362 research outputs found
MApping the Most Massive Overdensities (MAMMOTH) II -- Discovery of an Extremely Massive Overdensity BOSS1441 at
Cosmological simulations suggest a strong correlation between high
optical-depth Ly absorbers, which arise from the intergalactic medium
(IGM), and 3-D mass overdensities on scales of comoving Mpc.
By examining the absorption spectra of 80,000 QSO sight-lines over a
volume of 0.1 Gpc in the Sloan Digital Sky Survey III (SDSS-III), we have
identified an extreme overdensity, BOSS1441, which contains a rare group of
strong Ly absorbers at . 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 Ly emitters
(LAEs) down to , and reveal a large-scale
structure of Ly emitters (LAEs) in this field. Our follow-up Large
Binocular Telescope (LBT) observations have spectroscopically confirmed 19
galaxies in the density peak. We show that BOSS1441 has an LAE overdensity of
on a 15 comoving Mpc scale which could collapse to a massive
cluster with M at . This overdensity is among
the most massive large-scale structures at discovered to date.Comment: 12 pages, 8 figures. submitted to ApJ, Comments are welcom
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