A low mass cluster of extremely red galaxies at z = 1.10 in the GOODS Southern Field

Díaz-Sánchez, Anastasio; Villo-Pérez, Isidro; Pérez-Garrido, Antonio; Rebolo, Rafael
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 377, Issue 2, pp. 516-522.

Advertised on:
5
2007
Number of authors
4
IAC number of authors
1
Citations
10
Refereed citations
10
Description
We have studied the spatial clustering of high redshift (z > 1) extremely red objects (EROs) as a function of photometric redshift in the GOODS Southern Field using public data. A remarkable overdensity of extremely red galaxies (I - Ks > 4) is found at an average photometric redshift zphot = 1.10. Nine objects (six are EROs) within 50 arcsec of the brightest infrared galaxy in this overdensity present spectroscopic redshifts in the range 1.094 < zspec < 1.101 with a line-of-sight velocity dispersion of σv = 433+152-74 km s-1 typical of an Abell richness class R = 0 cluster. Other potential members of this cluster, designated as GCL J0332.2-2752, have been identified using photometric redshifts and the galaxy density profile studied as a function of radius. The mass of the cluster is preliminary estimated at Mcl ~ 5-7 × 1013Msolar. Using available Chandra data, we limit the rest-frame X-ray luminosity of the cluster to less than LX = 7.3 × 1042 erg s-1 (0.5-2.0 keV). This low-mass, low LX cluster at z > 1 shows the potential of EROs to trace clusters of galaxies at high redshift.