The Discovery and Properties of a Newly Discovered Compact Lensing Cluster CLIO at z=0.42: A unique JWST target

Christopher Conselice, Alex Griffiths, Mehmet Alpaslan, Brenda Frye, Adi Zitrin, Jose Diego, Haojing Yan, Zhiyuan Ma, Robert Barone-Nugent, Rachana Bhatawdekar, Simon Driver, Aaron Robotham, Rogier Windhorst, Stuart Wyithe

Research output: Contribution to conferenceAbstract

Abstract

We present the results of a new study of a unique compact lensing cluster we name CLIO at redshift z = 0.42, discovered through the GAMA survey using spectroscopic redshifts. Compact and massive clusters such as this are understudied, but provide a unique prospective on dark matter distributions and for finding background lensed high-z galaxies. The CLIO cluster was identied for follow up observations due to its almost unique combination of high mass and dark matter halo concentration, as well as having observed lensing arcs from ground based imaging. Using deep FORS2 and Spitzer imaging in combination with MUSE optical spectroscopy we identify 89 cluster members and background sources out to z = 5.79. We describe the physical state of this cluster, finding a strong correlation between environment and galaxy spectral type. We furthermore measure the total mass of CLIO to be 4$\times 10^{14}$ solar masses . We build and present an initial strong-lensing model for this cluster, and measure a relatively low intracluster light (ICL) fraction of ~7%. Due to its strong potential for lensing background galaxies and its low ICL, the CLIO cluster will be a target for our 110 hour JWST `Webb Medium-Deep Field' (WMDF) GTO program.
Original language English Published - Jan 2018

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