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Title: Mapping the Most Massive Overdensities through Hydrogen (MAMMOTH). II. Discovery of the Extremely Massive Overdensity BOSS1441 at z = 2.32

Journal Article · · Astrophysical Journal
;  [1]; ; ; ; ;  [2];  [3];  [4];  [5];  [6]; ;  [7]
  1. UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
  2. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611 (Australia)
  4. Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu Daejeon (Korea, Republic of)
  5. Instituto de Astrofisica, Pontificia Universidad Catolica de Chile, 7820436 Santiago (Chile)
  6. National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588 (Japan)
  7. The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

Cosmological simulations suggest a strong correlation between high optical-depth Lyα absorbers, which arise from the intergalactic medium, and 3D mass overdensities on scales of 10–30 h{sup −1} comoving Mpc. By examining the absorption spectra of ∼80,000 QSO sight lines over a volume of 0.1 Gpc{sup 3} in the Sloan Digital Sky Survey III (SDSS-III), we have identified an extreme overdensity, BOSS1441, which contains a rare group of strong Lyα absorbers at z=2.32±0.02. This absorber group is associated with six QSOs at the same redshift on a 30 comoving Mpc scale. Using Mayall/MOSAIC narrowband and broadband imaging, we detect Lyα emitters (LAEs) down to 0.7×L{sub Lyα}{sup ∗} and reveal a large-scale structure of LAEs in this field. Our follow-up LBT observations have spectroscopically confirmed 20 galaxies in the density peak. We show that BOSS1441 has an LAE overdensity of 10.8 ± 2.6 on a 15 comoving Mpc scale, which could collapse to a massive cluster with M ≳ 10{sup 15} M{sub ⊙} at z∼0. This overdensity is among the most massive large-scale structures at z∼2 discovered to date.

OSTI ID:
22872768
Journal Information:
Astrophysical Journal, Vol. 839, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
Country of Publication:
United States
Language:
English