TY - JOUR
T1 - A mature cluster with X-ray emission at z = 2.07
AU - Gobat, R.
AU - Daddi, E.
AU - Onodera, M.
AU - Finoguenov, A.
AU - Renzini, A.
AU - Arimoto, N.
AU - Bouwens, R.
AU - Brusa, M.
AU - Chary, R. R.
AU - Cimatti, A.
AU - Dickinson, M.
AU - Kong, X.
AU - Mignoli, M.
PY - 2011/2
Y1 - 2011/2
N2 - We report evidence of a fully established galaxy cluster at z = 2.07, consisting of a ~20σ overdensity of red, compact spheroidal galaxies spatially coinciding with extended X-ray emission detected with XMM-Newton. We use VLT VIMOS and FORS2 spectra and deep Subaru, VLT and Spitzer imaging to estimate the redshift of the structure from a prominent z = 2.07 spectroscopic redshift spike of emission-line galaxies, concordant with the accurate 12-band photometric redshifts of the red galaxies. Using NICMOS and Keck AO observations, we find that the red galaxies have elliptical morphologies and compact cores. While they do not form a tight red sequence, their colours are consistent with that of a ≈ 1.3 Gyr population observed at z ~ 2.1. From an X-ray luminosity of 7.2×1043 erg s-1 and the stellar mass content of the red galaxy population, we estimate a halo mass of 5.3-8×1013 M⊙, comparable to the nearby Virgo cluster. These properties imply that this structure could be the most distant, mature cluster known to date and that X-ray luminous, elliptical-dominated clusters are already forming at substantially earlier epochs than previously known.
AB - We report evidence of a fully established galaxy cluster at z = 2.07, consisting of a ~20σ overdensity of red, compact spheroidal galaxies spatially coinciding with extended X-ray emission detected with XMM-Newton. We use VLT VIMOS and FORS2 spectra and deep Subaru, VLT and Spitzer imaging to estimate the redshift of the structure from a prominent z = 2.07 spectroscopic redshift spike of emission-line galaxies, concordant with the accurate 12-band photometric redshifts of the red galaxies. Using NICMOS and Keck AO observations, we find that the red galaxies have elliptical morphologies and compact cores. While they do not form a tight red sequence, their colours are consistent with that of a ≈ 1.3 Gyr population observed at z ~ 2.1. From an X-ray luminosity of 7.2×1043 erg s-1 and the stellar mass content of the red galaxy population, we estimate a halo mass of 5.3-8×1013 M⊙, comparable to the nearby Virgo cluster. These properties imply that this structure could be the most distant, mature cluster known to date and that X-ray luminous, elliptical-dominated clusters are already forming at substantially earlier epochs than previously known.
KW - galaxies: clusters: general
KW - galaxies: clusters: individual: CL J1449-0856
KW - galaxies: high-redshift
KW - large-scale structure of Universe
UR - http://www.scopus.com/inward/record.url?scp=78651289961&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201016084
DO - 10.1051/0004-6361/201016084
M3 - Article
AN - SCOPUS:78651289961
SN - 0004-6361
VL - 526
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
IS - 16
M1 - A133
ER -