Enhancement of H i absorption associated with the z = 3.1 large-scale proto-cluster and characteristic structures with AGNs sculptured over Gpc scale in the SSA22 field

T. Hayashino, A. K. Inoue, K. Kousai, N. Kashikawa, K. Mawatari, Y. Matsuda, N. Tejos, J. X. Prochaska, I. Iwata, S. Noll, D. Burgarella, T. Yamada, M. Akiyama

Research output: Contribution to journalArticlepeer-review

Abstract

In the SSA22 field which exhibits a large-scale proto-cluster at z = 3.1, we carried out a spectroscopic survey for Lyman Break Galaxies (LBGs) with the VLT/VIMOS and identified 78 confident LBGs at z = 2.5-4. We stacked their spectra in the observer's frame by using a sophisticated method. Analysing the composite spectrum, we have revealed that the large-scale proto-cluster at z = 3.1 has a strong H i absorption dip of rest-frame equivalent width of-1.7 Å. Another strong absorption dip found at z = 3.28 is associated with a modestly high-density LBG peak, similar to that at z = 3.1. We have also detected an H i transparency peak at z = 2.98 in the composite spectrum, coincident with a void in the LBG distribution. In this paper, we also investigated the relation between LBGs, H i gas, and active galactic nuclei (AGNs) at z = 3-4 in the SSA22 field. Two AGNs at z = 3.353 and 3.801 are, respectively, associated with the LBG concentration of an overdensity factor δLBG ≠2 in the present statistics. Another structure at z = 3.453 is remarkable: 20 comoving Mpc-scale dense H i gas which is not associated with any apparent LBG overdensity but involving a pair of AGNs. Such structure may be a new type of the AGN-matter correlation. If the inhomogeneous structures over a comoving Gpc scale found in this paper are confirmed with sufficient statistics in the future, the SSA22 field will become a key region to test the standard cold dark matter structure formation scenario.

Original languageEnglish
Pages (from-to)5868-5887
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume484
Issue number4
DOIs
Publication statusPublished - 2019 Apr 1

Keywords

  • cosmology: observations
  • galaxies: active
  • galaxies: high-redshift
  • intergalactic medium
  • large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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