The MUSEHubbleUltra Deep Field Survey

Astronomy and Astrophysics, vol. 638, pp. A12

Abstract

Context.The Lyαemitter (LAE) fraction,XLAE, is a potentially powerful probe of the evolution of the intergalactic neutral hydrogen gas fraction. However, uncertainties in the measurement ofXLAEare still under debate. Aims.Thanks to deep data obtained with the integral field spectrograph Multi Unit Spectroscopic Explorer (MUSE), we can measure the evolution of the LAE fraction homogeneously over a wide redshift range ofz ≈ 3–6 for UV-faint galaxies (down to UV magnitudes ofM1500 ≈ −17.75). This is a significantly fainter range than in former studies (M1500 ≤ −18.75) and it allows us to probe the bulk of the population of high-redshift star-forming galaxies. Methods.We constructed a UV-complete photometric-redshift sample following UV luminosity functions and measured the Lyαemission with MUSE using the latest (second) data release from the MUSEHubbleUltra Deep Field Survey. Results.We derived the redshift evolution ofXLAEforM1500 ∈ [ − 21.75; −17.75] for the first time with a equivalent width rangeEW(Lyα) ≥ 65 Å and found low values ofXLAE ≲ 30% atz ≲ 6. The best-fit linear relation isXLAE= 0.07+0.06−0.03z− 0.22+0.12−0.24. ForM1500 ∈ [ − 20.25; −18.75] andEW(Lyα) ≥ 25 Å, ourXLAEvalues are consistent with those in the literature within 1σatz ≲ 5, but our median values are systematically lower than reported values over the whole redshift range. In addition, we do not find a significant dependence ofXLAEonM1500forEW(Lyα) ≥ 50 Å atz ≈ 3–4, in contrast with previous work. The differences inXLAEmainly arise from selection biases for Lyman Break Galaxies (LBGs) in the literature: UV-faint LBGs are more easily selected if they have strong Lyαemission, henceXLAEis biased towards higher values when those samples are used. Conclusions.Our results suggest either a lower increase ofXLAEtowardsz ≈ 6 than previously suggested, or even a turnover ofXLAEatz ≈ 5.5, which may be the signature of a late or patchy reionization process. We compared our results with predictions from a cosmological galaxy evolution model. We find that a model with a bursty star formation (SF) can reproduce our observed LAE fractions much better than models where SF is a smooth function of time.

Authors 21

1. Haruka Kusakabe

   University of Geneva

   Affiliation as printed

   Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

2. Jérémy Blaizot

   Lyon 1 Université · École Normale Supérieure de Lyon · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

3. Thibault Garel

   Lyon 1 Université · École Normale Supérieure de Lyon · University of Geneva · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

4. Anne Verhamme

   Lyon 1 Université · École Normale Supérieure de Lyon · University of Geneva · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

5. Roland M. Bacon

   Lyon 1 Université · École Normale Supérieure de Lyon · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

6. Johan Richard

   Lyon 1 Université · École Normale Supérieure de Lyon · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

7. Takuya Hashimoto

   University of Tsukuba

   Affiliation as printed

   Tomonaga Center for the History of the Universe (TCHoU), Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan

8. Hanae Inami

   Hiroshima University

   Affiliation as printed

   Hiroshima Astrophysical Science Center, Hiroshima University 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan

9. Simon Conseil

   Lyon 1 Université · École Normale Supérieure de Lyon · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

   Affiliation as printed

   Gemini Observatory/NSF’s OIR Lab, Casilla 603, La Serena, Chile

   Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

   Gemini Observatory/NSF's OIR Lab, Casilla 603, La Serena, Chile

10. B. Guiderdoni

    Lyon 1 Université · École Normale Supérieure de Lyon · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

    Affiliation as printed

    Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

11. Alyssa B. Drake

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany

12. Edmund Christian Herenz

    European Southern Observatory

    Affiliation as printed

    ESO Vitacura, Alonso de Córdova 3107,Vitacura, Casilla 19001, Santiago de Chile, Chile

13. Joop Schaye Aachen Leiden Observatory

    Leiden University · Leiden Observatory

    Affiliation as printed

    Leiden Observatory, Leiden University, PO Box 9513, 2300, RA Leiden, The Netherlands

14. Pascal A. Oesch

    University of Geneva

    Affiliation as printed

    Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

15. Jorryt Matthee

    ETH Zurich

    Affiliation as printed

    Department of Physics, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland

16. R. A. Marino

    ETH Zurich

    Affiliation as printed

    Department of Physics, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland

17. R. Pelló

    Centre National de la Recherche Scientifique · Aix-Marseille Université · Laboratoire d’Astrophysique de Marseille

    Affiliation as printed

    Aix Marseille Université, CNRS, CNES, LAM (Laboratoire d’Astrophysique de Marseille), UMR 7326, 13388 Marseille, France

    Aix Marseille Université, CNRS, CNES, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, 13388 Marseille, France

18. Michael V. Maseda Aachen Leiden Observatory

    Leiden University · Leiden Observatory

    Affiliation as printed

    Leiden Observatory, Leiden University, PO Box 9513, 2300, RA Leiden, The Netherlands

19. Floriane Leclercq

    Lyon 1 Université · École Normale Supérieure de Lyon · University of Geneva · Centre National de la Recherche Scientifique · Centre de Recherche Astrophysique de Lyon

    Affiliation as printed

    Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

    Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France

20. Josephine Kerutt

    University of Geneva · Leibniz Institute for Astrophysics Potsdam

    Affiliation as printed

    Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany

    Observatoire de Genève, Université de Genève, 51 chemin de Pégase, 1290 Versoix, Switzerland

21. Guillaume Mahler

    University of Michigan

    Affiliation as printed

    Department of Astronomy, University of Michigan, 1085 South University Ave, Ann Arbor, MI 48109, USA