CFHTLenS: weak lensing calibrated scaling relations for low-mass clusters of galaxies
We present weak lensing and X-ray analysis of 12 low-mass clusters from the Canada–France–Hawaii Telescope Lensing Survey and XMM-CFHTLS surveys. We combine these systems with high-mass systems from Canadian Cluster Comparison Project and low-mass systems from Cosmic Evolution Survey to obtain a sample of 70 systems, spanning over two orders of magnitude in mass. We measure core-excised L_X–T_X, M–L_X and M–T_X scaling relations and include corrections for observational biases. By providing fully bias-corrected relations, we give the current limitations for L_X and T_X as cluster mass proxies. We demonstrate that T_X benefits from a significantly lower intrinsic scatter at fixed mass than L_X. By studying the residuals of the bias-corrected relations, we show for the first time using weak lensing masses that galaxy groups seem more luminous and warmer for their mass than clusters. This implies a steepening of the M–L_X and M–T_X relations at low masses. We verify the inferred steepening using a different high-mass sample from the literature and show that variance between samples is the dominant effect leading to discrepant scaling relations. We divide our sample into subsamples of merging and relaxed systems, and find that mergers may have enhanced scatter in lensing measurements, most likely due to stronger triaxiality and more substructure. For the L_X–T_X relation, which is unaffected by lensing measurements, we find the opposite trend in scatter. We also explore the effects of X-ray cross-calibration and find that Chandra calibration leads to flatter L_X–T_X and M–T_X relations than XMM–Newton.
© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 April 22. Received 2015 April 2; in original form 2014 April 24. First published online June 5, 2015. The authors thank the anonymous referee for useful comments and suggestions. This work is based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agency. CFHTLenS data processing was made possible thanks to significant computing support from the NSERC Research Tools and Instruments grant programme, and to HPC specialist Ovidiu Toader. KK acknowledges support from Arvid och Greta Ohlins fond and Magnus Ehrnrooth foundation. KK and AF acknowledge Academy of Finland award, decision 1266918. AF, ML and MM have been supported by a DLR project 50 OR 1013 to MPE. CH, HHo, and BR acknowledge support from the European Research Council under the EC FP7 grant numbers 240185 (CH), 279396 (HHo) and 240672 (BR). TDK acknowledges support from a Royal Society University Research Fellowship. TE is supported by the Deutsche Forschungsgemeinschaft through project ER 327/3-1 and is supported by the Transregional Collaborative Research Centre TR 33 – 'The Dark Universe'. HHi is supported by the MarieCurie IOF 252760, a CITA National Fellowship, and the DFG grant Hi 1495/2-1. HHo, SG acknowledge support from the Netherlands Organisation for Scientific Research grant number 639.042.814. YM acknowledges support from CNRS/INSU (Institut National des Sciences de l'Univers) and the Programme National Galaxies et Cosmologie (PNCG). LVW acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Institute for Advanced Research (CIfAR, Cosmology and Gravity program). JPK acknowledge generous support from the ERC advanced grant: LIDA. LF acknowledges support from NSFC grants 11103012 and 11333001 and Shanghai Research grant 13JC1404400. MJH acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). Author Contributions: All authors contributed to the development and writing of this paper. The authorship list reflects the lead authors of this paper (KK, SG, EvU, HH, AF, ML) followed by two alphabetical groups. The first alphabetical group includes key contributors to the science analysis and interpretation in this paper, the founding core team and those whose long-term significant effort produced the final CFHTLenS and XMM-CFHTLS data products. The second group covers members of the CFHTLenS and XMMCFHTLS team who made a significant contribution to the project.
Submitted - 1410.8769v2.pdf
Published - MNRAS-2015-Kettula-1460-81.pdf