---
_id: '17645'
abstract:
- lang: eng
  text: The rapid decline in the number of strong Lyman Alpha (Lya) emitting galaxies
    at z > 6 provides evidence for neutral hydrogen in the IGM, but is difficult to
    explain with plausible models for reionization. We demonstrate that the observed
    reduction in Lya flux from galaxies at z > 6 can be explained by evolution in
    the escape fraction of ionizing photons, f_esc. We find that the median observed
    drop in the fraction of galaxies showing strong Lya emission, as well as the observed
    evolution of the Lya luminosity function both follow from a small increase in
    f_esc of Delta f_esc ~ 0.1 from f_esc ~ 0.6 at z ~ 6. This high escape fraction
    may be at odds with current constraints on the ionising photon escape fraction,
    which favor smaller values of f_esc < 20%. However, models that invoke a redshift
    evolution of f_ esc that is consistent with these constraints can suppress the
    z~7 Lya flux to the observed level, if they also include a small evolution in
    global neutral fraction of Delta x_HI ~ 0.2. Thus, an evolving escape fraction
    of ionising photons can be a plausible part of the explanation for evolution in
    the Lya emission of high redshift galaxies. More generally, our analysis also
    shows that the drop in the Lya fraction is quantitatively consistent with the
    observed evolution in the Lya luminosity functions of Lya Emitters.
article_processing_charge: No
article_type: original
author:
- first_name: Mark
  full_name: Dijkstra, Mark
  last_name: Dijkstra
- first_name: Stuart
  full_name: Wyithe, Stuart
  last_name: Wyithe
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
- first_name: Andrei
  full_name: Mesinger, Andrei
  last_name: Mesinger
- first_name: Laura
  full_name: Pentericci, Laura
  last_name: Pentericci
citation:
  ama: Dijkstra M, Wyithe S, Haiman Z, Mesinger A, Pentericci L. Evolution in the
    escape fraction of ionizing photons and the decline in strong Lyα emission from
    z &#62; 6 galaxies. <i>Monthly Notices of the Royal Astronomical Society</i>.
    2014;440(4):3309-3316. doi:<a href="https://doi.org/10.1093/mnras/stu531">10.1093/mnras/stu531</a>
  apa: Dijkstra, M., Wyithe, S., Haiman, Z., Mesinger, A., &#38; Pentericci, L. (2014).
    Evolution in the escape fraction of ionizing photons and the decline in strong
    Lyα emission from z &#62; 6 galaxies. <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/stu531">https://doi.org/10.1093/mnras/stu531</a>
  chicago: Dijkstra, Mark, Stuart Wyithe, Zoltán Haiman, Andrei Mesinger, and Laura
    Pentericci. “Evolution in the Escape Fraction of Ionizing Photons and the Decline
    in Strong Lyα Emission from z &#62; 6 Galaxies.” <i>Monthly Notices of the Royal
    Astronomical Society</i>. Oxford University Press, 2014. <a href="https://doi.org/10.1093/mnras/stu531">https://doi.org/10.1093/mnras/stu531</a>.
  ieee: M. Dijkstra, S. Wyithe, Z. Haiman, A. Mesinger, and L. Pentericci, “Evolution
    in the escape fraction of ionizing photons and the decline in strong Lyα emission
    from z &#62; 6 galaxies,” <i>Monthly Notices of the Royal Astronomical Society</i>,
    vol. 440, no. 4. Oxford University Press, pp. 3309–3316, 2014.
  ista: Dijkstra M, Wyithe S, Haiman Z, Mesinger A, Pentericci L. 2014. Evolution
    in the escape fraction of ionizing photons and the decline in strong Lyα emission
    from z &#62; 6 galaxies. Monthly Notices of the Royal Astronomical Society. 440(4),
    3309–3316.
  mla: Dijkstra, Mark, et al. “Evolution in the Escape Fraction of Ionizing Photons
    and the Decline in Strong Lyα Emission from z &#62; 6 Galaxies.” <i>Monthly Notices
    of the Royal Astronomical Society</i>, vol. 440, no. 4, Oxford University Press,
    2014, pp. 3309–16, doi:<a href="https://doi.org/10.1093/mnras/stu531">10.1093/mnras/stu531</a>.
  short: M. Dijkstra, S. Wyithe, Z. Haiman, A. Mesinger, L. Pentericci, Monthly Notices
    of the Royal Astronomical Society 440 (2014) 3309–3316.
date_created: 2024-09-06T07:24:26Z
date_published: 2014-04-17T00:00:00Z
date_updated: 2024-09-24T12:10:12Z
day: '17'
doi: 10.1093/mnras/stu531
extern: '1'
intvolume: '       440'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1093/mnras/stu531
month: '04'
oa: 1
oa_version: Published Version
page: 3309-3316
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  issn:
  - 1365-2966
  - 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: Evolution in the escape fraction of ionizing photons and the decline in strong
  Lyα emission from z > 6 galaxies
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 440
year: '2014'
...