Title: Detection of z ~ 2.3 Cosmic Voids from 3D Ly α Forest Tomography in the COSMOS Field

Abstract

We present the most distant detection of cosmic voids ( z ~ 2.3) and the first detection of three-dimensional voids in the Lyα forest. We used a 3D tomographic map of the absorption with an effective comoving spatial resolution of 2.5 h ^-1 Mpc and a volume of 3.15 × 10 ⁵ h ³ Mpc ³, which was reconstructed from moderate-resolution Keck I/LRIS spectra of 240 background Lyman-break galaxies and quasars in a 0.16 deg ² footprint in the COSMOS field. Voids were detected using a spherical overdensity finder calibrated from hydrodynamical simulations of the intergalactic medium (IGM). This allows us to identify voids in the IGM corresponding to voids in the underlying matter density field, yielding a consistent volume fraction of voids in both data (19.5%) and simulations (18.2%). We fit excursion set models to the void radius function and compare the radially averaged stacked profiles of large voids ( r > 5 h ^-1 Mpc) to stacked voids in mock observations and the simulated density field. Comparing with 432 coeval galaxies with spectroscopic redshifts in the same volume as the tomographic map, we find that the tomography-identified voids are underdense in galaxies by 5.95σ compared to random cells.

Authors:

Krolewski, Alex  ^[1];

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Lee, Khee-Gan  ^[2];

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White, Martin  ^[3];

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Hennawi, Joseph F.  ^[4];

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Schlegel, David J.  ^[2];

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Nugent, Peter E.  ^[3];

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Lukić, Zarija ^[2]; Stark, Casey W.  ^[5];

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Koekemoer, Anton M.  ^[6];

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Fèvre, Olivier Le ^[7]; Lemaux, Brian C. ^[8]; Maier, Christian  ^[9];

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Rich, R. Michael ^[10]; Salvato, Mara  ^[11];

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Tasca, Lidia ^[7]

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
4. Univ. of California, Santa Barbara, CA (United States)
5. Google Inc., Moutain View, CA (United States)
6. Space Telescope Science Inst., Baltimore, MD (United States)
7. Aix-Marseille Univ., and CNRS/IN2P3, Marseille (France)
8. Aix-Marseille Univ., and CNRS/IN2P3, Marseille (France); Univ. of California, Davis, CA (United States)
9. Univ. of Vienna (Austria)
10. Univ. of California, Los Angeles, CA (United States)
11. Max Planck Inst. fur Extraterrestrische Physik, Garching (Germany)

Publication Date:

2018-07-03

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); National Aeronautics and Space Administration (NASA)

OSTI Identifier:

1526532

Alternate Identifier(s):

OSTI ID: 1594744

Grant/Contract Number:  

[AC02-05CH11231; HF2-51361; NAS5-26555; SC0017860]

Resource Type:

Accepted Manuscript

Journal Name:

The Astrophysical Journal (Online)

Additional Journal Information:

[Journal Name: The Astrophysical Journal (Online); Journal Volume: 861; Journal Issue: 1]; Journal ID: ISSN 1538-4357

Publisher:

Institute of Physics (IOP)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS