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CARMA observations of massive Planck-discovered cluster candidates at z ≳ 0.5 associated with WISE overdensities: breaking the size–flux degeneracy

Rodríguez-Gonzálvez, C. and Chary, R. R. and Muchovej, S. and Melin, J.-B. and Feroz, F. and Olamaie, M. and Shimwell, T. (2017) CARMA observations of massive Planck-discovered cluster candidates at z ≳ 0.5 associated with WISE overdensities: breaking the size–flux degeneracy. Monthly Notices of the Royal Astronomical Society, 464 (2). pp. 2378-2395. ISSN 0035-8711.

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We use a Bayesian software package to analyse CARMA-8 data towards 19 unconfirmed Planck Sunyaev–Zel'dovich-cluster candidates from Rodríguez-Gonzálvez et al. that are associated with significant overdensities in WISE. We use two cluster parameterizations, one based on a (fixed shape) generalized-NFW (gNFW) pressure profile and another on a β gas density profile (with varying shape parameters) to obtain parameter estimates from the CARMA-8 data for the nine CARMA-8-detected clusters. Results from the β model show that our cluster candidates exhibit a heterogeneous set of brightness–temperature profiles. Comparison of Planck and CARMA-8 measurements show good agreement in Y500 and an absence of obvious biases. Applying a Planck prior in Y500 to the CARMA-8 gNFW results reduces uncertainties in Y500 and Θ500 dramatically (by a factor >4), relative to the independent Planck or CARMA-8 measurements. From this combined analysis, we find that our sample is comprised of massive (Y500 ranging from 3.3^(+0.2)_(−0.2) to 10+1.1−1.5 × 10^(−4) arcmin^2, sd = 2.2 × 10^(−4)), relatively compact (θ500 ranging from 2.1^(+0.1)_(−0.3) to 5.5^(+0.2)_(−0.8) arcmin, sd = 1.0) systems. Spectroscopic Keck/MOSFIRE data confirmed a galaxy member of one of our cluster candidates at z = 0.565. At the preferred photometric redshift of 0.5, we estimate the cluster mass M500 ≈ 0.8 ± 0.2 × 10^(15) M_⊙. We here demonstrate a powerful technique to find massive clusters at intermediate (z ≳ 0.5) redshifts using a cross-correlation between Planck and WISE data, with high-resolution CARMA-8 follow-up. We also use the combined capabilities of Planck and CARMA-8 to obtain a dramatic reduction, by a factor of several, in parameter uncertainties.

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Chary, R. R.0000-0001-7583-0621
Alternate Title:CARMA observations of massive Planck-discovered cluster candidates at z>0.5 associated with WISE overdensities: Breaking the size-flux degeneracy
Additional Information:Published by Oxford University Press on behalf of The Royal Astronomical Society 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US. Received: 27 July 2014. Revision Received: 18 August 2016. Accepted: 21 September 2016. Published: 03 November 2016. We thank the anonymous referee for a careful reading of the manuscript and would also like to acknowledge helpful discussions with Y. Perrott and A. Lasenby. We thank the staff of the Owens Valley Radio observatory and CARMA for their outstanding support; in particular, we would like to thank John Carpenter. Support for CARMA construction was derived from the Gordon and Betty Moore Foundation, the Kenneth T. and Eileen L. Norris Foundation, the James S. McDonnell Foundation, the Associates of the California Institute of Technology, the University of Chicago, the states of California, Illinois, and Maryland, and the National Science Foundation. CARMA development and operations were supported by the National Science Foundation under a cooperative agreement, and by the CARMA partner universities. The Planck results used in this study are based on observations obtained with the Planck satellite (, an ESA science mission with instruments and contributions directly funded by ESA Member States, NASA, and Canada. We are very grateful to the AMI Collaboration for allowing us to use their software and analysis techniques in this work and for useful discussions. A small amount of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Kenneth T. and Eileen L. Norris FoundationUNSPECIFIED
James S. McDonnell FoundationUNSPECIFIED
Caltech AssociatesUNSPECIFIED
University of ChicagoUNSPECIFIED
states of California, Illinois, and MarylandUNSPECIFIED
CARMA partner universitiesUNSPECIFIED
Canadian Space Agency (CSA)UNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:cosmology: observations, large-scale structure of Universe, infrared: galaxies, radio continuum: general
Issue or Number:2
Record Number:CaltechAUTHORS:20170303-064800712
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Official Citation:C. Rodríguez-Gonzálvez, R. R. Chary, S. Muchovej, J.-B. Melin, F. Feroz, M. Olamaie, T. Shimwell; CARMA observations of massive Planck-discovered cluster candidates at z ≳ 0.5 associated with WISE overdensities: breaking the size–flux degeneracy. Mon Not R Astron Soc 2017; 464 (2): 2378-2395. doi: 10.1093/mnras/stw2392
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74676
Deposited By: Ruth Sustaita
Deposited On:03 Mar 2017 16:42
Last Modified:03 Oct 2019 16:41

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