A Photometrically Detected Forming Cluster of Galaxies at Redshift 1.6 in the GOODS Field

Abstract

We report the discovery of a localized overdensity at z~1.6 in the GOODS-South Field, presumably a poor cluster in the process of formation. The three-dimensional galaxy density has been estimated on the basis of well calibrated photometric redshifts from the multiband photometric GOODS-MUSIC catalog using the (2+1)D technique. The density peak is embedded in the larger scale overdensity of galaxies known to exist at z=1.61 in the area. The properties of the member galaxies are compared to those of the surrounding field and we found that the two populations are significantly different supporting the reality of the structure. The reddest galaxies, once evolved according to their best fit models, have colors consistent with the red sequence of lower redshift clusters. The estimated M_200 total mass of the cluster is in the range 1.3 x 10^14 - 5.7x 10^14 Msun, depending on the assumed bias factor b. An upper limit for the 2-10 keV X-ray luminosity, based on the 1Ms Chandra observations, is L_X=0.5 x 10^43 erg s^-1, suggesting that the cluster has not yet reached the virial equilibrium.

6 pages, 5 figures (1 in color), uses emulateapj.cls Latex class file, accepted for publication in ApJ

References in corpus (5)

• The GOODS-MUSIC sample: a multicolour catalog of near-IR selected galaxies in the GOODS-South field
• The XMM Cluster Survey: A Massive Galaxy Cluster at z=1.45
• The VIMOS VLT Deep Survey: The build-up of the colour-density relation
• Large Structures and Galaxy Evolution in COSMOS at z < 1.1
• A new (2+1)D cluster finding algorithm based on photometric redshifts: large scale structure in the Chandra Deep Field South

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• The KMOS Cluster Survey (KCS) I: The fundamental plane and the formation ages of cluster galaxies at redshift $1.4<z<1.6$
• Star formation and quenching among the most massive galaxies at z~1.7
• The VANDELS survey: Discovery of massive overdensities of galaxies at z>2
• Across the Green Valley with HST grisms: colour evolution, crossing time-scales and the growth of the red sequence at $z=1.0-1.8$
• The KMOS Cluster Survey (KCS) III: fundamental plane of cluster galaxies at $z\simeq 1.80$ in JKCS 041
• Growing up in a megalopolis: Environmental effects on galaxy evolution in a supercluster at z~0.65 in UKIDSS UDS
• FORECAST: a flexible software to forward model cosmological hydrodynamical simulations mimicking real observations
• LBT-MODS spectroscopy of high-redshift candidates in the Chandra J1030 field. A newly discovered z$\sim$2.8 large scale structure