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Published September 20, 2016 | Published
Journal Article Open

The Next Generation Virgo Cluster Survey. XX. RedGOLD Background Galaxy Cluster Detections


We build a background cluster candidate catalog from the Next Generation Virgo Cluster Survey (NGVS) using our detection algorithm RedGOLD. The NGVS covers 104 deg^2 of the Virgo cluster in the u*, g, r, i, z-bandpasses to a depth of g ~ 25.7 mag (5σ). Part of the survey was not covered or has shallow observations in the r band. We build two cluster catalogs: one using all bandpasses, for the fields with deep r-band observations (~20 deg^2), and the other using four bandpasses (u*, g, i, z) for the entire NGVS area. Based on our previous Canada–France–Hawaii Telescope Legacy Survey W1 studies, we estimate that both of our catalogs are ~100% (~70%) complete and ~80% pure, at z ≤ 0.6 (z ≾1), for galaxy clusters with masses of M ≳ 10^(14) M⊙. We show that when using four bandpasses, though the photometric redshift accuracy is lower, RedGOLD detects massive galaxy clusters up to z ~ 1 with completeness and purity similar to the five-band case. This is achieved when taking into account the bias in the richness estimation, which is ~40% lower at 0.5 ≤ z < 0.6 and ~20% higher at 0.6 < z < 0.8, with respect to the five-band case. RedGOLD recovers all the X-ray clusters in the area with mass M_(500) > 1.4 × 10^(14) M⊙ and 0.08 < z < 0.5. Because of our different cluster richness limits and the NGVS depth, our catalogs reach lower masses than the published redMaPPer cluster catalog over the area, and we recover ~90%–100% of its detections.

Additional Information

© 2016 The American Astronomical Society. Received 2015 September 18; revised 2016 March 24; accepted 2016 March 24; published 2016 September 21. The French authors (R.L., S.M., A.R.) acknowledge the support of the French Agence Nationale de la Recherche (ANR) under the reference ANR10- BLANC-0506-01-Projet VIRAGE (PI: S.Mei). S.M. acknowledges financial support from the Institut Universitaire de France (IUF), of which she is a senior member. H.H. is supported by the DFG Emmy Noether grant Hi 1495/2-1. We thank the Observatory of Paris for hosting T.E. under its visitor program. We thank Olivier Ilbert for useful comments. We thank James G. Bartlett for the interesting discussions and for carefully editing the abstract and the conclusions. Facility: CFHT - Canada-France-Hawaii Telescope.

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Published - Licitra_2016_ApJ_829_44.pdf


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August 20, 2023
October 23, 2023