LYα FOREST TOMOGRAPHY FROM BACKGROUND GALAXIES: THE FIRST MEGAPARSEC-RESOLUTION LARGE-SCALE STRUCTURE MAP AT z > 2

Journal Article · Sat Nov 01 00:00:00 EDT 2014 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/795/1/L12· OSTI ID:22364594

Lee, Khee-Gan; Hennawi, Joseph F.; Eilers, Anna-Christina ^[1]; Stark, Casey; White, Martin ^[2]; Prochaska, J. Xavier ^[3]; Schlegel, David J. ^[4]; Arinyo-i-Prats, Andreu ^[5]; Suzuki, Nao ^[6]; Croft, Rupert A. C. ^[7]; Caputi, Karina I. ^[8]; Cassata, Paolo ^[9]; Ilbert, Olivier; Le Brun, Vincent; Le Fèvre, Olivier ^[10]; Garilli, Bianca ^[11]; Koekemoer, Anton M. ^[12]; Maccagni, Dario ^[13]; Nugent, Peter ^[14]; others, and

---

1. Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
2. Department of Astronomy, University of California at Berkeley, B-20 Hearst Field Annex 3411, Berkeley, CA 94720 (United States)
3. Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
4. University of California Observatories, Lick Observatory, 1156 High Street, Santa Cruz, CA 95064 (United States)
5. Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí Franquès 1, E-08028 Barcelona (Spain)
6. Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa-shi, Chiba (Japan)
7. Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)
8. Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700-AV Groningen (Netherlands)
9. Instituto de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile)
10. Aix Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France)
11. INAF-IASF, Via Bassini 15, I-20133, Milano (Italy)
12. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
13. INAF-Osservatorio Astronomico di Bologna, Via Ranzani,1, I-40127 Bologna (Italy)
14. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

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 {sup –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 {sup –1} Mpc × 14 h {sup –1} Mpc in the transverse plane and 230 h {sup –1} Mpc along the line of sight with a spatial resolution of ≈3.5 h {sup –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 {sup –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 deg{sup 2} 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 {sup –1} Mpc){sup 3}.

• OSTI ID: 22364594
• Journal Information: Astrophysical Journal Letters, Vol. 795, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COSMOLOGY
DENSITY
EMISSION SPECTRA
GALAXIES
LYMAN LINES
QUASARS
RED SHIFT
SIGNAL-TO-NOISE RATIO
SPATIAL RESOLUTION
THREE-DIMENSIONAL CALCULATIONS
UNIVERSE