nIFTy Cosmology” where this work developed. We further acknowledge the financial support of the University of Western 2014 Australia Research Collaboration Award for “Fast Approximate Synthetic Universes for the SKA”, the ARC Centre of Excellence for All Sky Astrophysics (CAASTRO) grant number CE110001020, and the two ARC Discovery Projects DP130100117 and DP140100198. We also recognise support from the Universidad Autonoma de Madrid (UAM) for the workshop infrastructure. RAS acknowledges support from the NSF grant AST-1055081. CS acknowledges support from the European Research Council under FP7 grant number 279396. SIM acknowledges the support of the STFC consolidated grant (ST/K001000/1) to the astrophysics group at the University of Leicester. ET acknowledge the support from the ESF grant IUT40-2. ; Peer-reviewed ; Publisher Version