The prevalence of galaxy overdensities around UV-luminous Lyman 𝛼 emitters in the Epoch of Reionization-Reference-Cited by-同舟云学术

The prevalence of galaxy overdensities around UV-luminous Lyman 𝛼 emitters in the Epoch of Reionization

Published:2022-07-23 Issue:4 Volume:515 Page:5790-5801
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Leonova E¹²³^ORCID,Oesch P A¹⁴,Qin Y⁵⁶⁷^ORCID,Naidu R P⁸^ORCID,Wyithe J S B⁵⁶,de Barros S¹^ORCID,Bouwens R J⁹,Ellis R S¹⁰,Endsley R M¹¹^ORCID,Hutter A¹²^ORCID,Illingworth G D¹³,Kerutt J¹,Labbé I¹⁴,Laporte N¹⁵¹⁶^ORCID,Magee D¹³,Mutch S J⁵⁶,Roberts-Borsani G W¹⁷^ORCID,Smit R¹⁸,Stark D P¹¹,Stefanon M⁹^ORCID,Tacchella S¹⁹^ORCID,Zitrin A²⁰^ORCID

Affiliation:

1. Department of Astronomy, University of Geneva , Chemin Pegasi 51, CH-1290 Versoix, Switzerland

2. GRAPPA, Anton Pannekoek Institute for Astronomy and Institute of High-Energy Physics, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam, the Netherlands

3. Nikhef , Science Park 105, NL-1098 XG Amsterdam, the Netherlands

4. Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen , Jagtvej 128, København N, DK-2200, Denmark

5. School of Physics, University of Melbourne , Parkville, VIC 3010, Australia

6. ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)

7. Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, Italy

8. Center for Astrophysics | Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA

9. Leiden Observatory, Leiden University , PO Box 9500, NL-2300 RA Leiden, the Netherlands

10. Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, UK

11. Steward Observatory, University of Arizona , 933 N Cherry Ave, Tucson, AZ 85721, USA

12. Kapteyn Astronomical Institute, University of Groningen , PO Box 800, NL-9700 AV Groningen, the Netherlands

13. Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California , Santa Cruz, CA 95064, USA

14. Centre for Astrophysics & Supercomputing, Swinburne University of Technology , PO Box 218, Hawthorn, VIC 3112, Australia

15. Kavli Institute for Cosmology, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UK

16. Cavendish Laboratory, University of Cambridge , 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK

17. Department of Physics and Astronomy, University of California , Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095, USA

18. Astrophysics Research Institute, Liverpool John Moores University , 146 Brownlow Hill, Liverpool L3 5RF, UK

19. Department of Physics, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea

20. Physics Department, Ben-Gurion University of the Negev , PO Box 653, Be’er-Sheva 84105, Israel

Abstract

ABSTRACT Before the end of the Epoch of Reionization, the Hydrogen in the Universe was predominantly neutral. This leads to a strong attenuation of Ly α lines of z ≳ 6 galaxies in the intergalactic medium. Nevertheless, Ly α has been detected up to very high redshifts (z ∼ 9) for several especially UV luminous galaxies. Here, we test to what extent the galaxy’s local environment might impact the Ly α transmission of such sources. We present an analysis of dedicated Hubble Space Telescope (HST) imaging in the CANDELS/EGS field to search for fainter neighbours around three of the most UV luminous and most distant spectroscopically confirmed Ly α emitters: EGS-zs8-1, EGS-zs8-2, and EGSY-z8p7 at zspec = 7.73, 7.48, and 8.68, respectively. We combine the multiwavelength HST imaging with Spitzer data to reliably select z ∼ 7–9 galaxies around the central, UV-luminous sources. In all cases, we find a clear enhancement of neighbouring galaxies compared to the expected number in a blank field (by a factor ∼3–9×). Our analysis thus reveals ubiquitous overdensities around luminous Ly α emitting sources in the heart of the cosmic reionization epoch. We show that our results are in excellent agreement with expectations from the Dragons simulation, confirming the theoretical prediction that the first ionized bubbles preferentially formed in overdense regions. While three UV luminous galaxies already have spectroscopic redshifts, the majority of the remaining fainter, surrounding sources are yet to be confirmed via spectroscopy. JWST follow-up observations of the neighbouring galaxies identified here will thus be needed to confirm their physical association and to map out the ionized regions produced by these sources.

Funder

Swiss National Science Foundation

Danish National Research Foundation

Australian Research Council

Swinburne University of Technology

Ulsan National Institute of Science and Technology

European Research Council

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STFC

United States-Israel Binational Science Foundation

National Science Foundation

Ministry of Science and Technology