We report the discovery of primeval large-scale structures (LSSs) including two proto-clusters in a forming phase at z=5.7. We carried out extensive deep narrow-band imaging in the 1 deg^2 sky of the Subaru/XMM-Newton Deep Field, and obtained a cosmic map of 515 Ly alpha emitters (LAEs) in a volume with a transverse dimension of 180 Mpc x 180 Mpc and a depth of ~40 Mpc in comoving units. This cosmic map shows filamentary LSSs, including clusters and surrounding 10-40 Mpc scale voids, similar to the present-day LSSs. Our spectroscopic follow-up observations identify overdense regions in which two dense clumps of LAEs with a sphere of 1-Mpc diameter in physical units are included. These clumps show about 130 times higher star-formation rate density, mainly due to a large overdensity, ~80, of LAEs. These clumps would be clusters in a formation phase involving a burst of galaxy formation.
@article{arxiv.astro-ph/0412648,
title = {The Discovery of Primeval Large-Scale Structures with Forming Clusters at Redshift 6},
author = {M. Ouchi and K. Shimasaku and M. Akiyama and K. Sekiguchi and H. Furusawa and S. Okamura and N. Kashikawa and M. Iye and T. Kodama and T. Saito and T. Sasaki and C. Simpson and T. Takata and T. Yamada and H. Yamanoi and M. Yoshida and M. Yoshida},
journal= {arXiv preprint arXiv:astro-ph/0412648},
year = {2008}
}
Comments
8 pages, 4 figures, to be published in ApJL. The paper with high resolution figures is available at http://www-int.stsci.edu/~ouchi/work/astroph/sxds_LSS/