English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report the discovery of a galaxy overdensity at z=1.11 associated with thez=1.110 high-redshift radio galaxy MG0442+0202. The group, CL0442+0202, wasfound in a near-infrared survey of z>1 radio galaxies undertaken to identifyspatially-coincident regions with a high density of objects red in I-K' color,typical of z>1 elliptical galaxies. Spectroscopic observations from the Kecktelescope reveal five galaxies within 35" of MG0442+0202 at 1.10<z<1.11. Thesemember galaxies have broad-band colors and optical spectra consistent withpassively-evolving elliptical galaxies formed at high redshift. A 45ks ChandraX-Ray Observatory observation detects the radio galaxy and four point sourceswithin 15" of the radio galaxy, corresponding to a surface density two ordersof 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 aradio-quiet, typeII quasar at z=1.863, akin to sources recently reported indeep Chandra surveys. The limit on an extended hot intracluster medium in theChandra 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, boundcluster at z>1, the success of the optical/near-infrared targeting ofearly-type systems near the radio galaxy validates searches using radiogalaxies as beacons for high-redshift large-scale structure. We interpretCL0442+0202 to be a massive cluster in the process of formation.Comment: 23 pages, 7 figure

Confirmation of a Radio-selected Galaxy Overdensity atz=1.11