MApping the Most Massive Overdensities (MAMMOTH) II -- Discovery of an Extremely Massive Overdensity BOSS1441 at z=2.32z=2.32

Sep 9, 2016
11 pages
Published in:
  • Astrophys.J. 839 (2017) 2, 131
  • Published: Apr 25, 2017
e-Print:

Citations per year

201620182020202220240246810
Abstract: (IOP)
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 h1{h}^{-1} comoving Mpc. By examining the absorption spectra of ∼80,000 QSO sight lines over a volume of 0.1 Gpc(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±0.02z=2.32\pm 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×LLyα0.7\times {L}_{\mathrm{Ly}\alpha }^{* } 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(15) M{M}_{\odot } at z0z\sim 0. This overdensity is among the most massive large-scale structures at z2z\sim 2 discovered to date.
Note:
  • 12 pages, 8 figures. submitted to ApJ, Comments are welcome
  • galaxies: clusters: general
  • galaxies: high-redshift
  • intergalactic medium