Spectroscopic Confirmation of a Radio-Selected Galaxy Overdensity at z=1.11

Abstract

We report the discovery of a galaxy overdensity at z=1.11 associated with the z=1.110 high-redshift radio galaxy MG0442+0202. The group, CL0442+0202, was found in a near-infrared survey of z>1 radio galaxies undertaken to identify spatially-coincident regions with a high density of objects red in I-K' color, typical of z>1 elliptical galaxies. Spectroscopic observations from the Keck telescope reveal five galaxies within 35" of MG0442+0202 at 1.10<z<1.11. These member galaxies have broad-band colors and optical spectra consistent with passively-evolving elliptical galaxies formed at high redshift. A 45ks Chandra X-Ray Observatory observation detects the radio galaxy and four point sources within 15" of the radio galaxy, corresponding to a surface density two orders of magnitude higher than average for X-ray sources at these flux levels, S(0.5-2keV) > 5e-16 erg/cm2/s. One of these point sources is identified with a radio-quiet, typeII quasar at z=1.863, akin to sources recently reported in deep Chandra surveys. The limit on an extended hot intracluster medium in the Chandra data is S(1-6keV) < 1.9e-15 erg/cm2/s (3-sigma, 30" radius aperture). Though the X-ray observations do not confirm the existence of a massive, bound cluster at z>1, the success of the optical/near-infrared targeting of early-type systems near the radio galaxy validates searches using radio galaxies as beacons for high-redshift large-scale structure. We interpret CL0442+0202 to be a massive cluster in the process of formation.

23 pages, 7 figures

References in corpus (16)

• A JavaScript Passive Evolution Calculator
• The Chandra Deep Survey of the Hubble Deep Field North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area
• A Classic Type 2 QSO
• The most distant structure of galaxies known: a protocluster at z=4.1
• New Results from the X-ray and Optical Survey of the Chandra Deep Field South: The 300ks Exposure
• Optical and Near-IR Imaging of Ultra Steep Spectrum Radio Sources - The K-z diagram of radio and optically selected galaxies
• Chandra Detection of a TypeII Quasar at z=3.288
• Merger shocks in galaxy clusters A665 and A2163 and their relation to radio halos
• Luminosity function of clusters of galaxies
• The Galaxy Population of Cluster RXJ0848+4453 at z=1.27
• An X-ray Selected Galaxy Cluster at z=1.11 in the Rosat Deep Cluster Survey
• Evidence for Cluster Evolution from an Improved Measurement of the Velocity Dispersion and Morphological Fraction of Cluster 1324+3011 at z = 0.76
• SPICES II. Optical and Near-Infrared Identifications of Faint X-Ray Sources from Deep Chandra Observations of Lynx
• Chandra detection of the intracluster medium around 3C294 at z=1.786
• Optical and Near-Infrared Spectroscopy of a High-Redshift, Hard X-ray Emitting Spiral Galaxy
• Very Red and Extremely Red Galaxies in the Fields of z ~ 1.5 Radio-Loud Quasars

Cited by in corpus (25)

• A Spitzer-Selected Galaxy Cluster at z=1.62
• The Massive Hosts of Radio Galaxies Across Cosmic Time
• Galaxy Clusters around radio-loud AGN at 1.3 < z < 3.2 as seen by Spitzer
• The Evolution of Active Galactic Nuclei in Clusters of Galaxies to Redshift 1.3
• The Angular Clustering of Distant Galaxy Clusters
• The Mid-Infrared Environments of High-Redshift Radio Galaxies
• The Cosmic Evolution of AGN in galaxy clusters
• The Galaxy Cluster Mid-Infrared Luminosity Function at 1.3<z<3.2
• Rapid Coeval Black Hole and Host Galaxy Growth in MRC 1138-262: The Hungry Spider
• The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program. III. Optical Spectroscopy
• The distribution of AGN in a large sample of galaxy clusters
• An enhanced merger fraction within the galaxy population of the SSA22 protocluster at z ~ 3.1
• HST Grism Confirmation of Two $z\sim 2$ Structures from the Clusters Around Radio-Loud AGN (CARLA) Survey
• Spectroscopic confirmation of a galaxy cluster associated with 7C1756+6520 at z=1.416
• Mapping the "invisible" circumgalactic medium around a z $\sim$ 4.5 radio galaxy with MUSE
• The Spitzer Extragalactic Representative Volume Survey (SERVS): The Environments of High-z SDSS Quasi-Stellar-Objects
• Large scale structures around radio galaxies at z~1.5
• The Environments of Luminous Radio - WISE Selected Infrared Galaxies
• Morphologies in a Cluster of Extremely Red Galaxies with Old Stellar Populations at z=1.34
• Clustering of red galaxies around the z=1.53 quasar 3C270.1
• Spectroscopic characterization of the protocluster of galaxies around 7C 1756+6520 at z ~ 1.4
• Three candidate clusters around high redshift radio-loud sources: MG1 J04426+0202, 3C 068.2, MS 1426.9+1052
• Hosts and environments: a (large-scale) radio history of AGN and star-forming galaxies
• AGN in deep radio/X-ray surveys: hunting the earliest massive galaxies
• Dissecting the strong lensing galaxy cluster MS 0440$+$0204 II. New optical spectroscopic observations in a wider area and cluster dynamical state