Outside the Lyman-break box: detecting Lyman continuum emitters at 3.5 < z < 5.1 with CLAUDS

Journal Article · Thu Apr 09 00:00:00 EDT 2020 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/staa920· OSTI ID:1617722

Meštrić, U. ^[1]; Ryan-Weber, E. V. ^[1]; Cooke, J. ^[1]; Bassett, R. ^[1]; Sawicki, M. ^[2]; Faisst, A. L. ^[3]; Kakiichi, K. ^[4]; Inoue, A. K.  ^[5]; Rafelski, M. ^[6]; Prichard, L. J. ^[7]; Arnouts, S. ^[8]; Moutard, T.  ^[9]; Coupon, J. ^[10]; Golob, A. ^[9]; Gwyn, S. ^[11]

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1. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia
2. Institute for Computational Astrophysics and Department of Astronomy and Physics, Saint Mary’s University, Halifax, Canada, Department of Astronomy and Physics, Saint Mary’s University, 923 Robie Street, Halifax, Nova Scotia, B3H 3C 3, Canada, Herzberg Astronomy and Astrophysics, National Research Council of Canada, 5071 West Saanich Rd., Victoria, BC V9E 2E7, Canada
3. IPAC, California Institute of Technology 1200 E California Boulevard, Pasadena, CA 91125, USA
4. Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
5. Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, 169-8555 Tokyo, Japan, Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, 169-8555 Tokyo, Japan
6. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
7. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
8. CNRS, Laboratoire d’Astrophysique de Marseille, Aix Marseille Université, UMR 7326, F-13388 Marseille, France
9. Institute for Computational Astrophysics and Department of Astronomy and Physics, Saint Mary’s University, Halifax, Canada
10. Astronomy Department, University of Geneva, Chemin d’Ecogia 16, CH-1290 Versoix, Switzerland
11. NRC-Herzberg, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada

ABSTRACT Identifying non-contaminated sample of high-redshift galaxies with escaping Lyman continuum (LyC) flux is important for understanding the sources and evolution of cosmic reionization. We present CLAUDS (CFHT Large Area u-band deep survey) u-band photometry of the COSMOS field to probe LyC radiation from spectroscopically confirmed galaxies at $$z$$ ≥ 3.5 and outside the standard Lyman-break galaxy colour-selection expectations. Complementary to the CLAUDS data, we use Subaru multifilter photometry, Hubble Space Telescope (HST) multifilter imaging, and the spectroscopic surveys D10K, VUDS, and 3D-HST. We present a sample of Lyman continuum galaxy (LCG) candidates in the redshift range 3.5 ≲ $$z$$ ≲ 5.1. Here, we introduce 5 LCG candidates, where two are flagged quality 1 and three quality 2. The estimated $$f_{\rm esc}^{\rm abs}$$ for quality 1 candidates are in the range $$\sim 5 - 73{{\ \rm per\ cent}}$$ and $$\sim 30 - 93{{\ \rm per\ cent}}$$. These estimates are based on our derived parameters from individual galaxies as inputs to a range of BPASS models as well as mean intergalactic medium (IGM) and maximal intergalactic and circumgalactic media (IGM+CGM) transmission. We conclude that our search for LCGs is most likely biased to lines of sight with low H i densities or free from Lyman limit systems. Our two best LCG candidates have EW (Lyα) ≤ 50 Å and we find no correlation or anticorrelation between EW (Lyα), $$f_{\rm esc}^{\rm abs}$$, and Robs, the ratio of ionizing to non-ionizing observed flux in the measured passbands. Stacking candidates without solid LyC detections (S/N < 3) results in an estimated $$f_{\rm esc}^{\rm abs}$$ from galaxies not greater than $$1{{\ \rm per\ cent}}$$.

• Sponsoring Organization: USDOE
• OSTI ID: 1617722
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 494 Journal Issue: 4; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English