Lyα forest tomography from background galaxies: The first megaparsec-resolution large-scale structure map at z > 2
- Max Planck Inst. for Astronomy, Heidelberg (Germany)
- Univ. of California, Berkeley, CA (United States). Dept. of Astronomy; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Univ. of California, Santa Cruz, CA (United States). Dept. of Astronomy and Astrophysics; Univ. of California Observatories, Santa Cruz, CA (United States). Lick Observatory
- Univ. of California Observatories, Santa Cruz, CA (United States). Lick Observatory
- Univ. de Barcelona (Spain). Inst. de Ciencies del Cosmos
- Univ. of Tokyo (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (IPMU)
- Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics
- Univ. of Groningen, Groningen (The Netherlands). Kapteyn Astronomical Inst.
- Univ. de Valparaiso, Valparaiso (Chile). Inst. de Fisica y Astronomia; Aix Marseille Univ., Marseille (France). Lab. d’Astrophysique de Marseille
- Aix Marseille Univ., Marseille (France). Lab. d’Astrophysique de Marseille
- Istituto Nazionale di Astrofisica (INAF), Milano (Italy)
- Space Telescope Science Inst., Baltimore, MD (United States)
- Istituto Nazionale di Astrofisica (INAF), Bologna (Italy). Osservatorio Astronomico di Bologna
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States). Dept. of Astronomy
- Ehime Univ., Matsuyama (Japan). Research Center for Space and Cosmic Evolution
We present the first observations of foreground Lyα forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with z ~ 2.3-2.8 within a 5' × 14' region of the COSMOS field. The transverse sightline separation is ~2 h-1 Mpc comoving, allowing us to create a tomographic reconstruction of the three-dimensional (3D) Lyα forest absorption field over the redshift range 2.20 ≤ z ≤ 2.45. The resulting map covers 6 h-1 Mpc × 14 h-1 Mpc in the transverse plane and 230 h-1 Mpc along the line of sight with a spatial resolution of ≈3.5 h-1 Mpc, and is the first high-fidelity map of a large-scale structure on ~ Mpc scales at z > 2. Our map reveals significant structures with ≳10 h-1 Mpc extent, including several spanning the entire transverse breadth, providing qualitative evidence for the filamentary structures predicted to exist in the high-redshift cosmic web. Simulated reconstructions with the same sightline sampling, spectral resolution, and signal-to-noise ratio recover the salient structures present in the underlying 3D absorption fields. Using data from other surveys, we identified 18 galaxies with known redshifts coeval with our map volume, enabling a direct comparison with our tomographic map. This shows that galaxies preferentially occupy high-density regions, in qualitative agreement with the same comparison applied to simulations. Our results establish the feasibility of the CLAMATO survey, which aims to obtain Lyα forest spectra for ~1000 SFGs over ~1 deg2 of the COSMOS field, in order to map out the intergalactic medium large-scale structure at ⟨z⟩ ~ 2.3 over a large volume (100 h-1 Mpc)3.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1523986
- Journal Information:
- The Astrophysical Journal. Letters (Online), Vol. 795, Issue 1; ISSN 2041-8213
- Publisher:
- Institute of Physics (IOP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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