We report on a wide-area (48'×9') imaging survey of faint galaxies in the R and I bands toward the 1338+27 field where an unusual concentration of five QSOs at z~1.1, embedded in a larger scale clustering of 23 QSOs, is known to exist. Using a quite homogeneous galaxy catalog with a detection completeness limit of I~23.5, we detect a significant clustering signature of faint red galaxies with I>21 and R-I>1.2 over a scale extending to ~20 h-150 Mpc. Close examination of the color-magnitude diagram, the luminosity function, and the angular correlation function indeed suggests that those galaxies are located at z~1.1 and trace the underlying large-scale structure at that epoch, together with the group of five QSOs. Since the whole extent of the cluster of 23 QSOs (~70 h-150 Mpc) is roughly similar to the local ``Great Wall,'' the area may contain a high-redshift counterpart of superclusters in the local universe. Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium.
The Astrophysical Journal
- Pub Date:
- February 2001
- Galaxies: Clusters: General;
- Cosmology: Large-Scale Structure of Universe;
- Galaxies: Quasars: General;
- 21 pages including 7 EPS color figures